Inverse identification of a bearing-stress-interface-slip relationship in mechanically fastened FRP laminates

The use of mechanically-fastened fibre-reinforced polymer (MF-FRP) strips has been recently proposed as a possible alternative solution to the most common externally-bonded (EB) sheets and laminates. Although several applications of MF-FRP strengthening on reinforced concrete (RC) structures are already available, further experimental and theoretical studies are needed for both achieving a thorough knowledge of their mechanical behaviour and formulating sound design rules.     

An experimental investigation of the properties of cross-ply laminate used for manufacturing of small aircraft components

This paper discusses the observations and results from an experimental investigation of cross ply laminates used to construct major structural components of a small aircraft manufactured in Australia. The static and fatigue experimental results are compared with established models in composites analysis and with the available data in composite databases. An analysis was done to statistically quantify any deviation of actual properties from the calculated values and investigate the differences in designed and actual capacities/operational life of the components made using this laminates.     

Computational and experimental crash analysis of the road safety barrier

The paper describes the computational analysis and experimental crash tests of a new road safety barrier. The purpose of this research was to develop and evaluate a full-scale computational model of the road safety barrier for use in crash simulations and to further compare the computational results with real crash test data. The impact severity and stiffness of the new design have been evaluated with the dynamic nonlinear elasto-plastic analysis of the three-dimensional road safety barrier within the framework of the finite element method with LS-DYNA code. Comparison of computational and experimental results proved the correctness of the computational model. The tests have also shown that the new safety barrier assures controllable crash energy absorption which in turn increases the safety of vehicle occupants.     

Computational and experimental investigation of delamination in L-shaped laminated composite components

Formation of initial delaminations and growth of existing delaminations in L-shaped laminates made of plies of a unidirectional carbon fiber reinforced epoxy resin is investigated computationally and experimentally. For this purpose an experimental test is designed which allows to realize load states for which delamination is the dominant failure mechanism. Two types of test specimens, with and without initial delaminations, are investigated and good agreement is obtained between the computational predictions and the experimental results concerning delamination emergence, delamination growth, growth stability, the structural response, and the maximum principal strains.     

On the response of thin-walled CFRP composite tubular components subjected to static and dynamic axial compressive loading: experimental

In this work the crushing response and crashworthiness characteristics of thin-wall square FRP (fibre reinforced plastic) tubes that were impact tested at high compressive strain rate are compared to the response of the same tubes in static axial compressive loading. The material combination of the tested specimens was carbon fibres in the form of reinforcing woven fabric in epoxy resin, and the tested tubes were constructed trying three different laminate stacking sequences and fibre volume contents on approximately the same square cross-section. Comparison of the static and dynamic crushing characteristics is made by examining the collapse modes, the shape of the load–displacement curves, the peak and average compressive load and the absorbed amount of crushing energy in both loading cases. In addition, the influence of the tube geometry (axial length, aspect ratio and wall thickness), the laminate material properties-such as the fibre volume content and stacking sequence-and the compressive strain rate on the compressive response, the collapse modes, the size of the peak load and the energy absorbing capability of the thin-wall tubes is extensively analysed.     

Numerical and experimental investigation of mixed‐mode fracture parameters on silicon nitride using the Brazilian disc test

Engineering applications of ceramics can often involve mixed‐mode conditions involving both tensile and shear loading. Mixed‐mode fracture toughness parameters are evaluated for applicability to ceramics using the Brazilian disc test on silicon nitride. Semi‐elliptical centrally located surface flaws are induced on the disc specimens using Vickers indentation and compression loaded to fracture with varying levels of mode mixity. The disc specimens are modelled via 3D finite element analysis and all three modes of stress intensity factors computed along the crack front, at failure load. We present a numerical and experimental investigation of four widely used mixed‐mode fracture criteria and conclude that the critical strain energy release rate criterion is simple to implement and effective for silicon nitride under mixed‐mode conditions.     

Numerical and experimental investigation of the strength of corrugated board packages

The buckling behaviour of corrugated paper packages was studied by means of an experimental and theoretical analysis. Mechanical behaviour of paperboard was first evaluated experimentally, then a local geometry FEM model, able to reproduce with a very good accuracy buckling loads obtained experimentally in the standard edge compression test, was developed. In order to investigate the buckling of a complete package, a finite element ‘corrugated board’ was introduced by means of a dedicated homogenization procedure. The FEM model of the package, assembled with this new element, can accurately predict the experimental data of incipient buckling observed during the standard box compression test, despite the few degrees of freedom and the minimal computational effort. Copyright © 2003 John Wiley & Sons, Ltd.     

On the relation between the mode I fracture toughness of a composite laminate and that of a 0° ply: Analytical model and experimental validation

This paper proposes a simple model to predict the fracture toughness of multidirectional carbon–epoxy composite laminates using the fracture toughness of the 0° ply. The model is based on a combination of Linear-Elastic Fracture Mechanics and lamination theory, and uses as material properties the ply elastic properties and the fracture toughness of the 0° ply measured in compact tension test specimens. A good correlation is obtained by comparing the model predictions and experimental data obtained in center-cracked specimens manufactured using different lay-ups and materials.     

Estimating the spatial distribution of power outages during hurricanes in the Gulf coast region

Hurricanes have caused severe damage to the electric power system throughout the Gulf coast region of the US, and electric power is critical to post-hurricane disaster response as well as to long-term recovery for impacted areas. Managing power outage risk and preparing for post-storm recovery efforts requires accurate methods for estimating the number and location of power outages. This paper builds on past work on statistical power outage estimation models to develop, test, and demonstrate a statistical power outage risk estimation model for the Gulf Coast region of the US. Previous work used binary hurricane-indicator variables representing particular hurricanes in order to achieve a good fit to the past data. To use these models for predicting power outages during future hurricanes, one must implicitly assume that an approaching hurricane is similar to the average of the past hurricanes. The model developed in this paper replaces these indicator variables with physically measurable variables, enabling future predictions to be based on only well-understood characteristics of hurricanes. The models were developed using data about power outages during nine hurricanes in three states served by a large, investor-owned utility company in the Gulf Coast region.