15 April 2023, Volume 42 Issue 7
    

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  • LIU Xiaobing1,2,3, TIAN Xuedong3, JIANG Huimin3, YANG Qun1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 1-7.
    Abstract ( 326 ) Download PDF ( 114 )   Knowledge map   Save
    Rectangular prisms are widely used in practical engineering. Rounding corner treatments can effectively reduce the wind load and improve wind-induced vibration performance. However, the aerodynamic characteristics of rectangular prisms with round corners experience an obvious Reynolds number effect. In order to study the Reynolds number effect of aerodynamic characteristics of 2:1 rectangular prism with round corners and reduce the error caused by Reynolds number in the analysis of wind load and wind-induced vibration of such prism structure, pressure-measured wind tunnel tests were carried out on five rigid models with different rounded corner ratios (0.1, 0.2, 0.3, 0.4 and 0.5). The Reynolds number ranges from 0.8×105 to 3.6×105. The mean drag coefficients, mean wind pressure coefficients, and Strouhal number of rectangular prisms with different rounded corner ratios were obtained and analyzed by wind tunnel test, and compared with the standard rectangular prism. The results show that different from the standard rectangular prism, the aerodynamic characteristics of the five rectangular prisms with round corners show a certain Reynolds number effect, which increases first and then decreases with the increase of the rounded corner ratio. The Reynolds number effect is the strongest when the rounded corner ratio is 0.2, and the obvious jump occurs when the Reynolds number is 2.8×105. The mean drag coefficients of different rectangular prisms with round corners decrease with the increase of the Reynolds number. Compared with other positions, the mean wind pressure coefficients at the side face and corner positions of the rectangular prisms with round corners are more obviously affected by Reynolds number, and the corner positions are the most obvious. The Strouhal number of the rectangle prisms with round corners is basically stable around 0.22 when the rounded corner ratio is 0.1, and around 0.24 and 0.31 before and after the jump when the rounded corner ratio is 0.2. At other rounded corner ratios, it increases first and then stabilizes with the increase of Reynolds number.
  • ZHAO Guixin, MENG Shuai, CHE Chidong, CHEN Li
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 18-24.
    Abstract ( 172 ) Download PDF ( 62 )   Knowledge map   Save
    Once emergency disconnection occurs for a deep-water drilling system, drilling mud should be released to avoid undesired axial loading from resonance while seawater must be refilled in case of riser collapse. The riser system following an emergency disconnection is a typical flow-conveying pipe system attached with an end-mass (Low Marine Riser Package). There are typically two methods utilized to calculate the natural frequencies of the pipe system via Galerkin method: (1) the end-mass is accounted for in the boundary conditions; (2) the end-mass is included in the equation of motion via a Dirac delta function. Although Paidoussis have pointed out that the first method is incorrect when the internal flow velocity is nonzero, a reasonable explanation has not been given. The orthogonality relations of a beam accounting for the end-mass in the boundary conditions is re-derived. Then the natural frequencies of the aforementioned pipe system is calculated employing first method and verified by comparing with the results adopting the second method. Then an experiment employing a cantilevered fluid-conveying pipe under gravity is introduced. The refined method can predict the critical internal flow velocity and the vibration frequency when the pipe loses stability. This new finding can not only explain the paradox in natural frequency calculation of the pipe system under consideration, but also provide as a workbench for dynamic analysis of fluid-conveying pipe systems with various boundary conditions.
  • WEN Shengjun, LI Liang, YU Jun, SU Menghao
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 25-32.
    Abstract ( 210 ) Download PDF ( 59 )   Knowledge map   Save
    In order to accurately describe the complex nonlinear characteristics of piezoelectric actuated positioning platform, a nonlinear mathematical model combining hysteresis, dynamics and creep was proposed based on the classical Hammerstein structure model and fractional operator model in series. The creep and hysteresis nonlinear characteristics of the model are described by fractional operator and PI model respectively, and the mechanical dynamic characteristics are expressed by second-order discrete transfer function. In addition, the parameter identification of the coupling model is considered, and the proposed coupling model is verified by the piezoelectric-actuated positioning stage. Under the action of 1-100Hz sinusoidal input voltage signal, compared with the Hammerstein structure model without considering creep characteristics, the root mean square error index of the coupling model proposed in this paper is reduced by more than 27%, and the relative error index is reduced by about 50%. The experimental results fully show the effectiveness of the coupling model proposed in this paper. Finally, based on the establishment of the model, the inverse creep and hysteresis models are designed to compensate the system, and the PID control algorithm is used to adjust the performance of the system. The simulation results show that the compound control scheme has a good tracking effect under low frequency and mixed frequency input signals.
  • HE Fan, MAO Qibo, LAI Longcheng, ZHAO Di, WU Zhijie
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 33-37.
    Abstract ( 218 ) Download PDF ( 77 )   Knowledge map   Save
    The natural frequency of the inertia actuator tuned by the inductor-negative resistance shunt circuit is presented. The tunable inertia actuator can be used as a tunable dynamic vibration absorber. Firstly, the theoretical model of tunable inertia actuator with inductor-negative resistance circuit was analyzed. Secondly, the relationship between the natural frequency of inertial actuator and the parameters of shunt circuit was analyzed theoretically and experimentally. Finally, with an example of a cantilever beam, the control performance of the designed tunable inertia actuator is experimentally verified. The experimental results show that on the premise of ensuring the stability of the shunt circuit system, the natural frequency of the inertial actuator increases with the decrease of the inductance. The natural frequency of inertial actuator can be tuned from the original 46.25Hz to 111.3Hz. When the natural frequency of the inertial actuator is tuned to the natural frequency of the cantilever beam, the vibration amplitude of the cantilever beam around targeted frequency is reduced by 90%. The results show that the natural frequency of the inertial actuator can be tuned by the electromagnetic shunt circuit. On the basis of not changing the physical structure of the inertial actuator, the natural frequency of the inertial actuator can track the external interference force frequency of the controlled structure, which can give full play to the vibration absorption capacity of the inertial actuator and restrain the structural vibration to the maximum extent.
