scholarly journals Experimental and Numerical Study of Low-Velocity Impact and Tensile after Impact for CFRP Laminates Single-Lap Joints Adhesively Bonded Structure

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1016
Author(s):  
Chunxing Hu ◽  
Guibin Huang ◽  
Cheng Li
Keyword(s):  
Lap Joints ◽  
Low Velocity Impact ◽  
Adhesively Bonded ◽  
Low Velocity ◽  
Adhesive Film ◽  
Velocity Impact ◽  
Cfrp Laminates ◽  
Single Lap Joints ◽  
Impact Energies ◽  
The Impact

To investigate the mechanical behavior of the single-lap joints (SLJs) adhesively bonded structure of carbon fiber reinforced polymer (CFRP) laminates under the low-velocity impact (LVI) and tensile-after impact (TAI), tests and simulations were carried out. A finite element model (FEM) was established based on the cohesive zone model (CZM) and Hashin criterion to predict the damage evolution process of adhesive film, intra- and inter-laminar of the SLJs of CFRP laminates, and its effectiveness was verified by experiments. Moreover, three different overlap lengths (20 mm, 30 mm, and 40 mm) and four different impact energies (Intact joint, 10 J, 20 J, and 30 J) are considered in the present study. Finally, the effects of different impact energies and overlap lengths on the residual strength of SLJs after impact were discussed. The results divulged that numerical results of impact and TAI processes of SLJs were in good agreement with experiment results. During the impact process, the damage of the laminates was primarily fiber and matrix tensile damage, whereas the adhesive film was damaged cohesively; the areas of damage increased with the increase of impact energy, and the normal stress of the adhesive film expanded from the edge to the middle region with the increase of impact force. The influence of LVI on SLJs adhesively bonded structures was very significant, and it is not effective to obtain a higher impact resistance by increasing the overlap length. For the tensile process, the failure mode of TAI of the SLJs was interface failure, the surplus strength of the SLJs gradually decreased with the increase of the impact energy because of the smaller overlap length, the overlap length more than 30 mm, and the low energy impact has almost no effect on the residual strength of the SLJs.

The Effect of the Impactor Diameter and Boundary Conditions on Low Velocity Impact Composites Behaviour

2007 ◽  
Vol 7-8 ◽  
pp. 217-222 ◽  
Author(s):  
Ana M. Amaro ◽  
Paulo N.B. Reis ◽  
A.G. Magalhães ◽  
Marcelo F.S.F. de Moura
Keyword(s):  
Boundary Conditions ◽  
Damage Model ◽  
Testing Machine ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Energies ◽  
The Impact

The aim of present work is to study the influence of the impactor diameter and boundary conditions on low velocity impact on carbon-fibre-reinforced epoxy laminates. Experimental tests were performed on [04,904]s laminates, using a drop weight-testing machine. Circular plates were tested under low velocity impacts for two diameters of the hemispherical impactor, 12.7 mm and 20 mm, and considering similar impact energies, 2.6 J for the first impactor and 3 J for the second one. Rectangular and square plates were analysed under low velocity impacts with different boundary conditions. The impacted plates were inspected by X-radiography. Numerical simulations were also performed considering interface finite elements compatible with three-dimensional solid elements including a cohesive mixed-mode damage model, which allows to model delamination between layers. The impact tests showed that both the impactor’s diameter and boundary conditions have influence on the delaminated area. Good agreement between experimental and numerical analysis for shape, orientation and size of damage was obtained.

Computational and Experimental Investigation of the Low Velocity Impact Behavior of Nano Engineered E-Glass Fiber Reinforced Composite Laminates

2012 ◽  
Author(s):  
Abu Rasel ◽  
Evan Kimbro ◽  
Ram Mohan ◽  
Ajit D. Kelar
Keyword(s):  
Composite Laminates ◽  
Energy Levels ◽  
Electrospun Nanofibers ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Low Velocity ◽  
Velocity Impact ◽  
Glass Fiber Reinforced ◽  
Impact Energies ◽  
The Impact

