Conference Papers

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Subject: search.filters.subject.Low-velocity impact

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    Influence of laminate thickness and impactor shape on low velocity impact response of jute-epoxy composite: FE study
    (Elsevier Ltd, 2019) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    This paper aims at numerical and parametric investigation on the outcome of low velocity impact (LVI) response of jute/epoxy (JE) composite of varied thickness subjected to impact at varied velocity of impact within LVI regime using different shaped impactors. The JE composite laminate with varying thickness of 6 mm to 10 mm is subjected to LVI at impact velocity varying from 2 m per second (mps) to 8 mps using impactors of hemispherical (HS), flat (F) and conical (C) shapes. Modelling and simulation of the proposed JE composite laminate is achieved using explicit software available commercially with target as deformable material and the impactor as a rigid body. Simulations are carried out for available possible combination of thickness, impact velocity and impactor shapes. Results reveal that thickness is one of the crucial factors that decide the LVI response of the proposed composite laminate. Laminate impacted with conical shaped impactor results in maximum absorption of energy and the laminate impacted with flat shaped impactor results in bigger and immediate damage. © 2019 Elsevier Ltd.
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    Parametric study on impact behaviour of sisal and cenosphere reinforced natural rubber-based hybrid composites: FE approach
    (Elsevier Ltd, 2021) Rajkumar, D.; Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    This paper aims to study the impact analysis of sisal fiber and cenosphere filler reinforced natural rubber composite using commercially available finite element software. The proposed green composite is studied for impact behaviour by varying the weight percentage of the cenosphere filler particles in a natural rubber sheet. Composite is modelled with stacking sequence sisal-rubber-sisal using finite element software and impacted by three different rigid impactors (Conical, Hemi-spherical and Flat) at the velocity of 8m/s. Modelling and simulation of this proposed composite laminate are solved using the explicit dynamic solver of Abaqus Computer-Aided Engineering Finite Element Modelling. The results of the low-velocity impact of the proposed green composite with sisal-rubber-sisal stacking sequence exhibit better energy absorption by varying the weight percentage of the Cenosphere. Also, the energy absorbed by laminate was more for the Conical impactor than the Hemi-spherical and Flat impactors and the extent of damage is more when impacted by the Flat impactor due to its larger contact area. © 2021 Elsevier Ltd. All rights reserved.
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    Dynamic impact resistance of composite sandwich panels with 3-D printed polymer syntactic foam cores
    (DEStech Publications, 2021) Tewani, H.R.; Bonthu, D.; Bharath, H.S.; Doddamani, M.; Prabhakar, P.
    Polymer-based syntactic foams find use in the marine industry as primary structural materials due to their inherent lightweight nature and enhanced mechanical properties relative to pure HDPE. 3-D printing these materials circumvents the use of joining assemblies, enabling the production of complex shapes as standalone structures. Although the quasi-static response of these 3D printed foams has been well studied independently in recent years, their dynamic impact resistance and tolerance as potential core material for sandwich panels have not been the focus. Moreover, 3D printing is known to impart directionality in the printed syntactic foams, which may introduce failure mechanisms typically not observed in molded foams. It is therefore important to investigate the mechanics of 3-D printed syntactic foam core composite sandwich structures under impact loading and characterize their failure mechanisms for establishing dynamic impact resistance. To this end, 3-D printed syntactic foams have been developed using rasters of High-Density Polyethylene (HDPE) and Glass MicroBalloon (GMB) fillers by adopting the Fused Raster Fabrication (FFF) technique. The current study is performed to assess the impact performance of these composite foam cores based on the volume fraction of fillers and print orientation. The weight percentage of GMB fillers in printed specimens ranges from 0% to 60% in increments of 20%. This study presents the impact response of these composite sandwich panels at different energy levels, in compliance with ASTM D7136/D7136M - 20. Observations suggest that an increase in GMB % in HDPE matrix improves the impact performance in terms of the peak load of the material, but the failure behavior becomes brittle to an extent. Observing the failed specimens under a Micro-CT scanner captures the failure morphologies and helps characterize failure processes during impact. It is noticed that core materials with higher GMB content are prone to individual raster breakage and delamination at the back face, in addition to debonding between individual rasters. Specimens printed along the longer dimension (y-direction) impart more warping in the final sandwich structures than that of specimens printed along the shorter dimension (x-direction). Therefore, they are more susceptible to delamination at the back face. Addition of GMB fillers mitigate the tendency of the sandwich panels to warp. © 2021 36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021. All Rights Reserved.