熱彈塑性及多軸疲勞理論應用於銲接結構疲勞壽命評估之研究

An Application of Thermal Elasto-Plastic and Multiaxial Fatigue Theory to the Welded Structure on Fatigue Life Prediction

鄧作樑(Tso-Liang Teng) ； 馮君平(Chin-Ping Fung) ； 張鵬祥(Peng-Hsiang Chang)

《中國航空太空學會學刊》 34卷4期 (2002/12) Pp. 319-329

https://doi.org/10.6124/TAASRC.200212_34(4).04

摘要

銲接結構於銲後產生之殘留應力由於受到後續實際疲勞負荷時會使得結構應力、應變歷程變得更複雜，若以單軸疲勞理論來作壽命預測，將過度簡化了元件的負荷狀態，不無日沃代表銲接結構實際狀況，故本文以熟彈塑性理論（考慮熱、結構分析模式）、多軸疲勞理論、有限元素法並整合疲勞壽命分析方法（累積損傷理論、雨流法），建立一套有效的銲接結構裂縫起始壽命分析程序，並利用Lawrence等針對平板對接銲及修補銲結構疲勞試驗之實驗結果，來驗證本文所建立之銲接結構疲勞壽命評估程序的正確性及適用性，另外將本文評估方法與BS 5400、AASHTO規範評估結果比較，顯示本文評估法較接近實驗值。

關鍵字

熱彈塑性理論 ； 殘留應力 ； 裂縫起始壽命

並列摘要

In many applications, welding components are subjected to complicated states of stress and strain which due to complex loading and welding residual stresses. Fatigue under these conditions, termed multiaxial fatigue theoic is an important design consideration for reliable operation of many welding components. This investigation develons an effective procedure by combining the thermal elastio-plastic theory, multiaxial fatigue theory and finite element methods to predict fatigue crack initiation (FCI) life in weldments. Herein, the FCI lives of butt weld joints and path weld are forecast using the proposed procedure. Furthermore, the FCI life predictions made herein are compared to those of the BS 5400, AASFITO standard specifications, and the Lawrence's summary experimental results. Comparative results demonstrate that fatigue life estimates made using the novel procedure closely approximate experimental results.

並列關鍵字

Thermal elasto-plastic analysis ； Residual stress ； Fatigue crack initiation life