engineering projects

ANALYSIS OF RESIDUAL STRESSES IN A BUTT WELD USING ANSYS SOFTWARE

Low carbon steels are prone to distortion and cracks due to residual stresses induced during welding. This project gives the information about the residual stresses induced in a butt weld joint due to welding. Experimentation was carried out on a plate made of low carbon steel having dimensions 0.115x0.048x0.006 meters. The type of welding chosen is Manual Metal Arc Welding (MMAW). Single pass welding was carried out. Experimental values calculated were taken as input for the analysis in ANSYS software. A model was generated in ANSYS 9.0 (A general purpose FEA software) using SOLID BRICK 8 NODE 70 (3D solid element with temperature dof) and PLANE 55 (A2D solid element with 4 nodes), as per the dimensions of the plate taken for the experimentation. A refined mesh is made based on the convergence criteria and the analysis is performed to estimate the temperature distribution. Firstly a transient thermal analysis was carried out by giving heat flux as the time varying input to estimate the temperature variation. The non linear material properties are fed for the heat transfer solution. Then coupled field analysis is carried out to get the residual stresses by coupling thermal analysis to static analysis. The variation of the temperature with time, and residual stresses are obtained. The variation of these are reported and discussed.

WELDING SIMULATION OF ALUMINUM ALLOY JOINTS BY FINITE ELEMENT ANALYSIS

Simulations of the welding process for butt and tee joints using finite element analyses are to presented. The base metal is aluminum 2519-T87 and the filler material is alloy 2319. The simulations are performed with the commercial software ANSYS 5.6 a general purpose FEA software, which includes moving heat sources, temperature dependent material properties, metal plasticity and elasticity, transient heat transfer and mechanical analyses. One-way thermo-mechanical coupling is assumed, which means that the thermal analysis is completed first, followed by a separate mechanical analysis based on the thermal history. The residual stress state from a three-dimensional analysis of the butt joint is compared to previously published results. To reduce computer times for the tee, a model containing both solid and shell elements was attempted. Unfortunately, the mechanical analysis did not converge, which appears to be due to the transition elements used in this coupled solid-shell model. Welding simulations to predict residual stress states require three-dimensional analysis in the vicinity of the joint and these analyses are computationally intensive and difficult. Although the state of the art in welding simulations using finite elements has advanced, it does not appear at this time that such simulations are effective for parametric studies, much less to include in an optimization algorithm.

ANALYSIS OF RESIDUAL STRESSES IN A BUTT WELD USING ANSYS SOFTWARE

 

Low carbon steels are prone to distortion and cracks due to residual stresses induced during welding. This project gives the information about the residual stresses induced in a butt weld joint due to welding. Experimentation was carried out on a plate made of low carbon steel having dimensions 0.115 x 0.048 x 0.006 meters. The type of welding chosen is Manual Metal Arc Welding (MMAW). Single pass welding was carried out. Experimental values calculated were taken as input for the analysis in ANSYS software.

A model was generated in ANSYS 9.0 (A general purpose FEA software) using SOLID BRICK 8 NODE 70 (3D solid element with temperature dof) and PLANE 55 (A 2D Solid Element with 4 nodes), as per the dimensions of the plate taken for the experimentation. A refined mesh is made based on the convergency criteria and the analysis is performed to estimate the temperature distribution. Firstly a transient thermal analysis was carried out by giving heat flux as the time varying input to estimate the temperature variation. The non-linear material properties are fed for the heat transfer solution. Then coupled field analysis is carried out to get the residual stresses by coupling thermal analysis to static analysis. The variation of the temperature with time, and residual stresses are obtained. The variation of these are reported and discussed.

FINITE ELEMENT ANALYSIS OF THE BENDING OF THE ROLLING MATERIAL IN ASYMMETRICAL SHEET ROLLING

Rolling is a process where the metal is compressed between two rolling rolls for reducing its cross sectional area. In a rolling process if the strip at the exit  of the rolls is bent either upward or downward than it leads  to a defect  known as front end bending of the strip and the rolling process in such condition is said to be asymmetric rolling. In asymmetric rolling process the work piece is bent to an unexpected shape. Its curvature may be caused by a speed difference, by lubricating mismatch or a radius difference of the work rolls ,and depends on various rolling parameters , such as ratio of peripheral  velocities of the upper roll and the lower roll, reduction ratio, average radius  of the work rolls, initial plate thickness and friction between the rolls and work piece. Front end bending may cause serious draw backs in terms of productivity and product quality. In addition, considerable damage to the equipment may result, especially when the bending is severe. Therefore it is of paramount importance to prevent front end bending to improve the product quality. Experiments in asymmetric rolling are more difficult than in conventional rolling because of the asymmetric tensile states. Numerical simulation techniques such as the FEM can provide a detailed study of the deformation state occurring in rolling process. Finite element simulation, which shows the influence of different diameters of the working rolls and of the degree of reduction on the bending of the work piece, has been performed in this work. The effect of various parameters on the front end bending of the work piece is discussed in this research. It is observed that the influence of the percentage deformation is greater than the influence of initial thickness in the front end bending of the plate. In this thesis a preliminary idea of developing a warping control system is discussed as a scope for the future research.