Characterisation of the impact induced damage in composites by cross-comparison among experimental non-destructive evaluation techniques and numerical simulations

2016 ◽  
Vol 231 (16) ◽  
pp. 3077-3090 ◽  
Author(s):  
A Riccio ◽  
S Saputo ◽  
A Sellitto ◽  
V Lopresto
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Composite Plates ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Premature Failure ◽  
Explicit Finite Element ◽  
The Impact ◽  
Non Destructive

Composite fibre-reinforced materials, under low velocity impacts, can experience simultaneous interacting failure phenomena, such as intra-laminar damage, fibre breakage and matrix cracking, and inter-laminar damage such as delaminations. These failure mechanisms are usually the subject of extensive investigations because they can cause a significant reduction in strength of composites structures leading to premature failure. In the present work, composite plates under low velocity impact are investigated. Experimental data, such as experimental curves and images from non-destructive inspections, are used to characterise the low velocity impacts-induced damage in conjunction with a non-linear explicit Finite element numerical model. The adopted numerical model, implemented in the FE code (Abaqus/Explicit) by a user-defined material subroutine (VUMAT), has been demonstrated to be very effective in predicting the damage onset and evolution and, in general, able to correctly integrate the experimental data by providing useful information about the impact damage localisation and evolution.

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.

scholarly journals Static Residual Tensile Strength Response of GFRP Composite Laminates Subjected to Low-Velocity Impact

2020 ◽  
Vol 10 (16) ◽  
pp. 5480
Author(s):  
Jong-Il Kim ◽  
Yong-Hak Huh ◽  
Yong-Hwan Kim
Keyword(s):  
Tensile Strength ◽  
Composite Laminates ◽  
Impact Damage ◽  
Image Correlation ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Stress Concentrations ◽  
Low Velocity ◽  
Full Field ◽  
The Impact

The dependency of the static residual tensile strength for the Glass Fiber-Reinforced Plastic (GFRP) laminates after impact on the impact energy level and indent shape is investigated. In this study, two different laminates, unidirectional, [0°2]s) and TRI (tri-axial, (±45°/0°)2]s), were prepared using the vacuum infusion method, and an impact indent on the respective laminates was created at different energy levels with pyramidal and hemispherical impactors. Impact damage patterns, such as matrix cracking, delamination, debonding and fiber breakage, could be observed on the GFRP laminates by a scanning electron microscope (SEM), and it is found that those were dependent on the impactor head shape and laminate structure. Residual in-plane tensile strength of the impacted laminates was measured and the reduction of the strength is found to be dependent upon the impact damage patterns. Furthermore, in this study, stress concentrations in the vicinity of the indents were determined from full-field stress distribution obtained by three-dimensional Digital Image Correlation (3D DIC) measurement. It was found that the stress concentration was associated with the reduction of the residual strength for the GFRP laminates.

Analysis on Low Velocity Impact Damage and Compressive Residual Strength of Composite Laminates

2014 ◽  
Vol 566 ◽  
pp. 463-467
Author(s):  
Pu Xue ◽  
H.H. Chen ◽  
W. Guo
Keyword(s):  
Experimental Data ◽  
Residual Strength ◽  
Composite Laminates ◽  
Damage Mechanics ◽  
Impact Damage ◽  
Numerical Results ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

This paper studies the impact damage under low velocity impact for composite laminates based on a nonlinear progressive damage model. Damage evolution is described by the framework of the continuum damage mechanics. The real impact damage status of composite laminates has been used to analyze the residual compressive strength instead of assumptions on damage area after impact. The validity of the methodologies has been demonstrated by comparing the numerical results with the experimental data available in literature. The delamination area has an error of 11.3%. The errors of residual strength and compressive displacement are 8.9% and 15%, which indicate that the numerical results matched well with the experimental data.

