Three dimensional fracture mechanics computations using tetrahedral finite elements

With the development of CAD packages which can create complicated 3-D models and mesh them with tetrahedral elements with relative ease, the application of finite element techniques in mechanical design has reached unprecedented proportions. However, the extension of these techniques to fracture mechanics studies is hindered by the unavailability of a general method to obtain fracture mechanics singularity strength (J, K, etc.) for tetrahedral meshes. An approach to obtain these parameters along a 3-D crack front using tetrahedral elements is presented here. The method is then validated on well-known crack geometries using tetrahedral meshes generated from commercially-available CAD-FEA packages , both elastic and elastic-plastic problems. Thesis Supervisor: David M. Parks Title: Professor of Mechanical Engineering Acknowledgments I wish to express my sincere gratitude to Prof. Parks for his constant support, encouragement and insightful guidance during my stay here at MIT. I have gained a lot from interacting with him and thoroughly enjoyed working with him. I also wish to thank Prof. McClintock for his advice on various aspects of fracture mechanics and above all for his patience and suggestions. A large share of my thanks goes to Dr. Simona Socrate, my co-advisor in this work. I admire her perseverance and penchant for perfection and working with her has been a memorable experience. Special thanks to Ray Hardin for taking care of many administrative details. Thanks to Tom, Kevin, Gu, Jorgen, Clarence, Steve, Yioula, Ethan, Brian, Prakash and other Mechanics and Materials lab mates Rami, Heather, Jeremy, Greg, Jennifer, Hyung-Soo and Yu for making my stay at MIT a wonderful experience. My friends Mahadevan, Venkatesan, Sreeram and other IITians have helped me a lot in feeling at home in the other side of the globe. I am indebted to my parents for their constant support and motivation all through my life. This work was supported by the D.O.E under grant number DE-FG02-85ER13331 to MIT.

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