  • QI Yayun1,2, DAI Huanyun2, WU Hao3, YANG Zhenhuan2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 38-45.
    Abstract ( 222 ) Download PDF ( 92 )   Knowledge map   Save
    With the increasing mileage and speed of operation, the wheel wear of high-speed EMUs in China is gradually increasing, at the same time, it has a certain impact on vehicle stability. Through a large number of line tests, it is shown that a large number of high-speed EMUs in China have a problem of carbody chattering, while a long distance of bogie hunting state appears in the operation. In this paper, in view of the above phenomenon, the wheel wear problem of the bogie hunting state of high-speed EMUs is analyzed, firstly, the high speed train vehicle dynamics model and Jendel wheel wear model are established, and the dynamic model validated by the test data, the wheel-rail contact parameters of the vehicle in the bogie hunting state are analyzed, and finally, the influence of with or without excitation, different hunting amplitude and line parameters on wheel wear studied. The results show that the wheel wear in the bogie hunting condition increases to different extend, while the larger the hunting amplitude value, the greater the wheel wear. In a long-term wear prediction of 200,000 km, it can be seen that tread wear is mainly concentrated between -40 mm and 30 mm, with a maximum wheel wear depth of around 0.58 mm. Therefore, it is necessary to pay attention to the stability of the hunting movement of the high-speed EMUs during the operation to avoid the phenomenon of wheel wear increasing caused by the bogie hunting.
  • HUANG Wei1, NING Xizhan1,2,3, WANG Zhen4, XU Xiaoyang5
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 46-53.
    Abstract ( 141 ) Download PDF ( 84 )   Knowledge map   Save
    Real-time hybrid simulation (RTHS) is an effective method to evaluate structural dynamic performance. However, the variable time-delay, caused by the dynamics of and interaction between the transfer system and the physical specimen, affects the accuracy and stability of RTHS seriously. To deal with this problem, an additive error model-based adaptive compensation method is proposed. In the method, the system, composed of the transfer system and physical specimen, is divided into the nominal and additive error models. The inverse of the nominal model is used as the feedforward controller to eliminate the primary time-delay of the system. An adaptive time-delay compensator is designed utilizing the additive error model to eliminate the residual time-delay further. The results show that the proposed method can effectively improve the simulation accuracy of RTHS and significantly reduce the dependence on the adaptive law of the adaptive delay compensation method. Moreover, the proposed method exhibits strong robustness.
  • YU Xu1, ZHAO Chang2, ZHUANG Haiyang2, CHEN Guoxing3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 54-64.
    Abstract ( 145 ) Download PDF ( 50 )   Knowledge map   Save
    Based on the influence law of dynamic pore pressure ratio changing on the stiffness of saturated sandy soil foundation, this paper proposes a novel and efficient shaking table model test method for the base-isolated structures on the variable stiffness foundation by controlling the time-holding compression ratio and intensity of the input ground motion. Besides, the influence law of the foundation stiffness on the dynamic characteristics of the base-isolation structure is also analyzed by combining with previous completed shaking table model tests of soil-pile-isolated structures on different foundations. The results indicate that the first-order natural vibration frequency of the base-isolation structure on variable stiffness foundation reduces with the increase of the relative stiffness ratio of structure to soil foundation. However, the damping ratio of the interaction system rises obviously, especially the isolation efficiency of the isolation layer decreases dramatically. The relative stiffness ratio of structure to soil significantly affects the floor acceleration response and interstorey displacement response of isolated structures. Compared with the rigid foundation, the larger the relative stiffness ratio of structure to soil is under strong earthquake, the more remarkable the floor acceleration response and interstorey displacement response of isolated structures are. Based on a series of shaking table model test results, the prediction formulas for the period extension rate, damping ratio, SSI influence rate of inter-storey drift angle, and SSI influence rate of displacement of isolation layer of isolated structure model with the small height-width ratio based on the relative stiffness ratio of structure to soil are preliminarily given in this paper. The research results of this paper can contribute to promote the more extensive application of structural vibration isolation technology.
    Key words: Variable stiffness foundation; Base-isolated structure; Shaking table test; Dynamic characteristics; Isolation efficiency
  • WEI Wei1,2, WANG Zhihai1,2, LIU Xiaoqin1,2, FENG Zhengjiang1,2, LI Jiahui1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 65-76.
    Abstract ( 187 ) Download PDF ( 89 )   Knowledge map   Save
    Aiming at the problem that the early and complex faults of rolling bearings are difficult to accurately diagnose and the determination of hyperparameters of the intelligent diagnosis model depends heavily on the prior knowledge of experts, an acoustic emission diagnosis method for rolling bearing faults based on Multidimensional Deep Feature Fusion (MDFF) and Improved Sparrow Search Algorithm (ISSA) is proposed. First, a multi-input convolutional neural network (CNN) diagnosis model is constructed using one-dimensional convolution and linear bottleneck inverse residual two-dimensional convolutional neural network. The input of the model is the rolling bearing acoustic emission signal and its wavelet time-frequency diagram. A quality index based on Brenner gradient and signal-to-noise ratio is proposed, and the best time-frequency image is selected from 108 wavelet bases to improve the quality of input data. Then, the feature pyramid network is used to fuse the one- and two-dimensional low-level and high-level features of the model to establish a deep fusion diagnostic model. Then, the random walk strategy of cross chaos mapping and adaptive weighting and fusion is introduced into the sparrow search algorithm to adaptively obtain the optimal hyperparameters of MDFFCNN. Experiments have shown that, compared with multiple mainstream intelligent diagnosis algorithms in the recent past, the proposed method can avoid manual selection of hyperparameters of the diagnosis model, and has higher diagnosis accuracy and stability for early-stage especially compound faults of rolling bearings, and the intelligent level of the model diagnosis process has been further improved.
