开孔泡沫金属动态力学性能及能量特性

Energy Dissipation Characteristics of Saturated Limestone during Impact

泡沫金属材料在防护吸能领域有着重要的应用前景,深入研究泡沫金属及其相关结构的冲击力学性能十分必要。通过Φ50 mm的分离式霍普金森杆(split Hopkinson pressure bar,SHPB)装置对开孔泡沫金属Fe、Ni、Fe-Ni合金(50 mm×10 mm)进行动态冲击试验。试验分析了应变和应变率对其力学性能及吸能特性的影响,通过对其峰值应力、波动应力、理想吸能效率等参数的对比分析多种冲击速度下不同泡沫金属材料的抗压强度与吸能性,为建筑、航天等工程的使用提供理论基础。研究结果表明:高冲击速度下峰值应力增大且Fe-Ni合金抗压强度最高,不同材料泡沫金属均存在波动应力且压密阶段时间各不相同。应变率介于600~1150时泡沫金属Ni吸能性最优,该区间外Fe-Ni合金更优。当应变率大于1000时,Fe-Ni合金理想吸能效率增幅较大,相较于700时提高了48%、为最优理想吸能材料。

Foam metal materials have important application prospects in the field of energy absorption and protection.It is necessa-ry to study the impact mechanical properties of foam metal and its related structures in depth.AdoptΦ50 mm split Hopkinson bar de-vice SHPB(split Hopkinson pressure bar)with opposite opening foam metal Fe,Ni,Fe-Ni alloy(50 mm×10 mm).The effects of strain and strain rate on its mechanical properties and energy absorption characteristics were analyzed through experiments.The com-pressive strength and energy absorption of different foam metal materials under various impact speeds were analyzed by comparing the peak stress,fluctuating stress,ideal energy absorption efficiency and other parameters,which provided a theoretical basis for the use of construction,aerospace and other projects.The results show that the peak stress increases at high impact speed and the compressive strength of Fe-Ni alloy is the highest.Foam metal of different materials has fluctuating stress and the compaction time is different.When the strain rate is between 600~1150,the energy absorption of foam metal Ni is the best,and the Fe-Ni alloy outside this range is better.When the strain rate is greater than 1000,the ideal energy absorption efficiency of Fe-Ni alloy increases greatly,which is 48%higher than that of 700.It is the best ideal energy absorption material.