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2024 Vol. 43, No. 12 Published: 2024-06-28 1 A study on the extreme wind pressure distribution induced by trains in semi-closed stations ZHENG Huadong1,2，ZHENG Haodong1,2，WANG Zhen1,2，XIE Weiping1,2，WU Bin1,2 To study the extreme wind pressure distribution in semi-closed stations, the wind pressures induced by high-speed trains passing through railway stations are simulated. The accuracy of the numerical model is also verified against the field-measured data. Based on this validated numerical model, the extreme wind pressure distribution at the train head and tail is analyzed for the two typical station regions (near platform Region I and far from platform Region II) under the traveling train speed of 250km/h, 300km/h and 350km/h, respectively. The corresponding empirical equations are established. The results show that there is a nonlinear relationship between extreme wind pressures and train speeds. At the same train speed, the extreme wind pressures in Region I and Region II decrease exponentially with the horizontal distance, whereas the decrease rate is inversely proportional to the vertical distance. When the horizontal distance is less than 15m, the positive extreme wind pressures due to train head in Region I are always larger than those in Region II at the same vertical distance, while the absolute values of the negative extreme wind pressures due to train head in Region I are always smaller than those in Region II. When the horizontal distance exceeds 15m, the extreme wind pressures gradually tend to be steady, and the corresponding steady values in Region I are larger than those in Region II. The empirical equations developed in this paper can accurately describe the extreme wind pressure distribution in the semi-closed station. The research results can provide reference for the structural design of semi-closed stations. 2024 Vol. 43 (12): 1-8 [Abstract] ( 155 ) HTML (1 KB)  PDF (2399 KB)  ( 96 ) 9 Research on fatigue simulation of stitch wire for high-speed railway catenary LIU Jidong，CHEN Junqing，GUAN Jinfa，HAN Feng，WU Jiqin To study the service status and fatigue life of stitch wire, research was conducted on the stitch wire breaking in high-speed railway contact networks, and fatigue research was conducted. Based on the design parameters of the Wuhan-Guangzhou high speed railway, a dynamic simulation model of the pantograph and catenary was constructed to analyze the vibration state of the stitch wire at speed of 300km/h. Due to the lifting effect of the pantograph on the contact suspension during operation, the stitch wire mainly vibrates in the vertical direction and continuously bears alternating bending loads at the clamp position. Stitch wire were established in UG and the solid model was imported into LS-DYNA, and the refined model was subjected to stress load calculation; the stress concentration position of the stitch wire is located at the connection with clamp. Import stress history data into ANSYS nCode DesignLife to analyze the fatigue life of stitch wire under bending loads; finally, based on the Miner cumulative damage principle, the fatigue life of the stitch wire of the Wuhan-Guangzhou high speed railway at speed of 300km/h was calculated to be 4.58×106; the operating speed increases to 350km/h, and the fatigue life is 1.17×106; speed increased to 400km/h, fatigue life is 4.80×105. 2024 Vol. 43 (12): 9-16 [Abstract] ( 77 ) HTML (1 KB)  PDF (2154 KB)  ( 65 ) 17 Fiber Bragg grating scanning spectral characteristics and temperature measurement error under rotor whirling conditions CHEN Sitong1，HUANG Junbin1，LIU Wen1，LI Zheyu2，GU Hongcan1，YAO Gaofei1 For the motor rotor temperature monitoring system based on the spatial coupled transmission method, the scanning spectral model of fiber Bragg grating (FBG) on the whirling rotor is established. The distortion law of the scanning spectra and the peak-finding results of each algorithm are firstly investigated. The results show that the whirling rotor leads to the shift of the reflection peaks and the reduction of the 3dB bandwidth in the scanning spectra of the FBG. The maximum scanning error of the center wavelength changes with a sinusoidal function as the phase difference between the coupling loss and the original reflection peaks changes. The position of the new reflectance peak is determined by the limiting relationship between the rate of change of the coupling loss, the original FBG reflectance and change rate. Coordinating the numerical relationship between the scanning rate of the demodulator and the frequency of the rotor whirl is the main method to mitigate spectral aberration. In addition, compared with the half-peak method and various fitting-type algorithms, the centroid method also significantly reduces the scanning error at the center wavelength. Then, the effects of the rotor whirl frequency and the demodulator scanning frequency on the system temperature measurement error are investigated by theory and experiment. The results show that the maximal temperature measurement error firstly decreases drastically, and then decreases slowly, and finally stays stable, with the increase of the ratio of the coupling loss period to the spectral scanning time (q-value). q>10 is the minimum condition to ensure that the system's temperature measurement error and its fluctuation are small. For rotor speed less than 200000rpm (whirl frequency less than 1667Hz), when the amplitude of the rotor radial vibration is less than 200μm, the axial ratio of the axial trajectory is less than 3, and the angle of axial line deflection is less than 0.1°, the use of a scanning frequency greater than 760Hz demodulator and the centroid method can ensure that the whirl induced temperature measurement error is less than 0.3 ℃. This paper provides a basis for the practical application of the rotor temperature monitoring system and the prediction of the temperature measurement error. 2024 Vol. 43 (12): 17-29 [Abstract] ( 49 ) HTML (1 KB)  PDF (2747 KB)  ( 38 ) 30 Numerical simulation and an experimental study of pulsed inlet self-excited oscillating air nozzles for air lift TANG Chuanlin1,2,3，LIANG Jingjing2，HU Dong1,2，YANG Fengling1,2，CHENG Honggui3 Air lift ( pneumatic pump ) is widely used in marine mining, drilling hydraulic mining, deep-water dredging and other occasions, which has attracted more and more attention from users. Scholars at home and abroad have done a lot of exploratory research on improving the efficiency of gas lift, and put forward that pulse air intake is one of the effective ways to improve the efficiency of air lift. Based on this, a Helmholtz air nozzle is proposed. The pulse jet generated by this nozzle is used as the air intake mode of air lift to improve the performance of air lift. Based on the wave vortex theory, the generation mechanism of the self-excited oscillating pulse jet is analyzed. the flow field in the self-excited oscillating air nozzle is numerically simulated by using Fluent software, Experimental research based on simulation results. The results shows that the structural parameters and operation parameters have a significant influence on the jet characteristics, the inlet pressure is 3bar, the cavity length is L=64mm, the frequency is 8Hz, the pressure pulsation fluctuation difference and amplitude are the largest, the air pulse jet is the most significant; the amplitude increases at first and then decreases with the increase of cavity length. The numerical simulation is consistent with the experimental results. The research results can provide reference for the engineering application of the integration of air pulse jet and air lift, and has high engineering application value. 