静的複数荷重システムによる高速き裂進展現象に関する研究

概要

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In some experimental studies for dynamic crack propagation, crack propagation velocities greater than 60% of shear wave velocity of the material have been observed. Mechanism of these fast crack propagations has not been clarified.In this experimental study, the cracks were critically accelerated by using a multi-loading system. One of the crack propagation velocities reached 74% of the shear wave velocity. Furthermore, the distributions of principal stress gradients near the propagating crack tip are observed using the Coherent Gradient Sensing method. Based on these stress gradient distributions, dynamic stress intensity factors for fast propagating crack tip are estimated.Two and three dimensional numerical simulations for these fast crack propagations are performed to estimate fracture energy flow and other parameters. The generation phase numerical simulations are achieved based on the experimental results, which are loading histories and crack propagation history. Energy flow to crack tip are visualized by 2-D numerical simulation. In 3-D numerical simulation, the relationship of 3-D fracture roughness and Φtotal parameters are obtained. The increase of the dynamic stress intensity factor with the increase of crack propagation velocity is measured in numerical simulations.
日本実験力学会の論文