Simulation of Low Velocity Impact Test on Carbon/Epoxy Composite Plates

2015 ◽  
Vol 1115 ◽  
pp. 523-526
Author(s):  
Ziamah B. Buang ◽  
S.M. Kashif
Keyword(s):  
Numerical Simulation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Composite Plates ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Element Analysis ◽  
Velocity Impact

Composite materials that have low weight and high strength properties are currently one of the promising materials for a vehicle’s body. However, the effect of low velocity impact on composite may cause failure through matrix cracking, fibre breakage and delamination which may reduce the structure strength. Low velocity impact can be analysed either by experimentation or numerical simulation. Numerical simulation which is also known as finite element analysis can show the degradation of the composite structure properties after an impact loading condition without doing any experimentation. Thus, in this paper, LS-DYNA is the finite element analysis software that is used to simulate a low velocity impact on composite structures.

Theoretical and experimental analysis for the impact response of glass fibre reinforced aluminium honeycomb sandwiches

2016 ◽  
Vol 20 (1) ◽  
pp. 42-69 ◽  
Author(s):  
Vincenzo Crupi ◽  
Emre Kara ◽  
Gabriella Epasto ◽  
Eugenio Guglielmino ◽  
Halil Aykul
Keyword(s):  
Experimental Data ◽  
Sandwich Structures ◽  
Low Velocity Impact ◽  
Balance Model ◽  
Model Parameters ◽  
Low Velocity ◽  
Internal Damage ◽  
Limit Loads ◽  
Load Carrying ◽  
The Impact

Honeycomb sandwich structures are increasingly used in the automotive, aerospace and shipbuilding industries where fuel savings, increase in load carrying capacity, vehicle safety and decrease in gas emissions are very important aspects. The aim of this study was to develop the theoretical methods, initially proposed by the authors and by other researchers for the prediction of low-velocity impact responses of sandwich structures. The developed methods were applied to sandwich structures with aluminium honeycomb cores and glass-epoxy facings for the assessment of impact parameters and for the prediction of limit loads. The values of model parameters were compared with data reported in literature and the predictions of the limit loads were validated by means of the experimental data. Good achievement was obtained between the results of the theoretical models and the experimental data. The failure mode and the internal damage of the sandwich panels have been investigated using 3D computed tomography, which allowed the evaluation of parameters of energy balance model, and infrared thermography, which allowed the detection of the temperature evolution of the specimens during the tests. The experimental and theoretical results demonstrated that the use of glass-epoxy reinforcement on aluminium honeycomb sandwiches enhances the energy absorption and load carrying capacities.

scholarly journals Enhanced Impact-Resistance of Aeronautical Quasi-Isotropic Composite Plates Through Diffused Water Molecules in Epoxy

2020 ◽  
Author(s):  
Furqan Ahmad ◽  
Fethi Abbassi ◽  
Mazhar Ul-Islam ◽  
Frédéric JACQUEMIN ◽  
Jung-Wuk Hong
Keyword(s):  
Carbon Fiber ◽  
Impact Resistance ◽  
Composite Plates ◽  
Hot Water ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Segmental Mobility ◽  
Impact Tests ◽  
Isotropic Composite ◽  
The Impact

Abstract In order to elucidate the hygroscopic effects on impact-resistance of carbon fiber/epoxy quasi-isotropic composite plates, low-velocity impact tests are conducted on dry and hygroscopically conditioned plates, respectively, under identical configurations. For the impact tests, plates were immersed in the hot water at 80 °C to absorb a different amount of moisture content (MC). Experimental results reveal that the presence of the MC plays a pivotal role by improving the impact-resistance of composite plates. Plates with higher percentage of MC could behave elastically to a larger strain, yielding larger deflection under impact loading. From SEM fractographies, it is observed that small disbanding grows at the interface of epoxy and carbon fiber due to absorbed MC. After absorbing MC, most of impact enegy is dissipated in hygroscopic conditioned composite plates throught elastic deformation and overall less damage is induced in wet composite plates compare to the dry plate. We can postulate that the presence of MC increases the elastic limit as well as ductility of the epoxy by promoting chain segmental mobility of the polymer molecules, which eventually leads to the enhancement of the impact-resistance of wet quasi-isotropic composite plates in comparison with the dry plate.

