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Loughborough University Institutional Repository Ballistic damage in hybrid composite laminates
| Content Provider | Semantic Scholar |
|---|---|
| Author | Phadnis, Vaibhav A. Pandya, Kedar S. Naik, N. Channa Keshava Roy, Anish Vadim, Vologodsky Silberschmidt |
| Copyright Year | 2018 |
| Abstract | Ballistic damage of hybrid woven-fabric composites made of plain-weave E-glassfabric/epoxy and 8H satin-weave T300 carbon-fabric/epoxy is studied using a combination of experimental tests, microstructural studies and finite-element (FE) analysis. Ballistic tests were conducted with a single-stage gas gun. Fibre damage and delamination were observed to be dominating failure modes. A ply-level FE model was developed, with a fabric-reinforced ply modelled as a homogeneous orthotropic material with capacity to sustain progressive stiffness degradation due to fibre/matrix cracking, fibre breaking and plastic deformation under shear loading. Simulated damage patterns on the front and back faces of fabric-reinforced composite plates provided an insight into their damage mechanisms under ballistic loading. 1. Background Woven fabric-based polymer-matrix composites (PMCs) are finding an increased use in defencerelated applications thanks to their high strength and stiffness and ability to produce structures with tailored shapes and mechanical properties. Additionally, such PMCs lead to better energy absorption in ballistic impact events, especially thanks to their balanced in-plane properties. Recent studies [1, 2] showed that a hybrid composite structure a combination of glassand carbon-based epoxy composites may further improve the energy absorbing capacity of such composites. Thus, it is of great interest to a scientific community to understand their mechanical behaviour in high-velocity impact events. In ballistic impact events, PMCs absorb projectile's kinetic energy by undergoing either elastic or permanent deformation. In the latter case, PMCs often exhibit different damage modes such as delamination, punching and fibre breakage. The condition for perforation, known as the ballistic limit velocity (V50), is one of the most important factors for design of a suitable protective structure in this regard [1-4]. It represents an average of equal numbers of highest partial-penetration velocities and lowest complete-penetration velocities of a projectile for a specific velocity range, resulting in 50% probability of partial penetration and perforation of a target. Recently, Naik and Doshi [2] reported on ballistic-impact behaviour of typical woven-fabric E-glass/epoxy thick composites employing an analytical approach and found that shear plugging was the major energy-absorbing mechanism in these laminates. The level of V50 was also calculated and found to vary non-linearly with a linear 11th International Conference on Damage Assessment of Structures (DAMAS 2015) IOP Publishing Journal of Physics: Conference Series 628 (2015) 012092 doi:10.1088/1742-6596/628/1/012092 Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd 1 increase in the laminate's thickness. Zhu [3] investigated a response of woven Kevlar/polyester laminates of varying thickness to quasi-static and dynamic penetration by cylindro-conical projectiles. Damage patterns in these composites were found to differ significantly under dynamic loading from those for quasi-static penetration conditions. There are some shortcomings of experimental ballistic schemes: typical experiments involve a plethora of safety protocols and often their output is difficult to quantify in a reliable manner given a short duration of such events. Thus, computer simulations are often employed as a virtual tool to analyse performance of structures in ballistic events and support their optimisation and design. Simulating the mechanical behaviour of a fabric-reinforced composite structure under ballistic impact is a challenging task. Unlike metallic components that can yield and dissipate energy by undergoing plastic deformation, composites can mostly dissipate energy through various damage processes that usually degrade stiffness of structural components. Hence, an advanced modelling tool that can adequately simulate such events is essential in the design process. However, due to the complexity of involved processes and mechanisms, most models attempt to provide acceptable tradeoff in performance analysis [4-8]. To model a woven-fabric down to a level of crossovers of individual yarn would certainly be preferred in order to study the underlying frictional and crimping effects, but such studies are computationally impracticable for dynamic problems. In this regards, this work focuses on the development of a FE model of a ballistic-impact response of woven-fabric-reinforced composites. The experimental studies, reproduced in numerical simulations, are discussed first, followed by a brief description of the developed FE model. Its results and discussion are presented next. 2. Ballistic experiments A ballistic-impact test apparatus operated by a single-stage gas-gun (Fig. 1) was used to carry out experimental studies. It consisted of a projectile-propelling mechanism, a chronograph for velocity measurement, a support stand for holding the specimen, a containment chamber, safety devices and a strain-measuring facility. Compressed air was used as a propellant in the system. The main components of this propelling mechanism were a cylindrical barrel to guide the projectile, a quick release valve to relieve the trapped air and a nitrogen gas-driven solenoid valve to operate this valve. The cylindrical barrel (through which a projectile was propelled) was 1.5 m long. Its inner diameter was chosen to suit a projectile used in these experiments. Figure 1. Ballistic test setup: (a) single-stage gas gun; (b) typical test specimen (a) |
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| Alternate Webpage(s) | https://dspace.lboro.ac.uk/dspace-jspui/bitstream/2134/19004/1/JPCS%202015%20Ballistic%20damage%20in%20hybrid%20composite%20laminates.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
