共查询到20条相似文献,搜索用时 0 毫秒
1.
SYSWELD was used to simulate in-service welding process of gas pipeline of X70 pipeline steel. Welding thermal cycle, stress and deformation of in-service welded joint were studied. The results show that peak temperature of coarse grain heat-affected zone (CGHAZ) of in-service welding onto gas pipeline is the same with routine welding, but ts/5, ts/3 and ts/1 decrease at certain degree. For the zone near welded seam, axial stress and hoop stress in the inner pipe wall are compressive stress when welding source passes through the cross-section that is studied, but residual axial stress and residual hoop stress after welded are all tensile stress. Transient deformation and residual deformation are all convex deformation compared with the original pipe diameter size. Deformation achieves maximum when welding thermal source passes through the cross-section that is studied and then decreases during the cooling process after welding. 相似文献
2.
3.
利用有限元分析软件MARC对"沟槽-蒙皮"结构的激光焊接过程进行三维数值模拟,涉及了激光焊接复合热源模型的确定,热力学边界条件的简化,数值模拟温度场的验证,以及残余变形和应力分布结果的分析和讨论.研究了结构上规则排列的多道焊缝的施焊顺序对焊接残余应力和变形的影响.结果表明,不同焊接顺序所产生的变形态相同,变形量有区别,而残余应力的分布则不同,以由外向中的对称顺序进行焊接时,结构的焊后残余变形最小,残余应力的分布比较均匀,峰值最小. 相似文献
4.
5.
焊接变形影响了结构的承载能力和精密性,尤其对飞行器等精密结构将造成非常严重的后果.为了对某钛合金飞行器叉形结构的焊接变形进行精确测量从而达到控制焊接变形的目的,制作了简化的1:3钛合金模型,根据不同测量方法的特点,对钛合金模型采用数值仿真计算对整体变形进行了模拟,采用数字图像相关技术对远焊缝区域进行检测,并采用三维扫描对工作臂变形角度测量等三种方法,对焊接变形进行测量分析,较于传统测量,采用模拟和试验测试相结合的方法能够紧密联系工程实际,更加全面准确,量化了焊接顺序对焊接变形的影响,找到最佳焊接顺序方案. 相似文献
6.
7.
文中采用MSC·Marc软件对天然气管道在役修补焊接过程进行数值模拟. 采用的焊接方式为钨极惰性气体保护焊. 焊接过程中熔池底部未熔化材料受高温后强度降低,管道内部的压力易导致其失效. 温度场分析结果表明,当焊接电流为220 A时,管道内壁温度峰值为1 131 ℃,低于管道材料的熔点,该温度下材料的屈服强度远高于管道内压. 当焊接电流介于240~260 A范围时,容易发生焊透缺陷. 盖板周围为封闭环焊缝,其应力场相比于直焊缝较复杂,模拟结果显示其等效残余应力分布不对称,在焊缝的收弧区域出现峰值,220 A焊接电流下为212.3 MPa. 盖板沿着管道径向方向发生收缩变形,最大变形量为1.79 mm. 相似文献
8.
9.
制造了反应堆压力容器顶盖和控制杆驱动机构(CRDM)管座贯穿件J形密封焊模拟件,测试了焊接过程温度和焊后残余应力;采用分段移动温度热源模型和热力耦合方法实现了三维焊接温度场和应力场的高效计算,并与试验结果进行了比较;基于模拟的三维残余应力场研究了J形密封焊的应力分布特征. 结果表明,采用的模型和方法能实现J形密封焊残余应力的高效数值计算,计算和试验结果符合较好;J形密封焊缝上的纵向应力大于轴向应力,贯穿件内外壁应力不均匀,焊缝和贯穿件坡上和坡下区域的应力大于侧坡区域应力. 相似文献
10.
从基于温度场的相似准则出发,建立并推导出了均匀热源模型的相似条件,利用该相似条件,对平板对接焊和角接焊分别进行了温度场、位移场和应力场的数值模拟计算与对比分析.结果表明,原模型与相似模型的温度场、位移场和应力场误差相当小,其误差分别仅为3.7%,4.7%,3.8%.基于均匀热源相似条件,对箱型结构的焊接残余应力与变形进行了数值模拟,得到了相似箱型结构焊接残余应力的变化规律和变形量随距离的变化曲线,其变形量的数值模拟结果与实际测量结果误差仅为9.8%,进一步验证了均匀热源模型相似条件的正确性. 相似文献
11.
