Development and characterization of structural adhesives for aerospace industry with alumina nanoparticles under shear and thermo-mechanical impact loads

2019 ◽  
Vol 234 (2) ◽  
pp. 490-507 ◽  
Author(s):  
UA Khashaba ◽  
Ramzi Othman ◽  
Ismael MR Najjar
Keyword(s):  
Contact Force ◽  
Bending Stiffness ◽  
Alumina Nanoparticles ◽  
Absorbed Energy ◽  
Impact Machine ◽  
Impact Properties ◽  
Weight Percentage ◽  
Mechanical Impact ◽  
Impact Bending ◽  
The Impact

The present work aims to improve the mechanical properties of Epocast 50-A1/946 epoxy via incorporation of alumina nanoparticles using an ultrasonic agitation method. The optimum weight percentage of alumina nanoparticles was determined based on the improvement in the shear and impact properties of the nanocomposites at room temperature and 50 ℃. Accordingly, neat epoxy panels and nanocomposite panels with 0.5, 1.0, 1.5, and 2.0 wt% alumina nanoparticles were fabricated. The shear and thermo-mechanical impact properties of the panels were measured using an instrumented drop-weight impact machine and an Iosipescu shear test fixture, respectively, according to ASTMs D5379 and D7136. The maximum improvement in shear strength and modulus was 10.9% and 8.1%, respectively, for the nanocomposites containing 1.0 and 1.5 wt% alumina nanoparticles. The predicted shear moduli of the nanocomposites agreed well with the measured values with a maximum error of 6.52%. The optimal performance of impact properties was achieved by incorporating 1.0 wt% of alumina nanoparticles. Namely, the maximum impact-bending stiffness, contact force, and absorbed energy were increased by 12.9%, 13.0%, and 23.4%, respectively. The test temperature of 50 ℃ was found to have a negative effect on the impact-bending stiffness and the maximum contact force. On the other hand, the absorbed energy was increased up to 12.1%.

scholarly journals Effect of reinforcement material on impact properties of epoxy

2017 ◽  
Vol 2 (3) ◽  
pp. 226-231
Author(s):  
Basim M. Fadhil ◽  
Payman Sahbah Ahmed ◽  
Ava Ali Kamal
Keyword(s):  
Carbon Fiber ◽  
Impact Test ◽  
Steel Fiber ◽  
Matrix Composites ◽  
Impact Machine ◽  
Impact Properties ◽  
Different Types ◽  
Experimental Works ◽  
Impact Characteristics ◽  
The Impact

Impact characteristics of Epoxy matrix composites is investigated by impact machine. Four different types of reinforcement are used in the experimental works: type one: 1.9wt% steel fiber, 1.9wt% carbon fiber,1.9 wt% carbon nanotube, 1.9 wt% woven carbon fiber.This work shows that reinforcing epoxy with (1.9 wt% of woven carbon fiber) improves the impact properties where energy, force and deformation values of impact test for this composite were 18.4J, 3580.59 N and 18 mm respectively while for epoxy were 2.927 J, 921.849 N and 18.413 mm respectively.

Experimental assessment of adding carbon nanotubes on the impact properties of Kevlar-ultrahigh molecular weight polyethylene fibers hybrid composites

2020 ◽  
pp. 152808372092148 ◽  
Author(s):  
Mansour B Bigdilou ◽  
Reza Eslami-Farsani ◽  
Hossein Ebrahimnezhad-Khaljiri ◽  
Mohammad A Mohammadi
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Weight ◽  
Energy Absorption ◽  
Hybrid Composites ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Absorbed Energy ◽  
Impact Properties ◽  
Damage Area ◽  
Ultrahigh Molecular Weight ◽  
The Impact

