Thermal-structural Coupling Analysis Research Articles

Thermal stress analysis of disc brake using analytical and numerical methods

This article presents study of the thermal stress development in brake disc and the associated life cycle of the disc. The thermal stress analysis of disc brake under the first brake application and the influences of thermal loads on stress development of the disc have been investigated. The temperature distribution was conducted as a function of disc thickness and braking time. The study was done on the disc brake of Sports Utility Vehicle with a model of DD6470C. Partial solution approach was used to solve analytical temperature distribution through the thickness. The model was done using representative areas of the disc exposed to high temperature whose distribution result was obtained as a function of disc thickness and braking time. The solutions of coupled thermal transient fields and stress fields were obtained based on thermal-structural coupled analysis. Based on the model developed for the study, the positions of high and low stress formations were investigated, and it has been observed that thermal stress and temperature gradient show similar behavior through the thickness of disc. Generally, high temperature and stress components were found on the rubbing surfaces of the disc.

Numerical research on thermal stress of steam cooler tube sheet mechanical structure

Steam cooler is one of the most important mechanical equipment in thermal power generation system and nuclear power generation system. The steam cooler bears a huge temperature gradient load when the working conditions are switched. In order to analyze the thermal stress of steam cooler tube sheet with high temperature load under harsh working conditions, the thermal-structural coupling analysis model of steam cooler tube sheet is constructed with finite element method. The results show that the stress concentration exists at the position connection between heat exchanger tube and cylinder. The maximum stress is located at the outermost heat exchanger tube with the peak stress of 320MPa. The heat exchanger tube layout alone cause higher stress. This situation should be avoided in the design of heat exchanger tube sheet. Furthermore, the strength and safety of the steam cooler tube sheet are evaluated with the stress linearization method. The steam cooler tube sheet design meets the safety requirements of structural strength under high temperature load.

Effect of residual stress in longitudinal and transverse weld on global stability of box section steel column

In order to study the influence of welding residual stress on the global stability of box section steel column, the simulation of the side effects from the welding process of Q345 box section steel column by ABAQUS thermal-structure coupling analysis was conducted. A temperature-displacement explicit analysis step was established, and the residual stress caused by the temperature difference of the welding specimen was simulated by applying the body heat flux directly to the solid element within the same thickness range of the weld seam and defining the load amplitude; The calculated welding residual stress was taken as the initial defect of the structure and the global stable bearing capacity of the box section steel column was solved by the arc length method. Considering the influence of thickness and welding residual stress on the global stability of box section steel column, the calculation results of 12 finite element models were compared. The results show that under the same body heat flux, the residual stress of steel columns with different thicknesses during welding is different, and the maximum value can reach 791MPa; Under the condition of the same residual stress, the global stability bearing capacity of the box section steel column will also change irregularity with the change of thickness, and the global stability bearing capacity can be reduced by 3.07% compared with that no residual stress.

Simulating and Predicting the Part Warping in Fused Deposition Modeling by Thermal-Structural Coupling Analysis.

As the most commonly used additive manufacturing technology, fused deposition modeling (FDM) still faces some technical issues caused by temperature change-induced unsteady thermal stress and warping. These issues can further lead to the deformation of printed parts and even terminate the printing process. In response to these issues, this article established a numerical model of temperature field and thermal stress field for FDM by finite element modeling and "birth-death element" technique to predict the deformation of the part. What makes sense in this process is that the logic of elements sort based on ANSYS Parametric Design Language (APDL) was proposed to sort the meshed elements, which was aimed to perform FDM simulation quickly on the model. In this work, the effects of the sheets shape and infill line directions (ILDs) on the distortion during FDM were simulated and verified. From the analysis of stress field and deformation nephogram, the simulation results indicated that ILD had greater effects on the distortion. Moreover, the sheet warping became most serious when the ILD was aligned with the diagonal of the sheet. The simulation results matched well with the experimental results. Thus, the proposed method in this work can be used to optimize the printing parameters for FDM process.

