Equivalent Homogenization Method For Mass Concrete Ceusidering The Effect Of Temperature On Elastic Modulus

During the construction process,mass concrete will have a temperature gradient inside the structure due to the influence of cement hydration heat,resulting in large temperature stress.In addition to the influence of external boundary conditions,the temperature stress is related to its own temperature field,elastic modulus,creep property,and thermal expansion coefficient.If the temperature stress is too large,it will cause damage to the concrete structure.Temperature analysis and control of dams in hydropower projects are key issues during their construction period.The strength and various thermodynamic parameters of concrete structures in early age will change with the progress of cement hydration reaction.According to the maturity and equivalent age theory,the influence of temperature on the development of concrete elastic modules can not be ignored.In order to consider the influence of temperature on the development of concrete elastic mode in concrete structure analysis,this paper uses ANSYS secondary development to realize the structural calculation program considering the influence of temperature on concrete elastic mode.On this basis,a method of elastic equalization equalization considering temperature influence is proposed.Using this method to simulate large-volume concrete structure construction,the modeling process will be more simple,and the calculation efficiency can be improved in practical engineering analysis.The specific research contents and main results of this paper are as follows:(1)According to the theory of equivalent age,the USERMAT is redeveloped in the process of stress calculation to realize the change of the value of the elastic modulus of different nodes.At the same time,according to the elastic aging creep model of creep degree,it is realized in USERMAT.Calculation of creep strain in concrete stress calculation.The calculation method of concrete temperature stress based on ANSYS considering the influence of temperature on elastic mode is completed.(2)The construction simulation analysis of the high arch dam structure is carried out.Comparing the results obtained by the above secondary development of ANSYS with the calculation results of the influence of the temperature on the elastic modulus,it is found that the stress results of the two methods are significantly different.Explain that considering the influence of temperature on the elastic mode can improve the accuracy of the calculation.(3)In order to simplify the elastic age treatment of the equivalent age,an equivalent homogenization method considering the influence of temperature on the elastic mode is proposed.The method homogenizes the concrete elastic mold in the same elevation or in the same construction warehouse,thereby improving the calculation efficiency and more scientifically reflecting the macroscopic mechanical properties of the material and temperature.The computational analysis verifies the reliability and efficiency of the proposed method.(4)Applying the equivalent homogenization method of the elastic mode to the stress analysis of the arch dam during construction period,the elastic model equivalent homogenization method is more effective in the stress calculation process during the construction period of the arch dam than the simple application of the equivalent age method.Simple and efficient.The stress results obtained by the homogenization elastic mode method are closer to the stress results obtained by the experimentally measured elastic modulus of the equivalent age method.