2024 Vol. 43 (12): 30-45 [Abstract] ( 45 ) HTML (1 KB)  PDF (1901 KB)  ( 32 ) 36 Influence of long-period ground motions on the cooperative work of SRC frame-RC core wall hybrid structures YANG Ke，WANG Bo，ZHU Chao，LIU Boquan，LI Hong Due to the abundance of low-frequency components in far-field long-period ground motions (FLPGMs), long-period structures, such as high-rise buildings, are susceptible to severe damage. The steel reinforced concrete (SRC) frame-reinforced concrete (RC) core wall hybrid structure is a kind of dual structural system widely used in regions with high seismic intensity. Ensuring its cooperative work is the key to realizing multiple seismic fortification lines and reasonable structural failure modes under severe earthquakes. In this paper, the influence of FLPGMs on the cooperative work of SRC frame-RC core wall hybrid structures is clarified by comparing it with that under conventional ground motions (CGMs). Its internal mechanism is preliminarily revealed based on the structural dynamic analysis model under harmonic excitation and empirical mode decomposition (EMD). The calculated examples show that the frame shear and overturning moment sharing ratios under FLPGMs are significantly greater than those under CGMs. The floor with the maximum frame shear sharing ratio is lower than that under CGMs. When the PGA of FLPGMs increases to 400 gal, the frame shear and overturning moment sharing ratios of the SRC frames exceed 40% and 70%, respectively. It will be difficult to ensure the seismic safety of SRC frame-RC core wall hybrid structures designed by the current code under FLPGMs. The influence of excitation frequency on the cooperative work of structures is related to the participation of vibration modes. Structural responses under low-frequency excitation (with a period of 0.5-2.0 times the structural period) are dominated by the lower mode. The predominant IMF component of FLPGMs is the cause of the increased frame shear shearing ratio. 2024 Vol. 43 (12): 36-45 [Abstract] ( 38 ) HTML (1 KB)  PDF (3108 KB)  ( 36 ) 46 Vertical dynamic analysis of the pile in unsaturated soils based on COMSOL YE Zi1,2，CHEN Yonghui1,2，KONG Gangqiang1,2，CHEN Geng1,2，XU Jie1,2，HU Nan1,2 The groundwater level determines that there is a large number of unsaturated soils on the soil surface, and its dynamic characteristics are significantly different from those of saturated medium or single-phase medium. As the main medium interacting with piles, unsaturated media have a critical effect on the dynamic behavior of piles. In this paper, considering the unsaturated characteristics of the soil around a dynamically loaded pile, based on the wave equation of the unsaturated poroelastic medium, the motion equation of the pile and the boundary condition, the Partial Differential Equation module in COMSOL Multiphysics software is used to establish a dynamic mathematical model of the interaction between the pile and the unsaturated soil with complex characteristics, such as stratification, transverse isotropy, inhomogeneity and so on. Meanwhile, several complex characteristics of soils and piles can also be reflected in this model. After verifying the correctness of the COMSOL model by comparing with the existing literature, a series of numerical examples were designed to discuss the influence of factors such as the soil saturation and inhomogeneity on the vertical dynamic impedance of a pile. 2024 Vol. 43 (12): 46-52 [Abstract] ( 55 ) HTML (1 KB)  PDF (1243 KB)  ( 25 ) 53 Multiscale concurrent topology optimization for cellular structures with multiple microstructures subjected to dynamic load JIANG Xudong1，WU Hao1，TENG Xiaoyan2，XIONG Yeping3 Topology optimization is an effective tool to perform the structure-material integrated design of a lattice structure with multiple microstructures for improving its mechanical performances. This paper aims to propose the concurrent design method for the lattice structure at both macro- and micro-scales considering the connectivity between neighboring microstructures for the dynamic stiffness maximization problem. Firstly, the double Helmholtz smoothing and piecewise projection scheme is introduced to identify the spatial distribution of multiple microstructure blocks at macroscale. Then, we optimize the spatial distribution of various microstructures by ordered SIMP method following the effective mechanical properties obtained by homogenization method. Meanwhile, the different microstructural unit cells share the same topology description within their boundary regions to ensure the connectivity. Subsequently, we implement the sensitivity analysis by adjoint variable method based on the “discretize-then-differentiate” approach, such that the consistent sensitivities are obtained on the space-time discretized system. Finally, we formulate the dynamic compliance minimization problem under the constraint of material volume fractions, and present the multiscale concurrent topology optimization method for structures periodically filled with multiple microstructures. Numerical examples demonstrate that this approach has the potential to perform the concurrent microscopic design of multiple unit-cells and their macroscopic layout for improving the load-carrying capacity and ensuring the geometrical connectivity between neighboring unit-cells. This method offers a theoretical reference for design of highly loading porous structures. 2024 Vol. 43 (12): 53-64 [Abstract] ( 44 ) HTML (1 KB)  PDF (2583 KB)  ( 30 ) 65 Muffling characteristics of flexible acoustic metamaterial to low-frequency noise CHEN Guitao1，LI Ying2，CHEN Chuang1，ZHANG Yanqing1，L Haifeng1 In order to control the low-frequency noise in the cabin of high-speed flying train, a flexible acoustic metamaterial based on Helmholtz resonance effect is proposed. Theoretical analysis was conducted on the noise reduction mechanism of the Helmholtz cavity, and the noise reduction characteristics of the unit cavity structure and array cavity structure were compared and analyzed using COMSOL software. The acoustic performance of flexible metamaterial was analyzed through the acoustic structure coupling module. The variation of the resonant frequency of the flexible acoustic metamaterial is studied parametrically, and analyzed the noise reduction characteristics of flexible acoustic metamaterials under different degrees of deformation. The casting process of divided draft was proposed to prepare flexible acoustic metamaterial samples, and the transfer loss of samples was measured using the four sensor testing principle. The research results show that there is a transmission loss peak at 300Hz in the test and simulation results of flexible acoustic Metamaterial, which shows the Helmholtz resonance frequency lower than the theoretical model and good low-frequency noise control effect. At the same time, flexible materials can avoid the impact of inertia on the installation environment, which is suitable for curved surface environment, and has good application prospects in the engineering field. 