Investigation of mode-II delamination fracture energy with a discontinuous computational homogenization model

Numerical methods for delamination analysis, such as the cohesive zone method, require fracture energy as an essential input. Existing formulations rely on a phenomenological relationship that links fracture energy to the mode of fracture based on linear elastic fracture mechanics (LEFM). However, doubts exist about the applicability of LEFM....

Towards electrochemical-performance evaluation of fiber-based batteries: Fiber-arrangement-based method and FE² multiscale framework

Conventional battery models (e.g., Pseudo-2D model) were developed especially for particle-based battery electrodes and have limitations in addressing the newly-emerging fiber-based ones. This thesis proposes numerical tools for efficient property evaluation of fiber-based electrodes and for multiscale simulation of battery electrochemical...

Tensorial effective transport properties of Li-ion battery separators elucidated by computational multiscale modeling

Existing battery modeling works have limitations in addressing the dependence of transport properties on local field variations and characterizing the response of anisotropic media. These limitations are tackled by means of a nested finite element (FE²) multiscale framework in which microscale simulations are employed to...

FE² multi-scale framework for the two-equation model of transient heat conduction in two-phase media

In the study of transient heat conduction in heterogeneous two-phase media, the local thermal non-equilibrium condition calls for the use of a two-equation model to appropriately describe different temperatures in the two phases. We propose for the two-equation model an FE² multi-scale framework that is capable of addressing...

Ductile fracture locus identification using mesoscale critical equivalent plastic strain

The ductile performance of high strength steel (HSS) from different steel grades, producers, manufacturing processes varies a lot. It is also difficult to conduct all kinds of reliable experiments to generate different stress status through different initial specimen geometries or by applying different load combinations in the civil...

Resin and steel-reinforced resin used as injection materials in bolted connections

Injection bolts are bolts in which the cavity produced by the clearance between the bolt and the wall of the hole is completely filled up with a two-component resin. Filling of the clearance is carried out through a small hole in the head of the bolt. After injection and complete curing, the connection is slip resistant. Recently the...

Stress-controlled weakly periodic boundary conditions: Axial stress under varying orientations

The accuracy of multiscale modeling approaches for the analysis of heterogeneous materials hinges on the representativeness of the micromodel. One of the issues that affects this representativeness is the application of appropriate boundary conditions. Periodic boundary conditions are the most common choice. However, when localization takes...

Computational homogenization simulation on steel reinforced resin used in the injected bolted connections

In this paper, compressive material tests on unconfined/confined resin and steel reinforced resin were experimentally evaluated in order to validate the numerical results. The uniaxial model which combines damage mechanics and Ramberg-Osgood relationship is proposed in this paper to describe the uniaxial compressive behaviour of resin and...

A rate-dependent multi-scale crack model for concrete

A multi-scale numerical approach for modeling cracking in heterogeneous quasi-brittle materials under dynamic loading is presented. In the model, a discontinuous crack model is used at macro-scale to simulate fracture and a gradient-enhanced damage model has been used at meso-scale to simulate diffuse damage. The traction-separation law for the...

Multiscale failure modelling of quasi-brittle materials

The conventional multiscale homogenization theory, which has mainly been applied to determine constitutive laws for bulk materials, suffers from two drawbacks when applied to softening materials. Firstly, the coarse scale response is sensitive to the finite element mesh used to discretize the coarse scale domain. Secondly, increasing the size of...