Entity finite element calculation method for time-varying effect of concrete structure

Abstract

The invention relates to an entity finite element calculation method for a time-varying effect of a concrete structure, which comprises the following steps of: 1) discretizing the stress process of concrete according to a stepwise method, and deducing creep strain increment in an nth time period; 2) fitting the creep coefficient expression into an exponential series form by using Matlab software;3) substituting the creep coefficient fitting expression into a creep strain increment calculation formula, and establishing a concrete uniaxial creep strain increment recurrence calculation formula;4) considering the creep Poisson effect, and establishing a concrete time-varying constitutive equation in the constitutive structure of the entity unit material; and 5) developing the time-varying constitutive structure of the concrete in the USERMAT subprogram of the ANSYS software by using the Fortran language. Compared with the prior art, time-varying effect value prediction of the concrete structure in a complex stress process under a spatial stress state can be realized, and the joint with a creep and shrinkage model of a common design specification is good.

Description

technical field [0001] The invention relates to the field of numerical prediction of time-varying effects of creep and shrinkage of concrete, in particular to a solid finite element calculation method of time-varying effects of concrete structures. Background technique [0002] The creep and shrinkage properties of concrete have a significant impact on the long-term performance of concrete bridges and other mass concrete structures exposed to dry environments. Taking long-span prestressed concrete bridges as an example, the time-varying characteristics of concrete cause the mid-span deflection to increase as the service life of the bridge increases, the loss of prestress increases, and the safety reserve of concrete against cracking decreases, which affects the operational safety and durability of the bridge structure. It is necessary to improve the prediction accuracy of time-varying effects of concrete structures to reduce damage and disease during the operation period of ...

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Problems solved by technology

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a solid finite element calculation method for the time-varying effect of concrete structures, to solve the problem that the prediction accuracy of the time-varying effects of concrete structures is not high under multi-axial stress states and complex stress history. Technical problems such as lack of connection between design code creep and shrinkage time-varying constitutive

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