2024 Vol. 43 (12): 65-71 [Abstract] ( 47 ) HTML (1 KB)  PDF (1807 KB)  ( 44 ) 72 The dynamics of a vibro-impact system with asymmetric characteristic constraints ZHANG Bailin1，LI Xianfeng1，ZHANG Hui2，MA Guofeng2 This paper investigates a non-symmetric collision vibration system with asymmetric constraints. The conditions for n-1-1 periodic motion are given and the Jacobi matrix is derived from the non-dimensional modeling. In utilizing with a combined parametric-state simulation method, the transition sets are presented on the (ω,δ) plane, and the dynamical behavior against ω are also examined. A new method is proposed to explore coexisting attractors. Whereby the variations of attractors are depicted in parameter space. 2024 Vol. 43 (12): 72-79 [Abstract] ( 60 ) HTML (1 KB)  PDF (1976 KB)  ( 24 ) 80 An experimental study on vortex-induced vibration of parallel Π-shaped composite girders QIN Chuan1，ZHOU Qiang1,2，WU Weihong3，XU Mingyang1,2，LI Mingshui1,2，ZHANG Chunming3 The present study utilized the spring-mounted sectional model testing to investigate the vortex-induced vibration (VIV) characteristics of a parallel Π-shaped composite girders under different spacing ratios and wind attack angles. The VIV amplitude, lock-in wind speed range, phase difference, and spectrum characteristics of the upstream and downstream sections were analyzed in detail to explore the VIV behavior of the parallel Π-shaped composite girders. The experimental results revealed that under various angles of attack (α = ±5°, ±3°, 0°) and spacing ratios (L/D=6~8), the vortex-induced vibration amplitude of the downstream section of the double-Π-shaped composite box girder bridge was significantly amplified due to the aerodynamic interference effects, while the upstream section was less affected, with its amplitude slightly smaller or similar to that of a single-Π-shaped composite box girder bridge. The lock-in range and vortex shedding frequency of the upstream and downstream sections of the bridge were almost unaffected by aerodynamic interference. However, there was a significant phase difference between the upstream and downstream sections of the bridge, and its value decreased linearly with the increasing of amplitude and wind speed. In additional, unlike the VIV performance of a single-Π-shaped composite box girder bridge, which was most severe at negative angles of attack, the VIV amplitude of the double-Π-shaped composite box girder bridge was larger at positive angles of attack, resulting in its most unfavorable angle of attack occurring at +5°. 2024 Vol. 43 (12): 80-87 [Abstract] ( 31 ) HTML (1 KB)  PDF (2611 KB)  ( 22 ) 88 Anti-penetration characteristics and response mechanism of carbon fiber reinforced plastic laminated structures under high-impact loading CAI Xuanming1，PAN Chenglong2，GUO Anxiao1，ZHANG Xun1，GAO Yubo1，FAN Zhiqiang1 Carbon Fiber Reinforced Plastic (CFRP) laminated structures are often subjected to the impact of foreign objects in high-impact service environments, which results in a number of unpredictable forms of damage and even uncontrollable damage patterns. In order to ensure the safety and reliability of these structures, the impact response and protection mechanism of carbon fiber composite laminated structures have been studied. Taking the carbon fiber composite laminated structure as the research object, a high-speed impact loading test device is constructed based on a first-stage light air gun, the linkage law between the energy absorption characteristics of the carbon fiber composite laminated structure and the impact energy is explored, the ballistic limit is determined by combining with the ballistic limit equations, and the damage modes under the effect of different impact velocities are clarified. At the same time, the cohesion unit is introduced to carry out numerical simulation research, which proves the damage mode of the cohesion unit between layers of the carbon fiber composite laminated structure, and reveals its damage mechanism under the high-speed impact loading environment. The results provide theoretical basis for the reverse design of composite laminated structures suitable for high-speed impact loading environment. 2024 Vol. 43 (12): 88-96 [Abstract] ( 58 ) HTML (1 KB)  PDF (2230 KB)  ( 9 ) 97 Damage assessment of recycled aggregate concrete filled-steel tubular column under impact load CHEN Huayan1，LIU Yongbin1，LUO Caisong1，HUANG Jianzhong1，XU Li1，FU Chaojiang1，QI Ai2 In order to study the damage of recycled aggregate concrete filled-steel tubular (RACFST) column under impact load, 16 RACFST columns were subjected to drop hammer impact tests. Based on the test, the finite element model of RACFST was established to analyze the influence of different impact velocity, impact mass and section steel content on the damage degree of RACFST column. By controlling impact mass and impact velocity, damage assessment grades were divided based on damage factor ds and elastic-plastic Angle θ, and the damage assessment curves of RACFST columns were fitted by simulation. The results show that the difference between FEM results and experimental results is less than 10%, and the former can reflect the change of the latter. The peak time of mid-span deflection in the impact process lagged far behind the peak time of impact force, and impulse was 1.23 times of momentum. With the increase of impact velocity, the mid-span deflection increased in a parabolic trend. The increase of impact mass has little effect on the peak of impact force but has a great effect on the mid-span deflection. With the increase of steel content in the section, the energy consumption of the member almost stabilized around 90%. The overall damage and local damage of the RACFST column could be quickly judged from the damage curve. 2024 Vol. 43 (12): 97-108 [Abstract] ( 44 ) HTML (1 KB)  PDF (3988 KB)  ( 22 ) 109 Multiscale modeling of the low-velocity impact and compression after impact behaviors of rib-stiffened plain woven composites WANG Weihan1，HOU Yuliang1，ZHAO Qiaoli2，LIU Yutong3，LI Cheng1 This study proposes multiscale models to investigate the low-velocity impact (LVI) and compression after impact (CAI) behaviors of plain woven composite (PWC) panels stiffened by T- and I-shaped ribs. Representative volume elements (RVEs) are constructed at the microscale and mesoscale to compute the effective properties of carbon-fiber yarns and PWC. Besides, in order to improve the computational efficiency without sacrificing the computational accuracy, an equivalent cross-ply laminate (ECPL) cell is introduced to represent the woven architecture using a local homogenization approach. Multiscale models of PWC panels stiffened by T- and I-shaped ribs are constructed to investigate the mechanical behavior and damage mechanisms. Initially, experimental and numerical tests with 8 J, 10 J and 12 J impact energies are performed to examine the LVI behavior of PWC rib-stiffened panels. Subsequently, the post-impact compressive behavior and properties are assessed by experimental and numerical CAI tests on these impacted panels. The dissimilarities between the experimental and numerical results are less than 6%, confirming the reliability of the proposed multiscale models. Moreover, the panels stiffened by I-shaped rib are found to exhibit better resistance to the compressive strength reduction due to LVI events. Besides, the primary damage modes of rib-stiffened PWC panels under LVI loads are matrix cracking and fiber breakage. In CAI cases, the existing impact damages are prone to lead to severe delamination within the rib-stiffened panels and accelerate final failure. 