Experimental Analysis & Optimization with Validation of Ball Valve Body of WCB Material

The ball valves are used in place of pipelines where the flow of fluid is needed. Ball valves have been mostly used for high temperature and high pressure valves which requires high quality products with confidentiality, reliability and durability. The ball has a bore or passage through the middle, so that when the port is in line with both ends of the valve, the flow of fluid will occur. When the valve is closed, the hole is perpendicular to the ends of the valve, and the flow is closed. The ball valve can revolve 90°, which has large size and weight, but it has not only an enormously more excellent confidentiality than other valves in the severely high temperature and high pressure environment When the ball valve is in closed condition the pressure exerted on the ball valve body due to that high pressure fatigue stresses and strain develop on the body of valve. Because of the high pressure and temperature on the ball valve body leakage of body take place which cause safety issue and ball valve failure. By this research stress strain analysis of ball valve body obtains and identifies the maximum and minimum stress and strain produced on the body of ball valve. The Max stress by parts was confirmed through thermal-structural coupled field analysis of major parts to evaluate safety. The objective of this research is to examine the effect of pressure and temperatures on valve components its analysis and optimization

Effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope

The alidade’s non-uniform temperature field of a large radio telescope is very obvious under solar radiation. Estimating a radio telescope’s pointing errors, caused by the alidade deformation under solar radiation, is significant to improve the telescope’s pointing accuracy. To study the effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope, a temperature experiment is first carried out in a 70-m radio telescope on a sunny day. According to the measured results, the temperature distribution rule of the alidade is summarized initially. In addition, the alidade’s temperature field is calculated by finite element thermal analysis. The simulated results are proved to be in good agreement with the experimental results. Finally, the alidade deformation under solar radiation is computed by finite element thermal-structure coupling analysis. The telescope’s pointing errors caused by alidade deformation are estimated via the alidade’s node displacements. The final results show that the effect of alidade thermal behavior on the telescope’s elevation pointing errors Δ ε 2 + Δ εr is much more than the effect on the telescope’s cross-elevation pointing errors Δ ε 1. The maximum of Δ ε 2 + Δ εr is more than 45″, while the maximum of Δ ε 1 is less than 6″. This study can provide valuable references for improving the pointing accuracy of large radio telescopes.

Study on thermo-mechanical coupling method of ship cabin with ceiling vent under fire condition

Objectives The performance analysis of ship cabin steel structures in fire situations is fundamental to structural fire resistance design. Compared with research conducted under traditional standard fire conditions, research based on the real fire temperature field can more accurately analyze the mechanical response behavior of cabin structures. Aiming at an open cabin (i.e. engine room) structure, a fire-heat-structure coupling method combining FDS and ANSYS is developed. Methods First, the FDS simulation is utilized to obtain the temperature information of the inside ship wall exposed to the fire, which is then used as the boundary condition transferred to the structural finite element analysis software ANSYS. Transient thermal analysis concerning the temperature field of the cabin structure is then conducted, and the thermal-structural coupling analysis of the ship cabin structure carried out in a real fire scenario. Results The results of the case study using the proposed method demonstrate that the stress distribution is not uniform due to the uneven temperature distribution. The maximum stress is concentrated at the edge of the cabin, with a value of 19 MPa. The structure does not reach the failure limit after being exposed to fire. Conclusions Compared with the traditional standard fire curve method, the proposed method has two advantages for addressing structural response: the non-uniform elevated temperature of the structure and real fire temperature rise. More attention should be paid to the change in structural internal force caused by non-uniform temperature rise in an open ship cabin.

Advances in Endovascular Intervention Using Biomaterials: Study on Heat Efficiency of Scissor-Type Ultrasonic Catheter Device.

To improve the performance of the ultrasonic device during the endovascular operation, a scissor-type ultrasonic catheter device with compound vibration was developed. The heat generated by friction between the target and the device affects its coagulation mechanism while the actuator contacts the tissue. The scissor-type ultrasonic catheter device proposed in this study is expected to improve heat generation performance because it has the action of rubbing the object when it is pushed by combined vibration. In addition, since it is constructed by simple notch processing, it can be miniaturized and can be expected to be introduced into catheters. However, the observation of ultrasonic vibration during frictional heating is difficult, which is an issue for device design. In this paper, a thermal-structure coupling analysis was done using the finite element method to calculate the heat generation efficiency and evaluate its coagulation performance.

