| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 93 === The forgeability of a material is a good indicator when evaluating different materials for industrial use. Normally, upsetting tests can help to create the forming limit diagram (FLD) of a material, which shows the forgeability of a material in various strain paths. Experimental results show that after large deformation, fractures do not occur on a free surface when testing materials with high ductility. Therefore, a notched upsetting test is proposed in this thesis. Applying notch designs on specimens would help to accelerate the fracture initiation. With different notch designs on a specimen, one can obtain different acceleration effects on the specimen. Also, compared to the specimen without notch design, various notch designs on the specimen would lead to different concentration effects on energy consumption. These concepts and results were demonstrated and supported by the results from finite element analysis, and were verified by notched upsetting tests. An indicator called the Energy Consumption Rate (ECR) was proposed for evaluating the effect of notch designs, and it showed good capability for forgeability evaluation.
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