scholarly journals Chopped Strand/Plain Weave E-Glass as Reinforcement in Vacuum Bagged Epoxy Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Srinivas Shenoy Heckadka ◽  
Suhas Yeshwant Nayak ◽  
Karan Narang ◽  
Kirti Vardhan Pant
Keyword(s):  
Shear Strength ◽  
Composite Laminates ◽  
Polymer Matrix Composites ◽  
Impact Resistance ◽  
Interlaminar Shear Strength ◽  
Fiber Volume ◽  
Glass Composites ◽  
Plain Weave ◽  
Specific Strength ◽  
Interlaminar Shear

Polymer matrix composites are one of the materials being extensively researched and are gaining a lot of importance due to advantages like high specific strength, greater flexibility in design, and reduced cost of manufacturing. In this study, tensile, flexural, impact, and interlaminar shear strength of chopped strand/plain weave E-glass composites were considered. Composite laminates with different stacking sequence were fabricated using Vacuum Assisted Resin Infusion Moulding (VARIM) technique. Fiber volume fractions (FVF) of 22%, 26%, and 30% were adopted. Experiments were conducted in accordance with ASTM standards. Results indicate that laminates with three layers of plain weave mat exhibited better tensile, flexural, and interlaminar shear strength. However, laminates with two layers of chopped strand mat and one layer of plain weave mat showed improved impact resistance. In addition, scanning electron microscopy was used to analyze the fracture surface.

Preparation and Characterization of Structural Damping Composites Toughened by Polyamide Nonwoven Fabrics

2016 ◽  
Vol 848 ◽  
pp. 189-195
Author(s):  
Nan Nan Ni ◽  
Yue Fang Wen ◽  
De Long He ◽  
Miao Cai Guo ◽  
Xiao Su Yi
Keyword(s):  
Shear Strength ◽  
Composite Laminates ◽  
Impact Resistance ◽  
Nonwoven Fabric ◽  
Mechanical Analysis ◽  
Interlaminar Shear Strength ◽  
Structural Damping ◽  
Nonwoven Fabrics ◽  
Compression After Impact ◽  
Interlaminar Shear

A new kind of structural damping composites was prepared by interleaving polyamide nonwoven fabrics (PNF) between the carbon fiber reinforced epoxy composite laminates. The damping behaviors of the composites made were experimentally investigated using cantilever beam test and dynamic mechanical analysis. The damping ratios of the nonwoven fabrics interleaved composites were compared with the ones of non-interleaved composites. In addition, the interlaminar shear strength and flexible modulus of the composites were also investigated, as well as the composite compression after impact (CAI), Mode I and Mode II interlaminar fracture toughness (GIC and GIIC), in order to evaluate the influence of the polyamide nonwoven fabric layers on the composite mechanical properties. It has been observed that the interleaved polyamide nonwoven fabric layers greatly improved the composite damping loss factors, and the composites containing 7 layers of PNF showed the best damping behavior. Meanwhile, the addition of PNF showed a negligible influence on the composite flexible strength and modulus and interlaminar shear strength. Most importantly, the CAI, GIC and GIIC tests indicated that the composite interlaminar toughness and impact resistance were significantly improved by the interleaved PNF. Finally, the reinforcing mechanism of this kind of composites is discussed.

Experimental study on the effect of stitch arrangement on mechanical performance of GFRP laminates manufactured on a basis of stitched preforms

2011 ◽  
Vol 46 (9) ◽  
pp. 1067-1078 ◽  
Author(s):  
Mateusz Koziol
Keyword(s):  
Shear Strength ◽  
Composite Laminates ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Interlaminar Shear Strength ◽  
Direction Parallel ◽  
Stitch Density ◽  
Stitch Length ◽  
Interlaminar Shear ◽  
Flexural Tests

This article presents the results of interlaminar shear and flexural tests of stitched polyester glass fiber laminates in dependence on stitch density and main geometric stitching parameters: stitch length and stitch spacing. Purpose of the study is to work out guidelines and indications for manufacturers of composite laminates who use or who plan to use stitching technique. It was found that stitching significantly improves interlaminar shear strength which increases with stitch density. However, stitching causes deterioration of in-plane flexural properties – the deterioration progresses when stitch density increases. Obtained results indicate that it is better to achieve increase in stitch density (resulting in improvement of interlaminar shear strength) by reduction of stitch length than by reduction of stitch spacing. Stitched laminate shows higher flexural strength and flexural modulus when bent into direction parallel to the stitch lines than when bent into the transverse direction. The results obtained within the study and their approximation constants may be a base for a new theoretical model simulating behavior of stitched laminate during static bending and enabling prediction of its mechanical performance.

