Research On Crack And Propagation Of PMMA Material Based On ABAQUS

Accessories with holes are widely used in engineering structure. Cracks regularly appear at the edge of the holes because of stress concentration and the contact between the components and parts in the assembly. PMMA is the most excellent transparent polymer material, which is commonly known as organic glass. It has high mechanical strength, better tensile and compression strength than ordinary glass. And, with respect to the same size of ordinary glass materials, the quality of PMMA can be reduced by more than half. Meanwhile, PMMA also has excellent processing performance, widely used in the field of aviation, machinery and so on. Therefore, in order to ensure the safety of the engineering structure and make full use of the material, it is very important to study the generation and propagation of the hole edge crack.This paper takes PMMA as the subject, the crack stress intensity factors, crack growth and arrest are studied. Firstly, this thesis studied the extended finite element method and analyzed different crack criterion, especially stress intensity factor and maximum principal stress criterion. At the same time, the reliability of crack simulation by ABAQUS is checked by crack simulation under static loading using XFEM.Secondly, in this paper, the influence of the length of the pre-crack, the radius of the circular holes, the width of the specimen and the position of the circular hole on the stress intensity factor of the PMMA plate is studied. Under the static load, by setting crack-stopping holes at the crack-tip, the effect of the stress intensity factor of the crack-stopping holes is studied.Moreover, in this paper, based on the split Hopkinson bar, through experiment and simulation, the dynamic crack propagation of PMMA plate with circular hole is studied, and the simulation results are compared with the experimental results to verify the effectiveness of the simulation model. On this basis, the influence of different radius of circular hole, length of pre-crack, radius of crack-stopping holes and vertical displacement between crack-tip and center of stopping-holes on the crack dynamic propagation is analyzed.Finally, the study is extended to the practical engineering of the windshield bird strike, and in order to study the deformation of the initiation a nd propagation of cracks and windshield, the failure mode of crack in traditional bird impact simulation is introduced.The results of the study showed that the different sizes of specimens have a great influence on the stress intensity factor. During dynamic loading, the radius of circular hole and the length of pre-crack have a significant effect on the crack initiation propagation time. When configuring stopping-hole at crack-tip, crack propagation can be effectively suppressed. Besides, the radius of stopping-holes and vertical displacement between crack-tip and center of stopping-hole will also affect the effect of crack arrest. The research results of this paper have some reference value for the engineering application of PMMA.