Rationalization in Deriving Element Stiffness Matrix by Assumed Stress Approach

Abstract

From the principle of minimum complementary energy, which is extended to take into account the possible discontinuity in stresses or displacements along the interelement boundaries, the finite element methods by both the assumed stress hybrid model and the equilibrium model can be formulated. This formulation enables the development of a rational method for consistent lumping of body and surface forces and the establishment of a criterion for the kinematical instability of a system. For the hybrid model, there is an optimum choice of the number of stress modes for a given boundary displacement approximation. Example calculations for plate-bending problems are included to substantiate the analytical predictions. Examples are also carried out to illustrate the convenience in taking transverse shear effects into account by the hybrid method.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1968
Accession Number
ADA447742

Entities

People

  • Pin Tong
  • Theodore H. Plan

Organizations

  • Massachusetts Institute of Technology

Tags

DTIC Thesaurus Topics

  • Abstracts
  • Air Force
  • Air Force Facilities
  • Boundaries
  • Defense Mechanisms
  • Displacement
  • Finite Element Analysis
  • Information Operations
  • Mechanical Properties
  • Mechanics
  • Physics Laboratories
  • Scientific Research
  • Stiffness
  • Structural Mechanics

Readers

  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Structural Dynamics.