弹塑性梯度材料热机耦合分析的有限元方法

陶瓷/金属功能梯度材料(FGMs)的组份及性能梯度分布,在航空航天高温热结构中有重要应用。材料性能在空间上的连续变化给这类结构强度设计的有限元分析造成了一定困难,针对上述问题,提出一种热弹塑性梯度有限元方法。该方法通过编写有限元软件ABAQUS的材料用户子程序(UMAT)来实现,在UMAT中将FGMs的弹塑性本构模型参数定义为空间坐标的函数;用热弹塑性梯度有限元方法对陶瓷-FGMs-金属典型的三明治板结构进行热机械分析。结果表明:FGMs组分布函数对其热应力分布有很大的影响,特别是在三明治结构的界面上,影响更为突出,这和现有文献的实验结果相符。

Graded finite element method for mechanistic analysis of heterogerous structure

In this paper, the developments of functionally graded materials and graded finite elements are reviewed. By taking into account of thermal and plastic behaviours of materials, a thermo-elasto-plastic graded finite element method has been derived. The method, being capable of describing spatially varying material properties, has been implemented in the commercial finite element code ABAQUS by using user-defined material subroutines for solving engineering problems. To illustrate the applicability of the method, a case example has been preformed to study the mechanical response of a ceramic-FGMs-metal sandwich structure. The merits of the method have discussed on the basis of the numerical results. Further developments of the method would be useful for skeletal muscle simulation.