Three-dimensional Numerical Analysis Of Residual Stress Of The Connecting Weld Between U-rib And Deck-plate

The orthotropic steel bridge deck is widely used in large and medium span bridges, due to the economic and durable characteristic, light weight and high strength. Because of its complex structure and numerous decks, many of which are connected by welding, so the welding residual stress is coming. The residual stress would reduce the performance of steel bridge deck, such as corrosion, fatigue resistance and stable performance etc. Today, complete control and elimination of the welding residual stress is impossible. And the residual stress still exists in the steel decks. In order to make sure that steel bridge deck is using safely, the magnitude and distribution of residual stress should be accurately understood. Experimental measurement of residual stress is time-consuming, this paper use the numerical simulation technology for quantitative analysis, the main work includes:(1) This part introduces the basic knowledge of welding residual stress, reviews the current development of numerical simulation of welding technology at home and abroad, summarizes the related theory and method of welding simulation, including the welding temperature field and stress field theory.(2) It is based on the Hong Kong-Zhuhai-Macao Bridge, this paper uses ANSYS finite element software to establish the three-dimensional model of connecting weld between U rib and deck-plate, selects the reasonable material parameters and heat source model, uses the element birth and death technology to simulate melting and filling of the welding solder, simulating temperature field and stress field.(3) This paper analyses the results of calculation and simulation, obtains the distribution of temperature field and stress field:with the moving of the heat source location, the weld metals temperature rises rapidly to melting; with the leaving of heat source, the temperature decreases rapidly and finally to room temperature. The weld residual stress of the deck-plate near the U-rib surface is about 1.2 times of the yield strength; the maximum compressive residual stress far from the weld zone is about 0.1 times of the yield strength. The maximum residual tensile stress of U-rib near the weld zone reaches to the yield strength; the maximum compressive residual stress far from the weld zone is about 0.1 times of the yield strength.(4) This paper analyses the influence on welding residual stress with the material parameters, welding process parameters and geometric parameters, and gets the more accurate simulation results to provide data’s support for the rational welding process.The simulation results show:the welding residual stress of the connecting weld between U-rib and deck-plate can be simulated by the ANSYS software. The calculation results and the distribution trend about the residual stress between deck-plate and U-rib are consistent with previous research. Variation of parameters has a great influence on welding residual stress.