Experimental study of post-buckled single-stringer composite specimens under fatigue loads with different load levels and load ratios

This study aims at better understanding the damage tolerance of stiffened composite panels subjected to fatigue loads in the post-buckling regime. Ten single-stringer hat-stiffened specimens with an initial delamination between the skin and the stringer foot were manufactured, and then tested under quasi-static and fatigue loads in post...

Comparison of numerical analyses of a composite wing component subjected to 4-point bending

In this paper, a comparison between six finite element models of a representative wing structural component performed in the context of Optimised Design for Inspection (ODIN) project of the European Cooperation in Science and Technology (COST) is presented. Six partners from six different countries involved in the project received the drawing...

Buckling-driven mechanisms for twisting control in adaptive composite wings

This study aims to design novel tailorable and effective mechanisms by controlling buckling behaviour in structural elements of a composite wing for future morphing application. Instead of the traditional design against buckling, the idea is to embrace this built-in instability by using the nonlinear post-buckling response to control...

Influence of interface ply orientation on delamination growth in composite laminates

The standard experimental procedures for determining the interlaminar fracture toughness are designed for delamination propagation in unidirectional specimens. However, in aerospace structural components, delamination usually occurs between plies at different orientations resulting in different damage mechanisms which can increase the value...

Teaching buckling of cylindrical shells through an effective laboratory demonstration

A laboratory demonstration for a Stability of Structures course is presented, consisting in the buckling test of two cylindrical shells: a 3 D-printed and a composite cylinder. The learning outcomes have been formulated by comparing what can be learnt from theoretical lessons and buckling tests. The activity follows the Interactive Lecture...

Fatigue analysis of a post-buckled composite single-stringer specimen taking into account the local stress ratio

The fatigue life prediction of post-buckled composite structures represents still an unresolved issue due to the complexity of the phenomenon and the high costs of experimental testing. In this paper, a novel numerical approach, called “Min-Max Load Approach”, is used to analyze the behavior of a composite single-stringer specimen with an...

Skin-Stiffener Separation in T-Stiffened Composite Specimens in Postbuckling Condition

An experimental and numerical investigation was conducted to study the skin-stiffener separation of single T-shape stiffener specimens in postbuckling condition. Three specimens were manufactured with a centrally located Teflon insert, and were loaded in compression until collapse. Deformation patterns and separation evolution were monitored...

Fatigue life and damage tolerance of postbuckled composite stiffened structures with indentation damage

The fatigue life and damage tolerance of composite stiffened panels with indentation damage are investigated experimentally using single-stringer compression specimens. The indentation damage was induced to one of the two flanges of the stringer of every panel. The advantages of indentation compared to impact are the simplicity of application...

Modelling strategies for numerical simulation of aircraft ditching

Ditching, which is a controlled landing of an airplane on water, is an emergency condition to be investigated in order to improve the aircraft global crashworthiness. The complex hydrodynamic phenomena involved in ditching events are difficult to simulate and the accuracy of the results depends on the capability to reproduce the forces...