Analysis On Thermal-Creep-Stress Field Of Early-age Concrete Based On The Customized ANSYS

With hydration of cement,the strength and the thermodynamic parameters of early age concrete structure change.And the effect on the calculated temperature field and the stress field of the temperature and age is significant,which is can't be ignored.In this article,based on ANSYS further development interface UPFs,a calculation model of temperature field and stress field for early age concrete was developed with consideration of equivalent age and hydration degree by writing and modifying user subroutines.And the method of sequential coupling was applied to solving the model,which is suited to engineering practice.The main research works are as follows:(1)The function of further development of ANSYS and UPFs were intensively studied and user subroutines for further development related to calculation of temperature stress field for early age concrete were emphatically introduced.At the same time,setting up environment for ANSYS further development and compilation,calling and debugging of subroutines were described in detail.(2)In this article,based on ANSYS further development interface UPFs,a calculation model of temperature field in consideration of effect on hydration degree of temperature and age was developed for early age concrete,as well as a caculation of stress field with an eye to concrete creep by writing and modifying user subroutines such as usrefl?ussbeg?usermat,which were validated in several examples.(3)The coupled field of temperature and creep stress was calculated by introducing the concept of equivalent age to the stress module and replacing parameters related to equivalent age in usermat.The difference between the coupled algorithm and the traditional algorithm was studied with a numerical example.And the results show that the coupled algorithm did better in reflecting the fact and the influence on hydration reaction rate of temperature than the traditional algorithm.(4)The subroutine developed in this paper was applied to finite element analysis and calculation of the temperature field and the stress field of a retaining wall in a pumping station of Tianjin.Calculated results agrees well with measured results with stress error in corresponding locations less than 0.3 MPa which meets the requirement of engineering precision.From the results of practical engineering calculation,the thin-wall concrete structure constructed by stages in cold environment is apt to form crack because of temperature.So arrangement of construction should avoid winter.And in winter construction,temperature control measures should be taken.