2024 Vol. 43 (12): 109-117 [Abstract] ( 25 ) HTML (1 KB)  PDF (2815 KB)  ( 15 ) 118 Seismic performance of a precast pier with novel socket connection under the compound effect of compression-flexure-torsion XIA Zhanghua1，XIE Jun1，FAN Qian1，CHEN Jinsheng2，LIN Yuanzheng3 In order to clarify and improve the ability of fabricated piers with Socket Connection to resist composite loads such as compression, bending and torsion, a novel socket connection method for prefabricated piers combining grouting sleeves and sockets was proposed for application in ordinary cap. The damage characteristics and hysteresis energy dissipation performance of cast-in-place piers, fabricated piers with grouting sleeves, fabricated piers with sockets and fabricated piers with novel socket connection through quasi-static tests under compound loads, and the effect of socket height on hysteresis performance was analyzed with numerical simulation, and discussed its application feasibility in shallow socket connection. The results show that the failure modes of the four specimens are the bending-torsional failures dominated by bending failure, among which the SU specimen has a slight phenomenon of pulling up, while the corresponding GSU specimen does not have this phenomenon, which is close to the RC specimen. The development trend of the shear force-pier top displacement skeleton curves of each specimen is relatively consistent. Due to the longitudinal steel bar of the GSU specimen is continuous, it has better overall performance, and its flexural load capacity is close to that of RC specimen, and is significantly larger than that of SU and GS specimens. The bending hysteresis energy consumption of the four specimens is relatively close. The torsional bearing capacity of the GSU specimen with the depth of the socket is 1D is slightly higher than that of the RC specimen, and is significantly greater than that of other fabricated pier specimens. The torsional stiffness, ductility coefficient and energy dissipation capacity of the GSU specimen are greater than that of the other three piers. When the depth of the socket is 0.5 times the cross-section width of the specimen, the flexural bearing capacity and torsional bearing capacity of the specimen with novel socket connection are higher than that of the cast-in-place RC specimen, which has a good ability to resist compression, bending and torsional loads, and can realize shallow socket connections. The research results can provide an experimental basis for the application of fabricated piers under the combined action of compression, bending and torsion. 2024 Vol. 43 (12): 118-130 [Abstract] ( 20 ) HTML (1 KB)  PDF (5094 KB)  ( 24 ) 131 Design and vibration reduction characteristic of rotating unit-type perforated meta-structures YAN Shiguang1,2，LI Yingli1,3，YIN Guohui1，YAO Song1 A class of perforated meta-structures with rotating units is proposed for the engineering demand of high-speed train floor vibration reduction, including quadrilateral element with staggered rectangular hole, quadrilateral element with cross rectangular hole and triangular element with polygonal hole. The mechanism of bandgap and the regulation law of parameters are analyzed by using Bloch theory and numerical simulation. Then according to the results of meta-structures band gap analysis, the 3D block meta-structure is established, including quadrilateral element with staggered rectangular hole, quadrilateral element with cross rectangular hole and triangle element with 45 degree concave polygonal hole. The bearing performance of block meta-structure is analyzed, and the vibration responses under different configurations are calculated to determine the optimal configuration based on the numerical analysis results of the damping characteristics. Then, 3D-printed samples are prepared and vibration tests are carried out to verify the vibration reduction effect of the structure. The results show that when using TPU material, the proposed superstructure damping blocks all meet the requirements of bearing capacity and strength. Among them, the meta-structure with polygonal hole and triangular element is the optimal configuration, and its attenuation range accounts for 66.9% in the frequency range of 0-5000Hz. Through the vibration test, it is found that, compared with the existing EMU (Electric Multiple Unit) absorber, the meta-structure with polygonal hole and triangular element has a wider attenuation range frequency, a greater attenuation amplitude of more than -15dB, and a better vibration reduction effect, which indicates its potential application prospect of train floor. 2024 Vol. 43 (12): 131-139 [Abstract] ( 20 ) HTML (1 KB)  PDF (2040 KB)  ( 34 ) 140 Dynamic response analysis of cracked concrete beams subjected to moving load considering the effect of reinforcement LI Huile1,2，YAN Huan2，WU Gang1,2 Due to the restraint effect of steel reinforcing bars, the local flexibility of cracked cross-sections of the concrete beam is different from that without reinforcement. Considering the influence of reinforcement, the dynamic equation of cracked concrete beams under moving load is established. Based on the force balance and deformation compatibility between the reinforcement and concrete, the local flexibility of cracked cross-sections is modified. The massless spring is used to simulate the crack, and natural vibration characteristics of the cracked beam are obtained taking into account the effect of the reinforcement. Dynamic responses of the reinforced concrete beam are acquired by solving the governing equation with Newmark method. Taking the simply-supported beam subjected to moving vehicle load as an example, responses of the cracked reinforced concrete beam under different load speeds, crack depths, crack locations, and reinforcement ratios are analyzed. The results show that the restraint effect of the steel reinforcing bars at the crack location can significantly affect dynamic responses of the beam. The displacement response of the cracked beam will generally decrease after considering the stiffness provided by the reinforcement. Moreover, the effect of the reinforcement shows an increasing trend as the severity of the cracking damage grows. The resonance phenomenon of the cracked beam under moving load is more detrimental compared to that of the undamaged beam. Resonance speeds of the cracked beam increase and resonance responses decrease to a certain extent after considering the effect of the reinforcement. Owing to the difference in the resonance speeds of the cracked and intact reinforced concrete beam, the displacement response of the intact beam is larger than that of the cracked beam under certain load speeds. 