热声载荷下薄壁结构非线性振动响应分析及疲劳寿命预测

贺尔铭;刘峰;胡亚琪;赵志彬

振动与冲击 ›› 2013, Vol. 32 ›› Issue (24) : 135-139.

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振动与冲击 ›› 2013, Vol. 32 ›› Issue (24) : 135-139.
论文

热声载荷下薄壁结构非线性振动响应分析及疲劳寿命预测

  • 贺尔铭,刘峰,胡亚琪,赵志彬
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Nonlinear Vibration Response Analysis and Fatigue Life Prediction of Thin-walled Structure under Thermal-acoustic loading

  • He Er-ming Liu Feng Hu Ya-qi Zhao Zhi-Bin
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摘要

基于时域分析法研究了金属薄壁结构在热声载荷下的非线性振动响应特性,并采用四种应力寿命模型预测了薄板梁的热声疲劳寿命。以典型薄板梁为研究模型,首先研究了单一噪声激励下薄板梁的时域响应特性及热载荷对其响应特性的影响机理,并仿真分析了薄板梁在热声激励下的非线性响应特性。在此基础上,运用雨流法统计了薄板梁根部的应力响应,并基于Miner线性累积损伤理论采用Goodman、Morrow、Walker和修正Walker应力寿命模型预测了薄板梁在不同工况下的热声疲劳寿命。研究结果表明:薄板梁的热模态基频在其热声疲劳问题中起主导作用;薄板梁热屈曲后的非线性跳变响应将增大应力幅值,从而严重削弱结构的预期寿命;噪声载荷是影响屈曲前薄板梁热声疲劳寿命的主要因素,而热载荷是影响屈曲后热声疲劳寿命的主要因素。因此在薄壁结构抗热声疲劳设计中必须重点考虑热声载荷联合作用的影响。

Abstract

The thermal-acoustic vibration response characteristics of metallic thin-walled structures were investigated based on time-domain analysis method, and four kinds of stress life models were employed to predict the thermal-acoustic fatigue life of a clamped thin-walled aluminum beam. Time-domain response characteristics of a typical beam model under acoustic loading and thermal-acoustic combined loading were determined via numerical simulation. No snap-through response is presented under any single acoustic loading level. On the contrary, in the thermally post-buckled condition, increasing sound pressure level is previously shown to evolve the response from vibration around one of the positions, to intermittent snap-through and finally to persistent snap-through between the two equilibrium positions. On this basis, a cumulative damage model was employed using a rainflow cycle counting scheme and fatigue estimates were made for 2024-T3 aluminum using four fatigue models, namely Goodman, Morrow, Walker, and modified Walker. The results show that: thermal fundamental modal of the beam in thermal-acoustic fatigue problems is predominant; the snap-through motion between multiple post-buckled equilibrium positions introduces very high alternating stress which weakens the fatigue life expectancy of the beam; acoustic loading is a major factor which determines pre-buckled configuration life of the beam, while thermal loading is a major factor which determines post-buckled configuration life. Therefore, anti-fatigue design of the thin-walled structure under thermal-acoustic loading must study the impact of the combined effects of thermal acoustic loading.



关键词

薄壁结构 / 热声载荷 / 时域分析 / 非线性跳变响应 / 雨流法 / Miner损伤理论

Key words

thin-walled structure / thermal-acoustic loading / time domain analysis / nonlinear snap-through / rainflow counting / Miner theory

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导出引用
贺尔铭;刘峰;胡亚琪;赵志彬. 热声载荷下薄壁结构非线性振动响应分析及疲劳寿命预测[J]. 振动与冲击, 2013, 32(24): 135-139
He Er-ming Liu Feng Hu Ya-qi Zhao Zhi-Bin. Nonlinear Vibration Response Analysis and Fatigue Life Prediction of Thin-walled Structure under Thermal-acoustic loading[J]. Journal of Vibration and Shock, 2013, 32(24): 135-139

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