Finite Element Analysis And Research On Cold Bending Process Of Large Diameter Steel Pipe

Cold bending pipe is a steel pipe which bended by pipe bender directly. Thus the cold bending pipe radius of curvature could meet the design requirements, to accommodate the alignment change demand in pipeline construction, which has been widely used in long-distance oil and gas pipeline project. At present, the scholars mainly worked at summarizing the bend forming technology and the forming process by experimental study and finite element analysis for single-step cold bending process. In theory research, the scholars primarily research in the mechanical properties of cold bending pipe under bending load. However, due to the complicated mechanical process of bending forming, it’s difficult to solve practical problem in production accurately and reliably only by analytical method. It has a large difference between the actual situation and the result which calculated by empirical formula according to simplified mechanical model. The technical summary which developed by experiences and a lot of trial authentication methods causing great consumption of time and manpower. And there isn’t any complete analysis and investigation for the whole-bending of cold bending pipe.In this paper we investigate the whole-bending process of cold bending pipe by the numerical simulation method. In order to analyses the influence of cold bending process parameters (cold bending step, the angle in each step) on the magnitude and distribution of stress-strain, appearance size (ellipse, wave degree, thickness, etc.), and the prediction of resilience amount of cold bending pipe. This study mainly investigates in the follow aspects:(1) Establish the finite element analysis model of the cold bending process, and determine the materials constitutive relation of cold bending pipe;(2) Make finite element analysis on cold bending process;(3) Make finite element analysis on stress-strain distribution of cold bending process of the large deformation steel pipe;(4) Calculate and analyses the resilience amount of cold bending pipe;(5) Calculate and analyses the influence of different cold bending step and the angle in each step on ellipse, wave degree, thickness of cold bending pipe.(6) Obtain the influence of different process parameters on the each indicator of cold bending pipe.Through this simulation method, we can calculate and predict the stress-strain distribution, appearance size and resilience law. Besides, we can also use the best mold size and structure which optimized by this simulation method to guide the improvement of cold bending device. Thus, our investigation greatly improved the quality and efficiency of cold bending products.