  • XU Zhenyang1, MO Hongyi1, BAO Song1, ZHAO Jianyu1, WANG Xuesong2, LIU Xin1, CHEN Zhanyang3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 77-88.
    Abstract ( ) Download PDF ( 57 )   Knowledge map   Save
    The characteristic analysis of blasting vibration signal is one of the most effective methods to study slope stability. Combining the strong local search ability of Simulated Annealing (SA) and the characteristics of global automatic optimization of Genetic Algorithm (GA). Fuzzy Entropy (FE) is selected as the fitness function of the modal component. Solve the optimal decomposition parameters of Variational Modal Decomposition (VMD). And then, by combing the Intrinsic Modal Function (IMF), criterion of trend item and complex correlation coefficient principle, the propose a trend term removal method. Since the Teager energy operator demodulation of single component signal has higher demodulation speed and accuracy than Hilbert transform. The VMD-Teager energy operator demodulation method based on trend term filtering is proposed, to obtain the energy distribution characteristics of blast vibration signals. The result demonstrates that VMD is more accurate and effective than EMD in removing signal trend terms. It can solve the problem, such as baseline deviation and low frequency interference existing in original vibration signal. The blasting vibration energy is mainly low frequency. PPV, primary frequency and energy perform a “W” pattern of transformation. The attenuation speed of PPV and primary frequency is in the same order of magnitude as the amplification coefficient. However, the attenuation speed and amplification coefficient of the energy peak are much higher than the variation speed of PPV and primary frequency, which are 3.42 ~ 5.9 times of PPV and primary frequency, and 2.07 ~ 3.12 times of amplification coefficient.
  • DU Zhonggang1, SUN Yonghou1, LIU Fuyun1,2, YE Mingsong2, DENG Jucai2, TANG Jinshuai1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 89-98.
    Abstract ( ) Download PDF ( 44 )   Knowledge map   Save
    Accurate and efficient coordinate acquisition methods are of great significance in parameter identification and performance optimization of modal analysis. Based on the free modal experiment of Rigid body vibration principle, the conversion relationship between the linear parameters and the angular parameters were analyzed. The equations of the excitation and response coordinates were derived. The inertial parameter expressions were obtained by combining the mass line method. By studying the influencing factors of the coordinate acquisition error, a simulation test platform of the engine dynamics model was built to further verify the method of coordinate acquisition and inertial parameter identification. As the test object with a certain type of gearbox, the data were smoothed and filtered by the convolution fitting algorithm based on Savitzky-Golay (SG). Comparing the accuracy of the electronic three-dimensions coordinate system method, the three-dimensions model method and the proposed method in the coordinate acquisition and then selecting the mass line method to identify the inertial parameters. The results were discussed with those calculated by the MPC moment of inertia test platform. The results showed that compared with the traditional method, the proposed method obtains coordinates directly from the modal experiment, which improved the efficiency greatly, reduced the cost significantly and it’s easier for users to operate equipment. At the same time, the maximum error of geometric coordinate acquisition and centroid coordinate recognition are about 3mm. And the relative error of moment of inertia is not more than 7%. Accuracy of inertial parameters and coordinates is better than other measurement methods. It has certain engineering value in practicing.
  • WU Jianghai, SU Mingzhu, YIN Zhiyong, SUN Yudong
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 99-105.
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    In order to study the fluid-structure coupling characteristics of woven composite laminate liquid-filled pipeline, a one-dimensional fluid-structure coupling dynamic model of pipeline is established based on the material constitutive equation and model physical equation by using the transfer matrix method. The model degenerates into isotropy for calculation method verification, and the fluid-structure coupling verification of composite FEM software is further carried out. The results show that the calculation results in this paper are consistent with the classical "4-equation" model and finite element three-dimensional model. After proving the correctness of the model and calculation method in this paper, the influence of the layer angle and volume fraction in the material pipe on the natural frequency and wavenumber of the liquid-filled pipeline is further studied and analyzed. The research results show that: increasing the volume fraction of the reinforcing material increases the natural frequency of the pipeline; the natural frequency decreases with the increase of laying angle; increasing the laying angle increases the wave number; on the contrary, with the increase of volume fraction, the wavenumber of pipeline decreases. The results of this paper can provide advice for the design and control of liquid-filled pipelines.
  • BAI Houyi1,2, ZHU Caichao1, ZHOU Ye1, CHEN Xiaojin1,2, FENG Houbin2, YE Wei2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 106-113.
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    Tooth interior fatigue fracture (TIFF), as the typical failure mode of carburized wind turbine gear, is one of the major limitations to improve the service performance of wind turbine gearbox. This work developed a TIFF reliability analysis model of carburized gear based on the stress-strength interference fuzzy function and material strength degradation theory. The equivalent stress is calculated using load duration distribution method and Dang Van multiaxial fatigue criterion. The model is verified by comparing with gear failure sample coming from a 2MW wind turbine. The effects of gear hardness gradient and micro-modification on TIFF is discussed in detail. The optimization of design parameters is obtained with the regression equation of material exposure. The results show that the core hardness and lead crown are the main influencing factor of TIFF. With the developed optimizing design, the TIFF reliability of discussed gear pair is improved from 0.968399 to 0.972678.
  • LU Yiyu1,2, ZHU Zhidan1,2, TANG Jiren1,2, LIU Wenchuan1,2, LING Yuanfei1,2,ZHANG Yangkai1,2, YANG Sheng3, YAO Qi1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 114-122.
