Skin-stringer separation in post-buckling of butt-joint stiffened thermoplastic composite panels

Two aeronautical thermoplastic composite stiffened panels are analysed and tested to investigate the buckling behaviour, the skin-stringer separation and the final failure mode. The panels are made of fast crystallising polyetherketoneketone carbon composite, have three stringers with an angled cap on one side, and are joined to the skin by a...

DIC-based monitoring on debonding crack propagation in wrapped composite joints

Wrapped composite joint is an innovative technique which connects steel hollow sections through bonding such that the fatigue performance is improved compared to welded joint. In this paper, a DIC-based method of monitoring surface strains is proposed to quantify the debonding crack propagation within the composite wrap layers during high cycle...

Parametric analysis of mechanical fastener disbond arrest features in bonded joints

The purpose of this research study is to analyse the effect of the design of mechanical fastener on their effectiveness as Disbond Arrest Features (DAFs). This was done by means of a sensitivity study using a 3D model using the Virtual Crack Closure Technique (VCCT) to model the disbond growth of a single lap shear specimen comparing the Strain...

Three-dimensional fatigue crack propagation simulation using extended finite element methods for steel grades S355 and S690 considering mean stress effects

The assessment of fatigue crack propagation of steel structures is essential and important especially to improve the application of high strength steel in construction. The load ratio R, reflecting mean stress effects, will be changed with crack extension in the steel structures with complicated geometry. In this paper, the Walker equation is...

Numerical study of quasi-static and fatigue delamination growth in a post-buckled composite stiffened panel

In this work, an approach based on the Virtual Crack Closure Technique, included in the commercial finite element code ABAQUS, is adopted to study the propagation of delamination in composite structures under quasi-static and fatigue loads. The methodology, originally capable of simulating only delamination under quasi-static loads, has...

Fatigue disbond growth in primary aerospace structures

A parametric finite element model incorporating virtual crack closure technique was developed in order to determine the critical disbond size and location for disbond growth in an adhesively bonded skin stiffened structure, subjected to uniaxial compression loading. The model was validated using static experimental tests on both pristine and...

Application of the virtual crack closure technique to calculate stress intensity factors for through cracks with an oblique elliptical crack front