In the present study, the effect of adding various percentage (0.1, 0.3, 0.5, and 0.9 wt.%) of carbon nanotubes on the impact properties of hybrid composites reinforced with the different stacking sequence of Kevlar fibers and ultrahigh molecular weight polyethylene was investigated. The obtained results showed that the composite with the configuration of sandwiched ultrahigh molecular weight polyethylene layers by Kevlar layers had the higher impact properties as compared with other hybrid configurations. Adding 0.1 wt.% carbon nanotubes in this configuration was caused to increase the normalized absorbed energy more than 6.5 times. The fracture surface of this configuration showed that the branching and expanding the damage area were the dominant mechanisms for the energy absorption of impactor. Also, the field emission scanning electron microscope illustrated that the carbon nanotubes by bridging, pulling out, and fracturing mechanisms increased the capability of energy absorption in the hybrid composites.

scholarly journals The low-velocity impact and post-impact properties of ultra-high-molecular-weight polyethylene fiber weft plain knitted structural composites

2019 ◽  
Vol 14 ◽  
pp. 155892501983252
Author(s):  
Cuiyu Li ◽  
Rui Zhang ◽  
Jingyan Jia ◽  
Gaopan Wang ◽  
Yameng Shi
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Contact Force ◽  
Compression Strength ◽  
Impact Compression ◽  
Impact Properties ◽  
Damage Area ◽  
Post Impact ◽  
The Impact ◽  
Ultra High Molecular Weight

This study investigated the impact and post-impact behavior of different layer weft plain knitted composite materials based on modified ultra-high-molecular-weight polyethylene/epoxy composites. The modified ultra-high-molecular-weight polyethylene weft plain knitted composites with 8, 12, 16 layers were prepared by vacuum-assisted resin transfer molding process and then subjected to impact and post-impact compression test. The impact properties were analyzed using the contact force–deflection and energy–time curves, and the post-impact compression was analyzed using the compression strength–strain curves. It can be obtained that the maximum contact force, absorbed energy, and residual compression strength after impact of the 16-layer specimen are 81.40%, 74.18%, and 73.25% more than those in the 8-layer specimen. respectively. According to the ultrasonic C-scan tests for the impact samples, the 16-layer specimen had the least damage area after the impact test, and the 8-layer composites damage area was 117.45% more than the 16-layer specimen.

Influence of Different Matrices on the Tensile and Impact Properties of Treated Kenaf Composites

2016 ◽  
Vol 1133 ◽  
pp. 136-140
Author(s):  
Noor Haznida Bakar ◽  
Koay Mei Hyie ◽  
A. Jumahat ◽  
Eli Nadia A. Latip ◽  
Anizah Kalam ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Tensile Properties ◽  
Testing Machine ◽  
Low Velocity ◽  
Impact Properties ◽  
Weight Percentage ◽  
Kenaf Fibre ◽  
Naoh Solution ◽  
Kenaf Composites ◽  
The Impact

This study investigated the mechanical behavior of the treated and untreated kenaf with different matrix resin (epoxy and polyester) using the tensile and low velocity test. The long kenaf fibre was treated with 6% of sodium hydroxide (NaOH) solution for twelve hours in room temperature. The tensile properties of composites at different weight percentage (10,15,20 and 25%) were studied by using Instron Universal Testing Machine according to the standard ASTM D638. Impact test was conducted using an instrumented drop tower device at 10J incident energy level according to the standard ASTM D3763. The results of the study indicated that the epoxy resin reinforced with treated kenaf fibre exhibited higher tensile properties. On the other hand, the impact properties of polyester resin reinforced with treated kenaf fibre show better matrix bonding compared to those with epoxy resin matrices.

Mechanical Properties of Kevlar Reinforcement in Kenaf Composites

2013 ◽  
Vol 465-466 ◽  
pp. 847-851 ◽  
Author(s):  
Noor Haznida Bakar ◽  
Koay Mei Hyie ◽  
Ahmad Safwan Ramlan ◽  
Mohd Khalid Hassan ◽  
Aidah Jumahat
Keyword(s):  
High Performance ◽  
Cost Savings ◽  
Natural Fibres ◽  
Impact Properties ◽  
Weight Percentage ◽  
Microstructure Observation ◽  
Press Method ◽  
Kenaf Composites ◽  
The Impact ◽  
Delamination Area

