Modeling and Prediction of Residual Stresses in Additive Layer Manufacturing by Microplasma Transferred Arc Process Using Finite Element Simulation

Author(s):  
Sagar H. Nikam ◽  
N. K. Jain

Prediction of residual stresses induced by any additive layer manufacturing process greatly helps in preventing thermal cracking and distortion formed in the substrate and deposition material. This paper presents the development of a model for the prediction of residual stresses using three-dimensional finite element simulation (3D-FES) and their experimental validation in a single-track and double-track deposition of Ti-6Al-4V powder on AISI 4130 substrate by the microplasma transferred arc (µ-PTA) powder deposition process. It involved 3D-FES of the temperature distribution and thermal cycles that were validated experimentally using three K-type thermocouples mounted along the deposition direction. Temperature distribution, thermal cycles, and residual stresses are predicted in terms of the µ-PTA process parameters and temperature-dependent properties of substrate and deposition materials. Influence of a number of deposition tracks on the residual stresses is also studied. Results reveal that (i) tensile residual stress is higher at the bonding between the deposition and substrate and attains a minimum value at the midpoint of a deposition track; (ii) maximum tensile residual stress occurs in the substrate material at its interface with deposition track. This primarily causes distortion and thermal cracks; (iii) maximum compressive residual stress occurs approximately at mid-height of the substrate material; and (iv) deposition of a subsequent track relieves tensile residual stress induced by the previously deposited track.

2010 ◽  
Vol 450 ◽  
pp. 461-465 ◽  
Author(s):  
Ibiye A. Roberts ◽  
Chang J. Wang ◽  
Mark Stanford ◽  
Kevin A. Kibble ◽  
Diane J. Mynors

Determining the three-dimensional residual stress fields and the associated distortions using numerical simulations for multi-layered parts has proved to be a challenge in additive layer manufacturing. This paper presents an innovative three-dimensional thermal-elasto-plastic finite element model for predicting the deformation and residual stress fields in TiAl6V4 parts built on steel platforms. The developed model utilises temperature dependent material physical and mechanical properties as well as latent heat of melting. Experiments conducted using surface profilometry showed good agreement with the simulation results. The finite element model was used to investigate the overall effect of the melting powder on the platform deformation and residual stresses for multiple layers of deposited powder.


2008 ◽  
Vol 375-376 ◽  
pp. 480-484 ◽  
Author(s):  
Guang Xiu Zhang ◽  
Bin Lin ◽  
Zhen Peng Shi

The generation and distribution of workpiece surface and sub-surface residual stress were predicted through the dynamic finite element simulation of the grinding ceramic process. The base of the simulation is that the thermo elastic-plastic finite element theory and the coupling of grinding forces and temperature were adopted. The results obtained from X-ray diffraction measurement compared well with the values calculated from theory. The correlation between grinding parameters and the ceramic residual stresses was investigated. The research results show that the normal grinding force is the primary factor responsible for the generation of residual stress in grinding ceramic. The mechanical effect of the grains is to affect the magnitude, the depth of penetration and the gradient of the residual stresses.


Author(s):  
Bridget Kogo ◽  
Bin Wang ◽  
Mahmoud Chizari

Abstract This study investigates and evaluates the welding residual stresses and deformations in the dissimilar material MSSS metals in order to verify the clamping effect on the residual stresses and deformations and entails comparison with the finite element simulation, the critically reflected longitudinal ultrasonic stress measurement and the hole-drilling residual stresses in a Butt-welded plate courtesy of Javadi et al [1]. The angular shrinkage measurement and vertical displacement were used to achieve this objective. The outcome of the study proved that the measurement of residual stress using protractor is an effective way of differentiating the influence of clamps on the longitudinal stresses.


Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 455 ◽  
Author(s):  
Xiaodong Xing ◽  
Xiaoming Duan ◽  
Xiaojing Sun ◽  
Haijun Gong ◽  
Liquan Wang ◽  
...  

Ultrasonic peening treatment (UPT) has been proved to be an effective way of improving residual stresses distribution in weld structures. Thus, it shows a great potential in stress modification for metal parts fabricated by additive manufacturing technology. In this paper, an investigation into the ultrasonic treatment process of AlSi10Mg specimens fabricated by selective laser melting (SLM) process was conducted by means of experimental and numerical simulation. The specimens were prepared using a SLM machine, and UPT on their top surface was carried out. The residual stresses were measured with an X-ray stress diffraction device before and after UPT. Meanwhile, a finite element simulation method for analyzing the influence of UPT on the residual stress field of specimens was proposed and validated by experiments. Firstly, the thermal mechanical coupling numerical simulation of the SLM process of the specimen was carried out in order to obtain the residual stress distribution in the as-fabricated specimen. Then, the transient dynamic finite element simulation model of the UPT process of the specimen was established, and the UPT effect analysis was implemented. In the UPT simulation, the residual stress was applied as a pre-stress on the specimen, and the specimen’s material mechanical property was described by the Johnson–Cook model, whose parameters were determined by Split Hopkinson Pressure Bar (SHPB) experiment. The residual stress distribution before and after UPT predicted by the finite element model agree well with the measurement results. This paper concludes with a discussion of the effects of ultrasonic peening time, as well as the frequency and amplitude of the peening needle on residual stress.


1971 ◽  
Vol 6 (2) ◽  
pp. 89-98 ◽  
Author(s):  
T R Gurney

By means of a form of finite-element analysis and use of a theoretical, radially symmetrical, temperature distribution, the residual stresses resulting from spot heating at the centre of a large circular plate have been calculated. The investigation was concerned in particular with defining the effect of variations in material yield stress, rate of heat input, and peak temperature on the residual-stress distribution.


2019 ◽  
Vol 13 (1) ◽  
pp. 4536-4557 ◽  
Author(s):  
K. Azizpour ◽  
H. Moshayedi ◽  
I. Sattari-far

Tensile residual stress is a major issue in integrity of the welded structures. Undesirable tensile residual stress in welding may reduce fracture toughness and fatigue life of welded structures. The low transformation-temperature (LTT) fillers, due to introducing compressive residual stresses caused by prior martensitic transformation, can reduce tensile residual stresses in the weld zone. The effects of using LTT fillers on welding residual stresses of high strength steel sheets are studied and compared with conventional fillers. 3D finite element simulations including coupled thermal-metallurgical-mechanical analyses are developed using SYSWELD software to predict the welding residual stresses. For validation of the finite element model, the residual stresses are measured through hole drilling strain gage method. The results indicate that using the LTT fillers cause a decrease of the longitudinal tensile residual stresses of the weld metal from 554 MPa to 216 MPa in comparison with conventional fillers. The transverse residual stresses of the weld line are changed from tensile 156 MPa to compressive 289 MPa with using LTT fillers instead of conventional fillers.


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