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某新型反应堆压力容器内壁设计了环形锻件与筒体内壁焊接的环形焊接结构。该种结构形式的焊缝首次在反应堆压力容器中出现,无成熟经验可以借鉴。为了了解该种复杂结构形式及大厚度焊缝的焊接残余应力幅值及分布规律,基于ANSYS有限元分析软件,建立了反应堆压力容器内壁环形锻件多层多道焊接三维有限元模型。在此基础上,以带状移动温度热源作为焊接热源模型计算出多层多道焊接的瞬态温度场结果,采用热-力间接耦合法,得到了焊接应力场计算结果。模拟结果表明,焊缝区域环向应力从上表面到下表面分布趋势为拉应力-压应力-拉应力,呈现自平衡的分布形式。根部焊道区域的环向应力为拉应力。焊缝上轴向应力最大为300 MPa左右;焊缝上下表面径向应力较大,达到400~500 MPa左右;峰值等效应力出现在焊缝根部区域,幅值最大约700 MPa。 相似文献
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研究证明,焊制的压力容器的焊接区存在着极大的残余应力。该残余应力的峰值大小和分布状态会直接对压力容器产生不良影响。所以,本文笔者探讨了减少压力容器焊接残余应力的方法.希望能提高压力容器的制造质量。 相似文献
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接管安全端异种金属焊接接头是压水堆核电站中连接主设备低合金钢压力容器接管嘴与不锈钢管道的一种典型结构,易发生一次侧应力腐蚀开裂,而焊接残余拉应力是造成此种应力腐蚀开裂的主要因素之一.因此,准确评估接管安全端异种金属接头的焊接残余应力分布至关重要.通过有限元模拟研究焊接残余应力旨在保障核电设备的结构完整性.介绍了接管安全端异种金属焊接接头的结构、材料与焊接工艺特点,综述了有限元模拟方法预测异种金属焊接接头残余应力分布的数值计算工作和典型流程,以及诸多因素对有限元模拟异种金属焊接接头残余应力的影响. 相似文献
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焊接残余应力的小孔法测试 总被引:1,自引:0,他引:1
应用小孔释放法对系列手弧焊接接头的焊接残余应力分布进行测试,讨论了焊接残余应力的分布规律及其相关影响因素,对加载法消除焊接残余应力的效果进行了初步的验证。结果表明,焊接接头的应力不均匀性和不确定性是影响钢制压力容器安全性的关键,采用加载法可以有效地改善这种非均匀应力分布状况。 相似文献
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焊接作为压力容器制造过程中最关键的一道工序,对压力容器的质量起着决定性的作用。在焊接过程中,不可避免地会产生大小不等的焊接应力,为了解决这一问题,阐释了压力容器焊接应力的产生原理以及危害,并有针对性地分析了降低压力容器焊接应力的方法。 相似文献
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S. A. Sokolov 《Russian Engineering Research》2018,38(3):151-156
A local approach is developed for calculating the fatigue strength of welded metal structures, selecting the basic weld structure, and identifying the group of welded structures corresponding to that basic structure. To that end, the stress state of typical welded structures is analyzed on the basis of two-level stress concentrators. The results may be used to develop standards for calculating the fatigue strength of welded metal structures. 相似文献
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由于含缺陷容器在补强下的安全评价对在役压力容器的使用有重要的意义,使用ANSYS软件,采用三维有限元方法,对带补强圈含肩部穿透裂纹接管在内压作用下结构的应力进行计算和分析。研究表明,在弹性范围内,此结构的最大Mises应力与内压呈线性关系,且结构最大Mises应力的位置为接管腹部下方容器和补强圈的焊接处。在内压一定的情况下,此结构的最大Mises应力比带补强圈无缺陷接管的应力大,比无补强圈无缺陷接管的应力小。此结论能够指导实际工程中对此类缺陷的补强和评定。 相似文献
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Yashar Javadi Mehdi Ahmadi Najafabadi Mehdi Akhlaghi 《Russian Journal of Nondestructive Testing》2012,48(9):541-552
Subsurface stresses in welded structures increase the likelihood of fatigue cracks and environmental induced material degradation. The ability to evaluate stresses at the surface as well as in the interior of welded structural members would substantially increase the accuracy of structure life estimation. The longitudinal critically refracted (L CR) wave is a bulk longitudinal mode that travels within an effective depth underneath the surface. It may be used to detect in-plane subsurface stresses in the structures. This paper presents a three dimensional thermo-mechanical analysis to evaluate welding residual stresses in dissimilar plate-plate joint of AISI stainless steel 304 and Carbon Steel A106-B type. After finite element simulation, the residual stresses were evaluated by L CR ultrasonic waves. Finally the results of two methods were compared and verified by hole-drilling method. This paper introduces a combination of ??Finite Element Welding Simulation?? and ??Ultrasonic Stress Measurement using the L CR Wave?? which is called as ??FEL CR??. The capabilities of FEL CR??. The capabilities of FEL CR in residual stress measurement are confirmed here. And also this paper evaluates residual stresses of dissimilar welded joints by LCR ultrasonic waves. It has been shown that predicted residual stress from three dimensional FE analyses is in reasonable agreement with measured residual stress from LCR method and also the results of both are verified with hole-drilling experimental measurements. 相似文献
