Papers by Keyword: Residual Stress

Abstract: The purpose of this review paper is to summarize the novel and advanced finite element simulation techniques devised in recent years to predict the welding residual stresses. The finite-element (FE) simulation methods are commonly used to predict the thermal, material, and mechanical effects of welding because of their efficiency and flexibility. This study presents an overview of the research, conducted to more accurately simulate the welding process. Some recommendations and simplification techniques presented by researchers are also discussed in this study which provides a foundation for further development in this field.

Abstract: The residual stress distributions of 7075 aluminum alloy rectangular thick plates after quench-hardening had been simulated firstly, then all the results were presented and compared with each other. Some deep theoretical analyses were also carried out. The results show that complicated residual stress distribution regularities in aluminum alloy thick plates can be obtained by the finite element analysis successfully.

Abstract: In the paper,the electrical discharge machining(EDM) technique was used to cut strips for cold-formed residual stress measurement of hat-shaped section.After adjusting the electrolyte ratio,designing specific the cutting tool and improving the methodof antiseptic treatment,the test results improved significantly. Electrical resistance strain gauges with EDM cutting technique were used to establish the magnitude and distribution of the residual stresses in cold-formed hat-shaped section.Based on the experimental findings, an idealized distribution pattern of the residual stress in cold-formed hat-shaped section is presented.

Abstract: Multi-pass welds are used in pipes with stainless steel. The complicated temperature field and residual stresses in these welded structures are very important. The finite element method is used to simulate residual stress in multi-pass butt-welds in this paper. Element birth technique is implemented to model multi-pass welded 304 Stainless Steel Pipes. One-way coupled Thermo-mechanical analysis is adopted to calculate the residual stresses, that the structural analysis takes the temperature distributions as thermal input. The results provide reference for the structure integrity assessment of welded pipes.

Abstract: The simulation of residual stress in Electron Beam Melting (EBM) process is critical for optimization of process conditions. However, there is no published literature on the simulation of residual stresses in this process. This paper considers finite element modeling of the temperature distribution through transient thermal analysis. The measured temperature and total heat flux from transient thermal analysis are then used as initial input parameters to the structural analysis. Consequently, deformations and residual stresses in structural analysis were measured. The titanium alloy, Ti6Al4V has been used, which is one of the most common materials for biomedical implants due to its high strength to weight ratio, corrosion resistance, and its biocompatibility features.

Abstract: In this project, the residual stress due to multipassed welding process at the fillet weld will be studied using 2D Finite Element Analysis (FEA) simulation method and experimental investigation. Due to the extensive capabilities and dedicated tools for the simulation of welding, including material deposit via element activation or deactivation and predefined or customized moving heat sources, SYSWELD 2010 was chosen as the FEA software. The material with a thickness of 9 mm was structural steel S355J2G3 for simulation and low carbon steel for the experiment. The clamping condition was selected to obtain the best relationship between simulation and experiment by using Strain Gage. The model was dedicated to multipassed welding using the robotic welding system

Abstract: Of hot rolling 100-meter heavy rail, the shrinkage masses or swell increments are different in different positions of transverse sections during the cooling process by the reason of profiled cross-section, which resulted in alternating bend, and the flatness and residual stresses are directly affected by bending deformation before straightening during the cooling process. In this paper, By studying the heat boundary conditions in cooling process, the regularity of bending deformation of hot rolling heavy rail during cooling is observed, adopting 3-D transient nonlinear FEM simulation. By controlling the deformation value of bending before straightening and the value after straightening, the influence of residual stresses after straightening from pre-bending values before straightening is analyzed, drawing a conclusion of the regularity that residual stresses are affected by different chord heights at the same straightening rule, and the calculated results have a good accordance with the real values in field scene.

Abstract: Given that the traditional hot temper passing process cannot fulfill the demand of high strength steel on residual stress level and stable processability, leveler and temper passing process with dual servo valve (LTP-DSV) is developed to solve this technical problem. LTP-DSV process employs leveler to reduce residual stress level of high strength steel; uses dual servo valve variable gain rolling force control technology to improve performance stability of high strength steel; improves surface quality of high strength steel by means of temper passing. The residual stress level of products is substantially reduced on condition that the performance of high strength steel is ensured. The actual production data shows LTP-DS process is able to improve the performance and quality of high strength steel from all aspects.

Abstract: In order to investigate the mechanism of surface cracks in silicon nitride ceramic (HIP-Si3N4) from the viewpoint of shear stress, the authors focused on torsion fatigue testing and observed the crack growth behavior under conditions where the stress ratio was R = - 1. Furthermore the residual stresses around the cracks were measured. Based on these results, mode II growth of surface cracks is discussed and it was concluded that under stress ratio R = -1, surface cracks grow slowly in mode II, for ΔKⅡ less than 3.6MPam1/2.

Abstract: In order to understand the phenomena caused by the contact stresses occurring within surface, non-destructive methods that can be related to contact conditions are necessary. The main purpose of this work is to study the relationship between magnetization location and direction, spherical Hertzian contact and changes in the magnetic field asymmetry. In the present work, we used a newly developed GaAs film sensor-equipped scanning Hall probe microscope (SHPM) and observed magnetic fields in tool steel plates before and after contact tests under 196N load, at room temperature in air. Medium carbon low alloy steels specimens (JIS S45C) were used in the experiments. Around the contact test area, changes in ‘S’ and ‘N’ poles generated by magnetization using a square magnet block were investigated.