Effect of long-term moisture exposure on impact response of glass-reinforced vinylester

2021 ◽  
pp. 147509022199616
Author(s):  
Fatemeh Alizadeh ◽  
Navid Kharghani ◽  
Carlos Guedes Soares
Keyword(s):  
Water Uptake ◽  
Failure Modes ◽  
Sea Water ◽  
Composite Plates ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Water Type ◽  
Interfacial Damage ◽  
Impact Properties ◽  
The Impact

Glass/Vinylester composite laminates are comprehensively characterised to assess its impact response behaviour under moisture exposure in marine structures. An instrumented drop weight impact machine is utilised to determine the impact responses of dry and immersed specimens in normal, salted and sea water. The specimens, which had three different thicknesses, were subjected to water exposure for a very long period of over 20 months before tested in a low-velocity impact experiment. Water uptake was measured primarily to study the degradation profiles of GRP laminates after being permeated by water. Matrix dissolution and interfacial damage observed on the laminates after prolonged moisture exposure while the absorption behaviour was found typically non-Fickian. The weight of the composite plates firstly increased because of water diffusion up to month 15 and then decreased due to matrix degradation. The specimens with 3, 6 and 9 mm thickness exhibited maximum water absorption corresponding to 2.6%, 0.7% and 0.5% weight gain, respectively. In general, the results indicated that water uptake and impact properties were affected by thickness and less by water type. Impact properties of prolonged immersed specimens reduced remarkably, and intense failure modes detected almost in all cases. The least sensitive to impact damage were wet specimens with 9 mm thickness as they indicated similar maximum load and absorbed energy for different impact energies.

Response and failure modes of biaxial warp-knitted flexible composite subject to low-velocity impact

2021 ◽  
pp. 152808372110154
Author(s):  
Ziyu Zhao ◽  
Tianming Liu ◽  
Pibo Ma
Keyword(s):  
Impact Energy ◽  
Linear Density ◽  
Failure Modes ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Minor Effect ◽  
Low Velocity ◽  
Velocity Impact ◽  
Flexible Composites ◽  
The Impact

In this paper, biaxial warp-knitted fabrics were produced with different high tenacity polyester linear density and inserted yarns density. The low-velocity impact property of flexible composites made of polyurethane as matrix and biaxial warp-knitted fabric as reinforcement has been investigated. The effect of impactor shape and initial impact energy on the impact response of flexible composite is tested. The results show that the initial impact energy have minor effect on the impact response of the biaxial warp-knitted flexible composites. The impact resistance of flexible composite specimen increases with the increase of high tenacity polyester linear density and inserted yarns density. The damage morphology of flexible composite materials is completely different under different impactor shapes. The findings have theoretical and practical significance for the applications of biaxial warp-knitted flexible composite.

Use of Statical Indentation Laws in the Impact Analysis of Laminated Composite Plates

1985 ◽  
Vol 52 (1) ◽  
pp. 6-12 ◽  
Author(s):  
T. M. Tan ◽  
C. T. Sun
Keyword(s):  
Impact Analysis ◽  
Laminated Composite ◽  
Composite Plates ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
The Impact ◽  
Theoretical Results ◽  
Theoretical Procedure ◽  
Good Agreement

The low-velocity impact response of graphite/epoxy laminates was investigated theoretically and experimentally. A nine-node isoparametric plate finite element in conjunction with an empirical contact law was used for the theoretical investigation. Theoretical results are in good agreement with strain-gage experimental data. The results of the investigation indicate that the present theoretical procedure describes the impact response of laminate for low-impact velocities.

scholarly journals Shape Memory Alloy Hybrid Composites for Improving Impact Properties

2021 ◽  
pp. X
Author(s):  
Chuanliang SHEN ◽  
Xiaodong XU ◽  
Xiaoyu MA ◽  
Yibo HU ◽  
Shan ZHANG ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Plate ◽  
Hybrid Composites ◽  
Mechanical Energy ◽  
Impact Resistance ◽  
Composite Plates ◽  
Impact Response ◽  
Impact Properties ◽  
The Impact

