自由杆对简支梁的多次弹塑性撞击

Multiple elastic-plastic impacts of simply supported beam struck by free-free bar

文章将单轴压缩模型应用于模拟多次撞击和分离过程中接触区的弹塑性接触行为,推导了弹性杆和弹塑性梁的动力学方程,并采用有限差分方法加以求解,研究了弹性自由杆撞击弹塑性简支梁的全过程。研究发现,整个撞击过程实际上是一个复杂的多次弹塑性撞击过程,存在两个以上的明显撞击区,每个撞击区包含了形式多样的复杂的次撞击过程。相对于第一个撞击区,剩余撞击区的撞击冲量不可忽略,所以多个撞击区将对撞击系统的物理行为产生重要影响。撞击产生的纵向应力波在弹性杆中的传播和反射,直接影响多次弹塑性撞击行为,使得撞击过程初期出现了撞击力突降为零的现象。杆撞击端曲率对第一次撞击力峰值的影响明显,但对整个撞击过程中动力学特征的影响有限。

The whole impact course of an elastic-plastic, simply supported beam struck by an elastic, freefree bar is investigated. The uniaxil compression model is applied to simulate the elastic-plastic deformation behavior of multiple contacts induced by multiple impacts and multiple separations. The finite difference method is yielded to solve the dynamic equations of the bar and the beam. The numerical simulations show that such a horizontal strike is indeed a complicated process of multiple elastic-plastic impacts. There are usually more than two impact zones,in which each of them consists of complicated multiple sub-impacts. It is found that the other impact zones might occupy considerable impact impulse compared to the first impact zone. Hence, the other impact zones have significant influence on the impact responses of the bar and the beam. The numerical investigations also show that the propagations and the reflections of the elastic stress wave in the bar directly influence the physical behavior of multiple elastic-plastic impacts. The reflection of the elastic stress wave at the bar＇s impact-end makes the impact force decrease suddenly to zero. The curvature of the impact-end of the bar influences the peak value of the impact force in the first impact course greatly, but has little influence on the dynamic characters of the whole impact course.