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Development of Finite Element Ductile Tearing Simulation Model Considering Strain Rate Effect

변형률 속도를 고려한 유한요소 기반 연성 찢김 해석 기법 개발

  • Received : 2015.08.19
  • Accepted : 2015.12.07
  • Published : 2016.02.01

Abstract

This paper proposes ductile failure simulation under high strain rate conditions using finite element (FE) analyses. In order to simulate a cracked component under a high strain rate condition, this paper applies the stress-modified fracture strain model combined with the Johnson/Cook model. The stress-modified fracture strain model determines the incremental damage in terms of stress triaxiality (${\sigma}_m/{\sigma}_e$) and fracture strain (${\varepsilon}_f$) for a dimple fracture using the tensile test results. To validate the stress-modified fracture strain model under dynamic loading conditions, the parameters are calibrated using the tensile test results under various strain rates and the fracture toughness test results under quasi-static conditions. The calibrated damage model predicts the CT test results under a high strain rate. The simulated results were then compared with the experimental data.

본 논문은 유한요소해석을 이용한 고변형률 조건에서의 연성파손 해석기법을 제안한다. 고변형률 하중이 작용하는 구조물에 대한 파괴거동 예측을 위해 본 논문에서는 Johnson/Cook 모델을 고려한 수정응력 파괴변형률 모델을 사용하였다. 제시된 모델은 인장 실험 모사해석결과로부터 얻어지는 삼축응력 및 파괴변형률에 의해 파손이 정의된다. 다양한 실험속도의 인장 실험결과 및 정적 하중조건에서의 파괴인성 실험을 이용하여 수정응력 파괴변형률 모델의 변수를 결정하였다. 결정된 모델을 이용하여 동적하중조건에서 파괴인성시편에 대한 해석을 수행하였으며 해석결과와 실험결과를 비교하여 해석기법을 검증하였다.

Keywords

References

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