考虑性态变化的早期混凝土多场耦合分析及其应用-水工结构工程专业毕业论文.docx

ABSTRACT The tensile strength of concrete is low in the early age after pouring, and mainly effected by its own heat generation of hydration, shrinkage deformation and other factors, surface temperature cracks are easy to appear in concrete structures, and the cracks will have a significant impact on the safety and quality of construction of the structures. Based on ABAQUS and its secondary development platform, a subroutine for calculation thermal、 mosture and stress field has been developed, and has been applied to practical engineering. In this paper, the main research works are as follows: Deeply research on the secondary development of ABAQUS software has been carried out, and the relevant subroutine used in thermal field and structure field simulation of the early age concrete are emphatic introduced. Meanwhile, the establishment of ABAQUS secondary development platform and subroutine calling process is described in detail. Based on ABAQUS secondary development platform, and using FORTRAN language, the thermal field subroutine UMATHT which takes the degree of hydration theory and the change of thermal parameters into account and FILM which simulates the third type of boundary conditions are developed. And based on the maturity theory, a viscoelastic structure field calculation subroutine which is based on double power creep function (Double Power Law, DPL) is composed. The validity of the developed subroutines is demonstrated through various numerical examples. Different caculation models of early concrete thermal field, including the traditional caculation models, the calculation model of considering the hydration reaction rate affected by hydration degree and the model of considering hydration degree and thermal parameters changing, are used to study the differences of different thermal field calculation models. It is found that the numerical calculation results of these three thermal field calculation models are not the same. In this paper it is also found