This paper presents computational and experimental investigation of the low velocity impact behavior of nano engineered E-glass fiber reinforced composite laminates. The Tetra Ethyl Orthosilicate (TEOS) chemically engineered glass nanofibers were manufactured using electrospinning technique and were investigated for their potential to improve the interlaminar properties. Plain weave fiberglass prepregs were used for manufacturing ten ply thick laminates. For production of the laminates with electrospinning interface layers the addition of the electrospinning sheets and an additional layer of resin film was used. The fabricated laminates were subjected to low velocity impacts of various energy levels to study the progressive damage and deformation mechanics of fiberglass laminates with and without electrospun nanofibers. The low velocity impact behavior was modeled using the transient dynamic finite element program LSDYNA. It was observed that the simulations results are in good agreement with the experimental results for lower impact energies. In addition, the simulated maximum impact force is smaller than the experimental value (soft response) at each drop height and at higher energy levels, the area under impact force vs time increases when electrospun nanofibers are used in the laminates. The study indicates that, the impact duration increases when electrospun nanofibers are used. Impact duration increases due to an additional damage accumulations in electrospun nanofibers layers. Both computational and experimental investigations clearly indicate that inserting interlaminar electrospun nanofiber layers improves the impact resistance of composites by absorbing additional impact energies.

Residual Strength after Low Velocity Impact in Carbon-Epoxy Laminates

2006 ◽  
Vol 514-516 ◽  
pp. 624-628 ◽  
Author(s):  
Ana M. Amaro ◽  
Paulo N.B. Reis ◽  
Marcelo F.S.F. de Moura
Keyword(s):  
Residual Strength ◽  
Testing Machine ◽  
Experimental Tests ◽  
Low Energy ◽  
Low Velocity Impact ◽  
Stacking Sequence ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Energies ◽  
The Impact

The aim of present work is to study the influence of low energy impacts on residual strength of carbon-epoxy laminates. Experimental tests were performed on [0,90,0,90]2s and [0,90]8 laminates using a drop weight-testing machine. The influence of the laminate stacking sequence is analysed under 1.5 J, 2 J, 2.5 J and 3 J impact energies, corresponding to a 0.91 ms-1, 1.05 ms-1, 1.18 ms-1 and 1.29 ms-1 of impact velocity, respectively. The impacted plates were inspected by CScan to evaluate the size, shape and position of the delaminations through the thickness of the plate. The same plates were inspected by C-Scan before the impact, to evaluate the eventual presence of defects produced during the manufacturing process. The residual flexural strength showed that the [0,90,0,90]2s laminates have better performance than the [0,90]8 ones. The explanation is related with the lower flexural stiffness of the antisymmetric lay-up relatively to the symmetric one.

Ballistic performance of quasi-isotropic CFRP laminates under low velocity impact

2021 ◽  
pp. 002199832110238
Author(s):  
Gyanesh Patnaik ◽  
Anshul Kaushik ◽  
Abhishek Rajput ◽  
Guru Prakash ◽  
R Velmurugan
Keyword(s):  
Numerical Model ◽  
Experimental Results ◽  
Low Velocity Impact ◽  
Fiber Reinforced ◽  
Low Velocity ◽  
Ballistic Performance ◽  
Velocity Impact ◽  
Cfrp Laminates ◽  
Wide Range ◽  
The Impact

The perforation characteristics of fiber reinforced laminates is crucial for the design of protective civil and military structures. This paper investigates the perforation characteristics (ballistic limit velocity, residual velocity, perforation energy) of cross ply and quasi-isotropic (QI) carbon fiber reinforced polymer (CFRP) laminates under the impact of a rigid conical steel bullet. The influence of thickness and ply orientation on these characteristics is also studied for a wide range of velocities. The perforation characteristics of these laminates were determined, numerically as well as experimentally. A numerical model is developed by using Hashin damage model to understand the behavior of laminates under high velocity impact. The accuracy of the model is assessed by comparing its prediction with experimental results of cross ply laminates. Then, impact perforation study of different possible configurations made of quasi-isotropic (QI) CFRP laminates, oriented at 0°, 90°, 45° and −45° directions are carried out with the help of validated numerical model. The perforation characteristics predicted with the help of numerical model is in good agreement with the experimental results. Optimal configuration is achieved in terms of energy absorption and damage resistance for better performance under impact loading.

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.