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    In order to further improve the rock-breaking ability of pulsed water jet, a supercharged pulsed water jet generating method was proposed to obtain a higher pulse pressure at a lower input pressure. To test the hard rock breaking performance of supercharged pulsed water jet, the flow field details were obtained by numerical simulation, and the effects of nozzle diameter, jet pressure and target distance on rock breaking performance were explored based on relevant test bench. The results show that the supercharged pulsed water jet has a better effect on breaking hard rock. Increasing the nozzle diameter, the rock-breaking performance first increases and then decreases. As the jet pressure increases, the jet axis velocity gradually increases, but at the same time, the energy loss caused by the gas-liquid exchange increases, and the rock-breaking effect is the best when the jet pressure is 60MPa under the current experimental conditions. The peak breaking volume occurs when the target distance is 100mm, and the optimum target distance for the maximum breaking depth is 25mm and 75mm, gradually moving back towards the nozzle. The research results have important guiding significance for promoting the application of supercharged pulsed water jet in engineering.
  • WU Lei1, ZHANG Xin1,2, WANG Jiaxu1,2, ZHAO Yike1, LIU Zhiwen3, WANG Lei4
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 123-132.
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    Aiming at addressing the problems that minimum entropy deconvolution (MED) tends to restore a few pseudo-dominant impulses and determines the filter length empirically in fault diagnosis, an enhanced and adaptive blind deconvolution method is proposed in this paper. A nonlinear transformation is designed to process the filtered signal so as to enhance the fault impulses, and then the filter coefficients are estimated by maximizing the kurtosis of the processed signal. In this context, it can avoid attaining unsuitable filter coefficients due to excessively large kurtosis caused by a few pseudo-dominant impulses. Meanwhile, this method provides a strategy for adaptively obtaining the filter parameters according to the signal to be analyzed, and overcomes the drawback that depends on experience. The analysis results of simulated signals and gear seeded-fault signal verified the effectiveness of the method. In engineering applications, the method successfully diagnosed the incipient gear crack damage in a train transmission system, and showed great superiority over the traditional MED in enhancing and adaptively restoring the periodic fault impulses.
  • WANG Qingjian1, WANG Sen1, WU Xing2, LIU Xiaoqin1, LIU Tao1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 133-142.
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    The main factors for improving the accuracy of visual vibration measurement depend on the number of samples in the captured image per unit period and the sharpness of the edge of the vibrating target in the image. However, the limited acquisition frequency and inherent resolution of industrial cameras will lead to obvious offset errors in the final obtained timing displacement signals due to the loss of spatial-temporal information. Therefore, this paper proposes a method for spatial-temporal enhancement and vibration measurement of rotor images. A fitting sample is inserted between two adjacent sample images through the video frame interpolation algorithm, thereby enhancing the number of samples collected in a unit period. In order to alleviate the phenomenon of blur, distortion and noise in the collected low-resolution images, the super-resolution reconstruction algorithm is used to restore the high-frequency information in the images. After weighing the time consumption of the algorithm and the consumption of computing resources, this paper integrates the video frame insertion and video reconstruction tasks to realize the feature information sharing of the two model tasks. The experimental results tested on the self-made high-speed vibration rotor image dataset show that compared with the current advanced algorithm, the model constructed in this paper is improved by 0.3dB and the lightweight model has better reconstruction accuracy than the advanced model while reducing the model parameters by 17.9%. The time-domain and frequency-domain signals measured at two sampling frequencies show that the vibration signals obtained by the proposed algorithm have better periodicity and stability.
  • WANG Ting1,2, WANG Hui3, ZHAO Yang3,4, LI Xinghong3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 143-153.
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    A high-precise finite element model of a 600MW large turbo-generator stator end winding is established. The modal parameters are obtained by modal analysis, which are in good agreement with the experimental data. Then, the digital mechanism model of stator end winding is set up. In the model, the shell is used to model double-layer winding and the supporting structures are treated as ring stiffeners and stringer stiffeners. Based on the discrete element method, the equivalent model of stiffened and ribbed conical shell for end winding can be established. After that, the natural and forced vibration equations of the end winding are established by Rayleigh- Ritz method with improved Fourier series which is suitable for different complex elastic boundary conditions. With the digital mechanism model, the modal parameters of end winding are determined. Comparing with the simulation results obtained by the finite element model, the rationality and correctness of the proposed digital mechanism model are verified.
  • LIU Boyi1, 2, WANG Ping1, 2, XU Jingmang1, 2, YAN Zheng1, 2, CHEN Jiayin1, 2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 154-161.
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    Wheel diameter difference will have an impact on the dynamic characteristics of vehicle passing through turnout, especially in the diverging route being. To reveal the influence mechanism, this paper takes a high-speed vehicle and a No.18 turnout into consideration to build a vehicle-turnout coupling model. The dynamics performance of high-speed vehicle passing through the turnout in the diverging route at a speed of 80 km/h under different scenarios of wheel diameter difference are carried out. The results showed that when the equivalent same-phase (wheels on the same side are all with smaller wheel diameters than the others) wheel diameter difference and the large wheel diameter is located on the side of the switch rail, the wheel-rail lateral force and the lateral acceleration of the car body will reduce. When the wheel diameter of the wheel on the stock rail side is larger than that on the switch rail side, the derailment coefficient and wheel load reduction rate will increase by equivalent counter-phase (The bigger wheel of the front wheel pair is in the opposite position to the bigger wheel of the rear wheel pair) wheel diameter difference when high-speed vehicles passing through turnout in the diverging route. Because of the uncertainty of wheel diameter difference during the real train operation, it should be avoided more than 1mm as far as possible to ensure the safety and stability of high-speed vehicle passing through the turnout in the diverging route. In addition, wheel wear is exacerbated when the wheel diameter of wheel on the switch rail side is larger than that on the stock rail side, so such situation should be avoided. As a result, life span of both wheel and rail could be prolonged.
