scholarly journals Effect of Hygrothermal Treatment on the Flexural Properties of Uhmpe Fibre/Epoxy Resin Composites

1997 ◽  
Vol 6 (4) ◽  
pp. 096369359700600 ◽  
Author(s):  
A.G. Andreopoulos ◽  
P.A. Tarantili
Keyword(s):  
Detrimental Effect ◽  
Flexural Modulus ◽  
Interlaminar Shear Strength ◽  
Flexural Properties ◽  
Resin Composites ◽  
High Modulus ◽  
Interlaminar Shear ◽  
Modulus Polyethylene ◽  
Fibre Matrix ◽  
Hygrothermal Treatment

Composite specimens with epoxy matrix containing original and treated Ultra High Modulus Polyethylene (UHMPE) fibres as reinforcement, were immersed in distilled water and kept for 10 months at temperatures ranging from 20 to 60 °C. Testing of flexural properties and interlaminar shear strength showed that in general the hygrothermal treatment had a detrimental effect on those properties, with the exception of flexural modulus which tends to increase after immersion at 20°C for specimens of poor fibre/matrix interfacial bonding.

scholarly journals THE FATIGUE BEHAVIOUR OF GFRP BARS - EXPERIMENTAL STUDY

2019 ◽  
Vol 22 ◽  
pp. 38-47 ◽  
Author(s):  
Ondřej Januš ◽  
František Girgle ◽  
Iva Rozsypalová ◽  
Vojtěch Kostiha ◽  
Lenka Bodnárová ◽  
...  
Keyword(s):  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Interlaminar Shear Strength ◽  
Experimental Program ◽  
Matrix Interface ◽  
Interface Damage ◽  
Gfrp Bars ◽  
Interlaminar Shear ◽  
Fibre Matrix

The paper describes an experimental program for studying the fatigue performance of GFRP bars, which has been initiated by the authors. Two different test configurations were used to assess the fatigue behaviour. The bare specimens were tested within the first series. A modified gripping system was used to reduce eccentricity when the bar was not directly fixed. However, the boundary conditions seem to affect the results. The second series consisted of a set of specimens of bars embedded in concrete. This configuration seems appropriate for determination of fatigue life of GFRP bars. Two S-N curves for bare bars and bars embedded in concrete were created and compared. Significant reduction of interlaminar shear strength at the beginning of fatigue loading proved matrix or fibre/matrix interface damage.

Structure–Property Relationships in Addition Polyimides. II. Resins from Three-Ring Aromatic Diamines Containing Carbonyl and Methylene Groups

1997 ◽  
Vol 9 (2) ◽  
pp. 161-176 ◽  
Author(s):  
Peter Delvigs ◽  
David L Klopotek ◽  
Paul J Cavano
Keyword(s):  
Interlaminar Shear Strength ◽  
Aromatic Diamine ◽  
Flexural Properties ◽  
Structure Property ◽  
Aromatic Diamines ◽  
Structure Property Relationships ◽  
Methylene Groups ◽  
Interlaminar Shear ◽  
Bridging Groups

The use of flexibilized three-ring aromatic diamine moieties was investigated in an effort to improve the processing characteristics of addition-type polyimide resins. A series of 10 diamines containing carbonyl and methylene bridging groups was synthesized. The diamines were polymerized with the dimethylester of 3,3′, 4,4′-benzophenonetetracarboxylic acid (BTDE), using the monomethyl ester of nadic acid (NE) as an endcap. The effect of diamine structure on the solubility and rheological properties during cure was determined. The effect of diamine structure and formulated molecular weight on the thermo-oxidative stability and glass transition temperature of the polyimides was also investigated. Unidirectional laminates were fabricated from selected resins, using carbon fibre as the reinforcement. Interlaminar shear strength and flexural properties of the laminates were determined. The results indicate that polyimides from some of the diamines containing methylene bridging groups have potential as matrix resins for long-term applications at temperatures up to 300 °C.

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.

