Numerical Simulation Of Residual Stresses Research Articles

Numerical Simulation of Residual Stresses and Structural Vibration of Welding Repaired Blades

Abstract Taking a typical aero-engine high-pressure compressor blade as the research object, the Gauss heat source was used to numerically simulate the repair process of blade surfacing welding. The temperature data and stress data of the blade were obtained when the heat source velocity was 1 mm/s, 2 mm/s, and 4 mm/s, respectively. The results showed that both the temperature and stress values decreased with the heat source velocity increasing. Then, the residual stress of the repaired blade is introduced into the modal analysis module as prestress, and the Campbell diagram is drawn to analyze the natural frequency and speed margin of the blade respectively. The results show that as the heat source speed increases, the frequencies of each order of the blade decrease. The speed margin of each resonance point is greater than 10%, and the modal dynamic stress corresponding to the resonance speed can be used as the primary criterion for blade failure.

A Numerical Simulation of the Seismic Performance and Residual Stress of Welded Joints in Building Steel Structures Based on the Finite Element Method

With the development of society and urbanization, higher requirements have been put forward for the safety and seismic resistance of building structures. The fatigue strength and seismic performance of welded joints have received close attention, especially as a crucial part of building steel structure. This study used the finite element simulation method to analyze the stress-strain of welded joints in building steel structures, and explore the influence of residual stress on their seismic performance. A stress-strain calculation model for welded joints in building steel structures was studied and constructed, and the accuracy of the model was verified through numerical calculation methods. The results showed that the residual stress peaks of the horizontal and vertical directions of the V-groove welded joint structure were 475 MPa and 325 MPa, respectively, and the longitudinal residual stress peaks were 525 MPa and 425 MPa, respectively. The seismic performance of four different steel structural plates was Q960>Q690>Q460>Q345. In summary, the numerical simulation of residual stress in the seismic performance of welded joints in building steel structures, when based on the finite element method, makes a contribution of clear value to the field of seismic performance of welded joints in building steel structures.

Numerical simulation of residual stress of butt-welded joint involved in complex column-beam welded structure

The objective of this work is to clarify the effect of the structural restraint and the adjacent welded joints in column-beam welded structure on the final residual stress distribution and its evolution process of the butt-welded joint between the diaphragm and the flange through numerical simulation method. Based on ABAQUS software, a three dimensional thermal-mechanical coupled method was developed to predict the residual stress distribution for multi-pass welded joints. To improve calculation efficiency, an effective computational approach that combines a relatively coarse mesh design and an instantaneous heat source model was proposed to analyze the residual stress distribution for complex welded structures. Firstly, both a fine mesh model with moving heat source and a relatively coarse mesh model with instantaneous heat source were employed to predict the residual stress distribution in the same thick-plate butt-welded joint made of high strength low alloy steel. The computational accuracy of the proposed computational method was verified through comparing the results of the fine mesh model with moving heat source and the corresponding experimental data. Then, the residual stress distributions of the column-beam welded structure, the butt-welded joint under structural restraint condition and free state were calculated using the proposed computational approach. Results suggest that the structural restraint and the adjacent welded joints in the structure have a significant effect on the residual stress distribution.

Numerical simulation of residual stress in post internal-welding process of bimetal composite pipe and optimization of welding sequence

With the increasing demand for energy, energy extraction is developing towards a more complex corrosive environment containing a large amount of CO2, H2S and Cl−. Bimetal composite pipes because of both good corrosion resistance and strength are getting more and more research and application. In this paper, L415/316L bimetal mechanical lined pipes were welded by two processes (single-side welding process and post internal-welding process) the residual stress of which was studied by combining numerical simulation and experiment. Then the welding sequences of the post internal-welding process were compared and analyzed. The results show that there is already a certain amount of residual stress in the pipe after overlay welding. The residual stress of single-side welding process and post internal-welding process is too large and distributes in the danger zone, which is easy to lead to failure. By adjusting sequence of the post internal-welding, it can effectively change the level of the residual stress and reduce the stress of the overlay layer, the internal-welding layer and the backing welding layer, which is beneficial to improve the safety of the bimetal mechanical lined pipe.

