高过载信号的脉宽对泡沫铝缓冲效率的影响

Influence of Pulse Width of High Overload Signal on Buffering Efficiency of Foam Aluminum

弹载仪器在冲击载荷作用下的缓冲保护研究备受关注,本文针对实弹测试中高过载信号的脉宽对泡沫铝缓冲材料的缓冲效率影响问题,提出了一种基于空气炮试验的缓冲效率研究方法。将缓冲测试装置的缓冲模型简化为单自由度缓冲模型,分析并建立了泡沫铝在高过载信号缓冲压缩下的应力-应变曲线。研究发现,高过载信号的脉宽通过影响高密度泡沫铝的应变率而去影响塑性平台区应力和缓冲效率,而低密度泡沫铝的缓冲效率基本不受脉宽变化的影响。研究结果表明:高过载信号的幅值约20 000g时,脉宽下降111μs, 1.55 g/cm3泡沫铝塑性平台区应力增大约15 MPa,缓冲效率下降约5.97%;0.5 g/cm3泡沫铝在高过载信号的幅值相同,脉宽下降126μs,塑性平台区应力和缓冲效率基本不变。

Research on the buffering protection of missile borne instruments under impact loads has received much attention.Aiming at the problem that the pulse width of high overload signal affects the cushioning efficiency of the cushioning material foam aluminum in live ammunition test,a research method of cushioning efficiency based on air gun test was proposed.The buffer model of the buffer test device was simplified to a single degree of freedom buffer model,and the stress-strain curve of foam aluminum under the high overload signal buffer compression was analyzed and established.It is found that the pulse width of the high overload signal affects the stress and buffer efficiency of the plastic platform area by affecting the strain rate of the high-density foam aluminum,while the buffer efficiency of low-density foam aluminum is basically not affected by the change of pulse width.The research results show that when the amplitude of high overload signal is about 20000g,the pulse width decreases by 111μs,the stress in 1.55 g/cm3 foam aluminum plastic platform area increases by about 15 MPa,and the buffer efficiency decreases by about 5. 97%;The amplitude of 0. 5 g/cm3 foam aluminum at high overload signal isthe same, the pulse width decreases by 126 μs, and the stress and buffer efficiency in plastic platform arearemain basically unchanged.