2024 Vol. 43 (12): 140-147 [Abstract] ( 32 ) HTML (1 KB)  PDF (2788 KB)  ( 28 ) 148 An experimental study on mass erosion for high speed and high mass projectile penetrate concrete DONG Kai,JIANG Kun,WANG Hao,WANG Jian,JIANG Chunlei,SHI Lü The mass erosion of kinetic energy projectile penetrating concrete target at high speed is an important reason for the reduction of penetration efficiency. The experiments of high hardness projectile with a mass of 20kg and a diameter of 100mm penetrating into C40 concrete at a speed of nearly 1.0 km/s were conducted in this paper. The erosion parameters of the projectile and the changes in the nose were described in detail, and the erosion mechanism of the large mass projectile was analyzed. The proportion of melting erosion and cutting erosion was calculated. The results show that when different projectiles penetrate the same concrete strength at the same initial velocity, the surface pressure of the projectile nose is affected by the weight of the projectile. When the velocity is larger than critical velocity, the surface pressure increases with the increase of the projectile weight. The mass erosion caused by projectile penetration into concrete is related to the weight of the projectile, and the erosion phenomenon is more pronounced when the projectile weight is smaller. The proportion of cutting erosion decreases with the increase of projectile hardness, amd increasing the material hardness of the projectile has a more significant effect on reducing the mass erosion for the large mass projectiles. 2024 Vol. 43 (12): 148-155 [Abstract] ( 26 ) HTML (1 KB)  PDF (1716 KB)  ( 3 ) 156 A compound control method of hysteresis nonlinearity and dynamic behavior in piezo-based scanning systems ZHANG Meng,LIU Yuwei,ZHANG Songlin,LIU Shicheng,FAN Pengju A compound control method is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems (PSS). The flexible mechanism and PEA are analyzed, and the dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in force feedback to directly augment the damping of the PSS. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The force feedback method is combined with the input shaping method to control the nonlinearity and mechanical resonance in high-speed PSS. The experimental results show that the tracking error at 50 Hz is reduced from 9.33% to 1.87% by compound control method. Compared with the open-loop displacement response, the tracking accuracy of the system is improved by about 4 times. Compared with the closed-loop control method using only force feedback, the tracking accuracy of the system is improved by about 1.6 times. 2024 Vol. 43 (12): 156-165 [Abstract] ( 34 ) HTML (1 KB)  PDF (2876 KB)  ( 6 ) 166 School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China TIAN Yaping,YANG Jianghui,WANG Ruibang,DOU Jianming,WANG Jianqin A parametric solution domain structure based on cell mapping theory and a control method based on radial basis function neural network are proposed to solve the dynamic characteristic transition and control problem of bevel gear system with backlash. The dynamics model of 7-degree-of-freedom spiral bevel gear was established by using the concentrated mass method. Then, the frequency and load parameter plane is constructed based on cell mapping theory, and the pseudo-fixed point continuous tracking algorithm is used to solve the transition rule of bifurcation, tooth surface impact, tooth no-meshing, tooth back contact and dynamic load characteristics of the straight bevel gear system. It is found that frequency and tooth impact are the main factors affecting the periodic bifurcation. With the increase of load, the tooth no-meshing and impact weaken, and the dynamic load coefficient increases. For the chaotic phenomena of the system in the plane, a parametric feedback controller is designed, and the fitness function is constructed based on Poincaré cross section Euclidean distance. The adaptive gravity search algorithm is used to optimize the controller parameters, so as to realize the effective control of chaos, quasi-period and periodic motions to periodic orbit. 2024 Vol. 43 (12): 166-172 [Abstract] ( 41 ) HTML (1 KB)  PDF (2082 KB)  ( 10 ) 173 Vibration characteristics analysis of a composite laminated cylindrical shell structure with ring supported HE Dongze1,2,GUO Kefan1,CAI Ying3,HUANG Shijun1,2,LI Weicheng1,2 In this paper, based on the first order shear deformation theory, the vibration characteristic analysis model of the ring-supported composite laminated cylindrical shell structure under different boundary conditions is constructed by wave based method(WBM). The displacement scaling parameters, displacement matrix and force parameter matrix are set by combining the wave function form as displacement variables. By combining the boundary condition matrices, the overall control equations of the composite cylindrical shell structure under ring support conditions are derived. The accuracy of the established vibration characteristic analysis model is verified by comparing with the results of existing literature. A related parametric analysis study is carried out to investigate the influence of material parameters, geometric parameters, and ring support positions. 2024 Vol. 43 (12): 173-180 [Abstract] ( 32 ) HTML (1 KB)  PDF (2981 KB)  ( 42 ) 181 Frictional stress wave propagation and attenuation characteristics on the flank face of a high-efficiency milling cutter ZHAO Peiyi,OUYANG Yijie,JIANG Bin,JIANG Yupeng During the high-efficiency milling, under the action of high-frequency and intermittent cutting loads, the contact angle and posture between the milling cutter and the workpiece change frequently, making the relative friction and stress waves generated at the tool-workpiece interface dynamically change, leading to difficulty in accurately identifying and predicting friction damage and wear life during high-efficiency milling. A dynamic contact relationship model between the milling cutter and the workpiece under the influence of cutter error and milling vibration was constructed. The frictional force on the flank face of the milling cutter tooth was solved. Based on the one-dimensional string theory, a solution method for calculating the propagation distance, change rate and attenuation rate of frictional stress wave on the flank face of the cutter tooth was proposed. The results show that the stress wave peak value and change rate are greater near the cutting edge. The attenuation process of frictional stress waves in high-efficiency milling cutters shows biased exponential attenuation. The correlation verification results of the stress wave calculation method show that the energy of the feature points on the flank face of the cutter teeth has a correlation of more than 0.8 with the experimental accumulated wear depth, verifying the accuracy of the model. 2024 Vol. 43 (12): 181-193 [Abstract] ( 19 ) HTML (1 KB)  PDF (3252 KB)  ( 10 ) 194 Flow field characteristics for slug leakage in a gas-liquid mixed pipeline FANG Liping1,2,LI Yuxing2,LIANG Jinlu1,ZHOU Xiong1 Gas-liquid mixed transportation is a common technology for oil and gas pipeline transportation. Compared with gas/liquid single-phase pipeline, when a gas-liquid mixed pipeline leaks, due to the interaction between the gas and the liquid phase, the flow is complicated. Slug flow study is most difficult. In order to study the characteristics of slug leak, the difference between single-phase pipeline and mixed pipeline leak dynamic pressure is studied, leakage process is simulated based on dynamic mesh and UDF, pressure, velocity and turbulent intensity are analyzed, then the flow field characteristic of slug leakage is obtained. The results show that, compared with the single-phase pipeline, when the leakage direction is the upper and middle parts, the leakage of the slug flow in the mixed pipeline forms an obvious downward dynamic pressure wave pulse, and the sustain leakage alternately appears multiple upward and downward signal pulses, and the amplitude of the signal is much larger than that of the normal flow signal. The downward dynamic pressure pulse generated at the moment of leakage is caused by the sudden drop of pressure. The pressure change caused by the moment of leakage is mainly reflected in the pipeline pressure. The dynamic pressure sensor installed through the pipeline can effectively reflect the pressure change generated at the moment of leakage. The arrival and departure positions of the liquid plug are the main factors affecting the pressure fluctuation of the pipeline. The combination of dynamic mesh simulation and experiment can be used to study the flow field characteristics of slug flow leakage in gas-liquid mixed pipeline. 