This paper investigates the method to improve the property that can decrease the impact response of composite plate. Embedding the super-elastic shape memory alloy wires into composite plates has increased the attention of material researchers. Super-elastic shape memory alloy has the properties of absorbing mechanical energy, large recoverable deformation and so on. In this study, experiments were conducted to analyze the impact properties of composite plates with Ni-Ti SMA wires. Composite plates with Ni-Ti SMA wires and without Ni-Ti SMA wires were subjected to two impacts respectively. This study measured the responses of two impacts. The results showed that the composite plate with Ni-Ti SMA wires were subjected to a second impact with a peak deflection of 5.47 mm, which was only 0.22 mm larger than the first impact. The relevant data of the composite plate without Ni-Ti SMA wires were 9.02 mm, 1.22 mm, and serious damage occurred. It was verified that the Ni-Ti SMA wires improved the impact resistance of the composite plate. After studying the impact tests of variable diameters of SMA wires embedded at the low layer of composite plate, it was shown that as the diameter of SMA wires increased, the impact resistance of composite plates was improved.

Finite Element Modeling of Local Damage in Kevlar/Carbon Fiber Sandwich Under Low Velocity Impact

2007 ◽  
Author(s):  
Saiphon Jacque ◽  
Robert Rizza ◽  
Mohammad Mahinfalah
Keyword(s):  
Carbon Fiber ◽  
Impact Load ◽  
Composite Plates ◽  
Low Velocity Impact ◽  
Face Sheet ◽  
Sandwich Composite ◽  
Low Velocity ◽  
Fiber Layer ◽  
Impact Properties ◽  
The Impact

Impact properties of carbon fiber and Kevlar or hybrid (3K carbon fiber/1500 Denier Kevlar) combination sandwich composite plates were numerically investigated in this study. The goal of this research was to define the change in impact properties as results of replacing the carbon fiber layer on the impact-side face sheet with combinations of carbon fiber/Kevlar or carbon fiber/hybrid. Information on impact energy and maximum impact force obtained from previous experiments were applied to validate the model input properties. The models were then used to characterize the mechanism of the reduction in the global stiffness of the sandwich plate due to the sequence of the damage in the foam core and the face sheet corresponding to the variation of the laminate mixture and loading energy. Results from this study could be of assistance to determining structure integrity with respect to the composite combination under impact load.

Effects of Absorbed Moisture Content on the Impact Response of Specially-Orthotropic Composite Plates

2019 ◽  
Author(s):  
Furqan Ahmad ◽  
Fethi Abbassi ◽  
Sajjad Miran
Keyword(s):  
Moisture Content ◽  
Composite Plates ◽  
Peak Force ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Constant Weight ◽  
Velocity Impact ◽  
Moisture Contents ◽  
The Impact

Abstract This paper addresses the hygroscopic effects on the impact response of specially-orthotropic carbon fiber reinforced polymer composite plates under low-velocity impact loading. The material used in this study is Toray T800/3900 which is consist of carbon fibers and epoxy resin. For different percentage of moisture content by weight in the composite plates, low-velocity impact tests were done by using the 8-ply unidirectional [UD] and cross-ply [CP] composite plates with newly designed mini-drop tower testing machine. To study the hygroscopic effects, specimens were impacted by constant weight of impactor (3.44 Kg) with fixed impact height of 0.70 m corresponding to 23.62 J impact energy. The experiments were carried out on plates with dimension of 125 mm × 125 mm × 1.5 mm for simply supported boundary conditions. All UD composite plates were broken into two parts, but the impactor bounces back after hitting the top layer of the CP composite plate for all conditions. The strength of the UD composite plates decreased with increase of moisture contents, but with the increased of moisture contents, a small change was observed in the peak force, time to peak force values and absorbed energy for the CP composite plates. The large size damage areas were observed for wet plates as compared to dry plates. Absorbed moisture contents also have effect on the impactor velocity and impactor displacement.

