一种判定杆系结构动力稳定的新方法——应力变化率法

针对结构动力失稳的判定问题，提出了一种适用于杆系结构动力稳定分析的应力变化率法.基于杆系结构发生动力失稳时的总应变能突变特征，推导总应变能同杆单元应力变化率之间的关系，并分析应力变化率的变化规律，建立了判定系结构动力失稳的应力变化率准则.以四种突间杆系结构为例，应用应力变化率准则进行了结构的动力稳定分析，并将结果同位移准则分析的结果进行了比较.结果表明，应力变化率准则可以有效判定杆系结构的动力失稳，并且在判定结构的局部失稳方面非常有效和明确.

New judgment method on dynamic instability of truss structures: stress rate method

Considering the judgment of dynamic instability of truss structures, a stress rate method for dynamic instability analysis of truss structures was proposed. Based on the catastrophic characters of the whole strain energy in truss structural instability, the relationship between the whole strain energy and the stress rate in the link element was educed, and the stress rate criterion for judging the instability of truss structures was built up through analyzing the changing law of stress rate. Taking four spatial truss structures as examples, the structural dynamical stability analyze was carried out applying the stress rate criterion, and the data of the stress rate criterion analysis was compared with those of the displacement criterion analysis. The results show that the stress rate criterion applies for the judgment of the truss structural instability, and the criterion is more effective and definite in the local instability.