The mechanical performance of the laminated aluminum-epoxy/glass fiber composites containing halloysite nanotubes: An experimental investigation

2020 ◽  
pp. 152808372096073
Author(s):  
Marwa A Abd El-baky ◽  
Mohamed A Attia
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Tensile Strain ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Halloysite Nanotubes ◽  
Interlaminar Shear Strength ◽  
Plane Shear ◽  
Bearing Strength ◽  
Interlaminar Shear

In this study, the effect of different weight percentages (wt. %) of halloysite nanotubes (HNTs) on the mechanical performance of glass laminate aluminum (Al) reinforced epoxy (GLARE) was investigated. GLARE (3/2) laminates with quasi-isotropic lay-up, [Al/[(0°/90°)/(45°/−45°)]s/Al/[(0°/90°)/(45°/−45°)]s/Al] filled with 0, 0.25, 0.5, 1, 2 and 3 wt. % of HNTs were fabricated using hand lay-up followed by compression molding. To explore the effect of HNTs on the mechanical properties, tensile, flexural, in-plane shear, interlaminar shear, bearing and impact tests were conducted. Results demonstrated that the inclusion of 1 wt. % of HNTs into GLARE leads to maximum improvements of 35.67, 8.50, 28.85, 50.47, 50.27, 30.43, 23.73, 72.08, 30.74, and 51.52% in tensile strength, tensile strain, Young's modulus, modulus of toughness, flexural strength, flexural strain, in-plane shear strength, interlaminar shear strength, bearing strength, and impact strength, respectively, compared to pristine GLARE. An enhancement of 38.89% in the flexural modulus was attained by adding 0.5 wt. % of HNTs to GLARE compared to pristine GLARE. The tensile strength, tensile strain, modulus of toughness, flexural strength, flexural modulus, flexural strain, in-plane shear strength, and interlaminar shear strength of GLARE filled with 3 wt. % of HNTs are 0.91, 0.88, 0.91, 0.91, 0.71, 0.83, 0.85, and 0.91 times those of the original GLARE. But Young’s modulus, bearing strength, and impact strength are 1.10, 1.15 and 1.20 times those of the original GLARE. To investigate the fracture mechanism, field emission scanning electron microscope (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX) were used. The microscopic images revealed that adding HNTs lead to the improvement in the interaction between the epoxy matrix and glass fiber, thereby improving the mechanical properties.

Polyimide fabric-reinforced polyimide matrix composites with excellent thermal, mechanical, and dielectric properties

2020 ◽  
Vol 32 (10) ◽  
pp. 1085-1093 ◽  
Author(s):  
Zonghu Pan ◽  
Shuhao Han ◽  
Jianhua Wang ◽  
Shengli Qi ◽  
Guofeng Tian ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
High Performance ◽  
Interlaminar Shear Strength ◽  
Resin Composites ◽  
Matrix Composites ◽  
Air Atmosphere ◽  
Interlaminar Shear ◽  
Thermoforming Process ◽  
Polyimide Matrix

Two types of thermosetting polyimide (PI) resin were prepared using a polymerization monomeric reactant method, and high performance PI fabric/PI resin composites were fabricated through a wet infiltration and thermoforming process. The properties of a PI fabric, PI resin, and PI/PI composites were comprehensively analyzed. The experimental results indicate that a resin end-capped with phenylacetylene achieves a better processability and heat resistance. The two composites exhibit excellent thermal, mechanical, and dielectric properties. They achieve a glass transition temperature of higher than 320°C and a 5% weight loss temperature of over 600°C under an air atmosphere. During mechanical testing, an interlaminar shear strength exceeding 35 MPa was achieved, whereas the maximum flexural strength was found to be greater than 400 MPa. Moreover, their dielectric constant at 1 MHz was below 3.4, with a dielectric loss of no more than 0.01.

