Peridynamics Study Of The Effect Of Microvoid On Spall Damage Of LY12Al

Spallation is an extreme failure phenomenon when material is subjected to high-speed impact.It exists widely in various engineering fields,such as military,aeronautics and so on,which has aroused widespread concern in academic and engineering circles.Meanwhile,on the one hand,the real material will inevitably exists microvoids,on the other hand,under high-speed impact,material will inevitably appear void nucleation and growth.Therefore,researchers in academia and engineering circles have carried out a lot of research work in theory,experiment and numerical simulation,and have made great progress.However,due to the essential discontinuity of spalling problem,it is difficult to study spalling problem by using the method based on continuum assumption.In this paper,spallation induced by high-speed impact is studied by peridynamics method which was developed in the latest ten years.The main research content is as follows: 1.According to the basic equations of peridynamics suitable for describing high-speed impact problems,the program was written in FORTRAN language.The flyer impacting the target plate of LY12 Al at different velocities was simulated and the results were compared with the experimental results in literature.The applicability of the theory in spallation problem is verified.2.In order to study the effect of micro-voids on spallation,a spallation model of small size without voids was established,and the effect of this model size on spallation was studied.The results were compared with those models with voids.In addition,the stress-time curve of the center particle on the free surface of the target shows that the stress-time curve is more suitable to describe spallation than the velocity-time curve.3.On the basis of the previous work,the evolution of the single square void in the target plate under high-speed impact was studied,and the results were compared with those without voids in the target plate to show its effects on spallation of LY12 Al,That is,a single small void near the spallation plane will affect the shape of the spallation plane,but will not affect the spallation time.4.Under high impacting velocity,the influence of different void spacing on the evolution of voids in the target plate with two voids was studied.The results were compared with those results obtained in the previous work when there are no voids or a single void in the target plate.The influence of different void spacing on spallation was obtained,and the critical distance between voids in this model was obtained.When the two voids are in the critical plastic zone,the interaction between the voids is affected by the distance of this two voids,when the distance is large,the body between the voids is affected,when the distance is small,the body between the voids and the void itself will be affected.