论文部分内容阅读
基于非局部近场动力学(PD)理论,在常规微弹脆性(PMB)本构模型基础上,引入能够反映物质点间作用强度随物质点间距变化规律的核函数修正项,以提高PD方法的定量计算精度;并通过附加物质点转动自由度建立以双参数描述的PD微极模型,突破了常规单参数PMB本构模型的泊松比限制等缺陷。通过引入动态松弛算法和粒子系统失衡力准则等系列数值算法,构建了能够自然模拟准脆性裂纹扩展全过程的PD算法体系。经典悬臂梁挠度曲线计算结果表明,本文模型和算法的定量计算误差小于3.5%,对含切口三点弯梁的裂纹扩展过程模拟结果与试验结果吻合。通过改变加载位置和初始裂纹位置,对三点弯梁的破坏模式和承载能力进行了分析。结果表明,裂纹始终由初始裂纹位置向加载位置扩展,且初始裂纹位置和加载位置越靠近三点弯梁中部时,结构的承载能力越低。
Based on the non-local near-field dynamics (PD) theory, based on the conventional micro-brittleness (PMB) constitutive model, a kernel function correction term that can reflect the variation of the interaction intensity between material points with the material point spacing is introduced to improve the PD method The PD microdropotential model described by two parameters was established by the degrees of freedom of additional material point rotation, which broke through the Poisson’s ratio limitations of the conventional single-parameter PMB constitutive model. By introducing a series of numerical algorithms, such as dynamic relaxation algorithm and particle system unbalance force criterion, a PD algorithm system that can simulate the whole process of quasi-brittle crack propagation is constructed. The calculation results of the classical cantilever deflection curve show that the quantitative error of the model and algorithm in this paper is less than 3.5%. The simulation results of the crack propagation process of the three-point curved beam with notch coincide with the experimental results. By changing the loading position and initial crack location, the failure modes and carrying capacity of the three-point bending beam are analyzed. The results show that the cracks always extend from the initial crack location to the loading location, and the closer the initial crack location and the loading location are to the middle of the three-point bending beam, the lower the carrying capacity of the structure.