垫片提高抗冲击能力的应力波衰减机理

引信零部件抗高过载冲击,目前大多文献和资料提到用弹塑性垫片材料进行缓冲、吸能,但是缓冲理论并不能解释垫片提高引信零部件耐高过载能力.为此,提出垫片提高引信零部件抗冲击能力的机理主要是应力波反射衰减,即机械滤波.根据应力波在不同界面的反射与透射理论,冲击应力波在通过结构件与垫片的分界面时,因大部分被反射而衰减,垫片提高被保护件抗冲击能力的主要原因不是弹性缓冲,而是机械滤波；垫片对于被保护件质心惯性加速度影响很小,却能显著衰减骑在质心加速度曲线上的应力波,降低二者的合力尖峰,并减少往复振动冲击的破坏.仿真表明:垫片滤波说比缓冲说更合理,并且,波阻抗越小的垫片,机械滤波效果越好；只要远小于有效缓冲厚度,垫片厚度对机械滤波贡献不大；使用不同材料的两层垫片优于同厚度的单一材质垫片,多层更好.

Stress Wave Reflecting Attenuation to Improve Anti-shock Capacity by Gasket

Most of researches on anti-shock for penetrating fuze suggests that elasto-plastic gasket materials can be used because of their properties of cushion and energy-absorption.But the theory of cushion can hardly explain that why the gasket can improve fuze parts anti-shock capacity.In this paper,stress wave attenuating by gasket was regarded as the major factor of anti-shock.The large percentage of stress wave was reflected at fuze-shell/gasket interface.The gasket had few effects on acceleration but significant on attenuating fluctuation of stress wave.The simulation results indicateed that(1) the less of the impedance,the better of attenuation;(2) the thickness of the gaskets had few effects on attenuation;(3)multilayer different gaskets were much better.