Experimental Investigation And Numerical Simulation For The Mechanical Properties Of Q345 Fillet Welded Joints

Fillet welded joints is a very common welded joint. It has many advantages such as free of joint angle, simple construction et al and has been wildly used in Vehicles, vessels, pressure vessels industry. Fillet weld joint has simple structure. However, as the bearing structure, the distribution of stress on welding seam is very complicated which causes different behavior of load-carrying properties. So a further study on contributory factor and design is desired. This work based on the former research is going to study the Q345 fillet welded joints through experiment and simulation. The main work is shown as below:(1) A tensile strength test is performed to Q345 steel plate and Q345 fillet welded joints to determine the mechanical properties and build the constitutive relation of the base metal and weld seam.(2) Do tensile strength tests on T-shaped, L- shaped and J- shaped fillet weld joints that taking Q345 as the base metal to get heat and weld size influence on mechanical properties: Uneven heat will reduce plasticity. To fillet welded joints, bearing capacity is not increased with the increase of weld dimension.(3) According to the constitutive relation gained from the experiment, using software ANSYS Workbench to simulate the process of tensile tests on T-shaped, L- shaped and Jshaped fillet weld joints. By comparing with the experiment data, the result proved the reliability of the finite element model.(4) Under the hypothesis that the fracture of fillet weld joints happened on the cross-section of the Maximum reduced stress, the maximum reduced stress and its cross-section are respectively obtained for T-shaped, L- shaped and J- shaped fillet weld joints, then according to bearing capacity and strength criterion the optimum weld feet size is designed and the finite element software proved the T-shaped fillet weld joints design theory. To Jshaped fillet weld joints the theory didn’t go well with simulation result and it was corrected.(5) Build a new model using finite element to study the impact of weld feet and weld seam on T-shaped, L- shaped and J- shaped fillet weld joints. As the weld feet increases, the load causing the same displacement goes up at first and then leveled off. The load will grow with the weld seam increasing.