Finite element simulation of 3D drilling in unidirectional CFRP composite
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Drilling is probably the most important conventional mechanical process and it is the most widely used machining operations. Prediction of cutting forces for any set of cutting parameters is essential in optimal design and manufacturing of products. It has been predicted that most of the problems associated with hole making operation, such as drilling, can be attributed to the force generated during cutting operation. In addition, prediction of force helps in design and evaluation of cutting tools and fixtures. The drilling of unidirectional carbon epoxy composite using conventional simple flute twist drill with/without the effect of chisel edge is analyzed. In this study, a series of drilling experiments are conducted on carbon fiber-reinforced composite laminates to determine quantitatively the effect of the chisel edge on the thrust force. In addition, tests are conducted to determine the effect of pre-drilling the laminate with a pilot hole. The results show a large reduction in the thrust force when a pilot hole is present which, in effect, removes the chisel edge contribution. An explicit finite element technique employing an Arbitrary Eulerian Lagrangian (ALE) is used in developing a finite element simulation of a 3Ddrilling process, one of the most complex material removal processes. In these simulations the work piece material and the air surrounding it are modeled using ALE elements. The generation of forces can be tracked using this tool. This objective of this thesis is finite element modeling of cutting forces and measuring the cutting forces generated during 3D-drilling process and comparing the forces with the experimental results. The results on the forces are found to be comparable between the FEA and experimental values. The work also discusses the challenges and methodology of using the LS-DYNA ALE capability for the drilling simulation.
Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering.
Includes bibliographic references (leaves 85-89)