Experimental And Numerical Simulation Study Of Welding Residual Stress In Stiffened Plate With Open Ribs

Q345 and Q420 two kinds of strength of steel plate are chosen in this paper.Use experiment and numerical simulation to study the welding residual stress distribution of plate-rib and T-rib stiffened plate,so as to put forward for stability and fatigue of two kinds of open stiffened plate welding residual stress simplified calculation method.The main contents and results are as follows:First,the strain release coefficient of two kinds of steel Q345 and Q420 was studied by uniaxial tensile test.The range of the release coefficient A and B within the elastic range was analyzed,and the value of strain release coefficient was changed to study the influence of strain release coefficient on residual stress distribution.Establish a finite element model of uniaxial tension,calculating the strain release coefficients of A and B,and compare the numerical simulation results with experimental results,the results are in good agreement,which proved the accuracy of numerical simulation methods.The strain release coefficients was modified plasticity.Use linear fitting to obtain the correction formula of the strain release coefficients.Second,the finite element model of plat-bar stiffened plate is established by ANSYS software.The kill-and-alive unit technology of ANSYS is applied to simulate the fusion and condensation of weld seam,and simulate the temperature field and stress field of stiffened plate,and obtain the distribution of welding residual stress.Considering the thickness and height of plate ribs,and the variation of the weld pool area,designed 9 specimens of Q345 and Q420,using blind hole method to test and obtain the longitudinal and transverse residual stress distribution of specimens,the test results and finite element simulation results are in good agreement,proved the accuracy of numerical simulation methods.Third,the finite element model of T-rib stiffened plate is established by ANSYS software.The kill-and-alive unit technology of ANSYS is applied to simulate the fusion and condensation of weld seam,and simulate the temperature field and stress field of T-rib stiffened plate,and obtain the welding residual stress distribution.Considering changes of the plate width,flange thickness and web thickness,designed 10 specimens of Q420 and 9 specimens of Q345,the blind hole method is used for testing,to obtain the longitudinal and transverse residual stress distribution of specimens,the test results and finite element simulation results are in good agreement,proved the accuracy of numerical simulation methods.Last,by changing the number of stiffener and length of the stiffened plate,Simplify analysis the opening stiffened plate finite element model.Study the changes of thermal-physical parameters(thermal conductivity,density,specific heat capacity),thermal-mechanical parameters(thermal expansion coefficient,Poisson ratio,elastic modulus)and welding process(welding sequence,welding speed,welding and heat pool area)influence on the stress distribution of welding the residual stresses.The results show that among the many factors affecting the residual stress of welding,the coefficient of heat dissipation,thermal conductivity and the number of stiffeners are the smallest,Poisson's ratio,thermal expansion coefficient,specific heat capacity,and the area of molten pool and the modulus of elasticity are the greatest.