考虑应变率效应的金属爆炸容器初始设计方法

Initial engineering design method for metal explosive vessels considering strain rate effects

针对爆炸容器初始设计常用的动力系数法存在的设计余量过大问题,通过将Johnson-Cook本构模型的应变率项纳入结构振动方程,推导出考虑应变率效应的等效静载荷计算方法。采用本文方法及常规动力系数法对不同半径的球形容器在1 kg TNT炸药加载下的壁厚进行了理论设计,并通过高置信度数值模型对两种方法所设计的容器的结构响应进行了数值计算。结果显示,两种方法所设计的容器均在弹性范围,但是本文方法的容器壁厚更小、结构应力更大。这表明通过考虑应变率效应,本文方法可合理降低设计载荷以减小设计余量,进而更充分地发挥材料与结构的力学性能,并可用于金属爆炸容器的初始设计。

For the problem of excessive design margin of dynamic coefficient method commonly used in the initial design of explosive vessels,the strain rate term of Johnson-Cook constitutive equation was incorporated into the structural vibration equation to derive the equivalent static load calculation method considering the strain rate effects.The derived method and the conventional dynamic coefficient method were used to conduct theoretical design of spherical vessels with different radius under 1 kg TNT explosive loading,and the structural response of the vessels designed by the two methods were numerically calculated by the high confidence numerical model.Results show that the vessels designed by the two methods are all in elastic range,while the thicknesses of vessels designed by the derived method are smaller and the structural stress of vessels designed by the derived method are larger.These show that the derived method can reasonably reduce the design loads by considering the strain rate effects to reduce the design margin,and then give full play to the mechanical properties of materials and structures,which can be used for the initial design of metal explosive vessels.