Numerical Analysis of Ultimate Mechanical Characteristics of Suspension Bridges’s Cable in High Temperature Fire

Relying on the joint research project, research is carried out on the ultimate mechanical characteristics of suspension bridge slings under high temperature fire. The establishment of a local transient temperature field heat transfer model based on the FDS software, and the analysis of the temperature distribution law of the fire source at different wind speeds. The most unfavorable fire condition is the combination of the fire source heat release rate of 300MW and the wind speed of 14m/s; the overall structure model of the bridge is modeled by ANSYS software. Firstly, the modal analysis of the whole bridge model is carried out to verify the accuracy of the modeling, and then the thermal structural coupling analysis is carried out under the most unfavorable fire conditions to obtain the structural response of the whole bridge structure under the sling fire. According to the change trend of the structure response of the cable under fire, the fire resistance limit of the bridge structure is obtained as 460°C; Under the most unfavorable fire burning situation, when the limit number of broken cable in the span is 3, the cable will be caused into collapsing continuously; the composite protective layer has a significant effect on the fire resistance of the cable.

Thermal-structural coupling analysis of beam screen in super proton-proton collider

High-energy colliders play an indispensable role in particle physics and high-energy physics. Beam screen is one of the key parts in the high-energy collider. It is used to transfer the heat generated by the beam in the pipeline to a cooling system, and absorb the residual gas to the cold bore through the pumping holes on the wall of the beam screen to ensure the vacuum stability at the same time. However, in the process of transferring thermal load, the deformation caused by temperature change will affect the structural stability of the beam screen. How to reduce the deformation as much as possible while ensuring the good heat transfer performance of the beam screen is one of the key issues in optimizing the structural design of the beam screen. In this paper, the heat transfer performance and mechanical property of the beam screen model are simulated and optimized based on the ANSYS simulation results to ensure the normal and stable operation of the beam in the super proton-proton collider. For the inner surface of the outer screen of the beam screen, the method of reducing the thickness of the copper coating is used to reduce the Lorentz force generated during operation. The calculation results from the relevant theoretical models show that when the thickness of the copper coating varies from 0 to 100 μm, the copper coating with a thickness of 75 μm can reduce the maximum deformation of the outer screen of the beam screen by 70.9%, while the maximum temperature of the beam screen can be increased by 1.1%. For the inner screen of the beam screen, a design scheme in which supporting ribs are arranged at intervals is used to reinforce the structure and improve the overall structural stability of the beam screen. The calculation results show that the maximum deformation of the inner screen of the beam screen can be reduced by 86.8% and the maximum temperature of the beam screen is reduced by 7.69%, compared with the case without supporting fins, when the interval between two adjacent supporting fins is 1 pumping hole. The research results provide important theoretical reference for the design of beam screen, which is the key component of the vacuum system of the new-generation high energy particle accelerator.

Study of dynamic vibration characteristics and suppression of CNC machine tool during operation

The rapid development of aerospace, automobile, national defense and other manufacturing industries has continuously improved the performance requirements of high speed and high positioning accuracy of the CNC machine tool feed system. As the thermal deformation error increases, the system structural rigidity decreases, the vibration increases, and accuracy of machine tool reduces. Existing research mainly focuses on the properties of mechanical and single thermal feed system, and less considers the dynamic performance under the action of thermal-mechanical coupling. For the improvement of feed system performance, it is very beneficiary. This paper takes the high-speed tool of CNC feed system as objective, combined with the actual working conditions to analyze the thermal characteristics, dynamic characteristics and vibration characteristics of the system under the effect of thermal-mechanical coupling. The thermal resistance and convective heat transfer of the key joint surface, the application of moving thermal loads, and the establishment of a simulation model to complete the steady-state temperature field, transient temperature field and thermal-structure coupling analysis. The results show that the maximum temperature rise of the feed system is 21.08 °C, The maximum thermal deformation is 17.264 um. The study found that the parameters such as flow rate and airflow temperature have a significant impact on the cooling effect, so the cooling device was further optimized. This paper proposes a control method for cutting chatter of CNC machine tools based on coupling of characteristics of thermal and mechanical. The thermal characteristic of the feed system and the thermal-mechanical coupling vibration characteristic test provides the maximum temperature error of 3.2 %, verifying the correctness of the theoretical method and analysis model. The highest temperature obtained by the test is 39.7 °C, indicating that the high-speed feed system has a large thermal effect. The relative error of the vibration amplitude of the test and simulation is 12.5 %, which verifies coupling in terms of thermal-mechanical. The accuracy of the vibration analysis method; the experiment depicts that the vibration amplitude increases by 19.7 % under the coupling effect of thermal and mechanical, indicating the effectiveness of dynamic characteristics of the high-speed feed system considering the thermal-mechanical coupling effect.

