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....

A microstructure-based graph neural network for accelerating multiscale simulations

Simulating the mechanical response of advanced materials can be done more accurately using concurrent multiscale models than with single-scale simulations. However, the computational costs stand in the way of the practical application of this approach. The costs originate from microscale Finite Element (FE) models that must be solved at every...

Micromechanical modeling of rate-dependent off-axis failure in thermoplastic composites

A micromechanical framework for modeling failure in unidirectional (UD) thermoplastic composites under rate-dependent off-axis loading is presented, with the aim to predict and analyze transverse matrix cracking under various load conditions. The onset of global softening in the micromodel corresponds to macroscopic matrix crack initiation. The...

Combining the thick level set method with plasticity

The Thick Level Set (TLS) method has been proposed as a new approach to the modeling of damage growth in solids. The fronts of damaged zones are implicitly represented as a level set of an auxiliary field whose evolution is accomplished by the level set method. The TLS model contains a characteristic length to obtain a non-local description...

Simulation of cusp formation in composite materials using the thick level set method

On the microlevel, cusps are formed during delamination crack growth under mode II loading conditions. In this work, the Thick Level Set (TLS) approach is used to simulate the cusp formation process. A plasticity model for polymers is implemented in the TLS method and a new loading scheme is devised to deal with permanent strain. A numerical...

Numerical/experimental study of the monotonic and cyclic viscoelastic/viscoplastic/fracture behavior of an epoxy resin

This paper investigates the viscoelastic/viscoplastic/fracture behavior of an epoxy resin. A state-of-the-art pressure-dependent elastoplastic constitutive model (Melro et al. 2013) is expanded to include viscoelasticity, viscoplasticity and a modified damage formulation with linear softening and shrinking pressure-dependent fracture surface. A...

Micromechanical validation of a mesomodel for plasticity in composites

In this paper, the performance of a recent homogenized orthotropic plasticity model for fiber reinforced composites (Vogler et al. (2013)) is investigated by comparing the model response against a micromechanical model. It is assumed that the micromechanical model which contains a recent plasticity model for polymers (Melro et al. (2013a,b))...

Experimental/numerical characterization of hygrothermal ageing in glass/epoxy composites

In this work, a combined experimental/numerical approach is used to investigate the effect of water ingression in glass/epoxy composite specimens. Interlaminar shear (ILS) specimens were immersed at 50◦C for multiple durations and tested. Re-dried specimens were also tested. Significant strength degradation of up to 50% was found for wet...

Experimental/numerical study of anisotropic water diusion in glass/epoxy composites

In this work a glass/epoxy composite commonly used in wind turbine blades is exposed to a humid environment at an elevated temperature. To research the anisotropic di_usion behaviour observed in unidirectional composite specimens, experimental results of slices cut along the three directional planes of the laminate immersed in demineralised...

Micromechanics-based validation of a mesomodel for matrix nonlinearity

The performance of a mesomechanical constitutive law for composites is assessed through comparison with micromechanical model results. In this paper, results are presented for non-monotonic strain histories obtained from mesomechanical simulation of a shear dominated delamination test.