An adaptive concurrent multiscale model for concrete based on coupling finite elements

Abstract

A new adaptive concurrent multiscale approach for modeling concrete that contemplates two well separated scales (represented by two different meshes) is proposed in this paper. The macroscale stress distribution is used as an indicator to identify critical regions (where the material is prone to degrade) with the explicit aim to enrich these zones with detailed mesoscale material information comprising three basic phases: coarse aggregates, mortar matrix and interfacial transition zone. Thus, the concrete initially idealized as a homogeneous material is gradually replaced and enhanced by a heterogeneous multiphase one. This technique is particularly powerful to handle cases where the region with nonlinear behavior is not easy to anticipate. Furthermore, the proposed approach does not require the definition of a periodic cell (or a RVE), and the meshes from distinct scales are totally independent. The new adaptive mesh technique is based on the use of coupling finite elements to enforce the continuity of displacements between the non-matching meshes associated with the two different scales of analysis. Besides that, mesh fragmentation concepts are incorporated to simulate the crack formation and propagation at the mesoscopic scale, without the need of defining complex and CPU-time demanding crack-tracking algorithms. The strategy is developed integrally within the framework of continuum mechanics, which represents an advantage with respect to other approaches based on discrete traction/separation-law. Numerical examples with complex crack patterns are conducted to validate the proposed multiscale approach. Furthermore, the efficiency and accuracy of the novel technique are compared against full mesoscale and standard concurrent multiscale models, showing excellent results.

On a volume averaged measure of macroscopic reinforcement slip in two‐scale modeling of reinforced concrete

“…In contrast to the classical structural formulation, 21 we introduce two independent large-scale fields: the effective displacement u and the effective reinforcement slip s. Following the procedure proposed in Reference 31, we aim at prolonging the large-scale components of the resolved fields (17,18) from the effective large-scale fields, that is, we want to establish an operator  such that (u M c , u M s ) = (u, s). More specifically, we consider a Taylor series expansion of the large-scale fields inside Ω □ , centered around…”

“…There are many different multiscale methods suitable for this task. Many of them have already been studied and used in modeling of plain concrete and even reinforced concrete . One method that shows potential is the FE 2 method, which couples the scales in a nested way, that is, the macroscopic response is obtained by computational homogenisation performed on the fine‐scale representative volume elements (RVEs), cf Figure .…”

Electrical-Thermal-Mechanical Analysis of Cable Connection with Screw-Connected Terminal Strips Using Finite Element Method

“…Analytical methods can be applied only in homogeneous ambient conditions and in simple geometries. Therefore, various numerical models have been developed to examine current carrying capacity of cables in various mounting situations [13,14,28]. COMSOL is a suite of finite element modeling software with a predefined set of physics interfaces.…”

Domain information transfer method and its application in quasi-brittle failure analysis

“…With damage evolution, some parts of macroscopic region need to be replaced with mesoscopic region, such as the concurrent model for the damage trans-scale evolution analysis in concrete 26,27 and the adaptive concurrent multiscale model with coupling elements. 28 Undoubtedly, the adaptive mechanism is useful in concurrent method. However, it brings some difficulties under concurrent framework.…”