  • WANG Daozhong, LI Guang, SONG Yadong, YAO Yuan
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 162-169.
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    In view of the measurement problem of vibration states of rail vehicles, a sliding mode observer designed according to the sliding mode theory algorithm was proposed, which uses measurable vibration data to estimate the vehicle vibration state. By establishing the simplified lateral dynamic model of rail vehicles, a robust sliding mode observer was designed based on the simplified lateral model. Real-time measuring the lateral velocity and yaw angular velocity of the frame was used to estimate lateral vibration displacements of it as well as lateral vibration states of the carbody. In order to verify the effectiveness of the observer, the SIMPACK dynamics software was used to establish a 54 DOF simulation model of a certain type of domestic high-speed train. The actual operation process was simulated by dynamic calculation, and the estimated value of carbody vibration states obtained by the method was compared with the simulation result. The results show that the lateral vibration velocity and displacement of the carbody can be estimated accurately during straight-line condition, while the lateral vibration velocity accuracy of the carbody on the curve can meet the requirements, which demostrates the scientificity and feasibility of the proposed sliding mode observer.
  • ZHOU Changwei1, LI Guoyong1, REN Mifeng1, YE Zefu2, YAN Gaowei1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 170-179.
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    Aiming at the problem that deterioration of fault diagnosis under multi-working condition caused by the training data and test data do not satisfy the assumption of independent and identical distribution. A discriminative joint probability based domain adaption for fault diagnosis was proposed. Firstly, a domain-invariant classifier with structural risk minimization is used as modeling framework. Then, a domain adaptation term based on the discriminative joint probability distribution difference is imposed on the framework. The term projects data into a common feature space, aligns the distribution of samples of the same category across domains, and maximizes the distribution differences between samples of different categories across domains. At the same time, the manifold regularization is used to preserve the local geometry of the data. Finally, the method was applied in the bearing fault diagnosis datasets of Case Western Reserve University (CWRU) and Paderborn University (PU). It was shown that the proposed method can effectively improve the prediction accuracy and generalization of the fault diagnosis model under multi-working condition.
  • MA Min, LI Jiwei
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 180-186.
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    To solve the problem that it is difficult for a single neural network to capture complex and deep capacitance vector features in the process of capacitance tomography image reconstruction, a electrical capacitance tomography image reconstruction algorithm (BSFF) based on squeeze-and-excitation networks(SENet) dual-path multi-scale feature fusion was proposed. Firstly, a multi-scale dense deep cavity convolution module was constructed to obtain a larger local receptive field and maintain a lower computational complexity, and multi-scale feature fusion was achieved to capture the multi-scale detail features of capacitance vector to enhance the representation ability of the model. Secondly, residual neural network is used to solve the degradation phenomenon in feature extraction of deep network, and SENet module is added to recalibrate the corresponding weight of the channel which the capacitance feature tensor belongs and calibrate the feature response. Finally, a two-channel multi-feature fusion hybrid model with bidirectional feature extraction capability is formed to better fit the nonlinear mapping relationship between capacitance tensor and dielectric constant. The Experimental results show that BSFF algorithm has higher image reconstruction quality and better robustness than Landweber iterative algorithm and CNN algorithm.
  • LIANG Shilei, ZHANG Lei, WANG Hui, WANG Yanyan
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 187-193.
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    Refined dynamic models of thin-walled beams with rounded corners are established based on one-dimensional higher order theory and pattern recognition algorithm, which is capable of accurately predicting their three-dimensional kinetic behaviors. First, an initial higher order model is formulated using the basis functions defined on the discrete cross-section, and axial vibration modes of generalized coordinates are decoupled by solving the generalized eigenvalue problem involved with the governing differential equations. Then the generalized eigen matrix is established to obtain the composition weight of each basis function with the application of principal component analysis, which is further used to “assemble” a set of deformation modes with clear structural interpretations. To further reduce the degrees of freedom of the new model, a reduced set of deformation modes are selected in the order of their priorities according to the accuracy requirements, and an improved one-dimensional higher order model is constructed for engineering calculations. Numerical results show that the presented model can accurately predict the dynamic characteristics and transient dynamic behaviors of thin-walled structures by employing 1% elements of compared two-dimensional plate/shell model, with frequency errors of the first 15order modes within 1.4%, and that it is applicable for thin-walled structures with slenderness ratios beyond 4.
  • HU Xiaorong, CAI Xiaofeng, CHEN Hao, LU Xiang
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 194-206.
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    Based on the unsaturated soil triple-shear strength criterion and the subloading surface model, the Bishop and Fredlund stress-variable method triple-shear subloading surface models for normally consolidated unsaturated clays were constructed and the calculated results of the two models were compared with the results of monotonic static triaxial tests and cyclic dynamic triaxial tests on unsaturated clays. The results show that the Fredlund stress variable model is closer to the test results. In the late stage of soil deformation in the static triaxial test, the deviations of the Fredlund and Bishop stress variable models from the test data were 2% and 10%, respectively; in the late stage of soil vibration in the dynamic triaxial test, the deviations of the Fredlund and Bishop stress variable models from the test results were 4.2% and 7.5%, respectively. In addition, the results of the true triaxial analysis of the proposed models show that the shear strength of the soil increases with the increase of the intermediate principal stress effect factor and the matrix suction in the static true triaxial test, with the deviation of about 11% for each successive simulation result as the matrix suction increases, and with the increase of the intermediate principal stress effect factor, the deviation of about 4% for each successive simulation result. The greater the minimum principal stress or intermediate principal stress in the dynamic triaxial test, the greater the ratchet effect and shear strength of the unsaturated clay. The strain deviation between simulations with different intermediate principal stresses was 3.3% and between simulations with different minimum principal stresses was 8.5%.