Mechanical behavior of in-service axial compression angle steel members strengthened by welding

This paper investigates the mechanical behavior of in-service angle steel members strengthened by welding through experimental and numerical study. Firstly, axial compression tests on strengthened angle steel members were conducted. All the specimens failed by flexural buckling. The test results indicated that the strengthened members performed higher bearing capacity and better ductility than the unstrengthened one. Subsequently, numerical models were established to simulate the behavior of the specimens using indirect thermal-structural coupling analysis. The comparison between the experimental and numerical results indicated that the numerical models are with acceptable accuracy. Finally, in order to develop a further understanding, parametric analysis was carried out based on the FE models, considering the influence of section types, slenderness ratios, strengthening member thickness and initial load levels. The results revealed that the strengthened sections of square tube or cross-shaped, and the strengthening member with the same thickness as the base member are recommended. In addition, the influence of initial load on ultimate bearing capacity of strengthened members can be ignored when the initial stress is no more than 0.4fy.

The Thermal and Structural Analysis of Vertical Stability Coil

The vertical stability coil is a new set of saddle shaped non-superconducting coil designed for the purpose of improving the control capability of plasma vertical movement. To avoid the electromagnetic shielding and en-hance the response performance, the vertical stability coil is installed in the inner wall of vacuum vessel. The subsequent disadvantage accompanying the benefit is that the coil is under severe neutron radiation. Besides the neutron radiation the coil will also encounter the ohmic heat once it is energized. The temperature rising of vertical stability coil is not allowed to beyond the specific threshold to guarantee the reliability of the coil com-ponents. Thus, the ohmic heat and nuclear heat calculation methods are presented and the detail temperature field is analysed by using ANSYS to check whether or not the coil can bear the thermal load. In addition, the thermal load will result in the thermal stress. To verify whether the thermal stress will lead to the structural damage, the thermal-structural coupling analysis is launched and the stress is evaluated based on ASME ana-lytical design. The analysis results will provide guidance for the local structural optimization of vertical stabil-ity coil.

Finite Element Analysis of Reaction Vessel for Measuring the Solubility of Supercritical Carbon Dioxide

The thermal-structural coupling analysis of the pressure vessel arecarried out by the finite element method to verify its safety, and the stress section are linearized. The results show that the analysis value of the temperature value of the vessel cavity are basically consistent with the change trend of the measured value, and the steady state error are only 2.7%; there is a large stress concentration at the opening of the upper window, and the maximum coupled stress value of the internal surface is 176.2 MPa. The maximum stress path is evaluated based on the analytical design standard JB4732-1995, and the structure satisfies the strength requirement.

Numerical Simulation Study on Radiation Section of Dehydrogenation Furnace

The three-dimensional numerical simulation of the radiation section of a dehydrogenation furnace was carried out by CFD, the thermal-structure coupling analysis was performed. The full-scale meshing of the geometric model was used in this paper, the temperature field and flow field of the furnace and the furnace tube were simulated. The thermal radiation values and temperature values of the simulation results were compared with the design values, it shows that the simulated values are in good agreement with the designed values. The corresponding numerical calculation can be performed for half or 4/1 of the geometry under the condition with the geometric symmetry of the furnace and the furnace tube being good. The simulation results can provide a reference for the design and optimization of the dehydrogenation furnace.

Numerical Simulation of Gear Heat Distribution in Meshing Process Based on Thermal-structural Coupling

The thermal balance state of high-speed and heavy-load gear transmission system has an important influence on the performance and failure of gear transmission and the design of gear lubrication system. Excessive surface temperature of gear teeth is the main cause of gluing failure of gear contact surface. To investigate the gear heat distribution in meshing process and discuss the effect of thermal conduction on heat distribution,a finite element model of spur gear is presented in the paper which can represent general involute spur gears. And a simulation approach is use to calculate gear heat distribution in meshing process. By comparing with theoretical calculation, the correctness of the simulation method is verified, and the heat distribution of spur gear under the condition of heat conduction is further analyzed. The difference between the calculation results with heat conduction and without heat conduction is compared. The research has certain reference significance for dry gear hobbing and the same type of thermal-structural coupling analysis.

