Dynamic Stability of Structural Degradation

该项目将检查当结构性能由于弹性损伤和软化而发生逐渐退化时，动态失效计算的预测价值。动态稳定性预测一方面需要稳健的解决策略，当局部破坏机制仍然受限时，这些策略能够在小区域的材料不稳定中幸存下来。另一方面，基本的数学模型及其计算实现必须足够敏感，以捕捉渐进式故障并以现实的方式控制其传播。为此，将采用不同的故障指标来跟踪动态不稳定性，并在显式和隐式解决策略中监测动态故障计算。主要目标是开发一种基于Lyapunov稳定性指标的自适应求解方法，该方法能够捕捉空间和时间域中的分叉。新的方法将用现实的结构问题来说明，这些问题表现出由于材料层面上的损伤和软化行为而导致的刚度和强度特性的下降。

The project will examine the predictive value of dynamic failure computations when progressive degradation of the structural properties takes place due to elastic damage and softening. Dynamic stability predictions require on one hand robust solution strategies which survive material instabilities in the small region when localized failure mechanisms remain confined. On the other hand, the underlying mathematical model and its computational implementation must be sufficiently sensitive to capture progressive failure and to control its propagation in a realistic manner. To this end, different failure indicators will be implemented for tracing dynamic instabilities and for monitoring dynamic failure calculations within explicit and implicit solution strategies. The principal objective is the development of an adaptive solution method based on Lyapunov stability indicators which capture bifurcations both in the space and in the time domain. The novel methodology will be illustrated with realistic structural problems which exhibit degrading stiffness and strength properties due to damage and softening behavior on the material level.