精密剪斷之有限元素分析

Abstract

對於精密剪斷加工特有的缺陷，本論文以有限元素法為基礎，根據Cockroft-Latham’s破壞準則提出一個評估破壞型態改變的判斷方法。本研究使用有限元素分析軟體ABAQUS模擬精密剪斷的斷面形狀，探討沖頭、模具圓弧半徑的改變對工件斷面形狀的影響。分析結果顯示，此方法判斷的剪斷面與破斷面交界位置與文獻的實驗結果相當接近，荷重與圓弧半徑的模擬結果得知，荷重的增加對於精密剪斷的破斷面所佔比例的減少是有利的，而尖銳的沖頭與模具反而造成負面的效果。

The main objective of this research is to study the defects appeared on shearing surface of fine blanking. Based on finite element analysis and Cockroft-Latham’s criterion, the study proposed an estimated method for distinguish of the shear and fracture zone on shearing surface. The finite element code ABAQUS was used to simulate the fine blanking shear surface characteristics. It was shown that the predicted shear and fracture zone percentage on shear surface had a good correlation to experimental results. Furthermore, increase of blank holder load is benefit to the reduction of the percentage of fracture surface proportion while sharp punch and die has negative affects to fine blanking parts.