几何非线性问题的能量原理及有限元增量格式

ENERGY PRINCIPLES AND FINITE ELEMENT INCREMENTAL FORMULATION FOR GEOMETRIC NONLINEAR PROBLEMS

  • 摘要: 几何非线性问题的数值解法是计算力学课程的重要内容。本文通过发展广义的大变形度量,分别构建了几何非线性问题的能量原理及有限元求解格式的统一表达。将物体参考构形区分为未知与已知平衡构形,阐明了虚位移原理、虚功率原理与增量虚位移原理,完全拉格朗日格式与更新拉格朗日格式,先线性化后离散与先离散后线性化,全量、增量与率本构关系等各原理与格式之间的相互关系。本文表达方式清晰统一,便于讲授、学习、理解和应用。

     

    Abstract: The numerical methods for geometric nonlinear problems are important topics in computational mechanics course. In this paper, the measurements of large deformation are generalized and developed, and a unified derivation and expression of the energy principles and the finite element solution formulations for the geometric nonlinear problems is established. The reference configurations of the deformable body are distinguished as the unknown and known equilibrium configurations. The relationships among some principles and formulations are clarified, including the principles of the virtual displacement, the virtual power, and the incremental virtual displacement, the total Lagrangian formulation and the updated Lagrangian formation, the solution strategies of linearization followed by element discretization and element discretization followed by linearization, and the constitutive equations with the total, incremental and rate variables. This paper provides a clear and uniform expression of the energy principles and the finite element solution formulations for the geometric nonlinear problems, which is convenient for teaching, learning, understanding and application.

     

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