Abstract
The quantitative assessment of the effect of the residual stress on fracture behavior was executed by some experiment and numerical analysis. First of all, artificial residual stresses were imposed on CT(Compact Tension) specimens by local heating using gas torch, and an appropriate distribution of residual stresses was obtained by thermal elastic-plastic FE analysis. To certify the result of the FE analysis, an experimental measurement was performed in accordance with ASTM standard. Fracture toughness test was executed on the several types of specimens. The first type was the specimen without residual stresses, and the others had different peak value of compressive residual stress at crack front via controlling the heat flux. All the test results were presented on th J resistance(JR) curves and discussed to verify the effect of compressive residual stresses on fracture behavior.
잔류응력이 판의 파괴 특성에 미치는 영향의 정량적 평가를 위하여, 균열이 존재하는 CT(Compact Tension) 시편에 가스 토오치 (gas torch)를 이용한 국부 가열을 실시하여 인위적인 잔류응력을 생성시키고, 열탄소성 유한요소해석을 통하여 생성된 잔류응력장을 평가하였으며, 잔류응력이 존재하는 시편과 잔류응력이 존재하지 않는 시편에 대한 파괴인성 실험을 실시하여 이들의 결과를 파괴저항 선도 상에서 비교, 분석함으로써 압축 잔류응력이 파괴 특성에 미치는 영향을 정량화하였다.