選擇性雷射熔融積層製造試片其破裂韌度量測與模擬驗證

Measurement and Simulation Verification of Fracture Toughness for Additive Manufacturing Specimens by Using Selective Laser Melting Process.

彭立函(Li-Han Peng)

指導教授 ： 李昌駿

國立清華大學/工學院/動力機械工程學系/碩士(2020年)

摘要

選擇性雷射熔融製程為金屬積層製造之一具有前瞻性之關鍵技術。因其擁有高自由度之製造特性，得以適用複雜幾何形狀設計之生產，故於航太與汽車工業等領域有良好的應用。此外，由於選擇性雷射熔融製程之獨有特點，其工件內部產生極高的溫度梯度，同時引致過大的殘留應力，故導致工件易發生脫層或是翹曲之現象。有鑑於此，本研究藉由製程導向之有限單元法分析方法，確立一熱機械順序耦合模擬技術之可行性，同時，以修正之熱源數學模型作為選擇性雷射熔融製程之發熱來源，用以模擬積層材料Inconel 718之機械響應，而藉由實驗量測得以驗證，以確認此模擬方法之正確性。另一方面，本研究亦使用選擇性雷射熔融製程完成三點彎曲破裂韌性試驗試片，並進行三點彎曲實驗，量測其破裂韌度，並以前述驗證之模擬方法分析其破裂韌度估算值結果進行比較，進一步驗證此研究模擬方法之實際適用性。

關鍵字

選擇性雷射熔融 ； 等效體積熱源 ； 三點彎曲測試 ； 破裂韌度

並列摘要

The selective laser melting process is one of the forward-looking technologies in metal additive manufacturing. Because of its high degree of freedom of manufacturing characteristics, it can design the product of complex geometric, and it has good applications in aerospace and automotive industries, too. In addition, due to the unique characteristics of the selective laser melting process, extremely high temperature gradients are generated inside the specimen, caused the excessive residual stresses, delamination and warpage of the specimen. In the light of this, this research uses a process-oriented finite element method analysis method to establish the thermo-mechanical sequential coupling simulation technology which use the modified heat source. The mechanical response of the Inconel 718 specimen manufactured by selective laser melting process was simulated. Then the value figured out by simulation method was verified by experimental measurements to confirm the correctness of the simulation method. On the other hand, this study also used the selective laser melting process to manufacture the three-point bending test specimen, and figure out the fracture toughness of the specimen. Using the aforementioned verification simulation method to figure out the estimated fracture toughness results and compared to the experimental value to further verify the practical applicability of the simulation method of this study.

並列關鍵字

Selective Laser Melting ； Equivalent Volume Heat Source ； Three-Point Bending Test ； Fracture Toughness

參考文獻

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