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浅析应力集中对焊接接头疲劳强度的影响 总被引:1,自引:0,他引:1
焊接结构能否承受交变动载荷主要是看焊接接头的疲劳强度.应力集中是造成焊接疲劳的一个重要因素,采用改善焊缝几何形状、焊接接头类型等措施来降低应力集中可以有效地提高焊接接头的疲劳强度. 相似文献
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Jae-Woong Kim Choong-Gi Kim 《International Journal of Precision Engineering and Manufacturing》2010,11(6):925-930
The welding process, incorporating rapid heating and cooling, generates distortion and residual stress in the welded structures.
In the design of a high quality welded structures, the weld distortion and residual stress have to be considered in advance.
Especially, for the thin metal welded structures, the thermal distortion and residual stress have a severe effect on the structure’s
precision, fatigue strength, buckling strength and so on. This study aims to analyze the design candidates of a laser welded
thin metal tube structure in the view point of welding distortion and residual stress. Three design candidates were fabricated,
and then the distortion was measured. And the residual stress distributions were calculated by using a commercial FEM package.
The analysis results show that the distortion and residual stress were affected according to the position of weld line and
the design of structure. By using the analyses the best one among the three design candidates was selected finally. 相似文献
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Bahadir Uyulgan Hakan Cetinel Tevfik Aksoy 《Journal of Mechanical Science and Technology》2011,25(9):2171-2177
In this study, 17Mn4 (P295GH) pressure vessels steel and AISI304 stainless steel were welded with ER309L austenitic consumable.
In experimental part of the study, tensile tests were conducted on welded plates and variation of hardness values along specimen
was measured. J-integral fracture toughness values were investigated for different crack locations. In order to determine
the regions where plastic deformation did not take place due to constraint, uni-axial tensile test was performed on welded
tensile specimen after attaching strain gauges. In numerical part of the study, finite element (FE) analyses were conducted
by fixing 2-D models precracked on different locations by using ANSYS software. In these models, stress triaxiality and plastic
deformation characteristics around crack tip were determined for each crack locations after stress — strain analyses. The
limitation on the extension of plastic deformation at diffusion line causes extra increase in stress triaxiality at crack
tip. 相似文献
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针对镁合金焊接结构疲劳强度评估方法不全面的问题,在等效结构应力法的研究基础上,提出了镁合金焊接接头疲劳寿命预测方法。基于 200 余个包含不同特征的镁合金接头疲劳试验数据,采用有限元数值模拟,计算试件接头焊趾处的等效结构应力。结合 ASME 标准中对曲线拟合的规范,进行镁合金接头寿命曲线拟合,得出了预测疲劳寿命的常系数 C d 和 h 。将拟合结果与铝材的疲劳寿命曲线进行对比,结果表明,镁合金接头在 1×107?次循环下的疲劳强度约为 31.6 MPa ,同等条件下约为铝材疲劳强度的 82% 。该镁合金接头疲劳寿命预测方法可用于评估镁合金结构疲劳强度是否满足轨道车辆车体结构使用需求。 相似文献
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测井仪耐压圆筒在外压作用下处于三向应力状态,按不同的失效准则和强度条件有不同的设计公式。文中运用最大剪应力理论和形状改变比能理论,推导出了测井仪器耐压圆筒在弹性极限范围内的最小壁厚和强度校核公式,并分析比较在不同强度理论下的结果,为快速计算耐压圆筒壁厚及强度校核提供了可靠的理论依据。 相似文献