焊接坡口形狀與殘余應(yīng)力應(yīng)變關(guān)系分析（本科畢業(yè)論文設(shè)計）
摘 要

由焊接產(chǎn)生的動態(tài)應(yīng)力應(yīng)變過程及其隨后形成的殘余應(yīng)力，是導(dǎo)致焊接裂紋和接頭強(qiáng)度與性能下降的重要因素。迄今為止，焊接殘余應(yīng)力一直是人們關(guān)注的熱點問題。而不同的坡口類型在進(jìn)行焊接時殘余應(yīng)力和焊接變形都不盡相同。因此，焊接坡口形狀與殘余應(yīng)力應(yīng)變關(guān)系的分析，對焊接的發(fā)展和研究有著重要的意義。
本課題的目的是研究焊接坡口形狀與殘余應(yīng)力應(yīng)變的關(guān)系。殘余應(yīng)力和應(yīng)變相互聯(lián)系，一般殘余應(yīng)力大的地方，焊接變形也比較大。對于不同形狀的坡口，坡口橫截面越大，熔敷金屬的量越大，焊接變形也就越大，相應(yīng)的殘余應(yīng)力也呈增大趨勢。本課題使用有限元分析軟件ANSYS，通過對V形，Y形和U形三種形狀焊接坡口模型進(jìn)行加載求解，數(shù)值模擬焊接殘余應(yīng)力和焊接變形。模擬得到的結(jié)果是Y形，V形和U形三種形狀焊接坡口模型施焊后，最大變形量和最大殘余應(yīng)力值依次遞增。本次模擬的結(jié)果與實驗所得基本吻合，故使用 ansys軟件建立的數(shù)值模擬分析方法，能夠較準(zhǔn)確的模擬出焊接時瞬態(tài)應(yīng)力場和焊接變形，為工程實踐提供依據(jù)。


關(guān)鍵詞：坡口類型，殘余應(yīng)力，焊接變形，ANSYS，數(shù)值模擬

ABSTRACT

The dynamic stress and strain process created by welding and the subsequent residual stress is the important factor resulting to welding cracks and joint strength and declining performance. So far, the welding residual stress has been a hot issue of concern. And the welding residual stress and deformation of different shapes of groove are different. Therefore, analysis of the relationship between the welding groove shape and the welding residual stress and strain is important for the welding research and development.
The purpose of this task is to study the relationship between the welding groove shape and the welding residual stress and strain. Residual stress is related to the deformation. In general, the location where the welding residual stress is large has large welding deformation. For the different shapes of the groove, the larger groove cross-section is, the larger amount of metal cladding, the greater welding deformation, and the trend of the residual stress is also increasing. This paper uses finite element analysis software ANSYS, loading and solving the V-shaped Y-shaped and U-shaped three welding groove model, and finally getting the numerical simulation of welding residual stress and welding deformation. The numerical simulation results are that, the largest deformation and residual stress of the Y-shaped V-shaped and U-shaped three welding groove model increases by degrees. The simulations are basically consistent with the experimental result, so the numerical simulation analysis of software ANSYS can simulate accurately for the welding transient stress field and welding deformation, and provide the basis for engineering practice.

Key words: groove shape, residual stress, welding deformation, ansys, numerical simulation

目 錄

中文摘要 Ⅰ
ABSTRACT Ⅱ
1緒論 1
1.1課題背景及課題意義 1
1.2國內(nèi)外現(xiàn)狀分析 2
1.2.1 焊接殘余應(yīng)力的有限元模擬 2
1.2.2 不同坡口形式與殘余應(yīng)力應(yīng)變 2
1.3研究內(nèi)容 3
2有限元基礎(chǔ)及ANSYS軟件功能簡介 4
2.1有限元法基本理論 4
2.2 ANSYS軟件的概述 4
2.2.1與CAD軟件的無縫集成 4
2.2.2極為強(qiáng)大的網(wǎng)格處理能力 5
2.2.3高精度非線性問題求解 5
2.2.4強(qiáng)大的耦合場求解能力 5
2.2.5程序面向用戶的開放性 6
2.3 Ansys基本操作 6
2.3.1 建立有限元模型 6
2.3.2 施加載荷并求解 6
2.3.3 查看分析結(jié)果 7
2.4 網(wǎng)格的劃分 7
2.4.1網(wǎng)格數(shù)量 7
2.4.2網(wǎng)格疏密 8
2.4.3單元階次 8
2.4.4網(wǎng)格質(zhì)量 8
2.4.5網(wǎng)格分界面和分界點 9
2.4.6位移協(xié)調(diào)性 9
2.4.7網(wǎng)格布局 9
2.4.8節(jié)點和單元編號 9
2.5 Ansys軟件的意義 9
3常見焊接坡口形狀與焊接殘余應(yīng)力應(yīng)變 11
3.1常見焊接坡口形狀 11
3.1.1 對接接頭坡口 11
3.1.2 T 形接頭坡口 11
3.1.3 角接接頭坡口 12
3.2焊接殘余應(yīng)力應(yīng)變 12
3.2.1殘余應(yīng)力的產(chǎn)生 12
3.2.2焊接應(yīng)力和變形的原因及分類 13
3.2.3焊接殘余應(yīng)力和變形 14
3.2.4減少焊接應(yīng)力和焊接變形的措施 15
4用ANSYS對3種坡口的焊接變形進(jìn)行分析 18
4.1問題描述 18
4.2有限元模型的建立 18
4.2.1定義材料屬性 19
4.2.2創(chuàng)建模型 19
4.2.3網(wǎng)格劃分 20
4.3加載求解 21
4.3.1加載邊界條件 21
4.3.2施加載荷步與求解 22
5仿真結(jié)果及分析 23
5.1焊接殘余變形 23
5.2焊接殘余應(yīng)力 25
5.3小結(jié) 27
6結(jié)論 28
致謝 29
參考文獻(xiàn) 30