Low Velocity Impact Resistance of CPVC Pipes Exposed to Natural Outdoor Weathering Conditions

2012 ◽  
Vol 445 ◽  
pp. 959-964
Author(s):  
Z. Khan ◽  
Necar Merah ◽  
A. Bazoune ◽  
S. Furquan
Keyword(s):  
Impact Resistance ◽  
Outdoor Exposure ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Pipe Material ◽  
Low Velocity ◽  
Impact Energies ◽  
The Impact ◽  
Impact Events ◽  
Outdoor Weathering

Low velocity drop weight impact testing of CPVC pipes was conducted on 160 mm long pipe sections obtained from 4-inch (100 mm) diameter schedule 80 pipes. Impact test were carried out for the base (as received) pipes and after their exposure to out door natural weathering conditions in Dhahran, Saudi Arabia. The results of the impact testing on the natural (outdoor exposure) broadly suggest that the natural outdoor exposures produce no change in the impact resistance of CPVC pipe material for the impact events carrying low incident energies of 10 and 20J. At the impact energies of 35 and 50J the natural outdoor exposures appear to cause appreciable degradation in the impact resistance of the CPVC pipe material. This degradation is noted only for the longer exposure periods of 12 and 18 months.

Coda Waves for Health Monitoring of Composites Under Low-Velocity Impact

2021 ◽  
Author(s):  
Subal Sharma ◽  
Vinay Dayal
Keyword(s):  
Ultrasonic Waves ◽  
Coda Waves ◽  
Low Velocity Impact ◽  
Coda Wave ◽  
Low Velocity ◽  
Fibrous Composite Material ◽  
Velocity Impact ◽  
Isotropic Composite ◽  
The Impact ◽  
Impact Damages

Abstract Coda waves have been shown to be sensitive to lab-controlled defects such as very small holes in fibrous composite material. In the real world, damages are subtler and more irregular. The main objective of this work is to investigate coda wave capability to detect low-velocity impact damages. The emphasis is to detect the presence of barely visible impact damages using ultrasonic waves. Detection of incipient damage state is important as it will grow over the life of the structure. Differential features, previously used in similar work, have been utilized to detect realistic impact damages on carbon fiber composites. Quasi-isotropic composite laminates were subjected to low-velocity impact energy ranging from 2J to 4.5J. Two differential features reported could be used detect the presence of damage. It is also observed that ply orientation can be a deterministic factor for indicating damages. The size and shape of the impact damage has been characterized using ultrasonic C-scans. Results indicate that coda waves can be used for the detection of damage due to low-velocity impact.

Low Velocity and Compression-After-Impact Response of Pin-Reinforced Sandwich Composites

1999 ◽  
Author(s):  
Uday K. Vaidya ◽  
Mohan V. Kamath ◽  
Mahesh V. Hosur ◽  
Anwarul Haque ◽  
Shaik Jeelani
Keyword(s):  
Impact Testing ◽  
Low Velocity Impact ◽  
Sandwich Composites ◽  
Low Velocity ◽  
Static Compression ◽  
Velocity Impact ◽  
Transverse Stiffness ◽  
Impact Studies ◽  
Compression After Impact ◽  
The Impact

Abstract In the current work, sandwich composite structures with innovative constructions referred to as Z-pins, or truss core pins are investigated, in conjunction with traditional honeycomb and foam core sandwich constructions, such that they exhibit enhanced transverse stiffness, high damage resistance and furthermore, damage tolerance to impact. While the investigations pertaining to low velocity impact have appeared recently in Vaidya et al. 1999, the current paper deals with compression-after-impact studies conducted to evaluate the residual properties of sandwich composites “with” and “without” reinforced foam cores. The resulting sandwich composites have been investigated for their low velocity (< 5 m/sec) impact loading response using instrumented impact testing at energy levels ranging from 5 J to 50 J impact energy. The transverse stiffness of the cores and their composites has also been evaluated through static compression studies. Compression-after-impact studies were then performed on the sandwich composites with traditional and pin-reinforcement cores. Supporting vibration studies have been conducted to assess the changes in stiffness of the samples as a result of the impact damage. The focus of this paper is on the compression-after-impact (CAI) response and vibration studies with accompanying discussion pertaining to the low velocity impact.

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