scholarly journals Evaluation of Energy Absorption Capabilities of Polyethylene Foam under Impact Deformation

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3613
Author(s):  
Baohui Yang ◽  
Yangjie Zuo ◽  
Zhengping Chang
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
High Strain ◽  
Early Stage ◽  
High Energy ◽  
Test Method ◽  
Test Theory ◽  
Strain Rates ◽  
Impact Properties ◽  
The Impact

Foams are widely used in protective applications requiring high energy absorption under impact, and evaluating impact properties of foams is vital. Therefore, a novel test method based on a shock tube was developed to investigate the impact properties of closed-cell polyethylene (PE) foams at strain rates over 6000 s−1, and the test theory is presented. Based on the test method, the failure progress and final failure modes of PE foams are discussed. Moreover, energy absorption capabilities of PE foams were assessed under both quasi-static and high strain rate loading conditions. The results showed that the foam exhibited a nonuniform deformation along the specimen length under high strain rates. The energy absorption rate of PE foam increased with the increasing of strain rates. The specimen energy absorption varied linearly in the early stage and then increased rapidly, corresponding to a uniform compression process. However, in the shock wave deformation process, the energy absorption capacity of the foam maintained a good stability and exhibited the best energy absorption state when the speed was higher than 26 m/s. This stable energy absorption state disappeared until the speed was lower than 1.3 m/s. The loading speed exhibited an obvious influence on energy density.

Effect of SiO2 Nanoparticles on the Mechanical and Low Velocity Impact Properties of Epoxy/Glass Composites

2016 ◽  
Vol 838 ◽  
pp. 29-35
Author(s):  
Michał Landowski ◽  
Krystyna Imielińska
Keyword(s):  
Flexural Strength ◽  
Energy Absorption ◽  
Impact Energy ◽  
Epoxy Matrix ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Nanoparticle Suspension ◽  
Impact Properties ◽  
Velocity Impact ◽  
The Impact

Flexural strength and low velocity impact properties were investigated in terms of possibile improvements due to epoxy matrix modification by SiO2 nanoparticles (1%, 2%, 3%, 5%, 7%wt.) in glass/epoxy laminates formed using hand lay-up method. The matrix resin was Hexion L285 (DGEBA) with Nanopox A410 - SiO2 (20 nm) nanoparticle suspension in the base epoxy resin (DGEBA) supplied by Evonic. Modification of epoxy matrix by variable concentrations of nanoSiO2 does not offer significant improvements in the flexural strength σg, Young’s modulus E and interlaminar shear strength for 1% 3% and 5% nanoSiO2 and for 7% a slight drop (up to ca. 15-20%) was found. Low energy (1J) impact resistance of nanocomposites represented by peak load in dynamic impact characteristics was not changed for nanocompoosites compared to the unmodified material. However at higher impact energy (3J) nanoparticles appear to slightly improve the impact energy absorption for 3% and 5%. The absence or minor improvements in the mechanical behaviour of nanocomposites is due to the failure mechanisms associated with hand layup fabrication technique: (i.e. rapid crack propagation across the extensive resin pockets and numerous pores and voids) which dominate the nanoparticle-dependent crack energy absorption mechanisms (microvoids formation and deformation).

