Damage Analysis for Mixed Mode Crack Initiation

Abstract

The paper presents a numerical simulation for mixed mode crack initiation based on the concepts of damage mechanics. A model with two scalar damage variables is introduced for characterization of damage in a material element. Then a tangent modulus tensor is derived for damage-coupled constitutive equations. A failure criterion is developed with the concept of damage accumulation not only to identify the location of damaged element with the crack initiation angle but also to determine the critical load for mixed mode fracture. The damage model developed is incorporated in a general-purpose finite element program ABAQUA through its UMAT subroutine. The finite element program is then used to perform numerical simulation for pre-cracked specimens under monotonic tensile loading. The thin plates are made of aluminum alloy and particulate composite embedded with a crack of inclined angle Beta = 0 deg, 30 deg, 45 deg and 60 deg for mixed mode fracture analysis. The predicted crack initiation loads and the angles of crack initiation agree well with the test results.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2000
Accession Number
ADA408454

Entities

People

  • C. L. Chow
  • Chun Ting Liu
  • Yuting Wei

Organizations

  • Air Force Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Air Force
  • Air Force Research Laboratories
  • Aluminum Alloys
  • Composite Materials
  • Computational Science
  • Constitutive Equations
  • Coordinate Systems
  • Crack Tips
  • Engineering
  • Material Degradation Processes
  • Materials
  • Mechanical Properties
  • Mechanics
  • Modulus Of Elasticity
  • Numerical Analysis
  • Simulations
  • Stresses

Fields of Study

  • Engineering

Readers

  • Computational Fluid Dynamics (CFD)
  • Materials Science (Mechanical Engineering).