热声载荷下复合材料薄壁结构的随机疲劳寿命估算

Random fatigue life estimation of composite thin-walled structures under thermo-acoustic loadings

复合材料薄壁结构承受着高温强噪声载荷,高温环境能够改变材料的性能,而强噪声能使薄壁结构发生大挠度非线性响应。热声载荷达到一定值后,结构的动态响应会出现屈曲甚至跳变响应。热声载荷下复合材料薄壁板非线性响应理论分析方法,采用时域蒙特卡洛法求解非线性运动方程,并根据应力峰值分布,采用线性损伤累积理论和S-N曲线估算结构的疲劳寿命。以碳/碳复合材料矩形板为例,计算了高温强噪声载荷作用下对薄壁板的动态响应和疲劳寿命。

Composite thin-wall structures are subject to high acoustic and severe thermal loadings. The high thermal environments can change properties of material, and the high acoustic loading can make thin-walled structures exhibit large deformation nonlinear response. Under certain thermo-acoustic loading conditions, a dynamic instability will give rise to buckling and even snap-through responses. A theoretical study on nonlinear response of composite panels under thermal-acoustic loadings is conducted. The nonlinear equation of motion is solved numerically by a Monte Carlo type approach. Based on the distribution of stress peaks, S-N curves are combined by means of linear damage accumulation theory to estimate fatigue life of structures. The dynamic response and fatigue life of carbon-carbon rectangular plate are calculated under thermal-acoustic loadings.