On the Behavior of Fiberglass Epoxy Composites under Low Velocity Impact Loading (original) (raw)
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Composite Structures, 2003
In the current investigation, damage resistance of stitched/unstitched S2-glass/epoxy composites is studied. Five layer stitched/unstitched plain weave S2-glass woven fabric composite laminates were manufactured using toughened SC15 epoxy resin system. For stitching, two configurations: one with 25.4 mm grid and other with 12.7 mm grid, were used with 6 mm pitch. Damage resistance was evaluated by subjecting 100 × 100 mm samples to low velocity impact loading at energy levels ranging 10–80 J using DYNATUP Model 8210, an instrumented impact test system. Three samples were tested at each energy level. The extent of damage was evaluated using ultrasonic C-scan. Results of the study indicate that stitching confined the damage size. As the damage was low over most of the energy range, the study was further extended to determine the effect of repeated impact loading. Under this study, laminates were subjected to repeated impact loading up to maximum of 40 impacts at energy levels ranging from 10 to 50 J. Results of repeated impact study are reported in terms of peak load, absorbed energy and projected damage area. All the laminates, sustained repeated impact loading up to 30 J. Beyond 30 J, laminates failed to carry repeated loading beyond certain numbers, which depended on the laminate configuration.
Analyzing Impact Behaviour of Glass Fiber Epoxy Composites for Higher Safety Systems
International conference KNOWLEDGE-BASED ORGANIZATION
This study investigates the impact behaviour of glass fiber epoxy composites with a focus on achieving enhanced safety. A drop weight impact test machine was used to perform a series of impact tests on the composite samples. Two different impactors as dimensions and three velocities were used to investigate the impact behavior of glass fiber epoxy composites. The study’s goal is to investigate the impact response of these composites and their potential for usage in impact protection applications. The study findings show that glass fiber epoxy composites have outstanding impact resistance properties, as well as high levels of the ability to absorb energy and withstand the initiation of damage. The findings suggest that both the impactor (as shape and dimensions) and the velocity of impact have a notable influence impact on the damage mechanisms and energy absorption capacity of the composite materials. The failure mechanisms detected in the composites were mostly delamination and fib...
Damage prediction in glass/epoxy laminates subjected to impact loading
In this paper, the impact behaviour of glass/epoxy laminated composite plates with (0/±�/90) S fiber orientation is investigated numerically at equal energy (40 J), equal velocity (2 m/s) and equal impactor mass (5 kg). In order to examine the stacking sequence effect, five different ± � fiber directions are chosen as 15°, 30°, 45°, 60° and 75°. Three different plate thicknesses as 2.9 mm, 5.8 mm, and 8.7 mm are also selected to survey the thickness effect on impact behaviour of glass/epoxy composite plates. The overlapped delamination area is obtained for composite plates with different stacking sequences and different thicknesses. A transient finite element code 3DIMPACT is used for numerical analyses. In this code an eight-point brick element and the direct Gauss quadrature integration scheme are used through the element thickness to account for the change in material properties from layer to layer. The Newmark scheme is also adopted to perform time integration step by step. In a...
Ballistic impact behaviour of woven fabric composite: Finite element analysis and experiments
A mechanical behaviour of plain-weave E-glass fabric/epoxy laminate composite plate exposed to ballistic impact is studied using a finite-element (FE) code Abaqus/Explicit. A ply-level FE model is developed, where a fabric-reinforced ply is modelled as a homogeneous orthotropic elastic material with potential to sustain progressive stiffness degradation due to fiber/matrix cracking, and plastic deformation under shear loading. The model is implemented as a VUMAT user subroutine. Ballistic experiments were carried out to validate the FE model. A parametric study for varying panel thickness is performed to compare impact resistance of the studied composite.
2015
The presented research was devoted to determining the influence of impactor geometry on the degree and character of failure of a glass fibre reinforced epoxy matrix subjected to low-velocity impact. Furthermore, the relevance of impact energy and lay-up configuration of each composite plate were analysed. The subject of the tests were autoclave manufactured 8-ply glass/epoxy prepregs of the following lay-up [0/90]2s, [±45]2s and [0/±45/90]s. The laminates were subjected to low-velocity impact tests according to norm ASTM D7136 with the application of hemispherical impactors: 12.7 mm (0.5"), 25.4 mm (1") and 38.1 mm (1.5"), for three impact energies 5, 10 and 15 J. The conducted tests indicate the correlation between the diameter of the indenter and the load applied, on the degree and character of damage of the glass/epoxy composites, i.e. the higher the load, the greater the laminate failure, regardless of the lay-up configuration. Similarly, the degree of failure is ...