Papers by Keyword: Thermal Stress

Abstract: The creep deformation of the cast copper cooling staves was researched based on the steady temperature field by using thermal - mechanical coupling finite element transient analysis method and ABAQUS software. The results show that the creep deformation only under the effect of thermal stress is slight and negligible compared to the deformation generated by thermal expansion. The total tress is not adequate to crack the stave body. Therefore, the cast copper stave can meet the requirements of blast furnace longevity.

Abstract: The paper proposes a comparison between two simulation methods of disc brake thermal regime which cause thermal stress. Those methods are the finite element analyses and the thermal image processing using grey level (or the luminosity variation) of disc brake emissivity. The authors consider that the variation of thermal image luminosity, images taken of a disc brake during intensive braking, is similar to one of the finite element analyses modeling the same conditions as the one of the experiment.

Abstract: This document explains the details of electric spindle thermal characteristics experiments. The temperature distribution, shaft deformation and the stress of temperature sensitive points are tested. Thermal characteristics are gathered about the different cooling strategies and different spindle speeds in the experiments results analysis. Choosing reasonable cooling strategy can use to design spindle cooling system. Thermal stress test can obtain accurate data at temperature sensitive points. The stress analysis can be used to reflect spindle deformation.

Abstract: This paper makes thermal stress analysis for local heating variable cross-section roll forming with ABAQUS finite element software. On the basis of traditional cold roll forming, local heating variable cross-section roll forming uses laser device to heat the sheet partly and employs ABAQUS to do thermal-mechanical coupling finite element analysis. This paper, adopting sequence thermal-mechanical coupling method, obtains the temperature field with heat transfer analysis step firstly, and then regards the obtained temperature field as known condition and employs static implicit algorithm to do thermal stress analysis, then the stress-strain field is obtained, which will be helpful in forecasting the stress-stain law of the local heating variable cross-section roll forming.

Abstract: Thermal stresses in 304 stainless steel plate-fin structure at steady condition were calculated by finite element method. A squential coupling calculation procedure was developed to obtain the temperature and thermal stress distribution. The effects of plate thickness, fin thickness and filler metal thickness on thermal stresses were discussed. The results show that the thermal stresses in plate-fin structure are complex and nonuniform. The peak thermal stresses are shown in the fillet. With the plate thickness and fin thickness increasing, the thermal stresses are increased. The peak stresses are decreased as the filler metal thickness increasing.

Abstract: In this paper, we analyze the bridge legs in which the largest deformation can be observed by conducting simulation via ANSYS tools and determine the membrane layer structure, which consists of one 0.1μm thick VOX thermal sensing layer and 7 other layers with thickness ratio 0.1μmSi3N4/0.3μmSiO2/0.1μmSi3N4/0.05μmNiCr/0.1μmSi3N4/0.3μmSiO2/0.1μmSi3N4. The stable and transient thermal simulation analysis of the microbridge is performed. From the stable thermal analysis of temperature field profile, the highest and lowest temperatures and the temperature heterogeneity of the bridge deck are 300.526K, 300.468K and 0.058K respectively. The thermal time constant 6.0ms is acquired from the transient thermal analysis, which can reach the requirement of 60fps frame rate. Moreover the joule heating effect is then examined, which has influence on temperature rise of bridge deck with 3V voltage applied between two legs. The highest temperature of bridge deck is 300.354K which is lower than 300.526K caused by thermal radiation. At last, the force simulation analysis of microbridge is performed, which is based on the forementioned thermal analysis, the largest deformation is 46.45nm, the largest equivalent stress is 2.503GPa.

Abstract: The time-varying temperature field and stress distribution of a concrete roof slab is actively investigated in this study with the aiding of the commercial package ANSYS. Fine finite element model of the concrete slab is constructed and different boundary conditions are applied to obtain the temperature distribution within the slab. The solar radiation model is utilized to estimate the solar radiation received by the slab and the shelter effects are also taken into consideration. The numerical models can successfully predict the structural temperature gradient and thermal stress distribution at different time. The made observations indicate that the simulated temperature variation of the concrete slab based on the solar radiation model agrees well with measurement results. It is seen that the numerical models can successfully predict the structural time-varying thermal effects.

Abstract: In this paper, temperature field and stress field have been simulated on a Langmuir Probe and its dissipation system in certain diagnostic equipment under intense radiation in use of Abaqus. The results show that there are strongest thermal stresses on the ceramic barrels inside the system, which would be extremely easy to get broken. The reasons to have such dreadful stresses are discussed in the paper. And improving suggestions to avoid extra stresses are put forward for the structure design of Langmuir Probe and its heat dissipation system due to the simulation results.

Abstract: This paper presents analytical solutions of the thermal stresses in a functionally graded solid cylinder with fixed ends in elastic region. These thermal stresses are due to the uniform heat generation inside the cylinder. Material properties of the functionally graded (FG) cylinder vary radially according to a parabolic form. The material properties are assumed to be independent of the temperature which are yield strength, elasticity modulus, thermal conduction coefficient, thermal expansion coefficient and Poisson’s ratio. The solutions for the thermal stresses are valid for both homogeneous and functionally graded materials.

Abstract: To perform the temperature compensation, a bimetallic thin film with different thermal expansion coefficients is deposited on the surface of the crystal plate. The thermal stress generated in the crystal and the thin film will cancel each other when temperature changes, thus improve the frequency stability of the crystal oscillator. In this paper, a finite element simulation was carried out for the crystal plate with bimetal, and then an experiment was performed to verify the FEM simulation results. The result shows that this approach achieves good temperature - frequency characteristics and reduces the frequency shift of crystal oscillator.