Three-dimensional transient finite element analysis for residual stresses in the laser aided direct metal/material deposition process

2005 ◽  
Vol 17 (3) ◽  
pp. 144-158 ◽  
Author(s):  
S. Ghosh ◽  
J. Choi
Author(s):  
Francis H. Ku ◽  
Pete C. Riccardella

This paper presents a fast finite element analysis (FEA) model to efficiently predict the residual stresses in a feeder elbow in a CANDU nuclear reactor coolant system throughout the various stages of the manufacturing and welding processes, including elbow forming, Grayloc hub weld, and weld overlay application. The finite element (FE) method employs optimized FEA procedure along with three-dimensional (3-D) elastic-plastic technology and large deformation capability to predict the residual stresses due to the feeder forming and various welding processes. The results demonstrate that the fast FEA method captures the residual stress trends with acceptable accuracy and, hence, provides an efficient and practical tool for performing complicated parametric 3-D weld residual stress studies.


2017 ◽  
Vol 21 (3) ◽  
pp. 1301-1307 ◽  
Author(s):  
Nejad Masoudi ◽  
Mahmoud Shariati ◽  
Khalil Farhangdoost

The aim of this paper is to develop means to predict accurately the residual stresses due to quenching process of an UIC60 rail. A 3-D non-linear stress analysis model has been applied to estimate stress fields of an UIC60 rail in the quenching process. A cooling mechanism with water spray is simulated applying the elastic-plastic finite element analysis for the rail. The 3-D finite element analysis results of the studies presented in this paper are needed to describe the initial conditions for analyses of how the service conditions may act to change the as-manufactured stress field.


Volume 3 ◽  
2004 ◽  
Author(s):  
S. Ghosh ◽  
J. Choi

Despite immense advances in Laser-Aided Direct Material Deposition process, many issues concerning the adverse effects of process parameters on the stability of variety of properties and the integrity of microstructure have been reported. Macroscopic aspects are important in predicting macroscopic defects or optimizing process conditions, while microstructural features such as phase appearance, morphology, grain size, spacing, or micro-defects are certainly no less important in determining the ultimate properties of the solidified product. Traditional solidification theories as applied to castings or related processes are inappropriate in describing solidification in high-energy beam processes involving significantly greater cooling rates. Due to the complexity and nonlinearity of this process, analytical solutions can rarely address the practical manufacturing process. This paper is an attempt towards a methodology of finite element analysis for the prediction of solidification microstructure and macroscopic as well as microscopic thermal residual stresses in this process. The computer simulation which is based on metallo-thermomechanical theory and finite element analysis for coupled temperature, solidification, phase transformation and stress/strain fields can prove to be a very useful tool in predicting the material behavior and optimizing the process parameters to obtain the best material properties. This model would reduce long and cumbersome experimental routes to predict the material behavior under similar loading conditions.


2002 ◽  
Vol 124 (2) ◽  
pp. 140-145 ◽  
Author(s):  
Jidong Kang ◽  
W. Steven Johnson ◽  
David A. Clark

A three-dimensional finite element analysis is developed for the cold expansion process in two aluminum alloys, 2024-T351 and 7050-T7451. The entire cold working process including hole expansion, elastic recovery, and finish reaming is simulated. Both isotropic hardening and kinematic hardening models are considered in the numerical calculations. The results suggest that a three-dimensional nature exists in the residual stress fields surrounding the hole. There are significant differences in residual stresses at different sections through the thickness. However, residual stress at the surface is shown to remain the same for the different plastic hardening models after the hole has recovered and finish reaming has been performed. The reaming of the material around the hole has slight effect on the maximum value and distribution of residual stresses. A comparison has been drawn between the FEA of average through thickness strain and a previous experimental investigation of strain that utilized neutron diffraction and modified Sachs boring on a 7050 aluminum specimen containing a cold expanded hole. The different methods show very good agreement in the magnitude of strain as well as the general trend. The conclusions obtained here are beneficial to the understanding of the phenomenon of fatigue crack initiation and growth at the perimeter of cold worked holes.


2012 ◽  
Vol 488-489 ◽  
pp. 1282-1287 ◽  
Author(s):  
H.D. Gopalakrishna ◽  
Vinod M. Srinivasa

This paper presents the numerical and experimental studies of the residual stresses in Al 2024 T3 specimens due to cold hole expansion (CHE) using ball and taper mandrel techniques. A three dimensional, non-linear finite element analysis has been performed to simulate the CHE process and experiments were conducted to determine the residual stresses due to CHE with 2 - 6 % expansion of holes. The residual stresses were determined experimentally by employing strain gauges around the hole during the expansion. Experimental and Finite Element Analysis (FEA) results showed that the residual stresses increased up to 5 % of hole expansion and decreased further in both the techniques of CHE and the same were greater in case of tapered mandrel than that of ball mandrel method. At the optimum expansion of 5%, the FE predictions and experimental results concurred with each other with a maximum deviation of 2%.


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