含能单晶微纳米力学性能试验研究及数值表征

利用微纳米压痕实验测定β-HMX 单晶(010) 晶面和α-RDX 单晶(210) 晶面的力学性能参数和微观破坏特征,并利用数值拟合确定了含能单晶的部分本构参数. 通过微纳米压痕实验连续刚度法(CSM) 得到HMX 单晶和RDX 单晶的弹性模量和硬度,RDX 单晶的硬度和模量都大于HMX 单晶,其硬度值均表现出一定的尺寸效应. 利用原子力显微镜(AFM) 分析了HMX 单晶和RDX 单晶的微观破坏机理,裂纹随着载荷的增大生成并扩展,裂纹面产生方向为晶体的最易解理破坏方向. 利用ABAQUS 有限元软件进行了纳米压痕数值模拟,结合微纳米压痕实验加卸载曲线,选取了合适的含能单晶塑性损伤本构模型的损伤本构参数. 

NANOINDENTATION EXPERIMENTS AND SIMULATIONS STUDIES ON MECHANICAL RESPONSES OF ENERGETIC CRYSTALS

Nano-indentation experiments and numerical simulations using ABAQUS software are performed to investigate the mechanics responses of energetic crystals. Continuous stiffness method based nano-indentation tests was employed to obtain the elastic modulus and hardness of β-HMX crystal (010) face and α-RDX crystal (210) face. The modulus and hardness can be induced from the load-displacement curves. The hardness value of the energetic crystals shows size effect. Microstructure fracture behaviors were analyzed using atomic force microscope (AFM) observations. It has been found that cracks initiate and expand with the increase of load force. The direction of the crack is also the cleavage direction of the energetic crystal. The finite element code ABAQUS is applied to simulate the nano-indentation experiments. Some parameters measured by the experiment have been used in validating the damaged plasticity constitutive model parameters for finite element simulations. The consistency between the experimental and the numerical simulated results is strong evidence for verifying the damaged plasticity constitutive model. The results presented here may be crucial in predicting the ignition mechanism of energetic crystals.