Ultrasonic evaluation of ballistic impact damage in thick section twill weave S2-glass/vinyl ester laminates

2000 ◽  
Author(s):  
M. V. Hosur
1999 ◽  
Vol 121 (4) ◽  
pp. 468-475 ◽  
Author(s):  
M. V. Hosur ◽  
U. K. Vaidya ◽  
A. Abraham ◽  
N. Jadhav ◽  
S. Jeelani

Fiber reinforced composites, due to their higher specific strength and specific stiffness, are replacing many metallic structures. Of these, thick composite laminates are of high interest in various, millitary, transportation and marine applications for their use in ballistic and shock protection. One such application is in Composite Armored Vehicle (CAV) integral armor comprising of thick section composite that serves as the primary load-bearing component. The current solution of the structural backing laminate utilizes an S2-glass/epoxy system processed using automated fiber placement method. While proven structurally suitable, this method is time consuming as well as expensive. This paper presents several alternative cost-effective manufacturing solutions for fabricating composite laminates of 20 mm (0.8 in.) nominal thickness (made of 45 layer, 2 × 2 twill weave S2-glass with 933 sizing/vinyl ester C-50 resin), consisted with them CAV application in focus. They include Vacuum Assisted Resin Transfer Molding (VARTM) and Vacuum Assisted Resin Infusion Modeling (VARIM) and their variations. The effectiveness of different affordable processing approaches adopted in fabricating the structural laminate is compared in terms of static and dynamic compression response of the laminations. Static studies have been conducted on thick composites using specimen based on Army Material Technology Laboratory’s (AMTL) recommendation for thick section composites, while dynamic response is studied on cubic specimen samples using a Split Hopkinson Pressure Bar (SHPB).


2012 ◽  
Vol 47 (7) ◽  
pp. 480-494 ◽  
Author(s):  
Bazle Z (Gama) Haque ◽  
Jessica L Harrington ◽  
John W Gillespie

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 806 ◽  
Author(s):  
Hom Nath Dhakal ◽  
Elwan Le Méner ◽  
Marc Feldner ◽  
Chulin Jiang ◽  
Zhongyi Zhang

Understanding the damage mechanisms of composite materials requires detailed mapping of the failure behaviour using reliable techniques. This research focuses on an evaluation of the low-velocity falling weight impact damage behaviour of flax-basalt/vinyl ester (VE) hybrid composites. Incident impact energies under three different energy levels (50, 60, and 70 Joules) were employed to cause complete perforation in order to characterise different impact damage parameters, such as energy absorption characteristics, and damage modes and mechanisms. In addition, the water absorption behaviour of flax and flax basalt hybrid composites and its effects on the impact damage performance were also investigated. All the samples subjected to different incident energies were characterised using non-destructive techniques, such as scanning electron microscopy (SEM) and X-ray computed micro-tomography (πCT), to assess the damage mechanisms of studied flax/VE and flax/basalt/VE hybrid composites. The experimental results showed that the basalt hybrid system had a high impact energy and peak load compared to the flax/VE composite without hybridisation, indicating that a hybrid approach is a promising strategy for enhancing the toughness properties of natural fibre composites. The πCT and SEM images revealed that the failure modes observed for flax and flax basalt hybrid composites were a combination of matrix cracking, delamination, fibre breakage, and fibre pull out.


2012 ◽  
Vol 46 (5) ◽  
pp. 527-547 ◽  
Author(s):  
Lvtao Zhu ◽  
Baozhong Sun ◽  
Hong Hu ◽  
Bohong Gu

2018 ◽  
Vol 27 (5) ◽  
pp. 096369351802700 ◽  
Author(s):  
G. Strugala ◽  
M. Landowski ◽  
M. Zaremba ◽  
J. Turowski ◽  
M. Szkodo

This paper discusses the impact resistance of glass-fibre reinforced polymer (GFRP) composites depending on the type of reinforcement – plain or twill weave. The values of impact energy were: 3J, 10J and 15J. Specimens featuring twill weave transferred higher force during the impact as compared with plain weave specimens. It was observed that an increase of impact energy was accompanied by an increase of the disproportion in transferred forces, in favour of twill weave specimens. Impact damage (in both types of weave) occurring as a result of 3J impact was undetectable with active thermography method. The damage area measured by means of active thermography for impact energy values equal to 10J and 15J proved that the type of reinforcement significantly influences the impact resistance of a composite. This has been justified by smaller damage areas with high spot intensity of damage in plain weave specimens and highly dispersed damage with lower intensity in twill weave specimens.


2020 ◽  
Vol 29 (9) ◽  
pp. 1465-1484
Author(s):  
Qingsong Wei ◽  
Bohong Gu ◽  
Baozhong Sun

Flexible fabrics have been widely used in body armor designs. Here we report ballistic impact damage of stacked cross-plied composite fabric and cross-plied laminated panels. The ballistic impact behaviors of stacked cross-plied composite fabric and cross-plied laminated panel have been tested with fragment-simulating projectiles under the strike velocity 550–600 m/s to explore the influence of the layers combination of fabric target on ballistic impact. Two types of macroscopic anisotropy continua finite element models based on fabric targets structures are established to analyze the ballistic mechanism of stacked cross-plied composite fabric and cross-plied laminated panels. The impact damage morphologies and energy absorptions have also been compared between the tests and finite element analysis results. We have found the stacked fabric construction absorbed more energy than their counterpart cross-plied laminated panel, while the laminated panel shows better structural integrity and stability during ballistic penetration.


2016 ◽  
Vol 713 ◽  
pp. 277-279
Author(s):  
Hyun Bum Park

In this study, structural design and analysis of the automobile bonnet is performed. The flax/vinyl ester composite material is applied for structural design. The Vacuum Assisted Resin Transfer Molding (VARTM) manufacturing method is adopted for manufacturing the flax fiber composite bonnet. A series of flax/vinyl ester composite panels are manufactured, and several kinds of specimens cut out from the panels are tested to obtain mechanical performance data. Based on this, preliminary structural design of the automobile bonnet is performed. Finally, this study is to investigate the residual compressive strength of the flax/vinyl ester laminate due to impact damages. Through investigation on compressive strength, design allowable of flax/vinyl ester laminate is determined by the experiment to address design criteria of the composite structure.


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