冷气式气体发生器爆破片极限破坏载荷的计算

Title Ultimate Breakage Load Calculation Method of Cold Gas Inflator Burst Disk

对于冷气式气体发生器,爆破片极限载荷的准确计算是发生器结构设计的关键。为了准确预测水压试验爆破片的破坏载荷,首先使用基于隐式算法的零曲率法和弧长法对爆破片极限载荷进行计算。与试验结果对比表明,这2种方法的极限载荷计算结果精度都达到97%以上。随后,为了弥补隐式算法在大载荷作用下接触非线性、难收敛的不足,基于弧长法关键位置应力矩阵状态变化规律分析结果,提出针对显式算法确定极限载荷值的方法:应力矩阵状态分析法,即在显式计算过程中跟踪爆破片中心位置三向应力变化,将其在厚度方向发生失稳时对应的载荷定义为极限载荷。最终的计算结果表明,使用应力矩阵状态分析法判定的爆破片极限载荷与试验结果的匹配精度为97.4%,且由于接触非线性相关影响被计入,爆破片变形计算结果更加准确。

For the cold gas inflator,high refinement of ultimate load forecast is the key to the structural design of the generator. First,the zero curvature method and the RIKS method were used for burst disk hydro-burst test ultimate load calculation. Compared with the results of the real test,the refinement of both of the two methods are above 97%. Then, to solve the nonlinear contact convergence issue of the implicit algorithm,the explicit algorithm was used to solve ultimate load based on the status of stress matrix analysis results of the RIKS method. The method of stress matrix status analysis was proposed to judge the ultimate load of explicit algorithm results. In the explicit calculation,the stress change at the center of the burst disk is tracked and the corresponding load when plastic instability occurs in the thickness direction is defined as the ultimate load. The refinement of the ultimate load of the explicit algorithm is 97.4% in contrast to the real test judging by the method of stress matrix status analysis. Because of the involvement of the effect of nonlinear contact, the refinement of displacement of burst disk is better than that of the implicit method.