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The blast resistance of a carbon fiber-reinforced epoxy (CFRE) resin has been investigated through experiments on a range of panels. The panels were subjected to blast loading by detonating small quantities of plastic explosive at a fixed stand-off distance. A ballistic pendulum was used to provide a measure of the impulse imparted to the specimen. Tests were undertaken at impulses up to those required to completely destroy the laminates. An examination of the damaged panels highlighted a number of different fracture mechanisms including delamination, top surface fiber buckling, fiber fracture, and shear failure along the edges of the plates. The impulses associated with the onset of fiber fracture and complete target failure were found to increase in a linear fashion for the range of panels considered here. The experimental data are compared with previously published results from similar tests on a woven carbon fiber-reinforced poly-ether-imide. Here, it was demonstrated that the CFRE offered a similar blast resistance to that of the thermoplastic—matrix composite. [ABSTRACT FROM AUTHOR]

Abstract: This two part paper examines the behaviour of fibre-metal laminates (FMLs) subjected to localised explosive blast loading. Part I presents the experimental observations of diamond and cross-shaped back face deformation, as well as pitting, global displacement and ring-buckling of the front face are also discerned. Part II presents quantitative analysis of the experimental data. When expressed in terms of non-dimensional parameters front and back face displacements fall within one plate thickness of a linear trend line. The threshold impulse for the onset of tearing is found to increase linearly with panel thickness. [Copyright &y& Elsevier]

Abstract: This paper examines the behaviour of fibre metal laminates (FML’s) subjected to localised explosive blast loading. Experiments are conducted on samples of varying thickness and material distribution. Plastic deformation, debonding, delamination, fibre fracture and matrix cracking have all been identified as energy absorption mechanisms. Widespread debonding is particularly evident between layers. Comparison between different plates of similar overall thickness shows no significant improvement in blast performance with increasing number of distinct material layers. This suggests that debonding does not absorb a significant proportion of the blast energy. [Copyright &y& Elsevier]

This two-part article presents the results of experimental and numerical work on the response of built-in mild steel quadrangular plates with different stiffener configurations (unstiffened, single, double, cross and double cross), subjected to blast loading. Part I studies the response of plates to uniform blast loading, while Part II examines the response to localised blast loading. The approach in both studies is similar—experimental results obtained from blast tests, using a ballistic pendulum, are presented and compared with finite element simulations. The numerical approach consisted of adiabatic analysis of a 1/4 symmetry plate model using ABAQUS/Explicit 5.8. Both temperature-dependent material properties and strain rate sensitivity are included in the numerical modelling. Large inelastic deformation is well predicted for the various stiffener configurations and sizes for both maximum displacement and deformation shape. Tearing is predicted by high-temperature bands. [Copyright &y& Elsevier]

Abstract: This two-part article examines the behaviour of aluminium alloy–glass fibre-reinforced polypropylene-based fibre–metal laminates (FMLs) subjected to localised explosive blast loading. Part I presents observations from the experiments on samples of varying thickness and material distribution, and investigates the influence of stacking configuration. This extensive study examines panels which have between two and five layers of aluminium, and up to eight plies of composite between each pair of aluminium layers. Diamond and cross-shaped back face damage is observed and varies according to panel thickness. Pitting, global displacement and ring buckling of the front face are also discerned. Some observations are related to wave propagation effects. Part II reports a quantitative analysis of the experimental data. Expressed in terms of non-dimensional parameters, front and back face displacements fall within one plate thickness of a linear trend line. The threshold impulse for the onset of tearing is found to increase linearly with panel thickness. [Copyright &y& Elsevier]

This two-part article presents the results of experimental and numerical work on the response of built-in mild steel quadrangular plates with different stiffener configurations (unstiffened (flat), single (S), double (D), cross (C) and double cross (DC)) subjected to blast loading. Part I reports on the response of these plates to uniform blast loading while localised blast loading is examined in Part II. The approach in both studies is similar—experimental results obtained from blast tests using a ballistic pendulum are presented and compared with finite element simulations. The numerical approach consists of adiabatic analyses of 1/4 symmetry plate model using ABAQUS/Explicit version 5.8. Temperature-dependent material properties, as well as strain-rate sensitivity, are included in the numerical modelling. Large inelastic deformation is well predicted for the various stiffener configurations and size for both maximum deflection and deformation shape. Tearing is predicted by high-temperature bands. [Copyright &y& Elsevier]

The effect of through-the-thickness stitching on the blast resistance of sandwich panels is investigated both experimentally and numerically. Panels based on three-dimensional woven S-glass/epoxy skins and a crosslinked PVC core were manufactured using a vacuum assisted resin infusion process. The panels were stitch-bonded using Kevlar 129 yarn, by means of a multi-needle stitch-bonding machine developed in a previous investigation. The performance of both orthogonal (0°) and biased (45°) stitching procedures were considered and their respective responses were compared to that of a similar unstitched panel. The blast resistance of the sandwich panels was modelled using finite element techniques. An examination of the blast-loaded samples highlighted a number of failure mechanisms, including crushing of the foam core, skin-core debonding, fracture of the glass fibre/epoxy skins, fibre-matrix debonding with fibre pull-out and delamination. If evaluated on the basis of specific impulse (applied impulse normalized by plate mass), the results indicate that stitching has no obvious effect on the blast resistance of the sandwich structures. Agreement between the finite element models and the experimental data was good over the range of loading conditions considered. Here, the FE models accurately predicted the overall deformation responses of the panels and also captured the primary failure modes. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the influence of varying core density on the blast resistance of sandwich panels based on crosslinked PVC cores and aluminium alloy skins. Initially, the findings of a series of compression and single edge notch bend and shear tests are presented in order to characterise the strength and toughness characteristics of the foams and generate data for input into the finite element models. Experimental blast tests employing a ballistic pendulum are then reported, where it is shown that damage within the sandwich panels becomes more severe as the density of the foam core is increased. Indeed, panels based on the lowest density foam (60 kg/m3) did not exhibit any fracture or debonding over the range of impulses considered, instead absorbing energy through plastic deformation in the metal skins and compression of the foam core. In contrast, significant damage, in the form of Mode I core cracking and debonding at the skin–core interface, was apparent in the higher density core systems. A finite element analysis has been employed to model the blast response of the sandwich structures. The FE models successfully predicted the post-test deformed shapes of the panels. These analyses were also used to determine the individual contributions of the skin and core to the energy-absorbing capacity of the various sandwich structures. Here, it was shown that the foam core absorbs more than fifty percent of the overall energy dissipated during the test. [Copyright &y& Elsevier]