热-机械载荷下U形对焊接头的安定性

Shakedown analysis of U-groove butt welded joints under cyclic thermo-mechanical loadings

结合非线性叠加法和通用有限元软件ABAQUS研究了内压和温度载荷下U形对焊接头的安定性,探讨了焊缝几何尺寸及焊接材料对压力管道安定性的影响.结果表明,当焊接材料的弹性模量、线膨胀系数和屈服应力与母材相差很大时,在焊接处产生较大的局部应力,可显著影响结构的安定性,而焊接坡口尺寸对安定域影响很小;建立了一种适于工程安定性评估的简化图解法.

The shakedown behavior of U-groove butt welded joints under cycle thermo-mechanical loadings was studied by ABAQUS according to the nonlinear superstition method. The effect of the geometrical scale of welding line,yield stress,thermal expansion coefficient and Young's modulus of the base material and weld material as well as the thickness of piping on the shakedown behavior were studied. Results showed that the geometry of welding line has little influence on the shakedown region,while the difference between the yield stress,thermal expansion coefficient and Young's modulus of the base material and welding material influence the shakedown behavior significantly due to the great local stress. Lastly,the shakedown estimation method of U groove butt welded joints was developed for engineering designs.