Exploration relation between interlaminar shear properties of thin-ply laminates under short-beam bending and meso-structures

2017 ◽  
Vol 52 (17) ◽  
pp. 2375-2386 ◽  
Author(s):  
Chunfang Huang ◽  
Mingchang He ◽  
Yonglyu He ◽  
Jiayu Xiao ◽  
Jiangwei Zhang ◽  
...  
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Composite Laminates ◽  
Design Space ◽  
Interlaminar Shear Strength ◽  
Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Short Beam ◽  
Beam Bending ◽  
Interlaminar Shear

Carbon fiber reinforced polymer matrix composite laminates with standard thickness plies (0.125 mm) usually have weak interlaminar shear strength, meanwhile, for thin-thickness laminate structures such as aircraft wing skin, it is difficult to design a balanced laminate with the standard plies. It is a possible way to improve the interlaminar shear performance of carbon fiber reinforced polymer composite laminates and enlarge the design space of the thin-thickness structures by using thin-plies technology. In this paper, the interlaminar shear strength of carbon fiber/epoxy laminates with thin prepreg thickness subjected to short-beam bending is investigated. Unidirectional, cross-ply and quasi-isotropic laminate specimens were prepared by using prepregs with different ply thicknesses. Results show that, with decreasing of the ply thickness, higher interlaminar shear strength and smaller coefficient of variation of the data are obtained. Compared to laminates made by standard thickness prepreg, the laminates with thin-thickness prepreg exhibit more homogeneous microstructures and more regularly interlaminar shear stress distribution. This indicates that inherent anisotropy of the laminate composites is weakened in the thin-ply laminates and show pseudo-isotropic behavior. Especially in the case of ply thickness less than 0.020 mm, the interlaminar shear stress distributions of the cross-ply and quasi-isotropic laminate are almost the same with that of isotropic materials according to the classic laminate theory. On the other hand, as expected, the design space of the thin-thickness laminate structures will be increased since more ply number are allowed and superior interlaminar properties can be obtained due to the pseudo-isotropic behavior of the thin plies.

scholarly journals Process Chain Development for the Fabrication of Three-Dimensional Braided Oxide Ceramic Matrix Composites

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6338
Author(s):  
Martin Kolloch ◽  
Georg Puchas ◽  
Niels Grigat ◽  
Ben Vollbrecht ◽  
Walter Krenkel ◽  
...  
Keyword(s):  
Shear Strength ◽  
Three Dimensional ◽  
Ceramic Matrix Composites ◽  
Fiber Composites ◽  
Interlaminar Shear Strength ◽  
Oxide Ceramic ◽  
Two Dimensional ◽  
Process Chain ◽  
Fiber Volume ◽  
Interlaminar Shear

Fiber composites with a three-dimensional braided reinforcement architecture have higher fiber volume content and Z-fiber content compared to a two-dimensional braided reinforcement architecture; as a result, the shear strength increases. Porous oxide fiber composites (OFCs) have the inherent weakness of a low interlaminar shear strength, which can be specifically increased by the use of a three-dimensional fiber reinforcement. In this work, the braiding process chain for processing highly brittle oxide ceramic fibers is modified; as a consequence, a bobbin, which protects the filament, is developed and quantitatively evaluated on a test rig with regard to tension and filament breakage. Subsequently, a braiding process is designed which takes into account fiber-protecting aspects, and a three-dimensional reinforced demonstrator is produced and tested. After impregnation with an Al2O3-ZrO2 slurry, by either a prepreg process or a vacuum-assisted process, as well as subsequent sintering, the three-dimensional braid-reinforced OFC exhibits an interlaminar shear strength (ILSS) which is higher than that of two-dimensional braid- or fabric-reinforced samples by 64–95%. The influence of the manufacturing process on the relative macropore content is investigated and correlated with the mechanical properties.

