Chapter 2: basic theories about finite element method are introduced, basic formulas about elastic-plastic finite element method and elastic-plasticmatrix are put forward.
第二章介绍了有限单元法的基本原理，详细推导了弹塑性有限元法的基本公式和弹塑性矩阵。
2
This paper presents a simplified plastic zone method with consideration of the influences of the plastic zone length on the stiffness matrix for elastic-plastic analysis of steel frames.
对于杆件单元，本文采用了一种变刚度的杆单元模型，建立了考虑塑性铰分布长度影响的构件单元刚度矩阵。
3
An explicit expression of stiffness matrix for a 3-dimensional beam made of elastic-plastic material is derived in the paper.