scholarly journals Mechanical Properties of Flax Tape-Reinforced Thermoset Composites

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5485
Author(s):  
Forkan Sarkar ◽  
Mahmudul Akonda ◽  
Darshil U. Shah
Keyword(s):  
Damage Tolerance ◽  
Impact Damage ◽  
Void Content ◽  
Polyester Resins ◽  
Thermoset Composites ◽  
Pull Out ◽  
Thermoset Resin ◽  
Comparable Performance ◽  
Interlaminar Shear ◽  
Flow Experiments

Three thermoset resin systems—bio-epoxy, epoxy, and polyester-with 30 v% flax fiber reinforcement have been studied to identify the optimal fiber–resin combination in a typical composite structure. Tensile, interface and interlaminar shear strength together with flexural and impact damage tolerance were compared in this study. The results revealed that mechanical and interfacial properties were not significantly affected by the different resin systems. Microscopy studies reveal that epoxy laminates predominantly fail by fibre linear breakage, polyester laminates by fiber pull-out, and bio-epoxy laminates by a combination of the two. The higher failure strains and pull-out mechanism may explain the better impact damage tolerance of polyester composites. Flow experiments were also conducted, revealing faster impregnation and lower void content with polyester resin, followed by bio-epoxy, due to their lower viscosities. Overall, bio-epoxy resin demonstrates comparable performance to epoxy and polyester resins for use in (semi-)structural bio-composites.

scholarly journals Impact damage tolerance of thermoset composites reinforced with hybrid commingled yarns

2016 ◽  
Vol 91 ◽  
pp. 522-538 ◽  
Author(s):  
Erdem Selver ◽  
Prasad Potluri ◽  
Paul Hogg ◽  
Costas Soutis
Keyword(s):  
Damage Tolerance ◽  
Impact Damage ◽  
Thermoset Composites ◽  
Commingled Yarns

Tolerance of Composite Pipes to Local Impact Damage

1996 ◽  
Vol 210 (3) ◽  
pp. 181-192 ◽  
Author(s):  
S R Reid ◽  
C Peng ◽  
J N Ashton
Keyword(s):  
Damage Tolerance ◽  
Impact Damage ◽  
Local Loading ◽  
Experimental Programme ◽  
Filament Wound ◽  
Nose Shape ◽  
Local Impact ◽  
Chopped Strand Mat ◽  
Composite Pipes

The results of an extensive experimental programme on local loading of composite pipes are presented. Particular attention is directed to the influence of projectile nose shape on the damage tolerance of the pipes. Both filament wound pipes and lined chopped-strand mat pipes are considered.

Thermal cycle effects on laminated composite plates containing voids

2018 ◽  
Vol 53 (4) ◽  
pp. 489-501 ◽  
Author(s):  
Shambhu K Gupta ◽  
Mehdi Hojjati
Keyword(s):  
Shear Strength ◽  
Thermal Cycle ◽  
Composite Structures ◽  
Laminated Composite ◽  
Composite Plates ◽  
Interlaminar Shear Strength ◽  
Void Content ◽  
Manufacturing Method ◽  
Polished Cross Section ◽  
Interlaminar Shear

Composite structures are often cured in an autoclave to acquire the required space grade quality. Now the industry is focusing on the out of autoclave manufacturing method which leads to more voids inside laminate with respect to those manufactured in the autoclave. In the present work, the influence of voids on microcrack formation under thermal cycling and environmental conditions was analyzed. Thermal cycle experiments were performed using liquid nitrogen and oven, followed by microscopic observation of the polished cross-section of the 90° layered plies. Cracks were monitored, counted, and measured with respect to void and void free areas. Void content was characterized using microscopic and ImageJ software was used. It was observed that the microcracks will be formed both around the voids and in void free areas. As the number of thermal cycle increases, the number of microcrack around the voids increases much faster than compared to the void free areas. Also it was observed that most of microcracks were propagated in the transverse direction. Interlaminar shear strength was measured. Results indicate that interlaminar shear strength reduces as the number of cycle rises due to the increase in the microcrack density. Finite element method was used to simulate the process. The micro, meso, and macro model were created with respect to original samples voids and positions to calculate the stress distribution and its concentration. Good agreement between experiment and simulation was observed.

scholarly journals Falling Weight Impact Damage Characterisation of Flax and Flax Basalt Vinyl Ester Hybrid Composites

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 806 ◽  
Author(s):  
Hom Nath Dhakal ◽  
Elwan Le Méner ◽  
Marc Feldner ◽  
Chulin Jiang ◽  
Zhongyi Zhang
Keyword(s):  
Vinyl Ester ◽  
Failure Modes ◽  
Hybrid Composites ◽  
Impact Damage ◽  
Matrix Cracking ◽  
Damage Mechanisms ◽  
Pull Out ◽  
Weight Impact ◽  
Falling Weight ◽  
The Impact

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.

A Study on the Mechanical Behavior of Jute-Epoxy Laminated Composite and its Hybrid

2020 ◽  
Vol 978 ◽  
pp. 250-256
Author(s):  
Janaki Dehury ◽  
Alok Behera ◽  
Sandhyarani Biswas
Keyword(s):  
Fiber Orientation ◽  
Laminated Composite ◽  
Matrix Cracking ◽  
Scanning Electron Micrographs ◽  
Standard Samples ◽  
Fiber Failure ◽  
Premature Failure ◽  
Fiber Waviness ◽  
Pull Out ◽  
Interlaminar Shear

This study was designed to examine the consequences of lamination sequence, fiber orientation and hybridization on tensile, flexural, physical, and inter-laminar properties of Jute-epoxy laminated composites and its hybrid. These laminates are partially biodegradable hence environment-friendly. Here six laminated specimens were fabricated using hand lay-up techniques with 4 layers of fiber or 40% fiber loading as per the ASTM standard. Samples were prepared with three different orientation of 00, 300 and 600 to the loading direction. The experimental outcome revealed that composite with 300 fiber orientation gives a better result in flexural, microhardness, and interlaminar shear strength. Generally, Final failure was due to delamination, fiber pull-out, fiber failure or matrix cracking. Scanning electron micrographs were used for improved understanding of fracture mechanics. A substantial quantity of voids, improper alignment, fiber waviness and heterogeneous interface were found resulted in premature failure.

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