軟鋼の衝撃弾塑性破壊靱性に関する研究 : 第1報,衝撃荷重における三点曲げ試験片のき裂先端近傍の変形解析

概要

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In this paper we describe a basic experimental study of the deformetion and strain in the vicinity of the crack tip under impact loading in an attempt to clarify the dynamic fracture mechanism of mild steel. The experimental apparatus was developed using an air gun for the high-speed three-point bend test which allowed the measurement of the displacement rate of the load point. We developed a new and simple method of measuring the displacement rate using a sliding variable resistor. The three-point bend tests were performed using the above apparatus with a high-speed impact load. Three-dimensional FEM calculations were performed to compare the experimental results with the simulated results. In the simulation computation of three-dimensional FEM, the constitutive equation of Johnston-Gilman type was proposed by the authors and has been used. Additionally, the dynamic responses of strain in the vicinity of the crack tip and the values of crack tip opening displacement (CTOD) were shown by both numerical calculations and experimental results. Finally, taking into consideration the FEM calculation results, we discussed the behavior of deformation near the crack tip.
1994-09-25