Effect of hybrid thermal cycling and shock on flexural properties of nanoclay/glass/epoxy nanocomposites

2021 ◽  
pp. 096739112110132
Author(s):  
A Bayat ◽  
M Damircheli ◽  
M Esmkhani
Keyword(s):  
Flexural Strength ◽  
Thermal Cycling ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Flexural Stiffness ◽  
Thermal Cycles ◽  
Epoxy Nanocomposites ◽  
Static Conditions

In present research, the flexural properties of glass/epoxy composites reinforced by nanoclay particles (3, 5 and 7 wt.%) under various hybrid thermal cycling and shock loadings (15 and 30 thermal cycles at immediate −70°C and +100°C temperatures) have been investigated. It was found that the flexural strength of 5 wt.% nanoclay/glass/epoxy nanocomposites under 15 and 30 hybrid thermal loadings was enhanced by 19.35% and 20.78%, respectively. Also, after 15 hybrid thermal loadings, the flexural stiffness of 5 wt.% clay/glass/epoxy nanocomposites increased by 9.30% compared to static conditions. More importantly, after 30 hybrid thermal loadings, by adding more filler contents, the flexural stiffness was increased. For instance, at 7 wt.% clay/glass/epoxy nanocomposites, the flexural stiffness enhanced 17.97% compared to neat composite. FESEM morphology images confirmed that presence of optimum filler contents changed the composites inherent properties. Therefore, the outcome of this research can show various remarkable advantages for researchers to apply nanoclay as nanofillers to reinforce composites structures under hybrid thermal cycling and shock applications.

scholarly journals Enhanced flexural properties of aramid fiber/epoxy composites by graphene oxide

2019 ◽  
Vol 8 (1) ◽  
pp. 484-492 ◽  
Author(s):  
Yinqiu Wu ◽  
Bolin Tang ◽  
Kun Liu ◽  
Xiaoling Zeng ◽  
Jingjing Lu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Flexural Strength ◽  
Interfacial Shear Strength ◽  
Flexural Modulus ◽  
Weight Fraction ◽  
Interfacial Shear ◽  
Aramid Fiber ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Pure Epoxy

Abstract The reinforcing effect of graphene oxide (GO) in enhancing the flexural strength and flexural modulus of aramid fiber (AF)/epoxy composites were investigated with GO-AFs at a weight fraction of 0.1-0.7%. The flexural strength and flexural modulus of the composite reached 87.16 MPa and 1054.7 MPa, respectively, which were about 21.19% and 40.86% higher than those of the pure epoxy resin, respectively. In addition, the flexural properties and interfacial shear strength (IFSS) of composite reinforced by GO-AFs were much higher than the composites reinforced by AFs due to GO improved the interfacial bonding between the reinforcement material and matrix.

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

Flexural Properties of Epoxy Composites Filled with Glass Powder: Preliminary Results

2011 ◽  
Vol 410 ◽  
pp. 309-312 ◽  
Author(s):  
Harry Ku ◽  
Peter Wong ◽  
J. Huang ◽  
H. Fung ◽  
Mohan Trada
Keyword(s):  
Flexural Strength ◽  
Epoxy Resin ◽  
Glass Powder ◽  
Epoxy Composites ◽  
Research Centre ◽  
Flexural Properties ◽  
Preliminary Results ◽  
Structural Applications ◽  
Flexural Tests ◽  
Sufficient Strength

Epoxy resin was filled with glass powder with a view to increasing strength of the composite for structural applications by a research Centre on composites, University of Southern Queensland (USQ). In order to reduce costs, the Centre wishes to fill as much glass powder as possible subject to maintaining sufficient strength of the composites in structural applications. This project varies the percentage by weight of the glass powder in the composites which are then subjected to flexural tests. The results show that composite with 25 % by weight of the glass powder produces the highest flexural strength and Young’s modulus combined with a reasonable fluidity for casting; the highest flexural strain was achieved when the percentage by weight of glass powder is 10 %.

Effect of Sizing Removal Method and POSS Coating on Flexural Properties of Carbon Fiber Epoxy Composites

2013 ◽  
Author(s):  
Fariz Ibn Afzal ◽  
Mrinal C. Saha ◽  
M. Cengiz Altan
Keyword(s):  
Carbon Fiber ◽  
Flexural Strength ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Carbon Fiber Composites ◽  
Heat Treated ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Oligomeric Silsesquioxane ◽  
Carbon Fiber Epoxy

Effects of sizing and surface modification on flexural properties of carbon fiber reinforced epoxy composites have been investigated. Carbon fiber was desized using three types of treatments, namely heat, acetone, and acetone-acid. In addition, these fibers were coated with three different types of Polyhedral Oligomeric Silsesquioxane (POSS) molecule. Composite panels were fabricated using the vacuum assisted resin transfer molding and samples were tested in flexure. Scanning electron microscopy analysis was performed to investigate the surface morphology and failure mechanisms. It was found that removal of sizing significantly reduced the flexural strength. About 19% and 29% reduction of flexural strength was reported for acetone treatment and heat treatment, respectively. Composites with POSS coated fibers showed improved properties, except for the heat treated fibers. Among POSS molecules investigated, the S10455 was found to be the best for improving the flexural properties of carbon fiber composites.

