Enrique Barbero

Computational analysis of temperature effect in composite bolted joints for aeronautical applications

This study focuses on the analysis of influence of temperature and bolt torque on aeronautical joint behavior. A single-lap joint, according to ASTM D5961, with a titanium bolt and composite plates was considered. A numerical model based on FEM was developed to evaluate the stress in both bolt and composite plates. Load—displacement curves, stress fields, and induced damage showed, significantly, the influence of temperature combined with torque level on the joint. It was found that in the plate, both maximum and minimum levels of torque considered produced damage above critical threshold. This fact should be accounted for, during the design process of the joint.

Influence of areal density on the energy absorbed by thin composite plates subjected to high-velocity impacts

This work analyses the influence that the areal density of a composite thin-plate, made of glass-fibre woven laminates and subjected to high-velocity impact, exerts on perforation-threshold energy, contact time, and energy-absorption mechanisms. The perforation-threshold energy increased with the areal density. Also, the contact time increased at impact energies above the perforation-threshold energy and decreased below this threshold. The main energy-absorption mechanisms at impact energies close to that causing perforation were found to be the deformation and failure of the fibres, regardless of the areal density. For higher impact energies, the main mechanisms were fibre failure and the energy absorbed by acceleration of the laminate.

Perforation of Composite Laminate Subjected to Dynamic Loads

This chapter focuses on the modeling of plain woven GFRP laminates under high-velocity impact. A brief review of the different approaches available in scientific literature to model the behavior of composite laminates subjected to high-velocity impact of low-mass projectiles is presented, and a new analytical model is proposed. The present model is able to predict the energy absorbed by the laminate during the perforation process including the main energy-absorption mechanisms for thin laminates: kinetic energy transferred to the laminate, fiber failure, elastic deformation, matrix cracking, and delamination.

Impact behavior of sandwich structures made of flax/epoxy face sheets and agglomerated cork

ABSTRACT The unremitting quest of natural and renewable materials able to replace their synthetic counterparts in high-performance applications has involved also sandwich structures. In this regard, the aim of this work is to characterize the impact response, in both high- and low-velocity conditions, of green sandwich structures made of agglomerated cork as core and flax/epoxy laminates as face sheets. Both bare cork, flax skins, and complete sandwich structures were subjected to impacts at three different energy levels representing the 25%, 50%, and 75% of the respective perforation thresholds. A gas gun was instead used to assess the high-velocity impact behavior of these green sandwich structures and evaluate their ballistic limit. This study shows that the buckling of cell walls of agglomerated cork enables to tailor the damage extension through-the-thickness in low-velocity impacts compared to traditional synthetic foams coupled with a considerable amount of energy absorption.