基于断裂相场的高分子黏结炸药裂纹演化及其力学性能退化分析

Analysis of crack evolution and mechanical properties degradation ofpolymer bonded explosives based on phase -field fracture

为了解高分子黏结炸药裂纹演化过程及其力学行为,综合考虑弹性、黏性以及热特性的影响及作用机制,提出了该材料热黏弹性断裂相场模型。基于断裂相场,建立了热黏弹性体的单一单元模型,对不同温度和应变率进行参数分析。然后,针对高分子黏结炸药开展该材料断裂相场的模拟及其模型参数校准。从而基于断裂相场在细观层面上阐明不同应变率、不同环境温度作用下高分子黏结炸药材料的裂纹演化及其力学性能退化的规律。结果表明,驱动断裂的能量和抗压强度随着应变率降低和温度的升高而呈现出减小的趋势,因此裂纹出现的时间越晚,扩展速度越慢。

In order to analyze the crack evolution process of polymer-bonded explosives (PBXs) and their mechanical behavior,a thermal-viscoelastic phase-field fracture model is proposed by considering the influence and mechanism of their elastic,viscous and thermal properties.Based on the proposed phase-field fracture model,a one-element model of the thermal-viscoelastic material is established,and the parameters are analyzed for different temperatures and strain rates.Then,based on the PBX,the simulation of the fracture phase field is performed and the model parameters are calibrated.Thus,based on the fracture phase field,the crack evolution of PBX material and its mechanical property degradation are further clarified from the meso-scale level under different strain rates and different ambient temperatures.The results show that the fracture driving energy and compressive strength tend to decrease with decreasing strain rate and increasing temperature,which delays the crack occurrence and the impede the crack propagation.