  • WEI Zilong1, SUN Xianfu1, YANG Fei1, YANG Guotao2, LUO Guowei3, YOU Mingxi1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 207-216.
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    The wheel polygons of high-speed comprehensive inspection train induce undesired deviations of track irregularity inspection data, which imposes an adverse effect on evaluating the status of track geometry. Focusing on the issue, this study initially investigates the anomaly feature of track inspection data in both time and frequency domains, and then establishes the model capable of simulating the dynamic vehicle-track interaction induced by wheel polygons and the multi-criteria evaluation approach of wheel polygons. The influence of the order, depth of wheel polygons as well as the wheel radius on the deviation of track inspection data is extracted, and the limit of wheel polygons for high-speed comprehensive inspection train is proposed. The results indicate that the low order of wheel polygons plays an important role in the reliability of inspection data, especially for the items of longitudinal level, cross-level, and twist, whereas both track alignment and track gauge are rarely affected. The change in the wheel radius caused by tread wear and reprofiling does not influence much on the accuracy of measured data, so that the minimum wheel radius allowed for high-speed comprehensive inspection train can be similar with the ordinary operating EMUs. The limit of wheel polygons instrumented by the track irregularity inspection device should be set to 0.10 mm.
  • ZHANG Xinzhi, HU Junxiong, ZHOU Yang, MA Weihua, WANG Zili
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 217-224.
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    The parts of the suspension frame of the medium and low speed maglev train are mainly connected by bolts. When the suspension failure of the train falls, the bolts at the connection between the parking brake skid and the supporting arm are subjected to greater shear action, so there is a risk of structural safety. The finite element model of the suspension frame is established by using HyperMesh, the bolt connection and contact relationship of the parking brake skid position are taken into account. The falling process of the suspension frame at different speeds is simulated based on ANSYS/LS-DYNA, the contact force fluctuation of each contact pair is calculated, and the stress change and distribution of the connecting bolt, the skid key, the sledge mounting seat and the supporting arm are analyzed. The results show that: The contact force of each contact pair reaches the peak at the moment of drop collision, then decreases in the process of small fluctuation; When the suspension frame in motion falls, each contact force is much larger than that of static suspension vehicle, the stress of connecting bolt increases significantly. The maximum equivalent stress of skid key, sleigh and sleigh mounting seat exceeds the yield limit of the material, there is structural safety risk, so attention should be paid to timely inspection in engineering.
  • ZUO Yanfei1, PANG Chenyi1, JIANG Zhinong2, FENG Kun3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 225-236.
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    Facing the multi-operating conditions and wide-band modal parameters identification requirements of gas turbine under operating conditions. Based on the vibration modal analysis of the typical gas turbine, considering the test data types, the measurement points selection in different position and orientation, and different operating conditions. A random subspace method for gas turbine operating modal parameters identification was proposed. Based on the measured vibration data, the operating modal parameters of certain typical gas turbine were automatically divided and identified. The results show that if the rows and blocks number are controlled respectively, the modal parameter information of different frequency bands contained displacement, velocity, and acceleration data is fully excavated, and merged by selecting the best results, it could better identify the modal parameters in the wide frequency domain which are dozens of times the gas turbine operating frequency; Reasonable selection of measuring points’ position and direction could obtain partial and whole modal in the interest frequency band; Using multi-rotating speed data, it is possible to distinguish the whole modal affected by the rotating frequency. It realizes the identification of the partial and whole modal, casing-domainded and rotor-domainded modal in the wide frequency range of the gas turbine, which could provide support for dynamic analysis, whole machine model updating, structural vibration state assessment, vibration fault feature extraction.
  • DU Wenlong1, LI Wei1, JIANG Song1, SHENG Lianchao2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 237-244.
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    In order to analyze the influence of load excitation on the coupled bending-torsional vibration characteristics for the rotor-bearing system, it takes the shearer permanent magnet motor rotor system as a case to establish the rotor-bearing system with electromagnetic excitation, meanwhile the load excitation is introduced to the eccentricities rotor system. The bending-torsional dynamic equations of rotor system considering the load excitation are obtained according to Lagrange equation, and the numerical simulation of the bending-torsional model is carried out based on the Runge-Kutta algorithm, focusing on the vibration characteristics of the rotor system under different load excitation. Results show that the load excitation will aggravate the degree of rotor eccentricity and but has a small effect on the frequency response of bending vibration, and the vibration response is dominantly determined by the rotation frequency component. On the contrary, the load excitation has a different effect on the torsional vibration, which will not only excite the corresponding frequency component in the vibration response and forms multiple-periodic motion, but also significantly increase the amplitude of torsional vibration angle (0.001rad), and the vibration response is dominantly determined by disturbance excitation frequency and the double rotation frequency component. In addition, the low frequency component of the cutting load will induce a large torsional vibration response (0.03 rad), accelerating the fatigue damage of the transmission system and affecting the stable operation of the rotor system. The research results can provide useful reference for the formulation of active vibration suppression control strategy of the rotor system in shearer.
  • SONG Zhiqiang, LIU Lin, WANG Fei, LIU Yunhe
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 245-253.
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    The distance between the faults of near-fault ground motions is generally within 20km. Since the reflection and transmission times of seismic waves in different rock formations are much smaller than those of far-fault ground motions, they generally do not meet the assumption of vertical incidence when they reach the surface. At present, few studies on the seismic resistance of asphalt concrete core dams consider the impact of near-fault ground motion oblique input. This paper selects the appropriate near-fault pulse-type ground motion records, and derives the equivalent nodal force formula under the complete wavefield decomposition scheme of the two-dimensional foundation side and bottom boundary when the P wave is incident obliquely, and simulates asphalt concrete through the near-fault P wave wave oblique input The core wall dam is subjected to near-field seismic waves. The influence of the near-fault P-wave pulse characteristics and input angle on the acceleration, stress, curvature of the asphalt concrete core wall and permanent deformation of the dam is analyzed. The results show: Comparing the dynamic response of the core wall and the dam when the seismic wave is incident vertically and obliquely, there are obvious differences. The characteristics of the near-fault ground motion pulse have a significant impact on each response.