Flexural, Compressive, and Interlaminar Shear Strength Properties of Kapok/Glass Composites

2008 ◽  
Vol 28 (14) ◽  
pp. 1665-1677 ◽  
Author(s):  
G. Venkata Reddy ◽  
T. Shobha Rani ◽  
K. Chowdoji Rao ◽  
S. Venkata Naidu
Keyword(s):  
Shear Strength ◽  
Strength Properties ◽  
Interlaminar Shear Strength ◽  
Glass Composites ◽  
Interlaminar Shear

Damage Development in Hybrid Composite Laminates under Three-Point Bending at Cryogenic Temperatures

2010 ◽  
Vol 452-453 ◽  
pp. 565-568
Author(s):  
Masaya Miura ◽  
Yasuhide Shindo ◽  
Tomo Takeda ◽  
Fumio Narita
Keyword(s):  
Shear Strength ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Maximum Shear Stress ◽  
Interlaminar Shear Strength ◽  
Cryogenic Temperatures ◽  
Damage Development ◽  
Hybrid Laminates ◽  
Interlaminar Shear ◽  
Woven Glass Fiber

This paper studies the damage behavior and interlaminar shear properties of hybrid composite laminates subjected to bending at cryogenic temperatures. Cryogenic short beam shear tests were performed on hybrid laminates combining woven glass fiber reinforced polymer (GFRP) composites with polyimide films, and microscopic observations of the specimens were made after the tests. A progressive damage analysis was also conducted to simulate the initiation and growth of damage in the specimens and to determine the interlaminar shear strength based on the maximum shear stress in the failure region. The predicted load-deflection curve and damage pattern show good agreement with the test results, and the numerically determined interlaminar shear strength is higher than the apparent interlaminar shear strength.

Addition of a small amount of multiwalled carbon nanotubes and flaked graphene to epoxy resin

2017 ◽  
Vol 36 (9) ◽  
pp. 640-654 ◽  
Author(s):  
Mateusz Koziol ◽  
Marcin Jesionek ◽  
Piotr Szperlich
Keyword(s):  
Carbon Nanotubes ◽  
Shear Strength ◽  
Flexural Strength ◽  
Epoxy Resin ◽  
Impact Resistance ◽  
Gelation Time ◽  
Interlaminar Shear Strength ◽  
Multiwalled Carbon ◽  
Professional Literature ◽  
Interlaminar Shear

The paper presents an attempt to evaluate the technically important properties of epoxy resin modified alternatively with multi-walled carbon nanotubes and flaked graphene. It is a presentation of experimental results supported by extensive referring to the professional literature. The nano-components were added in the amount which was economically justified and provides hope for a significant improvement of some of the properties of pure resin. Flowability, glass wettability, curing process and gelation time and curing shrinkage of the resin were evaluated. After the resin was cured, inner and outer hardness, thermal conductivity, flexural strength and impact resistance were measured. Glass fibre-reinforced laminates were also prepared with use of the nano-modified resin. The mechanical properties, interlaminar shear strength and flexural strength of the laminates, were evaluated for them. The obtained results showed either no effect or only technically slight effect of the nano-modification on the evaluated properties. Noticeable improvement in interlaminar shear strength and impact resistance for laminates containing resin filled with graphene can predestine this kind of modification as a method of increasing the delamination resistance of laminates.

Interlaminar Shear Property of Z-Pins Reinforced Woven Ceramic Matrix Composites

2011 ◽  
Vol 197-198 ◽  
pp. 1608-1612
Author(s):  
Wei Liu ◽  
Gui Qiong Jiao ◽  
Wei Xi Zhang ◽  
Wei Min Zhang
Keyword(s):  
Shear Strength ◽  
Failure Mechanisms ◽  
Impact Resistance ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interlaminar Shear Strength ◽  
Fracture Plane ◽  
Matrix Composites ◽  
Shear Property ◽  
Interlaminar Shear

Z-pins reinforced 2D ceramic matrix composites (CMCs), integratedly designed new materials, are developed to enhance 2D CMCs through-thickness in the form of Z-pins and to ensure significant increase in interlaminar fracture toughness, delamination resistance and impact resistance, and Z-pins reinforced 2D CMCs have much application. Finite element method was adopted to analyze stress distributions of Z-pins reinforced woven CMCs; the interlaminar shear tests were employed to measure interlaminar shear strength; fractographies were observed to examine failure mechanisms. The results are shown as the following: the insertion of Z-pins reduces concentrated stress fields and enhances the uniform stress distribution on the expected fracture plane. Interlaminar shear strength of Z-pins reinforced woven CMCs is increased as Z-pins insertion reaches a certain number. Interlaminar shear strength goes up with the rise of the number of inserted Z-pins. Z-pins shearing and fabric/matrix debonding are interlaminar failure mechanisms of Z-pins reinforced CMCs.

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