预制倒角对泡沫铝动态冲击变形及吸能的影响

Effect of prefabricated chamfer on the dynamic impact deformation and energy absorption of aluminum foam

为防止峰值过高导致的保护失效,对闭孔泡沫铝试件设置三种预制倒角(单倒角、双倒角、中部倒角),探究动态冲击过程中预制倒角对泡沫铝特征曲线、变形与吸能的影响。通过落锤设备进行低速冲击试验获取特征曲线,结合高速摄影设备、ARAMIS软件以及材料变形剖面分析了不同倒角试件的变形模式、能量吸收效率及其对峰值载荷的影响机理。结果表明:预制倒角使泡沫材料初始变形模式发生改变,有效降低了泡沫铝材料在动态冲击过程中的初始峰值载荷,其中单倒角降幅最为明显为26%;倒角种类决定平台区趋势及材料整体变形模式,中部倒角平台区呈硬化现象,载荷波动最明显;预置倒角对泡沫铝材料平台区的能量吸收效率无显著影响。

Aluminum foams with three types of chamfers were manufactured,with the aim to avoid protection failure caused by the high load impact.The characteristic curve,deformation mode and energy absorption ability were investigated.A drop hammer equipment was utilized to obtain the characteristic curve.The deformation mode and energy absorption efficiency were analyzed by a high-speed camera and the ARAMIS software.The results show that the peak load on the foam with prefabricated chamfer decreases during impact,due to the change of its initial deformation mode.In particular,the decrease degree of the peak load can reach 26%,which exists in aluminum foam with single chamfer.The plateau trend and the deformation mode are closely related to the chamfer type.Obvious load oscillation and plateau hardening can be found in specimens with middle chamfer.The chamfer has no significant effect on the energy absorption efficiency in the platform area of aluminum foam.