动载作用下复合型裂纹扩展的近场动力学模拟

Peridynamic study on mixed-mode crack propagation under dynamic load

构建改进的非局部近场动力学模型和粒子系统动力加载算法,开展复合型裂纹动力扩展过程模拟。在常规近场动力学微极模型中引入能反映非局部长程力尺寸效应的核函数修正项,以提高计算精度和收敛稳定性。通过模拟动载作用下含复合型裂纹混凝土三点弯梁的裂纹扩展与破坏过程并与试验结果对比,验证了本文模型和算法的可靠性。在此基础上,通过分组模拟分析了动载作用下,初始裂纹的位置、长度和方向对含复合型裂纹三点弯梁破坏模式、起裂时间与承载能力的影响规律。

An improved nonlocal peridynamic model and corresponding dynamic loading algorithms for a particle system have been proposed to simulate mixed-mode crack propagation subjected to dynamic load.A kernel function which could describe the internal length effect of long-range forces was introduced into the regular micropolar peridynamic model in order to improve the calculation accuracy and stability.The model was validated by analyzing the failure of a single-notched three-point bending concrete beam subjected to dynamic load and comparing the simulation results with experiments.A further investigation was taken into the effect of the location and orientation of the crack on the failure mode,cracking time and failure load of the three-point bending beam with pre-existing mixed-mode crack subjected to dynamic load.