Effect of Ozone Treatment on the Interfacial Properties of High Modulus Carbon Fiber/Epoxy Composites

2007 ◽  
Vol 546-549 ◽  
pp. 1547-1550 ◽  
Author(s):  
Xiao Jin Zhao ◽  
Wei Qin ◽  
Ben Li Wang
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Fiber Surface ◽  
Interlaminar Shear Strength ◽  
Epoxy Composites ◽  
Ozone Treatment ◽  
High Modulus ◽  
Surface Impregnation ◽  
Interlaminar Shear ◽  
Carbon Fiber Epoxy

High modulus carbon/epoxy composites have been attached more and more importance in the aeronautic field. Because chemical inert of high modulus carbon fiber surface and its poor impregnation for resin, it is essential to improve its polarity in order to enhance the interfacial performances of high modulus carbon/epoxy composites. In this paper, high modulus carbon fiber was treated by ozone oxidation method to modify its surfacial properties. AFM and SEM were used to observe the surface of the carbon fiber, as well as interlaminar shear strength of high modulus carbon fiber/epoxy composite was tested. The impregnation and the interfacial performances of the high modulus carbon/epoxy composites were studied. The results show that after ozone treatment, the surface impregnation of high modulus carbon fiber and the interlaminar shear strength property of high modulus carbon/epoxy composites can be improved obviously.

scholarly journals Healable Carbon Fiber-Reinforced Epoxy/Cyclic Olefin Copolymer Composites

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2165 ◽  
Author(s):  
Haroon Mahmood ◽  
Andrea Dorigato ◽  
Alessandro Pegoretti
Keyword(s):  
Carbon Fibers ◽  
Double Cantilever Beam ◽  
Flexural Modulus ◽  
Interlaminar Shear Strength ◽  
Mode I ◽  
Cyclic Olefin Copolymer ◽  
Cyclic Olefin ◽  
Mode I Fracture Toughness ◽  
Healing Efficiency ◽  
Interlaminar Shear

Cyclic olefin copolymer (COC) particles were dispersed in various amounts in an epoxy matrix, and the resulting blends were used to impregnate unidirectional carbon fibers (CF) by hand lay-up. The thermal stability was not substantially modified by the presence of COC particles. The mixture of the two polymers resulted in a phase separated blend and the flexural modulus and interlaminar shear strength progressively decreased with the addition of COC particles in the laminates. Mode I fracture toughness tests were executed on double cantilever beam specimens. The opened crack was then thermally mended at 190 °C for 1 h. The laminates containing 30 wt.% of COC particles showed a healing efficiency of ~180%.

Tensile and Flexural Properties of Montmorillonite Nanoclay Reinforced Epoxy Resin Composites

2015 ◽  
Vol 1112 ◽  
pp. 373-376 ◽  
Author(s):  
Zyad Salem Alsagayar ◽  
Abdul Razak Rahmat ◽  
Agus Arsad ◽  
Siti Noor Hidayah binti Mustaph
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Flexural Modulus ◽  
Resin Matrix ◽  
Flexural Properties ◽  
Resin Composites ◽  
Optimum Amount ◽  
Epoxy Nanocomposite ◽  
Epoxy Resin Composites ◽  
Flexural Tests

In this work, montmorillonite (MMT) nanoclay reinforced epoxy resin was prepared to study the effect of nano filler on tensile and flexural properties of its nanocomposite. MMT was first sonicated for 2 hours with an acetone where the ratio was 50 mL acetone: 1g clay. After being sonicated the clay was added to an epoxy resin matrix at 80 °C and mixed until the acetone was removed. Tensile and flexural tests were investigated to understand the effect of clay on the mechanical properties of MMT reinforced epoxy nanocomposite. In general, the mechanical properties of MMT/epoxy nanocomposites were slightly increased as the clay loading was increased up to 1 phr. However, for the amount of nanoclay more than 1 phr the result showed significantly decrease in mechanical properties. It was found that by adding the nanoclay up to 1 phr, the Young’s and flexural modulus increased around 6.75% and 6.61%, respectively. Since the nanoclay has higher elastic modulus as compared to epoxy resin, the addition of clay increased the modulus of its nanocomposites. On the other hand, at 2 phr of nanoclay the tensile strength, Young’s modulus, flexural strength and flexural modulus deceased around 44.12%, 17.24%, 17.84% and 10.77% respectively compared to pure epoxy. For more than 1 phr of filler the clay distributions might not be well dispersed and thus more agglomerations occurred in the composites. It can be concluded that, 1 phr of MMT filler was the optimum amount that can be reinforced with epoxy resin in term of tensile and flexural properties.

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