| Summary: | 碩士 === 國立高雄應用科技大學 === 模具工程系 === 103 === In this study, DEFORM 3D software was used to simulate the prediction of different processes of forming boss and rib by press forging blanks and investigate the influences that defects have on the relative ratio of different parts. Simulations were performed to create flow-through, stacked material, and other defects, as well as other forming states, during the formation of different boss and rib on rectangular cases using press forging. When simulating hot forging, the material properties of magnesium alloy AZ31 were obtained from a cylinder compression test. The availability of the material properties was determined by the true stress-true strain curves, which were obtained from the cylinder compression test at different temperatures and under a fixed strain rate. Subsequently, the material library of finite element simulations were inputted to confirm the usability of the material properties.
When simulating boss and rib, press forging simulations were conducted with different relative ratios and different deviations. Then, the influences that different ratios had on flow-through, folding, and changes in forming were analyzed. Finally, different friction factors were employed in the simulations and subsequent formations were observed and used as a reference for assessment.
In terms of the influences of the different boss ratios, results showed that a reduction in the relative diameter ratio effectively improved flow-through, and a reduction in height ratio influenced flow-through depth. In terms of the influences of the different rib ratios, results showed that different relative rib heights influences rib fill, changes in rib length ratio influences the difference in height during rib forming, and adjustments to relative rib thickness ratio influences rib fill. In terms of boss and rib deviation, the folding was significantly larger with the increase in deviation. In addition, the opening of the stacked boss changed with different deviation. With the increase in friction factors, the flow-through and folding were reduced during boss forming. The generation of folding was decreased with a reduced height difference during rib forming. Both the height differences in sidewall and the forming load were increased with the increase in friction factors when forming a rectangular frame.
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