说明：  讲述了在ABAQUS内umat的原理，umat接口的注意事项，umat的开发环境设置，主要是理论部分的内容及umat的使用方法，并解释了一部分非线性材料问题。
(This paper describes the principle of UMAT in ABAQUS, the matters needing attention of UMAT interface, the setting of development environment of UMAT, mainly the content of theoretical part and the use method of UMAT, and explains some nonlinear material problems.)