基于杆式弹性易损部件的非线性系统跌落冲击研究

Drop impact analysis of packaging system with bar type elastic critical components

针对多自由度缓冲包装产品设计中杆式结构部件在工作过程中容易发生损伤而引起系统失效问题,提出将产品主体假设为刚性,杆式结构处理成均匀分布的弹性体结构,进而建立刚性-弹性体的非线性耦合模型及运动微分方程,并运用差分方法进行求解,得到杆式易损零件非线性包装系统的数值解。算例结果表明:杆式易损部件的最大加速度位于杆的自由端,此处应力最小;最小加速度出现在杆的根部,此处应力最大。杆根部位置的最大应力是否超过弹性部件的比例极限成为产品失效的有效判据。

The critical components of bar type in multi-freedom cushioning packaging products are likely to be damaged and cause system failures during the work.It was proposed that the item of cushioning packaging products was assumed as a rigid component,and the critical components of bar type were simplified as uniform and elastic parts.The nonlinear coupling dynamics model,including the critical components and item was established and the corresponding differential equations of motion were derived and solved by using difference method.It was demonstrated that the maximum acceleration of the bar component occurs at its free end,where the stress is minimum,while the minimum acceleration occurs at its root where the stress is maximum.Whether the maximum stress at the root of the bar is beyond the elactic proportion limit is an effective parameter to determine whether the item loses its functions.