| Summary: | 碩士 === 淡江大學 === 機械與機電工程學系碩士班 === 98 === The thesis uses dynamic finite element method and continuum damage mechanics to study the tensile fracture in micro sheet metal forming. The tensile load, elongation, fractured surface and deformation history are discussed and compared with the experimental results.
First, instead of using power law for stress-strain curve in Lemaitre damage model, Swift model is applied to re-derive a new elastic-plastic damage model. Secondly, the tensile test of copper foil is conducted according to ASTM E345 standard and the mechanical properties are obtained. Subsequently, the accumulated damage curve of copper foil is generated for the criterion of fracture by the new elastic-plastic damage model.
The experimental results show that the elongation of copper foil specimen at break is 10.993mm. The fractured surface is at the middle of specimen and the direction is approximately horizontal. Besides, the elongation by numerical analysis at break is 11.468 mm and the position and direction of fractured surface are also close to the experimental results. By comparison of numerical and experimental results, it shows that the combination of finite element method and elastic-plastic damage model can be used to simulate the tensile fracture in micro sheet metal forming correctly in the thesis.
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