The development of high-performance materials made from natural resources are increasing worldwide in recent years. Natural fibres offer both cost savings and reduction in density when compared to Kevlar fibres. However, the strength of natural fibres is not as great as Kevlar. The following preliminary research investigated the use of Kevlar fibres in kenaf composites as a possible to improve the impact properties. The impact properties of Kevlar reinforced in kenaf composites was studied by using DYNATUP 9250 drop weight machine. According to the standard ASTM D638 Kevlar fibres in different weight percentage of 10,15,20 and 25 wt% were reinforced with kenaf/epoxy composites by using hand lay-up combined with cold-press method. It is clearly observed that the impact strength and hardness were increased with the addition of weight percentage of woven Kevlar in the kenaf composites. The highest energy was recorded at 12.76 J by hybrid composite in combination of 2Kevlar/Kenaf/2Kevlar. The microstructure observation of impacted hybrid samples indicated that the delamination area was increased with the increasing of the impact energy.

On the Microstructure and Impact Properties of Slow Injection A356 Die Castings with Local Pressurization

2009 ◽  
Vol 628-629 ◽  
pp. 587-592
Author(s):  
Yan Fei Bai ◽  
Hai Dong Zhao ◽  
Yuan Yuan Li ◽  
Zhi Xin Kang
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Fracture Mechanisms ◽  
Absorbed Energy ◽  
Impact Properties ◽  
Die Casting Process ◽  
Die Castings ◽  
Pressure Die Casting ◽  
The Impact ◽  
Slow Injection

Microstructure and impact properties of slow injection A356 die castings with local pressurization have been investigated. The microstructure in the casting different regions were analyzed and compared. The casting impact absorbed energy varies from 1.17 to 2.35J, and is higher than that of other pressure die casting process. Furthermore, fracture mechanisms of different regions in castings are discussed. The results show that, the impact absorbed energy decreases with increase in SDAS. Also significant fluctuations of the impact properties in the thick-walled and local pressurization regions are found.

Experimental study of the impact behavior of laminated composites stricken by sharp impactors

2012 ◽  
Vol 19 (3) ◽  
pp. 307-313 ◽  
Author(s):  
Mesut Uyaner ◽  
Memduh Kara
Keyword(s):  
Contact Force ◽  
Impact Behavior ◽  
Test Machine ◽  
Absorbed Energy ◽  
Nominal Thickness ◽  
Weight Test ◽  
Force Time ◽  
Drop Weight Test ◽  
The Impact ◽  
Composite Samples

AbstractIn this study, the influence of the impactor shape on the dynamic response of E-glass/epoxy laminates was investigated. Composite samples were impacted using steel 90° and 120° conical, 24 mm and 12 mm in diameter hemispherical, pyramidal impactors via a specially developed drop weight test machine. The impact tests were performed at impactor mass (20 kg) for impact velocity (2.5 m/s). Plate specimens consisting of 18 plies for tests (180×50 mm) with a nominal thickness (7 mm) were used. Contact force-time and contact force-deflection data obtained from the experiments were interpreted. It was found that the contact force was smaller in the 90° conical impactor while it was bigger in the 24 mm hemispherical one. Absorbed energies were also investigated. The absorbed energy obtained for pyramidal impactor was greater than that of the others. Furthermore, overall damage areas caused by the impactor were evaluated.

scholarly journals Simulation of Delamination Evolution of Slab Ballastless Track under Vertical Impact

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yu Liu ◽  
Qianqi Xu ◽  
Xiaodan Sun ◽  
Guotao Yang ◽  
Guotang Zhao
Keyword(s):  
Contact Force ◽  
Impact Energy ◽  
Zone Model ◽  
Vertical Deformation ◽  
Interfacial Damage ◽  
Absorbed Energy ◽  
Normal Stiffness ◽  
Track Irregularity ◽  
The Impact ◽  
Vertical Impact