Influence of Thermal Cycling on Flexural Properties and Simulated Wear of Computer-aided Design/Computer-aided Manufacturing Resin Composites

2017 ◽  
Vol 42 (1) ◽  
pp. 101-110 ◽  
Author(s):  
A Tsujimoto ◽  
WW Barkmeier ◽  
T Takamizawa ◽  
MA Latta ◽  
M Miyazaki
Keyword(s):  
Stainless Steel ◽  
Thermal Cycling ◽  
Computer Aided Design ◽  
Flexural Properties ◽  
Resin Composites ◽  
Thermal Cycles ◽  
Computer Aided Manufacturing ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

SUMMARY Objective: The purpose of this study was to evaluate the influence of thermal cycling on the flexural properties and simulated wear of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composites. Methods: The six CAD/CAM resin composites used in this study were 1) Lava Ultimate CAD/CAM Restorative (LU); 2) Paradigm MZ100 (PM); 3) CERASMART (CS); 4) Shofu Block HC (SB); 5) KATANA AVENCIA Block (KA); and 6) VITA ENAMIC (VE). Specimens were divided randomly into two groups, one of which was stored in distilled water for 24 hours, and the other of which was subjected to 10,000 thermal cycles. For each material, 15 specimens from each group were used to determine the flexural strength and modulus according to ISO 6872, and 20 specimens from each group were used to examine wear using a localized wear simulation model. The test materials were subjected to a wear challenge of 400,000 cycles in a Leinfelder-Suzuki device (Alabama machine). The materials were placed in custom-cylinder stainless steel fixtures, and simulated localized wear was generated using a stainless steel ball bearing (r=2.387 mm) antagonist in a water slurry of polymethyl methacrylate beads. Simulated wear was determined using a noncontact profilometer (Proscan 2100) with Proscan and AnSur 3D software. Results: The two-way analysis of variance of flexural properties and simulated wear of CAD/CAM resin composites revealed that material type and thermal cycling had a significant influence (p<0.05), but there was no significant interaction (p>0.05) between the two factors. The flexural properties and maximum depth of wear facets of CAD/CAM resin composite were different (p<0.05) depending on the material, and their values were influenced (p>0.05) by thermal cycling, except in the case of VE. The volume losses in wear facets on LU, PM, and SB after 10,000 thermal cycles were significantly higher (p<0.05) than those after 24 hours of water storage, unlike CS, KA, and VE. Conclusion: The results of this study indicate that the flexural properties and simulated wear of CAD/CAM resin composites are different depending on the material. In addition, the flexural properties and simulated wear of CAD/CAM resin composites are influenced by thermal cycling.

IMPROVEMENT OF FLEXURAL STRENGTH AND FATIGUE PROPERTIES OF GLASS FIBER/EPOXY COMPOSITES BY GRAFTING CELLULOSE NANOFIBERS ONTO THE REINFORCING FIBERS

2021 ◽  
Author(s):  
MOUHAMADOU MOUSTAPHA SARR, ◽  
HIRAKU INOUE ◽  
TATSURO KOSAKA
Keyword(s):  
Flexural Strength ◽  
Glass Fiber ◽  
Glass Fibers ◽  
Cellulose Nanofibers ◽  
Fiber Reinforced Polymer ◽  
Epoxy Composites ◽  
Vacuum Impregnation ◽  
Flexural Properties ◽  
Fiber Reinforced ◽  
Reinforced Polymer

Recently, cellulose nanofibers (CNFs) have been added as a modifier to fiber- reinforced polymer composites (FRPs) to improve their mechanical performance. In this study, vacuum impregnation of CNFs onto glass fibers (GF) was proposed to avoid processing high viscosity resin or the formation of aggregations in the matrix. Therefore, different CNF concentrations (from 0 to 0.1 wt%) were prepared and used to investigate the effect of CNFs on flexural properties of GF-CNF/epoxy composites by three-point bending tests. A field-emission scanning electron microscope was used to characterize the strengthening mechanisms. Fatigue tests were conducted at a stress ratio of 0.1 and a frequency of 5 Hz. The results indicated an improvement in flexural properties of glass fiber-reinforced polymer with increasing CNF concentrations. The flexural strength of CNF-modified GF/Epoxy composites (GF-CNF/EP) increased slightly up to 6 %. However, the fatigue life was significantly improved by 5 times in comparison with the neat GF/epoxy composite. This suggested that the use of CNFs onto the GF surface can contribute to improving the flexural fatigue of GFRP. Mouhamadou

