Embedding shape memory alloys (SMAs) in composites is a promising method resistance against impact loading.In the present paper, an attempt is made to quantify the improvement in damage mitigation properties of FRP (fibre reinforced plastic)composites by embedding SMA.Numerical modelling of low velocity impact was carried out topredict the delamination in composites and composites embedded with SMA and steel wires. Through modelling, effect of location and quantity of SMA material in decreasing the impact induced delamination size was also studied.Compression after impact (CAI) tests were carried out on pristine and SMA hybrid composite (SMAHC)specimens to quantify the change in damage resistance. Experimental results show an improvement in compressive load-carrying capacity after impact in SMAHC as compared to pristine composites.Experimental results match well with numerical findings in terms of; location of placement of SMA wire and optimum quantity of SMA wires. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.

R. Velmurugan

Department of Aerospace Engineering

Composite materials

Delamination

Fiber reinforced plastics

Numerical models

Steel fibers

Wire

Compression after impact

COMPRESSIVE LOADS

DAMAGE RESISTANCE

GFRP COMPOSITES

Hybrid composites

IMPACT-INDUCED DELAMINATION

Low velocity impact

POST IMPACTS

Shape memory effect

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Studies on shape memory alloy-embedded GFRP composites for improved post-impact damage strength

International Journal of Crashworthiness

Induced delamination due to low velocity impact results in degradation of load-carrying capacity of composite structures especially when loading is predominantly in compression. In this paper, size, shape and orientation of delamination that occur due to low velocity impact is obtained by numerical modelling and results are validated through experiments. Initially, numerical model is validated for single-mode fracture tests like double cantilever beam and end-notch flexure. Multimode failure phenomenon like low velocity impact was also simulated for different lay-ups such as cross-ply, angle-ply and quasi-isotropic and validated through experiments. Low velocity impact testing of laminates was done using drop weight impactor, and experimentally obtained force–time and energy–time history were compared with numerical results. Good match is obtained between simulations and experiments. Delamination size was also compared and it is found that numerical model correctly predicts the size, shape and orientation of delamination for all lay-ups. © 2017 Informa UK Limited, trading as Taylor & Francis Group.

Numerical and experimental study of multimode failure phenomena in GFRP laminates of different lay-ups

Several efforts were made over the years to control vibration of structural components made of composite materials. This paper consists of study on effect of using shape memory alloy (SMA) to increase the damping of glass fiber reinforced plastic (GFRP) composites. A comparative study between SMA and steel was made as reinforcement material in GFRP composites to enhance damping. Dimensions of each beam were calculated such that all the beams i.e. pristine GFRP beam, GFRP beam embedded with steel wires and GFRP beam embedded with SMA wires have same flexural stiffness and first mode of frequency of vibration. Damping ratio was measured experimentally through logarithmic decay method. Through experiments damping ratio obtained for SMA hybrid composite beam was found to be higher as compared to the pristine and steel hybrid GFRP composite beams. © 2018, DESIDOC.

Fulltext

Defence Science Journal

Comparative study of damping in pristine, steel, and shape memory alloy hybrid glass fiber reinforced plastic composite beams of equivalent stiffness

Composite laminates made of glass/epoxy with and without nano fillers were subjected to projectile impact. The laminates of different thicknesses were prepared by hand lay-up and compression molding processes. Laminates were made from glass woven roving mats of 610 gsm, epoxy resin and nano clay of 1-5 wt.% of matrix. A piston type gas gun setup was used to impact a spherical nose projectile of diameter 9.5 mm and mass of 7.6 g, on the nanocomposite laminates at impact velocities in the range of their ballistic limit and above. The energy absorbed during penetration and ballistic limit of the nanocomposite laminates were studied both experimentally and analytically. The analytical model also predicts the energy absorbed in various failure modes due to tensile failure of primary fibers, deformation of secondary fibers, delamination and matrix crack. Mechanical properties like tensile modulus, stress-strain function, shear modulus, and strain energy release rate were used as input to the analytical model. Laminates of three, five and eight layers have been considered for the analysis. The effect of clay dispersion in the matrix for different failure modes is discussed. Ballistic limit obtained from the model is validated with experimental results and good agreement is found. © 2014 Elsevier Ltd. All rights reserved.

International Journal of Impact Engineering

Energy absorption and ballistic limit of nanocomposite laminates subjected to impact loading

In the present study, impact behavior of Kevlar/Epoxy composite plates has been carried out experimentally by considering different thicknesses and lay-up sequences and compared with analytical results. The effect of thickness, lay-up sequence on energy absorbing capacity has been studied for high velocity impact. Four lay-up sequences and four thickness values have been considered. Initial velocities and residual velocities are measured experimentally to calculate the energy absorbing capacity of laminates. Residual velocity of projectile and energy absorbed by laminates are calculated analytically. The results obtained from analytical study are found to be in good agreement with experimental results. It is observed from the study that 0/90 lay-up sequence is most effective for impact resistance. Delamination area is maximum on the back side of the plate for all thickness values and lay-up sequences. The delamination area on the back is maximum for 0/90/45/-45 laminates compared to other lay-up sequences. © Versita sp. z o.o.

Central European Journal of Engineering

Experimental and analytical study of high velocity impact on Kevlar/Epoxy composite plates

PNRPU Mechanics Bulletin

COMPUTATIONAL SIMULATION OF THE DAMAGE ACCUMULATION PROCESSES IN CRACKED SOLIDS BY THE USER PROCEDURE UMAT OF SIMULIA ABAQUS

Journal	Data powered by TypesetInternational Journal of Crashworthiness
Publisher	Data powered by TypesetTaylor and Francis Ltd.
ISSN	13588265
Open Access	No