Simulation of temperature field and stress field of v-groove butt joint

The parameters of the heat source model have significant influence on the temperature field and sequentially affect the residual stress field. In this paper, a neural-network programme based on the Levenberg–Marquardt algorithm is developed to predict the parameters of Goldak's double-ellipsoidal heat source model. The analytical solution of the heat conduction equation based on the double-ellipsoidal heat source is obtained by integrating a series of instant point heat sources over the volume of the ellipsoidal heat source. The transient temperature distribution and the sizes of the molten pool are obtained under various welding processes by using the analytical method. Then, a neural-network programme is employed to train and predict the heat source parameters. These results of temperature and molten pool size obtained by the numerical simulation with the predicted heat source parameters are calibrated by the published experimental results. The numerical results show a good agreement with the experimental measurements. Finally, the developed Levenberg–Marquardt neural network is employed to predict the heat source parameters in the multi-pass welding process in the laboratory. By comparing the finite element (FE) numerical results with experimental results, the heat source parameters have been successfully identified in the multi-pass welding process.

Welding parameters have important affect on welding quality. In this paper, temperature field and residual stress field simulation of thin 316L stainless steel plate are performed by finite element method. The welding process is multi-pass butt TIG(Tungsten Inert Gas) welding. Simulation model are established by SYSWELD code with multi-pass bead. A Gaussian heat source representing the arc energy is verified and the temperature distribution in multilayer welding process is simulated. Then the results are compared with test results measured by thermal-couples. Effects of welding speed and interpass cooling time during multi-pass on temperature field and stress field are studied. The results show that the faster the welding speed and the longer the cooling time, the higher the residual stress will be.

In order to control the thermal stress of forming process,based on "element birth and death" technology of finite element method,a numerical simulation of three-dimensional temperature field and stress field during multi-track and multi-layer laser metal deposition shaping(LMDS) process is developed with ANSYS parametric design language(APDL).The dynamic variances of temperature field and stress field of forming process are calculated with the energy compensation of interaction between molten pool-powder and laser-powder.The temperature field,temperature gradient,thermal stress field and distribution of residual stress are obtained.The results indicate that although the nodes on different layers are activated at different time,their temperature variations are similar.The temperature gradients of samples are larger near the molten pool area and mainly along z-direction.The transient thermal stress has concentrated in large temperature gradient area,which is in accordance with thermal stress forming theory.Through analyzing the residual stress of the as-formed samples in different directions,distribution rule of residual stress is achieved from temperature gradient perspective.And formation mechanism of residual stress is verified with an indirect way.Finally,it's verified that the analysis results are consistent with actual situation by the experiments with same process parameters.

Aiming at saving defects and cracks of dissimilar metal materials laser welding, the finite element analysis of temperature field and new welding process of stainless steel/Al, stainless steel/Cuwere developed in this work.Taking stainless steel/Al, stainless steel/Cu dissimilar materials laser welding for example, the physical model was established, and the finite element simulation of three-dimensional temperature field of laser welding was carried out based on Abaqus CAE. The results show that the simulation of temperature field provides reference for experimental process parameters, fiber laser welding is applicable to stainless steel/Cu, stainless steel/Al with lower laser welding defect.The process parameters were optimizedto achieve better welding quality and solve welding defects.The accurate prediction of temperature field distribution in dissimilar materials laser welding is great significance for practical process guidance.

Finite element analysis(FEA) simulation of temperature and stress field was applied in dry-type transformer casting, curing, and cooling process in this paper. Considering to the material's performance changing along with temperature, the paper adopted nonlinear analysis. A 3D FEA model of the dry-type transformer winding transient temperature field and thermal-stress field was theoretically built, and a mathematical model of the initial condition, boundary condition, and latent heat disposal was built as well, then A FEA analysis was finished for the stress frame 3D temperature field and thermal-stress field of the typical winding. The result indicated that the numerical simulation can basically reflect the dynamic changing of the temperature and stress field in the casting, curing and cooling process, and it nicely tallied with the actual measurement. (5 pages)