Experimental Analysis for the Effect of Impactor Geometry on Carbon Reinforced Composite Materials

2017 ◽  
Vol 25 (9) ◽  
pp. 677-682 ◽  
Author(s):  
Faruk Elaldi ◽  
Busra Baykan ◽  
Can Akto
Keyword(s):  
Composite Materials ◽  
Carbon Fibre ◽  
Composite Plates ◽  
High Strength ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Damage Area ◽  
Reinforced Composite ◽  
Contact Surfaces ◽  
The Impact

For the last three decades, composites have become very preferable materials to be used in the automotive industry, structural parts of aircraft and military systems and spacecraft, due to their high strength and modulus. Composite materials are sometimes exposed to invisible or visible damage due to impact loading during their service life. In this study, the effect of impactor geometry with four different contact surfaces on woven carbon fibre-reinforced composite plates having three different thicknesses are investigated. In the first stage, composite plates were manufactured with the ply orientations of [45/-45/0/90/45/-45]2s, [45/-45/0/90/45/-45]3s, [45/-45/0/90/45/-45]4s based on conventional usage. In the second stage, carbon fibre-reinforced composite test panels were exposed to low velocity impact tests to obtain force-time, energy-time and force-displacement curves. Finally, semi and full penetration of composite panels and damage magnitude were determined. It was found that the impactor geometries with lower contact surfaces such as conical and ogive types were much more penetrative on composite plates than the other geometries, but they caused larger damage area in the vicinity of the impact point.

Low Velocity Impact on Woven Kenaf Fiber Reinforced Composites

2014 ◽  
Vol 629 ◽  
pp. 503-506 ◽  
Author(s):  
Al Emran Ismail ◽  
M.A. Hassan
Keyword(s):  
Impact Velocity ◽  
Composite Plates ◽  
Fiber Reinforced Composites ◽  
Low Velocity Impact ◽  
Reinforced Composites ◽  
Low Velocity ◽  
Kenaf Fiber ◽  
Velocity Impact ◽  
The Impact ◽  
Woven Kenaf

This paper presents the experimental investigations on the low velocity impact response of woven kenaf fiber reinforced composites. Kenaf yarns are weaved with an orientation of 00 of warp and 900 of weft to form woven kenaf mat. Three woven kenaf mats are stacked together to achieve the specified sequences. The woven stacked kenaf mats are hardened with polymeric resin and compressed to squeeze off any excessive resin and to minimize voids content. The hardened composite plates are perforated using different impact velocities. Impact responses of the composite plates are examined according to stacking sequences, impact velocities and fragmentation patterns. According to the present results, the impact strength is strongly related with the impact velocity. If higher impact velocity is used, the performances of load bearing are reduced. It is obvious that no significant features of composite fragmentations occurred from the perforated holes. However, relatively larger area of mechanical damages is found distributed around the holes, indicating the capability of composites to absorb energy effectively.

Comparison of the impact damage resistance of non-hybrid and intra-ply hybrid carbon/E-glass/polypropylene non-crimp thermoplastic composites

2018 ◽  
Vol 38 (1) ◽  
pp. 31-45 ◽  
Author(s):  
Gaye Kaya
Keyword(s):  
Damage Tolerance ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Thermoplastic Composites ◽  
Low Velocity ◽  
Impact Properties ◽  
Compression After Impact ◽  
Post Impact ◽  
The Impact ◽  
Hybrid Carbon

This study aims to compare the low-velocity impact and post-impact properties of intra-ply hybrid carbon/E-glass/polypropylene non-crimp thermoplastic composites with non-hybrid carbon/PP and E-glass/PP non-crimp thermoplastic composites. Impact test was performed at four energy levels as 15 J, 30 J, 45 J and 60 J. Post-impact properties of hybrid thermoplastic composites were tested by compression after impact method for each energy level to understand the impact damage tolerance of intra-ply hybrid carbon/E-glass/PP non-crimp thermoplastic composites. The effect of hybridization on energy absorption of composites was not significant, while C-scan results showed that the intra-ply hybrid non-crimp thermoplastic composites had smaller impact damage areas in comparison to the non-hybrid samples. Compression and compression after impact tests results confirmed that the intra-ply hybridization increased the toughness of the composite laminates. Also, the residual compression strength/modulus increased with hybridization which indicated to damage tolerance.

Sign in / Sign up

Export Citation Format

Share Document