Probabilistic Response of Composite Plates for Damage Initiation due to Low Velocity Impact

2018 ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad
Keyword(s):  
Composite Plates ◽  
Laminated Plates ◽  
International Standards ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Stochastic Response ◽  
Low Velocity ◽  
Fiber Failure ◽  
Velocity Impact ◽  
Damage Initiation

The low velocity impact (LVI) result of laminated targets is an imperative study to evaluate its failure for applications to inconsequential structures. The work has extensive applications to off shore and naval industry. Safety and reliability assessment as per the international standards is one of the basic objectives of the study. LVI on composite plates is performed taking the material parameters and loading condition as random variables. Graphite fiber reinforced laminated plates are vulnerable to damage due to impact by foreign objects and in plane loading. In order to evaluate the safe load carrying capacity and the reliability under impact, dynamic analysis of composite plate subjected to LVI is carried out. Probabilistic finite element method (PFEM) is performed to determine the stochastic response. During impact, the in-plane damage modes such as matrix cracking, fiber failure and shear cracking are modeled using a failure criterion. The out of plane de-lamination is modeled using cohesive surfaces. The randomness associated with the system properties due to the inherent scatter in the geometric and material properties and input loads are modeled in a stochastic fashion. Random parameters represent various characteristics appearing in the performance function. The stochastic response and reliability forecast of the system is determined by Gaussian processes response surface method (GPRSM) and validity of method for the present problem is establish using Monte Carlo simulation (MCS) procedure. The safety level qualification is achieved in terms of reliability level targeted.

scholarly journals Numerical Modelling of Ballistic Impact Response at Low Velocity in Aramid Fabrics

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2087 ◽  
Author(s):  
Norberto Feito ◽  
José Antonio Loya ◽  
Ana Muñoz-Sánchez ◽  
Raj Das
Keyword(s):  
Numerical Model ◽  
Mechanistic Model ◽  
Computation Time ◽  
Impact Angle ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Computational Time ◽  
Low Velocity ◽  
Aramid Fabrics ◽  
The Impact

In this study, the effect of the impact angle of a projectile during low-velocity impact on Kevlar fabrics has been investigated using a simplified numerical model. The implementation of mesoscale models is complex and usually involves long computation time, in contrast to the practical industry needs to obtain accurate results rapidly. In addition, when the simulation includes more than one layer of composite ply, the computational time increases even in the case of hybrid models. With the goal of providing useful and rapid prediction tools to the industry, a simplified model has been developed in this work. The model offers an advantage in the reduced computational time compared to a full 3D model (around a 90% faster). The proposed model has been validated against equivalent experimental and numerical results reported in the literature with acceptable deviations and accuracies for design requirements. The proposed numerical model allows the study of the influence of the geometry on the impact response of the composite. Finally, after a parametric study related to the number of layers and angle of impact, using a response surface methodology, a mechanistic model and a surface diagram have been presented in order to help with the calculation of the ballistic limit.

Safety and Reliability Analysis of Composites Under Low Velocity Impact

2016 ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad ◽  
Manander Singh
Keyword(s):  
Material Properties ◽  
Limit State ◽  
Composite Plates ◽  
Probability Of Failure ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
State Function ◽  
Random Parameters ◽  
Low Velocity ◽  
Velocity Impact

Low velocity impact on composite plates is studied taking material properties and initial velocity as random parameters. Graphite fiber reinforced composite plates are susceptible to damage due to impact by foreign objects and in plane loading. In order to assess the safe load carrying capacity and the probability of failure under impact, dynamic analysis of composite plate subjected to low velocity impact is carried out. Finite element method is used to study impact. During impact, the in-plane damage modes such as matrix cracking, fiber failure and shear cracking are modeled using a failure criterion. The out of plane de-lamination is modeled using cohesive surfaces. The uncertainties associated with the system properties due to the inherent scatter in the geometric and material properties and input loads are modeled in a probabilistic fashion. Random parameters represent various characteristics appearing in the limit state function. The probabilistic analysis and reliability prediction of the system is carried out using Gaussian response surface method and validity of method for the present problem is establish using Monte Carlo simulation (MCS) procedure. Sensitivity analysis of the probability of failure with respect to random parameters considered is an important study for design optimization. The safety level qualification is achieved in terms of reliability level targeted. The mean and standard deviations of random variables show an appreciable influence on the probabilistic failure. Systematic changes in the input parameters are governed by the probabilistic sensitivity tools to achieve target reliability.

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