The Effects of Voids on the Flexural Properties and Failure Mechanisms of Carbon/Epoxy Composites

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
M. A. Suhot ◽  
Chambers A. R.
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Flexural Strength ◽  
Failure Mechanisms ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Void Content ◽  
X Ray ◽  
Initiation And Propagation

Although the effect of voids on the mechanical properties of composite failures has been well researched, their effect on the failure mechanisms has not been well characterised. This study investigated the effect of the void content on the flexural strength of carbon/epoxy composites and to explain in terms of the failure mechanisms. The results showed that a 2% increase in void content reduced the flexural strength by 12.7%. Using optical microscopy, X-ray tomography and acoustic emission it was found that voids had no effect upon compression crack initiation but were found to influence the initiation and propagation of delaminations. A combination of in-situ acoustic emission and X-ray tomography proved to be a powerful tool in providing evidence of the failure mechanisms.

Indentation Tests for Sintered Silver in Die-Attach Interconnection After Thermal Cycling

2021 ◽  
Author(s):  
Fei Qin ◽  
Shuai Zhao ◽  
Yanwei Dai ◽  
Lingyun Liu ◽  
Tong An ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Silver Layer ◽  
Thermal Cycles ◽  
Nano Indentation ◽  
Die Attach ◽  
Indentation Tests ◽  
Sintered Silver

Abstract Thermo-mechanical reliability assessment for sintered silver is a crucial issue as sintered silver is a promising candidate of die-attachment materials for power devices. In this paper, the nano-indentation tests are performed for sintered silver in typical die-attach interconnection under different thermal cycles. Based on thermal cycling test, the Young's modulus and hardness of sintered silver layer have been presented. It is found that the Young's modulus and hardness of sintered silver layer changes slightly although the microstructure of sintered silver also presents some variations. The stress and strain curves for different thermal cycling tests for sintered silver based on reverse analysis of nano-indentation are also given. The results show that the elastoplastic constitutive equations change significantly after thermal cycling tests, and the yielding stress decreases remarkably after 70 thermal cycles. The experimental investigation also show that the cracking behaviors of sintered silver depends on its geometry characteristics, which implies that the possible optimization of sintered silver layer could enhance its thermo-mechanical performance.

scholarly journals Thermo-mechanical behavior of epoxy composite reinforced by carbon and Kevlar fiber

2018 ◽  
Vol 225 ◽  
pp. 01022
Author(s):  
Falak O. Abasi ◽  
Raghad U. Aabass
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Carbon Fibers ◽  
Epoxy Composites ◽  
Fiber Reinforced ◽  
Fiber Loading ◽  
Kevlar Fiber ◽  
Carbon Fiber Reinforced ◽  
Short Carbon

Newer manufacturing techniques were invented and introduced during the last few decades; some of them were increasingly popular due to their enhanced advantages and ease of manufacturing over the conventional processes. Polymer composite material such as glass, carbon and Kevlar fiber reinforced composite are popular in high performance and light weight applications such as aerospace and automobile fields. This research has been done by reinforcing the matrix (epoxy) resin with two kinds of the reinforcement fibers. One weight fractions were used (20%) wt., Epoxy reinforced with chopped carbon fiber and second reinforcement was epoxy reinforced with hybrid reinforcements Kevlar fiber and improved one was the three laminates Kevlar fiber and chopped carbon fibers reinforced epoxy resin. After preparation of composite materials some of the mechanical properties have been studied. Four different fiber loading, i.e., 0 wt. %, 20wt. % CCF, 20wt. % SKF, AND 20wt. %CCF + 20wt. % SKF were taken for evaluating the above said properties. The thermal and mechanical properties, i.e., hardness load, impact strength, flexural strength (bending load), and thermal conductivity are determined to represent the behaviour of composite structures with that of fibers loading. The results show that with the increase in fiber loading the mechanical properties of carbon fiber reinforced epoxy composites increases as compared to short carbon fiber reinforced epoxy composites except in case of hardness, short carbon fiber reinforced composites shows better results. Similarly, flexural strength test, Impact test, and Brinell hardness test the results show the flexural strength, impact strength of the hybrid composites values were increased with existence of Kevlar fibers, while the hardness was decrease. But the reinforcement with carbon fibers increases the hardness and decreases other tests.

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