可變形切削刀具的正交金屬切削之熱固耦合有限元素分析模型研究

A Coupled Thermal and Mechanical Finite Element Model of Orthogonal Metal Cutting with Deformable Cutting Tools

林煜銘(Yu-Ming Lin)

指導教授 ： 戴兢志

大同大學/工程學院/機械工程學系所/碩士(2009年)

摘要

本研究應用有限元素分析軟體ANSYS/LS-DYNA，建立一套以Lagrange運算法為基礎，具有熱固耦合的金屬正交切削有限元素分析模型，模型中刀具材料為碳化鎢，工件材料為AISI 4340鋼，且兩者均視為可變形體，材料模型的建立均採用Johnson and Cook的動態構成方程式。切屑剝離準則採用以材料的破壞應變值作為判斷依據的元素破壞法。
建立後的模型可以模擬刀具對工件的正交切削過程，包含切屑的形成機構以及刀具的受力及溫度分佈。在形成的切屑與刀具的各項分析結果顯示，此模型分析結果與實際切削結果的趨勢相當接近且與金屬切削理論相符。本研究探討切削速度與刀具斜角等因素對金屬正交切削過程的影響。

關鍵字

有限元素分析 ； 金屬正交切削過程 ； 熱固耦合模型

並列摘要

In this research, commercial finite element software ANSYS/ LS-DYNA is used to establish a coupled thermo-mechanical model based upon Lagrange formulation to simulate the orthogonal metal cutting processes. The materials used for cutting tool and workpiece in the model are tungsten carbide and AISI 4340 steel, respectively. Both of them are modeled by the Johnson and Cook dynamic constitutive material equation. Cutting tool is modeled as a deformable body, but not rigid body. This will facilitate understanding the behavior of the cutting tool while machining. The element failure law based upon a failure strain for a material is used for the chip separation criterion.
The simulated model can be implemented to explore the variations during orthogonal metal cutting process, including the chip formation mechanism and the distribution of stress/strain and temperature on the tool, chip and workpiece. The simulated results are quite close with the trend of the cutting results actually and agree well with theory of metal cutting. This research probes into the cutting speed and rake angle of the tool to analyze influence on the orthogonal metal cutting process.

並列關鍵字

Finite element simulation ； Orthogonal metal cutting process ； Coupled thermal-mechanical model

參考文獻

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