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.

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.

Experimental studies on interlaminar shear strength and dynamic mechanical analysis of luffa fiber epoxy composites with nano PbO addition

2021 ◽  
pp. 152808372110523
Author(s):  
Kumaresan Gladys Ashok ◽  
Kalaichelvan Kani
Keyword(s):  
Shear Strength ◽  
Dynamic Mechanical Analysis ◽  
Epoxy Matrix ◽  
Weight Percent ◽  
Mechanical Analysis ◽  
Interlaminar Shear Strength ◽  
Epoxy Composites ◽  
Dynamic Mechanical ◽  
Interlaminar Shear ◽  
Composite Samples

In the present study, the significance of nanofiller lead oxide (PbO) on the dynamic mechanical analysis (DMA) and interlaminar shear strength (ILSS) performance of luffa fiber–reinforced epoxy composites was investigated. The epoxy matrix was altered with nanofiller PbO of different weight percent through a mechanical stirring process. The PbO-added luffa fiber epoxy composites were made through hand layup preceded by the compression molding method. The prepared composite samples were investigated for ILSS and DMA. The test results lead to the inference that the 1.25 wt% PbO nanofiller–added composite samples attained 25%, 17%, and 55% of higher loss modulus, storage modulus, and ILSS, respectively, as compared with the other prepared samples. The morphological investigation was conducted on the fractured surface of the interlaminar tested samples. The micrographic images show the bonding nature of the luffa fiber with the epoxy matrix, fiber breakage, and fiber pullouts. The characterization studies such as FTIR, XRD, and EDX were conducted on the fabricated composite samples. The XRD studies show that the rise in weight percent of the nanofiller PbO enhances the crystallinity of the composite samples. Moreover, the composite sample prepared with 1.25 wt% nanofiller PbO can be used to prepare low-cost roofing materials for sustainable housing projects.

scholarly journals Surface Modification of Carbon Fibers by Grafting PEEK-NH2 for Improving Interfacial Adhesion with Polyetheretherketone

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 778 ◽  
Author(s):  
Elwathig. Hassan ◽  
Tienah. Elagib ◽  
Hafeezullah Memon ◽  
Muhuo Yu ◽  
Shu Zhu
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Carbon Fibers ◽  
Interfacial Adhesion ◽  
Mechanical Analysis ◽  
Interlaminar Shear Strength ◽  
Thermoplastic Composites ◽  
Negative Effects ◽  
Covalent Bonds ◽  
Interlaminar Shear

Due to the non-polar nature and low wettability of carbon fibers (CFs), the interfacial adhesion between CFs and the polyetheretherketone (PEEK) matrix is poor, and this has negative effects on the mechanical properties of CF/PEEK composites. In this work, we established a modification method to improve the interface between CFs and PEEK based chemical grafting of aminated polyetheretherketone (PEEK-NH2) on CFs to create an interfacial layer which has competency with the PEEK matrix. The changed chemical composition, surface morphology, surface energy, and interlaminar shear strength were investigated. After grafting, the interlaminar shear strength (ILSS) was improved by 33.4% due to the covalent bonds in the interface region, as well as having good compatibility between the interface modifier and PEEK. Finally, Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscopy (SEM) observation also confirmed that the properties of the modified CF/PEEK composites interface were enhanced. This work is, therefore, a beneficial approach towards enhancing the mechanical properties of thermoplastic composites by controlling the interface between CFs and the PEEK matrix.

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.

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.

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