Crack Growth Behavior Of Glass Materials Under Vibration Conditions By Numerical Simulation And Experiment

SiC ceramics has many outstanding properties, such as high hardness, high thermal conductivity, good heat resistance, low coefficient of thermal deformation, so it become the preferred space reflect lens materical since 1990s.However, SiC mirror inevitably has cracks during the preparation process and follow-up process. In the process of launching to orbit, it will suffer from sinusoidal vibration which caused by the engine thrust ripple and random vibration which caused by the noise during take-off and high-speed flight. In this condition, the inside original cracks usually will grow quicker, and eventually it leads to material fracture. Since this fracture above often occurs suddenly, without any previous signs, and cause irreparable catastrophic accident, it is of great important significance to study on the SiC materials crack propagation behavior under vibration condition.In this paper, brittle materials crack propagation process under vibration condition is analyzed, using the combination method of numerical simulation and experiment. Because it take a long time to study crack growth of SiC matericals under vibration condition, and lots of samples are needed, the cost is higher. Therefore, the typical fragile material glass is selected as research object, and the crack propagation of glass in the vibration condition is studied.Cohesive theory can describe brittle materials damage behavior well, so it is used as the theory basis. In the vibration loading condition, the FE analysis software Abaqus is used to model the two kinds of simulation plans, which are implicit static polynomialФfunction model and explicit dynamics exponentialФfunction model. And the required parameters are selected and calculated. Two-dimensional model is created to simulated glass cracks growth behavior under the vibration, the vibration frequency is between 100rad/s and 1000rad/s, the amplitude is between 1mm and 5mm.The experiment of the glass crack growth under vibration is carried out. The prefabricated crack is created by Vickers hardness tester, sine full-wave vibration is simulation with ZD-TF vibrating table, then analyzing crack propagation behaviour and finally getting how frequency influences crack growth. The crack propagation of SiC materials in the horizontal vibration condition is simulated by three-dimensional model, the frequency is between 100rad/s and 1000rad/s, the amplitude is between 3mm and 5mm. Through calculating the main crack propagation form is summarized, and how vibration frequency, amplitude impact the behavior of crack growth are analyzed. And frequency are 600rad/s, 800rad/s, 1000rad/s, amplitude is 5mm, the angle between crack and vibration direction are 0o, 30°, 45°, 60°, 90°are calculated, getting the rule that the angle between crack direction and vibration direction influences crack growth.