基于分形理论和节点分离有限元的泡沫铝防护结构数值仿真研究(英文)

利用数字图像处理技术对泡沫铝截面的分形特征进行了分析,使用对数线性回归方法计算了泡沫铝的分形维数。Serpinski垫片可以被用于泡沫铝截面建模。通过调整迭代次数和分割参数可以获得不同分形维数、不同相对密度的泡沫铝模型。使用节点分离的Lagrange有限元方法对超高速碰撞过程进行了分析,通过将数值仿真结果与实验结果对比表明了建模方法以及仿真方法的有效性。通过数值仿真,获得了等面密度的铝防护板以及泡沫铝防护板的弹道极限曲线。对比表明,泡沫铝板的防护性能明显优于铝板。泡沫铝材料适合应用于航天器防护。

Numerical Investigation of Aluminum Foam Shield Based on Fractal Theory and Node-separation FEM

Fractal feature of aluminum foam (Al-foam) section is analyzed with digital image processing technique, and fractal dimension of Al-foam is evaluated with logarithmic linear regression method. Sierpinski carpet can be used to model Al-foam section. Al-foam with different fractal dimensions and relative density can be obtained by adjusting iteration times and division parameters. Sierpinski sponge is extended from Sierpinski carpet and used to model 3D Al-foam bumper. Node-separation Lagrangian finite element method (FEM) is introduced to simulate the hypervelocity impact (HVI) process. The modeling and simulation method is calibrated by the comparison of numerical results and experimental data. Ballistic limit curves of Al-foam and aluminum alloy bumper with the same areal density are obtained by simulations. The results show that the protection performance of Al-foam bumper is much better than aluminum alloy bumper. Al-foam is well suited for spacecraft shield application.