  • DING Liangliang1, WANG Kai1, CHEN Lili2, ZHANG Qiang1, CHEN Wenkang1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 254-261.
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    In light of the fact that the water hammer effect causes a significant increase in pressure oscillation when sand plugging occurs during hydraulic fracturing of ultra-deep wells, a prediction model for the water hammer effect of fracturing sand plugging is established and numerically solved using the finite difference method, taking into account the characteristics of the multiphase flow, proppant properties, wellbore friction, high construction pressure, and sand plugging formation mechanism. The prediction model's calculation findings are compared to field data of sand plugging during fracturing in a high-pressure deep well. The findings reveal that the highest error is less than 2.92 percent, indicating that the model is reliable. A comparative analysis was carried out on the influence of fracturing operation parameters. The results indicate: 1) The water hammer pressure fluctuation rises as the fracturing fluid displacement rises, although displacement has minimal influence on water hammer velocity. 2) The kinetic energy increases as the two-phase flow density increases, and the pressure fluctuation of the water hammer effect increases significantly, but the wave velocity drops initially and then increases as the sand ratio increases. 3) The variation of the water hammer pressure rises as proppant density increases, and the change in water hammer wave velocity is dictated by proppant density and proppant elastic modulus.
  • HU Weihua, YUAN Xiaojie, TANG Dehui, XU Zengmao, LU Wei, TENG Jun
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 262-266.
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    This paper proposes an automated modal parameter identification method of bridge based on mobile sensing. The mobile sensing unit consists of a power vehicle and a rigid trailer. The power vehicle is equipped with a data acquisition and transmission module and “Beidou” timing module. The rigid trailer is equipped with an accelerometer. The connection between the power vehicle and the trailer is designed so that the vibration signal of the bridge can be effectively acquired. In the modal experiment, the mobile sensing unit automatically records the structural vibration in different measuring points. The phase time synchronization between the mobile measuring unit and the fixed reference unit is realized by the “Beidou” timing module. The bridge modal parameters can be extracted efficiently by the automated stochastic subspace identification algorithm from the vibration information obtained from the fixed measuring unit and the mobile sensing unit. High spatial resolution can be obtained based on mobile sensing system, and then accurate structural mode shape information can be identified. The mobile sensing system is applied to the modal tests of a through tied arch bridge and the modal parameters are identified efficiently.
  • SHAO Wenyang, YANG Guangwu, XIAO Shoune, LIU Zhuangzhuang
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 267-272.
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    In order to solve the simulation problem of shock working condition of a locomotive fuel tank under fluid-structure coupling, the results of four simulation methods such as the combination of virtual mass method and transient method are compared with the small fuel tank model, and the shock test is carried out based on the standard shock spectrum. At the same time, the simulation results are compared with the test values. The comparison results show that the simulation method combining virtual mass method and transient method is the most accurate to analyze the  shock working condition of the box under the condition of fluid-structure coupling. Taking the working condition of 1/3 tank oil height as an example, the three-dimensional stress of this type of fuel tank under shock working condition is calculated. The calculation results show that under the condition of 1/3 tank oil height, the shock stress is less than the allowable stress value, which meets the service requirements. The research results have certain guiding significance for analysing the shock stress of the structure under the condition of fluid-structure coupling.
  • ZHU Liangyu, CUI Qianwen, HU Chaofan, HE Shuilong
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 273-280.
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    Aiming at the problems of inconsistent distribution of bearing vibration data under different working conditions, under-adaptation and over-adaptation in the adaptive process of the source domain and target domain, a fault diagnosis method based on substructure optimal transport for bearings under different working conditions is proposed. First, the fault features in the bearing vibration data are extracted through wavelet transform, and the fault sample set is constructed. Then cluster the bearing fault sample sets in the source domain and the target domain to generate a substructure of the source domain and target domain fault sample data. And adaptively assign different weights to the data substructure of the source domain, and assign the same weight to the data substructure of the target domain to complete the mapping of the data substructure of the source domain. Finally, using the mapped source domain data substructure and its corresponding labels, the support vector machine model is trained and the fault diagnosis of the bearing under the target working condition is realized through the trained model. The proposed method is verified on the mechanical comprehensive fault simulation experimental platform and the bearing dataset of Case Western Reserve University, and compared with traditional machine learning and other transfer learning methods. The experimental results show the effectiveness and superiority of the method.
  • WANG Pengcheng1,2, DENG Aidong1,2, LING Feng1,2, DENG Minqiang1,2, LIU Yang1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 281-288.
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    As a key component of the transmission system of a wind turbine, the rolling bearing is vital to the safe and stable operation of the entire unit. Aiming at the problem of rolling bearing fault diagnosis, On base of extracting cyclo-stationarity of repetitive transients from envelope spectrum based on prior-unknown blind deconvolution technique, a SEBD bearing fault diagnosis method based on particle swarm optimization (PSO) optimization is proposed to realize the adaptive selection of SEBD filter length. Firstly, take the maximum fault characteristic frequency ratio (CFR) as the fitness function, and use the PSO algorithm to optimize the filter length; then, use the obtained optimal filter length to perform SEBD processing; finally, according to the envelope spectrum feature of the signal after SEBD processing realizes the effective identification of bearing faults. The effectiveness of PSO-SEBD is verified by analyzing the simulation signal and the public bearing failure data of Paderborn University in Germany. By comparing with several commonly used diagnostic methods and analyzing under noisy environment, it shows that this method has better diagnostic performance and anti-noise ability.