Effect of Residual Stress on Hydrogen Diffusion in Thick Butt-Welded High-Strength Steel Plates

Thick high-strength steel plates are increasingly being used for ship structures. Moreover, hydrogen enters the process of manufacturing and service, and large residual tensile stress occurs near the weld. Such stress can facilitate the diffusion and accumulation of hydrogen in the material, leading to hydrogen embrittlement fracture of the shell. Therefore, residual-stress-induced diffusion and accumulation of hydrogen in the stress concentration region of thick butt-welded high-strength steel plate structures need to be studied. In this study, manual metal arc welding was realized by numerical simulation of residual stress in a thick butt-welded high-strength steel plate model using the thermoelastic–plastic theory and a double ellipsoidal heat source model. To analyze residual stress, a set of numerical simulation methods was obtained through comparative analysis of the test results of relevant literature. Residual and hydrostatic stress distributions were determined based on these methods. Then, hydrogen diffusion parameters in each region of the model were obtained through experimental tests. Finally, the results of the residual stress field were used as the predefined field of hydrogen diffusion to conduct a numerical simulation analysis. The distribution of hydrogen diffusion under the influence of residual stress was obtained based on the theory of stress-induced hydrogen diffusion. The weak area of the welding joint was found to be near the weld toe, which exhibited high hydrostatic stress and hydrogen concentration. Further, the maximum hydrogen concentration value of the vertical weld path was approximately 6.1 ppm, and the maximum value of the path parallel to the weld centerline and 31 mm away from the weld centerline was approximately 6.22 ppm. Finally, the hydrostatic tensile stress in the vertical weld path was maximized (~345 MPa), degrading the material properties and causing hydrogen-related cracking. Hence, a reliable method for the analysis of hydrogen diffusion according to residual stress in thick high-strength steel plates was obtained. This work could provide a research basis for controlling and eliminating the adverse effects of hydrogen on the mechanical properties of ship structures and ensuring the safe service of marine equipment.

Numerical Simulation of Residual Stress and Deformation in Wire Arc Additive Manufacturing

In this paper, multi-layer and multi-pass arc additive manufacturing experiments were carried out on the Q345 substrate using Y309L welding wire. Based on MSC. Marc software, a thermal-elastic-plastic finite element method was developed to numerically simulate the temperature field, stress field, and deformation during the additive manufacturing process. The effects of the substrate thickness and interpass temperature on the temperature field, stress field, and deformation were discussed. The results indicated that the deposition materials at different positions experienced different thermal cycles, which might lead to the non-uniform microstructure and mechanical properties within the workpiece. The interpass temperature and the thickness of the substrate influenced the residual stress distribution in the additive manufactured structure. A low interpass temperature and thin substrate was able to effectively reduce the tensile residual stress. The thick substrate resulted in a small angular deformation of the substrate during the additive manufacturing process.

Experimental Investigation and Numerical Simulation of Residual Stress and Distortion of Ti6Al4V Components Manufactured Using Selective Laser Melting

Experimental Investigation and Numerical Simulation of Residual Stress and Distortion of Ti6Al4V Components Manufactured Using Selective Laser Melting

Friction stir welding of Al-SiC composite sheets: a numerical simulation of residual stresses

Friction stir welding of Al-SiC composite sheets: a numerical simulation of residual stresses

Prediction and numerical simulation of residual stress in multi-pass pipe welds

AbstractA numerical simulation procedure is presented to predict residual stress states in multi-pass welds in oil transportation pipes. In this paper, a two-dimensional thermo-mechanical finite element model is used to calculate the temperature distribution, hardness, and the distribution of residual stresses during multi-pass welding of pipes of dissimilar metals and varying thicknesses. In this model, the temperature dependence of the thermal and mechanical properties of the material was considered. The present model was validated using the hardness measurement. Good agreement was found between the measurement and the numerical simulation results. The simulated result shows that the two-dimensional model can be effectively used to simulate the hardness test and predict the residual stress in the pipe weld. The simulation results and measurements suggest that the model with moving heat source can obtain a good prediction of residual welding stress. Both the two-dimensional and the three-dimensional modeling can be used to estimate the residual stresses in different weld regions and help saving time.