2024 Vol. 43 (12): 194-202 [Abstract] ( 16 ) HTML (1 KB)  PDF (2970 KB)  ( 3 ) 203 Non-Gaussian random vibration damage analysis of logistics based on a Gaussian mixture model method GUO Tao1,GE Changfeng2,XIA Sixuan1,YIN Cheng1,LIN Kang1,QIAN Jing1,3 Aiming at the obvious non-Gaussian property of vibration signals in transportation environment, a non-Gaussian random vibration damage analysis method based on Gaussian mixture model is proposed. To describe the amplitude probability density distribution of the vibration signal, the moving root mean square of acceleration is introduced to represent the vibration intensity of the signal, and the Gaussian mixture model is used to describe the probability density distribution of root mean square of acceleration. On this basis, combined with Tovo-Benasciutti method and Dirlik method, a non-Gauss broadband frequency domain fatigue damage calculation method is derived. Finally, the fatigue damage analysis of measured vibration signals with different kurtosis is carried out with rain flow counting method as a reference. The results show that compared with traditional fatigue damage calculation methods in frequency domain, the calculation accuracy of the proposed non-Gaussian fatigue damage method is significantly improved. 2024 Vol. 43 (12): 203-211 [Abstract] ( 20 ) HTML (1 KB)  PDF (1905 KB)  ( 8 ) 212 Adaptive segmental quasi-static analysis of all-channel effective magnetorheological dampers GU Sanbao,LI Yinong,WU Huan,ZHENG Ling For the all-channel effective magnetorheological damper ( MRD ), the shear yield stress of magnetorheological fluid in damping channel will change with the change of position. In the design stage of MRD structure, the quasi-static model is often used to represent the relationship between the size of MRD structure and the damping force, and to predict the output damping force of the damper. Traditional quasi-static models usually assume that the magnetorheological fluid's shear yield stress in the damping channel is equal everywhere, so its accuracy is low, which does not conform to the magnetic circuit characteristics of the all-channel effective MRD. Based on the above problems, a novel adaptive segmental quasi-static modeling method is proposed, which considers the relationship between the magnetorheological fluid's shear yield stress and the position of the damping channel. This method first uses the overall low-order fitting for the magnetic field strength of the damping channel and divides the low-order fitting result into 0/1 states according to the set error threshold, completing the segmental fitting at last. This paper analyzed circuit characteristics of all-channel effective MRDs by electromagnetic finite element simulation. The novel quasi-static models for two all-channel effective MRDs with different structures are established. Finally, the rationality and accuracy of the novel quasi-static model are verified by a damping characteristic test. 2024 Vol. 43 (12): 212-220 [Abstract] ( 20 ) HTML (1 KB)  PDF (4360 KB)  ( 5 ) 221 Dynamic response parameters prediction models of isolated-span conductor lines in ultra-heavy ice zones after ice-shedding ZHANG Liguang1,2,TENG Yu3,DONG Songzhao1,2,WANG Wei1,2,LI Zhanling1,2,GAO Yingbo3,YAN Bo3 The design ice thickness for the ultra-high voltage DC lines in ultra-heavy ice zones may arrives at 60 mm~80 mm, and isolated-span lines are usually employed. In this paper, the finite element models of the ultra-high voltage DC lines in ultra-heavy ice zones are set up, the dynamic responses of the lines with different span length, elevation difference ratio under different ice thickness, ice-shedding rate and wind speed are numerically simulated, and the dynamic response characteristics are analyzed. The conductor jump height envelop, transverse swing amplitude and axial unbalanced tension are defined. Combining the numerical simulations and the BP neural network algorithm, the prediction models for the dynamic response parameters with span length, elevation difference ratio, ice thickness, ice-shedding rate and wind speed as input are established. The prediction models provide instruction for the tower head design of the ultra-high voltage DC lines in ultra-heavy ice zones. 2024 Vol. 43 (12): 221-231 [Abstract] ( 30 ) HTML (1 KB)  PDF (5762 KB)  ( 7 ) 232 A study on correlation-based algorithms for automatic imaging of variable thickness CFRP ultrasonic defects WANG Tao1,DENG Wanxin2,WANG Haijun3,YU Cijun1 A correlation-based automatic imaging algorithm is proposed to address the labor-intensive process of variable thickness CFRP ultrasonic defect imaging. Embedded artificial defects are prepared in the specimens, and ultrasonic phased array detection is used to acquire data. Firstly, based on the theory of discrete sequence correlation, time-shift processing is applied to the ultrasonic A-scan signals of different thickness CFRP specimens to align the baseline. Subsequently, the necessary reference signals are generated from defect-free regions using autocorrelation theory. By analyzing the correlation results and utilizing the Euclidean distance, defect signals are distinguished from non-defect signals, and a color-coded image is generated based on the Euclidean distances. Ultimately, the defect size was statistically measured using an edge detection algorithm based on machine vision and the Hough circle transform. The overall mean error rate was less than 7%, with a maximum error rate of 16.25% and a minimum error rate of 0.25%. The results demonstrate that this algorithm can be extensively applied to the automated ultrasonic testing of variable thickness CFRP. 2024 Vol. 43 (12): 232-240 [Abstract] ( 19 ) HTML (1 KB)  PDF (2383 KB)  ( 2 ) 241 Analysis of the dynamic characteristics of a small caliber gun’s bullet engraving process WANG Shaoquan1， LI Qiang1， FAN Jiangtao1， WEI Liansheng1， QU Zhensen2， XIN Chunhong2 In order to optimize forcing cone structures and analyze the dynamic characteristics of the engraving process under different forcing cone structures of a small caliber gun, established an internal ballistic equation system considering changes in projectile resistance and introduced it into finite element solution via using the vuamp subroutine to achieve the coupling calculation model of internal ballistics calculation and finite element simulation in the engraving process. The feasibility of the model was verified through simulation analysis of the full barrel motion of the projectile. Simulated and analyzed the velocity, acceleration, and resistance curves and variation patterns of the projectile during the engraving process under different forcing cone taper, rifling depth, and concave line width. The result indicates