Cohesive analysis of a 3D benchmark for delamination growth under quasi-static and fatigue loading conditions

This paper evaluates the capabilities of the recently developed CF20 cohesive fatigue model, which can predict crack initiation as well as the rates of crack propagation by relying on intrinsic relationships between a stress-life diagram and its corresponding Paris law. The model is validated here using a partially reinforced double...

Overcoming the cohesive zone limit in composites delamination: modeling with slender structural elements and higher-order adaptive integration

Cohesive element (CE) is a well-established finite element for fracture, widely used for the modeling of delamination in composites. However, an extremely fine mesh is usually needed to resolve the cohesive zone, making CE-based delamination analysis computationally prohibitive for applications beyond the scale of lab coupons. In this work, a...

FEM analysis of a Mode III fracture mechanics test specimens for cohesive law determination of fibre composite

Delamination is one of the common failure types in the fiber composites. The trailing edge in the wind turbine blades, for example, is one of the structural components where the delamination is driven by mode III under predominantly flapwise loading. There has been an extensive effort in developing test procedures and test specimens for...

High Order Adaptively Integrated Cohesive Elements: Development, implementation and testing on composite delamination

Composite delamination represents one of the most critical failure mechanisms occurring in composite structures. In case complex structures are being designed, numerical methods need to be employed. One of the methods to numerically simulate delamination in a Finite Element environment is through the employment of the Cohesive Elements, which...

Simulation of cusp formation in mode II delamination

On the microlevel, cusps are formed during delamination crack growth under mode II loading conditions. In this work, two different approaches to simulate this process are presented. Firstly a cohesive zone method where cohesive segments are introduced between a pair of neighbouring elements when the traction between those elements exceeds the...

Delamination and debonding failure of laminated composite T-joints

Composites are increasingly being used in aerospace, automotive and other industries. The T-joint (also named stringer stiffened skin) is a typical connection, broadly used in thin-walled structures, such as the wing and fuselage of aircraft. This thesis presents the analysis of the delamination and debonding failure of laminated composite T...

Methods for the prediction of fatigue delamination growth in composites and adhesive bonds: A critical review

An overview is given of the development of methods for the prediction of fatigue driven delamination growth over the past 40 years. Four categories of methods are identified: stress/strain-based models, fracture mechanics based models, cohesive-zone models, and models using the extended finite element method. It is highlighted that most models...

Discontinuities in materials and structures: A unifying computational approach

Failure mechanisms in materials and structures can be studied on different length scales. On a structural level, failure can be observed as the propagation of a single crack. However, when zooming into the apparent crack tip, it is revealed that the actual failure process is set by the nucleation and growth of multiple micro-cracks that together...