Numerical characterization of residual stresses in a four-point-bending experiment of textured duplex stainless steel

The resulting shapes in production processes of metal components are strongly influenced by deformation induced residual stresses. Dual-phase steels are commonly used for industrial application of, e.g., forged or deep-drawn structural parts. This is due to their ability to handle high plastic deformations, while retaining desired stiffness for the products. In order to influence the resulting shape as well as component characteristics positively it is important to predict the distribution of phase-specific residual stresses which occur on the microscale of the material. In this contribution a comparative study is presented, where two approaches for the numerical simulation of residual stresses are applied. On the one hand a numerically efficient mean field theory is used to estimate on the grain level the total strain, the plastic strains and the eigenstrains based on macroscopic stress, strain and stiffness data. An alternative ansatz relies on a Taylor approximation for the grain level strains. Both approaches are applied to the corrosion-resistant duplex steel X2CrNiMoN22-5-3 (1.4462), which consists of a ferritic and an austenitic phase with the same volume fraction. Mean field and Taylor approximation strategies are implemented for usage in three dimensional solid finite element analysis and a geometrically exact Euler–Bernoulli beam for the simulation of a four-point-bending test. The predicted residual stresses are compared to experimental data from bending experiments for the phase-specific residual stresses/strains which have been determined by neutron diffraction over the bending height of the specimen.

Numerical simulation of residual stresses in hot isostatic pressed SiC/GH4738 composites

In this paper, the residual stresses in hot isostatic pressed SiC/GH4738 composites were investigated using numerical simulation. First, the finite element model of the SiC/GH4738 composites was built using ABAQUS. Then, the hot isostatic press process was simulated, where the paths of temperature and pressure were considered. The residual stress distributions were obtained, and the changes in interfacial residual stresses with angle were analyzed. Finally, the effect of process parameters on residual stresses was analyzed. The simulation results show that maximum temperature, holding time, and fiber volume content have little influence on the distribution of interface residual stress but have great influence on the magnitude of interfacial residual stress. The results will help to influence the design and preparation of SiC/GH4738 composites.

Three-Dimensional Numerical Simulation of Residual Stress of Z-Pin Composites During Curing Process

By using the coupled thermos-mechanical method, a three-dimensional finite element model of composite was established during the curing process. The accuracy of the simulation model was validated by performing a comparison with the literature results. Based on the model, a three-dimensional finite element method is applied to conduct analysis of the effect exerted by the curing related parameters on residual stresses in the curing process for the Z-pin AS4/3501-6 composite. The results indicate that the resin stress and fiber Z-direction stress increase with the curing process, especially during the cooling stage. The bottom stresses of both resin and fiber are observed to be lower than that of top layer. The stress of rich-resin zone at pin/fiber interface is higher but the deformation is smaller. The stress of resin and fiber increases as the volume shrinkage ratio of resin is on the rise.

Numerical Simulation of Residual Stress and Deformation of SUS310S Stainless Steel Local Vacuum Electron Beam Welded Joint

Numerical Simulation of Residual Stress and Deformation of SUS310S Stainless Steel Local Vacuum Electron Beam Welded Joint

Numerical simulation of residual stresses in aluminum alloy welded joints

The lightweight design makes thin-plate welded structures used widely, especially for the aluminum alloy thin-plate welded structure, it is very important to study the fatigue fracture properties of the structure considering the influence of residual stress. A solid model of a butt joint of aluminum alloy with a double-pass weld is established. Both the welding temperature fields and residual stress fields are simulated through the thermal elastic–plastic method. The welding experiment is also performed with the corresponding joint, which is welded by means of metal inert-gas (MIG) welding. Consequently, the computational and experimental results of residual stress are in good agreement. Moreover, the thermal elastic–plastic method is employed to calculate the residual stress fields of typical welded joints. Based on the inherent strain theory, the transverse and longitudinal inherent strain of the joints are decomposed from the total strains and applied to both solid and shell models of the three types of joints to calculate the residual stress fields of them. The results of the solid and shell models using the two methods are practically consistent, which indicates that the inherent strain method can predict the residual stress on the shell model efficiently and accurately. Thus, the method of predicting the welding residual stress of thin-plate structures based on the inherent strain is proposed, which provides a reference for the structural fatigue assessment under the influence of residual stress.

Numerical Simulation of Residual Stress for Laser Welding of Ti-6Al-4V Alloy Considering Solid-State Phase Transformation

In the present work, a thermal-metallurgical-mechanical model which considered the influence of phase transformation was used to predict the residual stress field of Ti-6Al-4V after laser welding. In this model, the Johnson–Mehl–Avrami equation was used to predict diffusional solid-state phase transformations: α phase to β phase during heating and β phase to α phase during cooling. The Koistinen–Marburger equation was used to predict diffusionless solid-state phase transformation of β phase to martensite during cooling. The properties of material were obtained using a mixing rule based on the phase fraction and the property of each pure phase. By applying this model, the effect of solid-state phase transformations of Ti-6Al-4V alloy on temperature field and stress field during laser welding was considered in the simulation. In addition, experiments were carried out for comparison, which significantly verified the accuracy of the applied model.