12.
Aero-engine blisk welded by electron beam welding(EBW) method is a complicated structure. Fixtures were used to control the deformation of blisk during its manufacturing process. Finite element method was utilized to study the evolution of the welding residual stress and deformation of this structure. In which an attenuation function was applied to the double ellipsoid heat source model based on the characteristic of EBW, and the effects of fixtures on the welding residual stresses and deforamtion were also reserached. The simulation results showed that the temperature contour of weld cross section vertical to the weld centerline followed a “V” shape. Moreover, large welding residual stress and distortion were found in the interface between blisk and fixtures. The stress concentration was reduced sufficiently in starting and end part of weldment as the fixtures were removed after welding process, while the removing operation had almost no effects on the welding residual stress in the middle section of weld bead. 相似文献
13.
Numerical simulation of the welding deformation for the side sill of the bogie frame based on local-global method 总被引:2,自引:0,他引:2
Considering the limitation of computational capacity, a new finite element solution is used to simulate the welding deformation of the side sill of railroad car' s bogie frame based on the local-global method. Firstly, a volumetric heat source defined by a double ellipsoid is adopted to simulate the thermal distributions of the arc welding process. And then, the local models extracted from the global model are computed with refined meshes. On these bases, the global distortions of the subject studied are ascertained by transferring the inner forces of computed local models to the global model. It indicates that the local-global method is feasible for simulating the large welded structures by comparing the computed results with the corresponding actual measured values. The work provides basis for optimizing the welding sequence and clamping conditions, and has theoretical values and engineering significance in the integral design, manufacturing technique selection of the bogie frame, as well as other kinds of large welded structures. 相似文献
14.
15.
1 INTRODUCTIONInthepasttwentyyears,greatdealsofquantita tiverelationshipsonmicrostructuralevolutioninhot rollingandhotworkinghavebeenestablishedbasedonmanyexperimentalsimulations,whichprovidees sentialmathematicalmodelfornumericalsimulationonmicrostruct… 相似文献
16.
基于计算机仿真技术,定义随温度变化的材料热物理属性,建立316不锈钢连续油管对接焊接轴对称模型,分析焊接速度对焊后油管接头的残余应力和变形的影响。结果表明,在连续管道焊接过程中,焊接速度影响焊接温度场和焊后残余应力的分布;油管内壁最大残余压应力出现在距离焊缝中心22 mm接近母材的位置处,且轴向应力和环向应力的变化同步,油管外壁环向应力和轴向应力变化不同步;随焊接速度的增加,油管外壁残余应力逐渐增大,内壁残余应力和焊接变形逐渐减小,焊接变形可释放部分焊接残余应力,在一定程度上可降低焊后残余应力。 相似文献
17.
18.
文中基于SYSWELD有限元分析软件对Q345/316L异种钢焊接过程的瞬态温度分布、残余应力及变形进行了数值模拟,并通过试验对其模拟结果进行了验证. 试验测量结果与数值模拟结果吻合良好,证明了利用SYSWELD模拟异种钢焊接的可靠性. 结果表明,异种钢焊接温度场呈不对称分布,Q345侧的高温区域范围更大. 不论是横向残余应力还是纵向残余应力,沿焊缝方向均呈帽状分布且在焊缝中部位置存在最大残余应力;在垂直于焊缝中央截面上,纵向残余应力与横向残余应力在焊缝和焊缝附近区域分布是不连续的,存在较大的应力梯度且应力状态也较复杂,而最大残余应力出现在Q345侧的熔合线处. 不同的热输入下模拟结果表明,在保证焊接接头质量的前提下,最好采用小热输入的焊接工艺. 相似文献
19.
借助有限元分析手段对不同点固焊形式的对接焊焊接过程进行模拟,经分析得到焊接变形和应力分布情况,采用实验手段验证试验结果。结果表明,点固焊位置相同,长度越长,获得的变形量越小;起、收弧的两端面点固焊变形在起、收弧两侧翘起,焊缝位置点固焊翘起的位置发生在与焊缝位置平行的两侧自由端;点固焊长度越长,仿真和实测结果的残余应力分布波动性越大;在起、收弧两端面点固焊获得的残余应力峰值最小;起、收弧两端面点固焊、点固焊2处残余应力值均降低,点固焊3处残余应力值增大。证明了有限元模型的正确性和有效性。 相似文献