During the running of a high-speed train, the wheel may bounce on the rail due to the track irregularity. The wheel bounce could generate a vertical impact, leading to the initiation and expansion of delamination between layers of the track structure. In this paper, the evolution of the interfacial damage and delamination subjected to the vertical impact is simulated using finite element analysis (FEA). In the FEA, a bilinear cohesive zone model (CZM) is adopted to simulate the interface between the track slab and the CA mortar layer. For different levels of impact energy, the contact force, vertical deformation, absorbed energy, area of interfacial damage, and area of delamination are calculated and compared. The effects of the tangential and normal stiffness of the interface on the distribution of interfacial damage and delamination are investigated. The results show that the contact force, vertical deformation, absorbed energy, area of interfacial damage, and area of delamination increase with the increase of the impact energy. The area of interfacial damage in the compression stage is closely related to the tangential stiffness, whereas the area of delamination depends on the normal stiffness. The normal stiffness that gives the largest area of delamination is recommended to be taken as the lower bound of the normal stiffness for both controlling the delamination and preventing an exceedance of the track irregularity limit.

scholarly journals Charpy Impact Properties of Hydrogen-Exposed 316L Stainless Steel at Ambient and Cryogenic Temperatures

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 625 ◽  
Author(s):  
Le Thanh Hung Nguyen ◽  
Jae-Sik Hwang ◽  
Myung-Sung Kim ◽  
Jeong-Hyeon Kim ◽  
Seul-Kee Kim ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Low Temperatures ◽  
316L Stainless Steel ◽  
Charpy Impact ◽  
Cryogenic Temperatures ◽  
Absorbed Energy ◽  
Impact Properties ◽  
Charging Time ◽  
The Impact

316L stainless steel is a promising material candidate for a hydrogen containment system. However, when in contact with hydrogen, the material could be degraded by hydrogen embrittlement (HE). Moreover, the mechanism and the effect of HE on 316L stainless steel have not been clearly studied. This study investigated the effect of hydrogen exposure on the impact toughness of 316L stainless steel to understand the relation between hydrogen charging time and fracture toughness at ambient and cryogenic temperatures. In this study, 316L stainless steel specimens were exposed to hydrogen in different durations. Charpy V-notch (CVN) impact tests were conducted at ambient and low temperatures to study the effect of HE on the impact properties and fracture toughness of 316L stainless steel under the tested temperatures. Hydrogen analysis and scanning electron microscopy (SEM) were conducted to find the effect of charging time on the hydrogen concentration and surface morphology, respectively. The result indicated that exposure to hydrogen decreased the absorbed energy and ductility of 316L stainless steel at all tested temperatures but not much difference was found among the pre-charging times. Another academic insight is that low temperatures diminished the absorbed energy by lowering the ductility of 316L stainless steel.

Mechanical and low-velocity impact properties of epoxy-composite beams reinforced by MWCNTs

2018 ◽  
Vol 53 (5) ◽  
pp. 693-705 ◽  
Author(s):  
Mehdi Ranjbar ◽  
Saeed Feli
Keyword(s):  
Tensile Strength ◽  
Young’S Modulus ◽  
Contact Force ◽  
Young's Modulus ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Impact Properties ◽  
Velocity Impact ◽  
Pure Epoxy ◽  
The Impact

The effect of different weight percentages (wt.%) of MWCNTs includes 0, 0.17, 0.34 and 0.51% on the mechanical and low-velocity impact properties are presented on the example of the pure epoxy and epoxy/fiberglass composites beams. A sonication technique is used to disperse MWCNTs in the epoxy network and the nanocomposite beams are fabricated using hand lay-up technique. In tensile tests, the value of Young’s modulus, tensile strength and strain at break are reported. In the low-velocity impact tests on the MWCNTs/fiberglass/epoxy, the time-history response of contact force, displacement and velocity of the impactor and indentation and displacement of the beam are measured and presented. The results show that compared to pure epoxy, Young’s modulus and tensile strength of epoxy/MWCNTs are increased 21.98% and 58.32% at 0.34 wt.% of CNTs, respectively, and raised 1.05 and 1.17 times at 0.17 wt.% of CNTs for the epoxy/fiberglass/MWCNTs, respectively. It is observed that the excellent improvement in the impact properties is achieved for 0.34 wt.% of CNTs. A series of polynomial formulations as a function of wt.% of CNTs are proposed to calculate the Young’s modulus, peak contact force and maximum beam deflection at the impact position.

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