that the influence of slope chamber taper on the projectile's dynamic parameters during the extrusion process is not monotonic, while the changes in rifling depth and concave line width monotonically affect the projectile's dynamic parameters. This method can provide reference and guidance for the design and optimization of gun barrel structures and bearing band. 2024 Vol. 43 (12): 241-247 [Abstract] ( 33 ) HTML (1 KB)  PDF (1700 KB)  ( 33 ) 248 Influence of installation of piezoelectric stack energy harvesters placed at rail bottom on dynamic performance of a vehicle-track system DU Chengyun1, WANG Jianjun1, JIN Hao2, TANG Lihua3 Piezoelectric energy harvesting technology has received a lot of attention in the field of rail transportation. However, the current studies mainly focused on the structural design of piezoelectric energy harvester. The installation of energy harvesters will attach new devices into the track structure, which may affect the dynamic performance of the vehicle-track system and even threaten its operation safety. However, the effect of the installation of energy harvesters on the dynamic performance of the vehicle-track system has rarely been reported. Based on piezoelectric stack energy harvesters installed at rail bottom, a dynamic analysis model of vehicle-track-harvester coupled system is developed. The vertical vibration equations of rails and ballasts with single or multiple energy harvesters are established, and theoretical solutions are obtained by using a new fast explicit integration method program written in Matlab. The correctness of the procedure is verified by comparing the results with those of the existing literature. Further, for two installation methods of single and multiple energy harvesters, the effects of the equivalent stiffness of energy harvester on the dynamic performance of the vehicle-track system (such as rail displacement, rail acceleration, fastener force and body acceleration) are investigated, and the relationship between equivalent stiffness and train comfort is also evaluated. The results show that when the equivalent stiffness of the energy harvester is varied in the range of 0~60×106N/m, with the increase of the equivalent stiffness of the energy harvester, the maximum rail displacement, rail acceleration decreases and the fastener force decreases, the car body acceleration keeps almost unchanged, and the comfort of train running shows a small change. When the equivalent stiffness of the energy harvester is selected in the range of 0~2×106N/m, the installation of the energy harvester has little effect on the dynamic performance of the vehicle-track system. The study results provide a theoretical guidance for the design and installation of piezoelectric stack energy harvesters in the rail system. 2024 Vol. 43 (12): 248-259 [Abstract] ( 54 ) HTML (1 KB)  PDF (2306 KB)  ( 6 ) 260 An experimental study on modelling and damping force tracking control of a magnetorheological damper ZHANG Jiyang1, ZHANG Ze1, CUI Long2,DU Hao1 In order to improve the accuracy of damping force tracking control of magnetorheological damper, the forward and inverse dynamic models of magnetorheological fluid damper are established by using vector weighted average algorithm (INFO) and Bayesian nonlinear regression (BP) network respectively. The compound control strategy of feedforward inverse model and fuzzy control feedback is constructed, and the semi-active tracking control of damping force is realized. The tracking effects of inverse model feedforward control and compound control strategy and the tracking applicability of compound control strategy in each frequency band are compared by experiments. The results show that the compound control strategy can achieve better tracking effect, and the tracking accuracy is 6.4% higher than that of the feedforward inverse model control strategy; the approximation accuracy of the composite control strategy is more than 95% in the 0-7 Hz frequency band; in the 7-10 Hz frequency band, it can also achieve 85% approximation accuracy, which verifies the effectiveness of the force tracking control algorithm. 2024 Vol. 43 (12): 260-265 [Abstract] ( 23 ) HTML (1 KB)  PDF (1562 KB)  ( 8 ) 266 Resonant column tests on dynamic shear modulus and damping ratio of rubberized cemented soil GUO Duanwei1, 2, HE Jie1, SONG Dexin3, WANG Ren1, LI Fengshan2 As an economical and environmentally friendly corrosion-resistant lightweight filler material, rubberized cemented soil has many application prospects in coastal port engineering and lighthouse foundation construction. Based on the resonant column test, we investigate the dynamic properties of rubberized cemented soil under different rubber content, cement content, and surrounding pressure and focus on the influence of each influencing factor on its dynamic shear modulus and damping ratio. Test results show that the cumulative axial strain of rubberized cemented soil under consolidation pressure increases with the increase of rubber content and surrounding pressure and decreases with the increase of cement content. The degree of attenuation of the dynamic shear modulus curve of rubberized cemented soil decreases with the increase of rubber content and the decrease of cement content, and the non-linear characteristic decreases while it is less affected by the surrounding pressure. The maximum dynamic shear modulus decreases with the increase of rubber content and increases with the increase of cement content and surrounding pressure. When the rubber content is low, or the cement content is high, the maximum dynamic shear modulus is most affected by the content change. The rubber admixture slows down the dynamic shear modulus's decay and promotes its earlier decay at lower surrounding pressure. A decrease in cement content and increase in surrounding pressure delay the decay and make the decay relatively larger. The damping ratio increases monotonically with the increase of dynamic shear strain. Increasing the rubber content and decreasing the surrounding pressure will increase the damping ratio. When the cement content is less than 15%, the damping ratio increases with the increase of cement content, while when the cement content is more than 15%, the damping ratio decreases instead. 2024 Vol. 43 (12): 266-275 [Abstract] ( 21 ) HTML (1 KB)  PDF (2678 KB)  ( 7 ) 276 A rolling bearing fault diagnosis method based on multi-scale knowledge distillation and continual learning XIA Yifei1,2, GAO Jun1, SHAO Xing1, WANG Cuixiang1 In order to alleviate the catastrophic forgetting problem caused by the single-task bearing fault diagnosis method under different working conditions, a rolling bearing fault diagnosis method based on multi-scale knowledge distillation and continual learning (CL-MSKD) is proposed. The one-dimensional convolutional neural network is used as the main framework of CL-MSKD, and the cosine normalization layer is used as a multi-task shared classifier. The model knowledge is preserved and transmitted through the knowledge distillation of label and feature scales. CL-MSKD can diagnose bearing faults under different working conditions with a unified structure network model, continuously learn and save knowledge through knowledge compression method, and finally alleviate the catastrophic forgetting problem in the incremental stage, and improve the bearing fault diagnosis performance under cross-working conditions. The experiment show that CL-MSKD can effectively alleviate catastrophic amnesia and maintain good diagnostic effect. In the case of large differences in task environments, the accuracy index can still reach 97.09%, which is better stability and higher precision than other incremental methods. 