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金属薄壁开孔结构在强热声载荷下,表现出大挠度强非线性响应特性,疲劳寿命缩短。基于时域的基础上,利用有限元法(FEM)结合降阶模态法(ROM)获取4边固支开孔薄板在不同热、声载荷组合下的位移和应力的动态响应,并进行响应时间历程和功率谱(PSD)的统计分析。采用雨流计数法和Morrow平均应力模型,结合Miner线性累积损伤理论对结构进行疲劳寿命的预估和分析。结果表明:屈曲后的位移响应由热声载荷的相对强弱决定。此外,屈曲前结构随热、声载荷的增加,寿命缩短。屈曲后,持续跳变使得结构的寿命缩至最短;进入间歇跳变区域,间歇时间短的跳变要比间歇时间长的跳变造成的结构损伤大,即快频跳变引起的损伤更大。跳变结束后,随着温度的升高,寿命先延长后缩短。
Metal thin-walled open-hole structure in strong thermoacoustic load, showing a large non-linear response to large deflection, shorten the fatigue life. Based on the time domain, the dynamic response of the displacement and stress of 4-side perforated thin-walled plates under different thermal and acoustic loads is obtained by using finite element method (FEM) combined with reduced order mode (ROM) Time history and power spectrum (PSD) statistical analysis. The rain flow count method and Morrow average stress model were used to estimate and analyze the fatigue life of the structure with the Miner’s theory of linear cumulative damage. The results show that the displacement response after buckling is determined by the relative strength of thermoacoustic loading. In addition, pre-buckling structure with heat, acoustic load increases, shorter life expectancy. After buckling, the continuous jump makes the life of the structure reduced to the shortest. When entering the intermittent transition region, the transitional intermittent transition has a greater structural damage than the intermittent transition, which means the damage caused by the fast transition is larger . After the transition, as the temperature increases, the life of the first to extend and shorten.