In thermal fatigue test, the key point is whether the temperature field on the top surface of cylinder head induced by the heat source can well match it in real service. In order to produce the target temperature field in service which is measured by thermocouples, shaped laser beam generated by diffractive optics element (DOE) is chosen as the heat source to irradiate on the top surface of cylinder head. The DOE is designed based on the Gerchberg-Saxton (GS) algorithm and the simulated temperature field is calculated by finite element model (FEM). The results show that the simulated and experimental temperature field can well match the target one which demonstrates that this method is feasible to produce the target temperature field and can be used in thermal fatigue test.

A numerical-experimental investigation of heat distribution, stress field and crack susceptibility in Ni60A coatings

Simulation of temperature field and stress field of selective laser melting of multi-layer metal powder

Simulation of temperature field and residual stress in high-power laser self-melting welding process of CLF-1 steel medium-thick plate

Residual stresses resulted from localized non-uniform heating and subsequent cooling during welding processes enact an important role in the formation of cracks and welding distortions and have severe effect on performance of welded joints. The present research performs a three dimensional transient thermo Elasto-plastic analysis using finite element technique to simulate welding process. Welding simulation procedure is developed using the parametric design language of commercial code ANSYS for single pass T and butt welded joints. The procedure verified with predicted residual stress field found in literature to confirm the accuracy of the method. The material of the weld metal, HAZ and the base metal are assumed to be the same. With regards to high temperature gradient in weld zone, temperature dependant thermal and mechanical properties have been incorporated in the simulation. Also in this work the technique of element birth and death was employed to simulate moving heat source and the weld filler variation with time. Temperature and residual stress fields were discussed.

The temperature field and thermal stress field of cast-hot-working-die (CHWD) steel under high density electropulsing were investigated by finite element analysis method. The simulation analysis showed that, during the electropulsing discharging process, the existence of specimen notch resulted in the concentration effect of electric current, namely that the increase of current density in local position. The electric current with high density induced the concentration release of Joule heat and the formation of heat affected zone (HAZ) ahead of specimen notch tip. Because the expanding of HAZ with high temperature was restricted by the neighboring matrix with low temperature, the thermal compressive stress formed in the former during electropulsing discharging. The metallurgy process, under the condition of high temperature and pressure and accompanying thermal compressive stress, was regarded as being beneficial for enhancing mechanical properties and thermal fatigue resistance of CHWD steel and prolonging service lifetime of die in extremely high temperature condition.

In order to control the thermal stress of forming process, based on “element birth and death” technology of finite element method, a numerical simulation of three-dimensional temperature field and stress field during multi-track & multi-layer laser metal deposition shaping(LMDS) process is developed with ANSYS parametric design language (APDL). The dynamic variances of temperature field and stress field of forming process are calculated with the energy compensation of interaction between molten pool-powder and laser-powder. The temperature field, temperature gradient, thermal stress field and distribution of residual stress are obtained. The results indicate that although the nodes on different layers are activated at different time, their temperature variations are similar. The temperature gradients of samples are larger near the molten pool area and mainly along z-direction. Finally, it’s verified that the analysis results are consistent with actual situation by the experiments with same process parameters.

Simulation of temperature field during nanoscale orthogonal cutting of single-crystal silicon by molecular statics method

Temperature field simulation and asymmetric heat transfer distribution of dissimilar steel welded with external transverse magnetic field

Double wires submerged arc welding is more and more widely applied. However, due to the immaturity of the welding process, the quality of double wires submerged arc welding is still not so good, and its application in the offshore platform engineering is limited. The paper adopt the simple flat plate welding, uses the finite element software ANSYS to simulates the temperature field of double wire submerged arc welding process. During the temperature field simulation process, double ellipsoid heat source model is used as a load heat source, composite convection coefficient is adopted to simulate heat loss, the element's birth and death is considered to simulate welding material injection, welding speed is assigned as a constant. At last, a good result of temperature field is obtained.