FEM Simulation And Multi-Objective Parameters Optimization On Large-Sized Straight Weld Pipe's Mechanical Expanding Process

The process of mechanical expanding of large size LSAW pipe is studied in the paper. Mechanical expanding processing and corresponding equipments are key technologies to build production line of straight-seam welded pipe with large diameter. In the paper, the mechanical expanding process of large size LSAW pipe is simulated by FEM and optimization technology, and the principal processing parameters are multi-objective optimized.A large number of numerical simulations on the mechanical expanding process of line pipe are performed by MARC software. Based On the simulations about the pipe specification such asφ1401.5×22 mm,φ1207.8×19 mm,φ630×9 mm, the effects of die's radius, fillet radius of die's brim and expanding ratio on the deformation course are analyzed in detail.The mechanical expanding is a plastic deformation process which is involved with errors in outside dimension and geometrical form of the cross-section of cylindrical billet, material properties, friction condition, degree of deformation, diameters of dies, and so on. The precision of dimension and geometrical form of the final products depends on effects of all these parameters.It can be abstracted as a multi-objective optimization problem that searches optimum combination of the above four key technological parameters under the condition of meeting precision of final products. This paper realized optimization of mechanical expanding technological parameters by multi-objective optimization based on MSC.Marc, nonlinear software of finite element method, and genetic algorithm of optimization, and designing a genetic algorithm program in Python with weighted array algorithm. The present outcome provides a theory basis for parameters selection during the practical course of mechanical expanding, which is provided with important theory significance and practical values.