承受內壓力管螺紋接頭強度之模擬分析

Simulation Analysis on Strength of Threaded Pipe Connectors under Internal Pressure

鍾明翰(Ming-Hung Chung)

指導教授 ： 陳政順

國立臺北科技大學/機電學院/製造科技研究所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00040

摘要

管螺紋接頭常用於管件接合，往往需輸送高壓液體及氣體，在螺紋連接處會產生應力集中而使連接強度相對於其他部位較為脆弱，故螺紋連接處之強度成為整體結構是否失效的重要關鍵。本文針對1 1/4 PT，材料為鋁合金6061-T6之管螺紋接頭，於鎖緊後螺牙承受內壓負載之破壞模擬分析；利用非線性有限元素方法進行應力應變模擬分析，探討管螺紋在預緊力作用及承受內壓負載時，其螺牙及附近部位的應力應變等機械行為。在本個案中，分析結果顯示，公、母螺紋管承受內壓負載達41.37MPa時，在螺牙部位之等效應力超越材料之降伏強度而產生永久變形，其等效應變接近0.025。經由實驗測試，在此壓力下，於螺紋接合處也開始產生破裂，同時，透過接觸應力分析可知，管螺紋接頭鎖緊之最末牙牙根處因應力集中問題，所產生之應力值最大，成為影響整體系統強度之關鍵。

關鍵字

管螺紋接頭 ； 有限元素法 ； 應力分析

並列摘要

Threaded pipe connector is commonly used in jointing pipelines which are found in the high pressure liquid and gas transportation. At the thread joints, the stresses and strains are easily raised and weaken the strength of pipe systems due to such kind of stress concentration effect. Therefore, it is essential to analyze and understand the mechanical responses around the threaded portion of pipe to avoid the structural failure. This paper is mainly focus on stress and strain analysis of threaded pipe connector made of Al 6061-T6 material(1 1/4PT) under pre-load and internal pressure loading. In this study, nonlinear finite element method was used to simulate the stress-strain behavior of the threaded. In this case study, the results showed that the equivalent stress was larger than the yield strength of natural, and the parts defeat occurred, the equivalent strain was around 0.25 at the threaded portion when the threaded pipe connectors under internal pressure loading around of 41.37MPa. The experimental test also showed that the crack was found at threaded ports of pipe under the internal pressures of 41.37MPa. It was also found that the maximum normal contact stress generated at the root of the last tooth of thread and was the critical portion of threaded pipe connectors subjected to internal pressure.

並列關鍵字

Threaded pipe connector ； Finite element method ； Stress analysis

參考文獻

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