载荷脉宽对圆柱壳瞬态响应的影响分析

Influence of load's pulse duration on transient responses of cylindrical shells

为认识载荷脉宽对圆柱壳瞬态响应及其对X射线冲击响应模拟等效性的影响规律,定义了等效性评价指标即平均应变差异。以四种不同尺寸的典型圆柱壳为对象,分别加载六种冲量相同、脉宽不同的三角形脉冲载荷,通过数值模拟,获得了平均应变差异Δε随脉宽变化的关系,从结构特性角度分析了变化的原因。发现Δε主要受t/τ(脉宽占比)控制,t/τ≤0.45时,平均应变差异在20%以内。所得结果可为模拟X射线冲击环境的试验设计、结果评估和数值模拟提供参考。

In order to understand the influence of load＇s pulse duration on transient responses of cylindrical shells and fidelity of simulating X-ray shock responses,the average strain difference,namely,the simulating fidelity evaluation index,was defined.Six triangular pulse loads with the same impulse but different pulse durations were exerted on four cylindrical shells with different sizes.The relation of average strain difference Δεwith varying pulse duration was obtained using numerical simulations.The variation cause was discussed from view point of structural characteristics.It was found that the average strain difference Δεis mainly controlled by t/τ（the ratio between the load pulse duration and the time of stress wave propagating along the circumference of cylindrical shell）;when t/τ≤0.45,the average strain difference is less than 20%.The results provided a reference for design and evaluation of test simulations of X-ray shock responses and relevant numerical simulations.