Numerical Simulation Of The Procedure Of Wide Plate Tensile Test Of Pipeline Steel

With the development needs of the pipeline in recent years, wide plate tensile test is widely used in pipeline girth weld performance assessment. Compared with the small size specimens test, wide plate tensile test conducted to test larger sample size, to reflect the actual project the problems in a more realistic engineering situations, such as material inhomogeneity, welding residual stress and thickness and other conditions on the structural properties of the pipe. Wide plate tensile test can be used for the following purposes:(1) to evaluate the performance of the pipeline weld steel ring;(2) of pipeline steel ring weld defect tolerance assessment;(3) to determine the capacity of the pipeline steel ring weld strength limit;(4) to determine changes in the pipeline weld steel rings describe limit;(5) steel pipe welding procedure qualification;(6) pipeline steel weld integrity assessment.Wide plate tensile specifications size requirements: girth welds should be a central location in the weld plate length. The reducing length of both sides of a wide segment should be 2.25W(W is the width of the value of the sample less wide segment). The width and length of the specimen’s both ends is 1.25 W and 1.00 W respectively. Between the ends and cut wide section apply smooth and continuous arc to make the transition, the transition radius is not less than 0.30 W. During the test, according to the difference in performance of the sheet,caused deformation occurred in the weld on the right side plate, the overall uneven deformation.In the case of defect of 3.5mm×50mm crack, pipe specimen reached 4.8% in the overall deformation, but the crack is still reliable.Through the stress-strain curve experiments,accesses the elastic-plastic mechanics data of X70 steel weld and base metal, provide data support for finite element simulation.Through the wide tensile simulation test of X70 pipeline steel plate, get the weld and base metal stress-strain curve data and gaps cracks CMOD values were compared with the experimental results obtained good agreement was found between the two. It shows that the finite element numerical model this article adopted to simulate the process of wide plate tensile test has the rationality and feasibility.Then carry out the X80 pipeline steel wide plate tensile test simulation analysis, set in three different crack gap size, and analyze distributed tensile stress in the process, finally found out that increasing the depth of the gap will cause significant stress concentration, and also caused crack gap displacement CMOD increased significantly.