Stress Analysis Of Transient Thermal Structure Of Arch Dam

The temperature load is one of the basic loads of the statically indeterminate structure in arch dam. The influence on arch dam that the temperature stress is caused by the temperature is worth researching. The shape of arch dam is very thin. It is sensitive about the variation of temperature of air and water.The heat-conduction theories, thermal-structure coupling and three-dimensional finite element method are applied in this thesis. Taking a hollow sphere for example, deal with the calculation formula derivation of temperature stress coupled field under the action of external force and transient change of temperature with boundary conditions. The calculation formulas are calculated by use of mathematics software MATLAB. The model under the same conditions is also calculated by using the commercial finite package ANSYS. By comparing the results of MATLAB and ANSYS, verifying the feasibility of dealing with the problems of transient coupled thermo-mechanical analysis by use of ANSYS. Through the comparison of the results which are solved by MATLAB and ANSYS of different grid segmenting strategies on the model of hollow sphere, the relative error of temperature and stress are about5%when mesh size is a fifth of the thickness of hollow sphere. Because hollow sphere and arch dam have similar characteristics, it gives a basis for the division of the grid of arch dam.The pattern of meshing of the hollow sphere is extended to arch dam. Adopting the same element of hollow sphere carried out direct thermal-structural coupling analysis. A parameter which is introduced is strain energy of arch dam. Through the analysis of forces on arch dam under the action of transient thermal loading in12months, the studies show that the most unfavorable load behind the minimum temperature is15to20days when a period of temperature drop. And the worst loaded behind the maximum temperature is5to10days when a period of temperature rise. That is, the time is February1st to5th and20-25July when the worst condition of arch dam. The maximal radial displacements of arch dam and air temperature have presented an anti-correlation. When the air temperature has gone up, the maximal radial displacement of arch dam has diminished. When the air temperature has abated, the maximal radial displacement of arch dam has increased. Finally, through the precision analysis of the finite element analysis of the numerical solutions, estimating the exact value of strain energy. Through the comparison of the relative error of strain energy which getting from that the pattern of meshing of the hollow sphere is extended to arch dam and estimating the exact value of strain energy in12months, verifying the feasibility that the pattern of meshing of the hollow sphere can extend to arch dam.