Thermal-structural coupled analysis and improvement of the diaphragm compressor cylinder head for a hydrogen refueling station

When applied in the hydrogen refueling station, the diaphragm compressor with super-high pressure ratio will experience a high discharge temperature of over 200 °C, especially for that with large capacity and horsepower. Considering the thermal stress, the structural strength and deformation of the cylinder head are crucial to the reliability and efficiency of the diaphragm compressor. In this paper, a thermal-structural coupled analysis was proposed, based on which the deformation and stress of the diaphragm compressor cylinder head under high-temperature and high-pressure conditions were obtained. And the fatigue life of the studs on the cylinder head was also estimated based on the stress results obtained in the thermal-structural coupled analysis. The experimental method was conducted for verifying the numerical results. The results indicated that during the operation of the compressor, the temperature in the discharge holes was the highest, resulting in not only plastic deformation but also large stress concentration, and the high thermal stress could reach up to the strength limit of the material. A structural improvement was therefore proposed to decrease the stress in the region of the discharge holes by cutting a larger hole and attaching a new separate one for valve installation. Further stress analysis showed that the stress in the same region of the improved structure was significantly reduced, which guaranteed the safety of the compressor.

Adaptive Method to Reduce Thermal Deformation of Ball Screws Based on Carbon Fiber Reinforced Plastics.

In high-speed precision machining, thermal deformation caused by temperature rise affects the accuracy stability of the machine tool to a significant extent. In order to reduce the thermal deformation of ball screws and improve the accuracy, a new adaptive method based on carbon fiber reinforced plastics (CFRP) was proposed in this study and the thermal deformation of ball screws was determined. By using the sequential coupling method, the thermal–structural coupling analysis of a ball screw was conducted based on the finite element method (FEM). The analysis results were verified through a comparison with the experimental results. Based on the verification, an FE model of the improved ball screw was established to study its thermal characteristics. The key design parameters of the improved ball screw were optimized based on the Kriging model and genetic algorithm (GA). The thermal reduction effect of the improved ball screw was validated through the experimental results. The results indicate that the adaptive method proposed in this research is effective in reducing the thermal deformation of ball screws.

Multi-axis low-cycle creep/fatigue life prediction of high-pressure turbine blades based on a new critical plane damage parameter

To study the multi-axis low-cycle creep/fatigue life of high-pressure turbine blades, a multi-axis low-cycle fatigue life prediction model based on a new critical plane damage parameter is proposed in this paper. Firstly, based on the thermal-structural coupling analysis of high-pressure turbine blades, the law of stress-strain distribution under the complex load of centrifugal load, temperature load and the aerodynamic load is obtained. Secondly, the multi-axis low-cycle fatigue life prediction model and the L-M equation are applied to predict the fatigue life and creep life of blade respectively. Furthermore, different experimental loading schemes are used to study the fatigue damage mechanism for the creep/fatigue interaction under high temperature condition, and a creep/fatigue interaction life prediction model is simultaneously provided. And finally, the experiment results demonstrate the rationality of the multi-axis low-cycle fatigue life prediction model and the creep/fatigue interaction should not be ignored.

Thermal-structural dynamic analysis of a satellite antenna with the cable-network and hoop-truss supports

Thermally induced structural disturbances of the flexible appendages on a satellite usually occur during eclipse transitions. As a large-scale space structure consists of rod members, cyclic thermal shock induced vibrations such as the divergent thermal flutter may be crucial for its functional serving. In this article, the motivation is to estimate the dynamical behaviors of the AstroMesh antenna under solar flux shock. For this purpose, we developed a numerical approach for the thermal-structural coupling analysis of tensegrity structures considering the pre-stressed state after the form-finding process. The Euler-Bernoulli beam theory, the pre-stressed bar model, and the Fourier thermal element are employed in conjunction with the special consideration on the effect of structural deformations on absorbing solar flux. It is found that, unlike the single boom structure, thermal deformations of the AstroMesh antenna are mainly caused by the temperature variation along rod axis-direction, rather than the temperature gradient on rod cross-section. Besides, the phenomenon of thermally induced vibrations can hardly happen in the AstroMesh antenna.