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Analysis of Damaged Material Response Using Unified Viscoplastic Constitutive Equations

통합형 점소성구성식을 이용한 손상재료거동해석

  • 하상렬 (포항공과대학교 대학원) ;
  • 김기태 (포항공과대학교 기계공학과)
  • Published : 2005.02.01

Abstract

In decades, a substantial body of work on a unified viscoplastic model which considers the mechanism of plastic deformation and creep deformation has developed. The systematic scheme for numerical analysis of unified model is necessary because the dominant failure mechanism is the defect growth and coalescence in materials. In the present study, the unified viscoplastic model for materials with defects suggested by Suquet and Michel was employed for numerical analysis. The constitutive equations are integrated based on the generalized mid-point rule and implemented into a finite element program (ABAQUS) by means of user-defined subroutine (UMAT). To evaluate the validity of the developed UMAT code and the assessment of the adopted viscoplastic model, the results obtained from the UMAT code was compared with the numerical reference solution and experimental data. The unit cell analysis also has been investigated to study the effect of strain rate, temperature, stress triaxiality and initial defect volume fraction on the growth and coalescence of the defect.

Keywords

Unified Viscoplastic Constitutive Model;FEM;Generalized Mid-Point Rule;Strain Rate-Dependent Effect;Unit Cell Model

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