  • JIANG Yan, ZHAO Bo
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 289-300.
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    This paper uses a  longitudinal-torsional ultrasonic rolling method(LTUR)to strengthen the surfaces and improve properties of teeth flanks. Based on the Hertz contact mechanisam and Meshing theory, the model of equivalent stress from LTUR is first built.  Furthermore, the process of the method is simulated and analyzed using FEM ways. Finally, the corresponding experiment device is constructed and some experiments are performed. After comparing the simulating and analytical results, applying longitudinal torsional ultrasound can effectively improve the contact stress. In this paper, the contact stress with or without ultrasonic vibration is increased by about 1.7 ~ 2 times, which causes the material to yield and then complete the strengthening. From experiments, it is shown that LTUR can improve surface properties of teeth flanks to some extent. The residual stress on the tooth surface increases with the increase of damping torque. The residual stress along the tooth profile first increases and then decreases, and the residual stress value is the largest at the pitch circle. The microhardness presents time-varying characteristics along the tooth profile. Simultaneously, the surface topography is also changed, peak-valley space is widen and the roughness is declined to about 45%~55% of its original values. Therefore, the method in this paper can strength the teeth flank, improve surface property, raise residual stresses and microhardness as well as decrease the surface roughness. In summary, this method can improve the surface quality.
  • QI Yongsheng1,2, GONG Yurui1,2, GAO Shengli3, LIU Liqiang1,2, LI Yongting1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 301-311.
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    At present, the fault diagnosis technology of rotating machinery based on deep learning has attracted wide attention because of its powerful layer-by-layer processing and built-in feature transformation function. However, the traditional depth network for fault diagnosis requires a lot of label data, and the diagnosis results depend on the number and accuracy of labels. For this reason, a semi-supervised fault diagnosis method based on center loss-improved convolutional autoencoder is proposed. Firstly, the fault signal is converted into time-frequency graph by continuous wavelet transform to refine the fault feature representation. Then an improved convolutional autoencoder network structure is constructed, and batch normalization(BN) and Dropout are introduced to prevent over-fitting in the feature extraction stage. Then in the classification stage, the center loss is introduced into the Softmax loss function to build a joint loss function to make the fault features achieve smaller intra-class distance and greater feature differences, and further improve the classification accuracy. Finally, the proposed method is verified by Case Western Reserve University bearing data set and bearing fault experimental platform. The results show that in the case of a small number of label samples, effective fault diagnosis can be achieved and the diagnosis accuracy can be improved.
  • YANG Menggang1, LI Mengcheng2, HU Shangtao1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 312-320.
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    The transverse pounding responses and damping system of the high-speed railway simply supported beam bridge considering the fling-step effect of near-fault earthquakes are investigated. A 32-m simply-supported girder bridge with 5 spans was taken as the background, and the finite element model of the bridge was established in Abaqus. The difference between the transverse seismic responses of bridge under far-field and near-fault earthquakes were analyzed. The applicability of traditional shear key was studied. The damping performances of three kinds of damping systems were compared and analyzed, including the combination of shear key and cable, cable restrainer, and shock absorber. The results show that compared with the far-field earthquakes, the traditional shear key fails completely due to the fling-step effect of near-fault earthquakes, and the risk of unseating increases significantly. The seismic performance of the "shear key+cable" method is improved as the gap between the shear key and bearing padstones decreases. The damping effectiveness of the cable restrainer increases with the decrease of restraining displacements. The optimal stiffness of the shock absorber can significantly reduce the seismic response of the bridge. By comprehensive comparison, the shock absorber is the most effective damping system.
  • DANG Yu1, LI Guobao1, XIE Pengfei2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 321-332.
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    Based on the spectral characteristics of the floor response spectrum of base isolated structure, the spectral curve is divided into sections for regression analysis to determine the shape of the spectral curve of each section, and a double-peak floor design response spectrum of base isolated structure is obtained. Consider the main factors that affect the floor response spectrum of base isolated structure, such as the dynamic parameters of the seismic isolation structure, site characteristics, ground motion intensity, the interaction between the seismic isolation structure and the equipment, and equipment damping. Using the orthogonal experiment method, analyze the floor response spectrum of base isolated structure-equipment combination system. Taking the maximum goodness of fit as the goal, the characteristic parameters of the floor design response spectrum are calibrated section by section, and the calculation formula of each characteristic parameter is statistically fitted. Through the verification of three actual base isolated engineering-equipment examples, the results show that the established standardized floor design response spectrum can faithfully reflect the spectral characteristics of the floor response spectrum, restore the curve changes of the floor response spectrum, and the spectrum value of each section of the curve can better envelop the floor response spectrum. Compared with the results of time-history analysis method, the error of seismic action of each equipment obtained based on the floor design response spectrum is within 10%, indicating that the floor design response spectrum has high accuracy and good engineering practicability.
  • WANG Min1, QIN Guojun1,2, LIAO Yifan1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(7): 333-340.
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    Aiming at the noise interference problem in diesel engine cylinder fault diagnosis, an adaptive weighted multi-scale morphological decomposition (AWMMD) method was proposed to extract fault features from vibration signals of each cylinder head surface. Firstly, a new combined difference morphological filter was constructed based on three combination operators, which was used to decompose vibration signals in multi-scale. Secondly, a genetic algorithm based adaptive weight assignment algorithm for each scale morphological pattern component was designed with Teager energy kurtosis as the evaluation index, and a weighted multi-scale morphological decomposition method was proposed. Finally, the adaptive weight and the morphological mode components of multi-scale decomposition were combined to obtain the optimized fault feature extraction results. The results of simulation signal test and diesel engine fault simulation signal analysis show that the proposed method can effectively suppress noise interference and extract fault features.