共查询到10条相似文献,搜索用时 515 毫秒
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NondestructivetestofweldresidualstressesbyacoustoelastictechniqueJiaoFujie;ZhangWenjunandYuanZhikang(ShanghaiUniversityofEngi... 相似文献
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H. Purmohamad A. Kermanpur M. Shamanian 《Journal of Materials Engineering and Performance》2010,19(1):13-21
The residual stresses developed during the circumferential butt gas tungsten arc welding (GTAW) process of Incoloy 800H pipes
were simulated using the finite element method. A decoupled thermostructural model was developed in three dimensions. The
element birth and death technique was used for the addition of filler material in the weld pool. The Goldak double ellipsoidal
model was used to simulate the distribution of arc heat during welding. The plastic behavior of the material was described
by Von Mises yield function and the bilinear kinematics hardening was assumed. To validate the thermostructural model, both
temperature and residual stress distributions within the pipes were measured using thermocouples and strain gages, respectively.
Good agreements were found between the experimental and simulation results. The model was then used to predict distribution
of residual stresses during the GTAW of Incoloy 800H pipes and to study effects of process parameters on the residual stresses. 相似文献
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为提升液压支架修复的可靠性和经济性,对超声等离子焊接的应用效果进行了数值模拟和试验研究。根据所设计超声等离子弧焊系统的焊枪结构与焊接工艺参数建立了超声场有限元模型,基于COMSOL求解等离子气体的速度场、电弧密度场和声压场。对修复后的液压支架试样进行了显微硬度、残余应力及冲击韧性等力学性能测试。结果表明,超声波可在同等条件下将电弧压力提升20%以上,并在4 mm电弧直径内显著增强电流密度,有效减小热影响区范围和残余应力;等离子气体流速与电弧密度在靠近支架焊缝区域以近似相反的变化趋势分布,二阶特征频率振源能够在电极附近产生驻波;修复后支架的平均硬度和室温冲击吸收能量相比母材分别提升了44.6%和45.8%。 相似文献
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Y Abdallahoui H Walaszek C Peyrac H‐P Lieurade M Cherfaoui 《Welding International》2013,27(4):282-293
Summary A non‐destructive method for measurement of residual welding stress is described. The results are in good agreement with another proven semi‐destructive method. Excellent practical perspectives for a vast range of parameters, important to welders, with a direct influence on length of service life are given. The welding process creates complex residual stress fields which may now be evaluated experimentally by various semi‐destructive or destructive methods. In the case of welded compounds, these stresses are often high and may reach the elastic limit of the base metal, thus influencing the mechanical properties of welded assemblies. A new non‐destructive, ultrasonic technique of evaluating stresses is presented here. The potential uses of this technique are to measure near surface stress and apply it to the optimisation of welding processes. 相似文献
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The arc characteristic of ultrasonic assisted TIG welding 总被引:1,自引:0,他引:1
Many applications of ultrasonic-assisted methods were used during metal solidification, but they could not be introduced into weld pool. In this paper, a way of ultrasonic assisted TIG welding is introduced. By directly imposed ultrasonic vibration on welding arc, the vibration interacts with arc plasma and passes to the weld pool. Measurement results show that arc pressure is significantly increased with the ultrasonic vibration and the arc pressure distribution models are changed. Bead-on-plate welding tests on SUS304 confirm that this technology can influence the style of metal melting and increase weld penetration depth. 相似文献
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文中采用基于焊缝形貌的温度热源模型高效计算其热过程,通过单丝CO2气体保护焊堆焊件的温度场计算和焊缝形貌比较验证该热源模型的正确性,采用小孔法测试表面应力验证基于该热源模型的残余应力计算结果.结果表明,基于焊缝形貌的给定温度热源模型适用于缆式焊丝CO2气体保护焊的焊接温度场高效数值模拟;缆式焊丝CO2气体保护焊的上表面焊缝区域及焊缝中心沿厚度方向的应力分布与埋弧焊基本一致,但远离焊缝区域的纵向压缩应力幅值大于埋弧焊纵向压缩应力. 相似文献