本研究利用以有限元素ANSYS模擬局部圓錐形凹槽對管路彎頭在循環負載下行為的影響，材料上選用許多科技廠房在運輸原料管路上常使用的SUS316不鏽鋼，並以局部圓錐形凹槽的深度變化與夾角變化為模擬條件，探討循環負載下局部圓錐形凹槽尖端的應力與應變。在凹槽深度方面，本研究考慮由0.1 mm開始，以每0.1 mm開始增加至0.5 mm，共五種深度變化，而在凹槽夾角方面，本研究考慮由15°開始，以每7.5°增加至82.5°，共十種角度變化，以深度變化與角度變化的組合共計包含50種模型。由模擬的結果可以分為彈性結果與塑性結果兩部分進行說明。首先彈性結果部分，在彈性循環負載凹槽深度變化條件下可以發現，夾角越小的凹槽，其最大應力與最大應變的變化就越大。而在彈性循環負載凹槽夾角變化條件下可以發現，深度越深的凹槽，其最大應力與最大應變的變化就越大。此外在彈性循環負載條件下可以進一步發現，對於最大應力與最大應變的變化來說，凹槽夾角較凹槽深度的影響大。接下來塑性結果部分，在塑性循環負載凹槽深度變化條件下，夾角越小的凹槽，其最大應力與最大應變的變化就越大。而在塑性循環負載凹槽夾角變化條件下，深度越深的凹槽，其最大應力與最大應變的變化就越大。此外相較於彈性負載條件，在塑性循環負載條件下，凹槽深度與凹槽夾角對於最大應力與最大應變變化的影響都不大。

In this study, ANSYS is used to simulate the behavior of the local conical groove on pipe elbows under cyclic load. The material is SUS316 stainless steel, which is commonly used in the pipelines of transportation in many factories. The depth changes and the angle changes of the local conical groove are the simulation conditions. The depth changes and the angle changes are the simulation conditions to discuss the stress and strain at the tip of the local conical groove under cyclic load. The depth changes of the local conical groove starts from 0.1 mm and increasing every 0.1 mm to 0.5 mm, a total of five depth changes. And the angle changes of the local conical groove starts from 15° and increasing every 7.5° up to 82.5°, there are total ten angle changes. There are total fifty models. The simulation results can be divided into two parts: elastic and plastic results. In the elastic results, it can be found that the smaller angle of the groove leads to the greater change in the maximum stress and the maximum strain under the condition of changing the groove depth and the elastic cyclic load. Under the condition of changing the angle of the groove and the elastic cyclic load, it can also be found that the deeper groove leads to the greater change in the maximum stress and the maximum strain. In addition, under the elastic cyclic load, it can be further found that changing angle of the groove has a greater influence than changing the depth of the groove. In the next part of the results, under the condition of changing the depth of the groove and the plastic cyclic load, the smaller angle of the groove leads to the greater change in the maximum stress and the maximum strain. Under the condition of changing the angle of the groove and the plastic cyclic load, the deeper groove leads to the greater change in the maximum stress and the maximum strain. In addition, compared with the result of elastic load, changing the groove depth and changing the groove angle have little influence on the maximum stress and maximum strain changes than that under the plastic cyclic load.

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