Numerical Simulation of Residual Stresses in Multipass Gas Metal Arc-Welded Joints of Thick Aluminum Alloy Plates

Numerical simulation was utilized to investigate the residual stresses in the multipass gas metal arc-welded joints of high-strength Al-Zn-Mg alloy plates. In order to elevate the reliability of numerical simulation, the heat source model, parameters characterizing the thermal and mechanical properties, boundary conditions, material constitutive model and finite element meshing were discussed in detail. As a novelty of this paper, the modified Arrhenius constitutive equation of the base material and the filled material was obtained according to the results of high-temperature tensile tests. Distributions of stress on the upper and bottom surface of the joint were obtained based on numerical simulation. Special attention was paid to the evolutions of local residual stress on the bottom surface of the joint, and it’s found that residual stresses on the bottom surface of the joint were almost unchanged after the weld seam approached a certain thickness. Blind-hole method and x-ray method were adopted to detect the residual stresses on the surfaces to verify the accuracy of the results obtained by numerical simulation.

Numerical Simulation of Residual Stress in P91 Repair Welding Incorporating Martensitic Transformation

The type IV cracking is one of the main reasons for service failure. The repair welding is implemented to solve this problem. The residual stress in P91 repair welding incorporating martensitic transformation (MT) is acquired through finite element simulation. In the simulation, the ABAQUS and the user subroutines FILM, DFLUX, HETVAL, USDFLD, UEXPAN and UHARD are adopted. The effect of MT latent heat on temperature and the effects of the volume expansion, the yield strength change and the transformation plasticity on stress are considered. The results show that there is full MT in the repair welding area and the old welding area. The MT latent heat makes the temperature of the repair welding area increase. The residual stress of the repair welding area decreases because MT relieves the thermal stress. Before repair welding, the residual stress distribution is M-shape, which is consistent with the experimental results. After repair welding, the residual stress of repair welding area decreases and the residual stress of old welding area increases.

激光冲击圆杆曲面诱导的残余应力数值模拟

激光冲击圆杆曲面诱导的残余应力数值模拟

Numerical Simulation of Residual Stresses due to Multipass Welding in High Strength Steel Plates and Validation against Experimental Measurements

Multipass arc welding is commonly used for thick plates assemblies in shipbuilding. Sever thermal cycles induced by the process generate inhomogeneous plastic deformation and residual stresses. Metallurgical transformations contribute at each pass to the residual stress evolution. Since residual stresses can be detrimental to the performance of the welded product, their estimation is essential and numerical modelling is useful to predict them. Finite element analysis of multipass welding of a high strength steel is achieved with a special emphasis on mechanical and metallurgical effects on residual stress. A welding mock-up was specially designed for experimental measurements of in-depth residual stresses using contour method and deep hole drilling and to provide a simplified case for simulation. The computed results are discussed through a comparison with experimental measurements.

Numerical simulation of residual stress in laser based additive manufacturing process

Minimizing the residual stress build-up in metal-based additive manufacturing plays a pivotal role in selecting a particular material and technique for making an industrial part. In beam-based additive manufacturing, although a great deal of effort has been made to minimize the residual stresses, it is still elusive how to do so by simply optimizing the processing parameters, such as beam size, beam power, and scan speed. Amid different types of additive manufacturing processes, Direct Metal Laser Sintering (DMLS) process uses a high-power laser to melt and sinter layers of metal powder. The rapid solidification and heat transfer on powder bed endows a high cooling rate which leads to the build-up of residual stresses, that will affect the mechanical properties of the build parts. In the present work, the authors develop a numerical thermo-mechanical model for the measurement of residual stress in the AlSi10Mg build samples by using finite element method. Transient temperature distribution in the powder bed was assessed using the coupled thermal to structural model. Subsequently, the residual stresses were estimated with varying laser power. From the simulation result, it found that the melt pool dimensions increase with increasing the laser power and the magnitude of residual stresses in the built part increases.