靶板抗轮盘碎片撞击能力的数值模拟

为研究机匣抵抗轮盘碎片撞击的能力和破坏方式,找到机匣结构优化设计的方法.用显式非线性动力学软件Dytran计算1/3轮盘碎片与单层和双层靶板的撞击过程.碎片及靶板均选用Johnson-Cook材料本构模型,结合Gruneisen状态方程.撞击过程基于Lagrange算法采用显式有限元计算.结果发现,靶板主要破坏方式为整体塑性变形、剪切撕裂和拉伸断裂;间距较大时双层靶板的弹道极限速度随间距的增加而增大;前靶板厚度比例较小或较大时弹道极限速度较大;单层靶板的抗击穿能力优于厚度均布的双层靶板.因此,通过对双层靶板的厚度和间距进行合理的搭配,能达到比同等厚度的单层靶板更好的抗击穿性能. 

Numerical simulation of the disk fragment impacting resistance of plate target

The aero-engine casing structure must be able to withstand the large dynamic impact ultimate load generated during a disk burst accident. In order to investigate the ballistic resistance and failure pattern of the casing with the impact of disk fragment, find out structure optimize method, the phenomena of 1/3 disk fragment impacting on single and double layers plate target are simulated using nonlinear dynamical analysis software Dytran. Johnson-Cook material model was introduced for the disk fragment and the plate target, along with Gruneisen equation of state. Impaction was based in Lagrange method, and simulated using explicit FEM. Simulation results show that the major failure patterns of the plate target are plastic deformation, shear and tensile fracture, and that the single-layer plate has greater resistance than any other double-layered plates in contact or with standoff distance, with thickness of each plate both half of the single-layer plate. Conclusions are also made that the ballistic limit velocity increases with the distance when it is beyond a certain value, and that the greater resistance is obtained in low or high proportion of the first layer with a constant of the total thickness. So that, resistance of double-layered plate targets may exceed that of the single plate, by reasonably arranging the thickness and the standoff distance of two plates.