The Thermal Fracture Technique on Laser Cutting of Brittle Materials

• Main Authors: Tzu-hsiang Lin, 林子翔
• Other Authors: Jao-hwa Kuang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/75850974365441636175

碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 98 === The finite element method has employed to simulate the laser thermal cracking process for brittle materials. The varieties of temperature and thermal stress distributions around the crack tip were studied. The effect of cracking parameters, i.e. laser power, focus moving speed, plate thickness, crack length, cooling effect… etc., on the crack propagation has also investigated. The stress intensity factor around crack tip is considered as the key parameter to dominate the crack propagation. The thermal-plastic-elastic finite element model was employed to simulate the temperature and stress distributions. The strain energy release rate and stress intensity factor solved from virtual crack closure technique and displacement extrapolation method are employed to illustrate the crack state in this study. Five crack length models were used to show the stress intensity factor variations around the crack tip. Numerical results indicate that the head flux on the surface, substrate thickness and adopting cooling sources may affect the crack propagation, crack delay significantly. The results in this study also demonstrate the feasibility of employing finite element method in the exploring crack propagation mechanism in laser thermal cracking process.