2024 Vol. 43 (12): 276-285 [Abstract] ( 27 ) HTML (1 KB)  PDF (1584 KB)  ( 18 ) 286 Time-step group-based higher-order accurate time integration algorithms for structural dynamics LI Hongjing, YANG Yin Higher-order accurate time integration methods can provide highly precise estimations for time-dependent problems, especially for complicated dynamic behavior involving abundantly high frequency contents. However, the existing higher-order accurate time integration methods generally have the drawback that they require large amount of computational efforts, which restrict their applications to linear and nonlinear dynamic response analysis of practical structures. In this article, a novel higher-order accurate and efficient time integration algorithm is proposed for structural dynamic problems. The theoretical solutions governing the state equations of the system are employed to construct the group-by-group procedure, in which a time-step group consisting of p time steps is regarded as the unknown time interval to be solved, and all p solutions within the time-step group are obtained simultaneously only by the matrix multiplications. Both numerical characteristics and test examples from linear and nonlinear dynamic problems show that, the proposed time-step group method is higher-order accurate and stable with controllable numerical dissipation, and highly accurate solutions of structural dynamic response can still be obtained stably even in the case of selecting larger time steps. Compared to traditional second-order accuracy time integration methods, the computational effort of the time-step group method has been decreased greatly. 2024 Vol. 43 (12): 286-297 [Abstract] ( 34 ) HTML (1 KB)  PDF (2755 KB)  ( 46 ) 298 Cumulative damage effect of the caisson wharf induced by air and underwater explosions IU Jinghan1,2, TANG Ting1, WEI Zhuobin1, LI Lingfeng1, DONG Qi1 In order to study the cumulative damage effect of caisson wharf induced by air contact explosion and close proximity underwater explosion, the caisson wharf model tests and finite element models were established to analyze the damage process and mechanism of the caisson wharf subjected to combined air and underwater explosion. The results show that the caisson wharf has different failure modes subjected to air and underwater explosion. Under air contact explosion, only the upper structure of caisson wharf is seriously damaged, where a blast hole is observed locally on. Under close-in underwater explosion, both the caisson and the upper structure are obviously damaged. The concrete cover in blast side of caisson is broken. There are transverse cracks at the connection between panel and pipe trench. The damage phenomenon and damage degree of the wharf is disturbed by the superimposition of air and underwater explosions. The secondary damage of wharf forms on the first damage, and is similar with that under single blast. The connection of panel and is weak area due to stress concentration subjected to combined air and underwater explosion. The sealed plate slightly damages due to sand pack buffer mechanism. 2024 Vol. 43 (12): 298-306 [Abstract] ( 22 ) HTML (1 KB)  PDF (2256 KB)  ( 5 ) 307 A study on dynamics of a double-layer hydraulic power anti resonance vibration isolator YIN Zhaomin, TENG Handong double-layer hydraulic dynamic anti resonance isolator was designed and manufactured based on the principle of dynamic anti resonance to address the issue of low-frequency vibration isolation. A hydraulic power anti resonance isolator model was established, and the factors affecting the isolation performance and frequency of the double-layer hydraulic isolator were studied. A prototype of the hydraulic isolator principle was processed and frequency sweep tests were conducted. The research results indicate that the stacking method can significantly affect the position of the second resonance point, thereby affecting the isolation effect; Compared to single frequency dynamic anti resonance isolators, double-layer isolators formed by superposition can significantly improve isolation performance and isolation bandwidth by adjusting parameters. 2024 Vol. 43 (12): 307-311 [Abstract] ( 19 ) HTML (1 KB)  PDF (1050 KB)  ( 30 ) 312  Sea Launch Dynamics in Rough Sea Condition Considering Strain Rate Effects WANG Deng，SHAO JianShuai， LI MingJun，YAN Song，JIANG Yi Launch vehicle sea launch is a complex and nonlinear system. With relative motion between the launch vehicle and frame-type launcher, nonlinear and discontinuous impact loads between the adapter and guide rail occur at different speeds. Evaluating the strain rate effects of the adapter model is crucial. In this paper, we developed an improved phenomenological macro model based on polyurethane foam experimental data to accurately capture the system dynamics. We established two dynamic models of the sea launch system, one with and one without considering the strain rate effect of the adapter, and studied the dynamic characteristics of the launch vehicle during sea launch under high sea conditions. The results indicate that the strain rate effects have a significant impact on the contact load between the adapter and guide rail and the rolling motion law of the sea launch. This directly affects the safety assessment and design of the rolling limiting device for sea launch. Overall, the research provides important insights into the engineering and theoretical aspects of launch vehicle sea launch, highlighting the requirement to consider the strain rate effects of the adapters in sea launch dynamics modeling and safety assessment. 2024 Vol. 43 (12): 312-321 [Abstract] ( 59 ) HTML (1 KB)  PDF (2563 KB)  ( 40 ) 322 Effects of impact dissipated energy of aero-engine blades on casing containment capacity CAO Tienan1, YANG Zhizhong1, WANG Jingyuan1, YAN Jiqiang2, ZHANG Daijun2 For the requirements of fine design of aero-engine casing, the influence of blade dissipated energy on casing containment in the process of blade loss was studied. Combined with ballistic impact test and finite element numerical simulation, the TC4 target plate, regarded as principle simulated component of casing containment, was researched. The sensitivity of casing containment capacity to blade impact dissipated energy was revealed, and the accuracy and rationality of the numerical analysis method were verified. Based on the established simplified fan model, the energy conversion mechanism of blade-casing in different stages of casing containment was clarified, and the sensitivity of casing containment capacity to the major parameters of blade material during the collision between blades and casing was analyzed. The results show that the blade dissipated energy during impact and collision has a significant effect on the containment capacity of the casing, and it can be considered to improve the containment capacity of casing by enhancing the elongation, improving the hardening coefficient, and reducing the elastic modulus of blade material in engineering design. 2024 Vol. 43 (12): 322-330 [Abstract] ( 38 ) HTML (1 KB)  PDF (2007 KB)  ( 14 )

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