纤维金属帽形结构低速冲击力学性能研究

Low speed impact experiment and simulation of fiber metal cap structure

为了研究纤维金属混合材料帽形结构的动态冲击性能,采用落锤机和夹具测量碳纤维和铝合金的动态参数,采用拉伸机测量静态参数,对2种参数进行对比分析,研究应变率对于材料应力的影响,分别采用指数函数、三次多项式和幂函数拟合二者之间的关系,分析应变率影响材料强度的机制。在落锤机上进行不同速度的低速冲击实验,分别采用动态参数和静态参数进行仿真,验证动态参数的有效性。研究冲击速度和材料对帽形结构抗冲击性能的影响。结果表明:应变率主要影响材料的强度,在应力与应变率的关系中,三次多项式具有较好的拟合效果,碳纤维的拉伸、剪切应力随相应应变率的增加而增加,而压缩应力随着压缩应变率的增加而减小,铝合金的拉伸应力随着拉伸应变率的增加先增加后减小;对不同速度的冲击实验仿真,采用动态参数更接近真实的受力情况;比吸能随着冲击能量的增加而提高,与铝合金和碳纤维相比,纤维金属材料具有优良的抗冲击性能。

In order to study the dynamic impact performance of fiber metal mixed material cap structure,the dynamic parameters of carbon fiber and aluminum alloy are measured by drop hammer machine and fixture,and the static parameters are measured by tensile machine.The two parameters are compared and analyzed to study the influence of strain rate on material stress.The relationship between them is fitted by exponential function,cubic polynomial and power function respectively,The mechanism of strain rate affecting material strength is analyzed.Then,the low-speed impact experiments at different speeds are carried out on the drop hammer machine,and the dynamic parameters and static parameters are used to verify the effectiveness of the dynamic parameters.Then the effects of impact velocity and material on the impact resistance of cap structure are studied.The results show that the strain rate mainly affects the strength of the material.In the relationship between stress and strain rate,the cubic polynomial has a good fitting effect.The tensile and shear stresses of carbon fiber increase with the increase of corresponding strain rate,while the compressive stress decreases with the increase of compressive strain rate,and the tensile stress of aluminum alloy first increases and then decreases with the increase of tensile strain rate;The dynamic parameters are used to simulate the impact experiment at different speeds,which is closer to the real force situation;The specific energy absorption increases with the increase of impact energy.Compared with aluminum alloy and carbon fiber,fiber metal materials have excellent impact resistance.