Investigation of the Effects of Core Thickness on Low Velocity Impact Behaviors of Aluminum Honeycomb Composites

2021 ◽  
Author(s):  
Kasım Karataş ◽  
Okan Özdemir

Honeycomb structures are used where the weight to strength ratio is important. They are also preferred to absorb the energy from the blows received. In this study, low velocity impact behavior of aluminum honeycomb composites with different core thicknesses were investigated. Aluminum honeycombs used in this study are AL3003 honeycombs of 10 mm and 15 mm thicknesses. Glass fiber reinforced epoxy sheets with a thickness of 2 mm were used as the surface sheet material. Composite plates were produced by vacuum infusion method. The upper and lower face plates were cut in dimensions of 100x100 mm. The cut plates were attached to the core material with adhesive and a sandwich structure was formed. After bonding, low velocity impact tests were performed on these test samples at 40J, 100J and 160J energy levels using the composite CEAST Fractovis Plus impact testing machine. According to the results obtained from the impact tests, at higher energy levels, 15 mm thick composites have 10-15% higher energy absorption capacity than 10 mm.

2018 ◽  
Vol 11 (4) ◽  
pp. 46-52
Author(s):  
Aidel Kadum Jassim Al-shamary

In this study, the effect of low velocity impact  response of Kevlar/carbon hybrid composite has been investigated. Then the impacted specimens were subjected to compression and buckling tests at room temperature experimentally. The height, width and thickness of the specimens are 150, 100 and 2.1 mm, respectively. Impact tests have been performed under different impact energy levels by using low velocity impact testing machine. Compression and buckling tests were conducted by Shimadzu testing machine. According to obtained results, the damage increases by increasing the impact energy level in the subjected specimens to impact test.  Compression strength value is higher about 3  times than buckling strength value.


1999 ◽  
Author(s):  
Uday K. Vaidya ◽  
Mohan V. Kamath ◽  
Mahesh V. Hosur ◽  
Anwarul Haque ◽  
Shaik Jeelani

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.


1993 ◽  
Vol 2 (3) ◽  
pp. 096369359300200
Author(s):  
H. Kaczmarek

In order to reduce hidden damage caused in CFRP by low velocity transverse impact, testing procedures must be established by understanding the impact phenomena and the roles of various parameters on damage initiation and growth. Hence, composite plates were stressed and an original method, “ultrasonic tomography,” was applied to detect delaminations on the interfaces. The results show the similarity of the damage growth resulting from static indentation and low velocity impact.


2006 ◽  
Vol 306-308 ◽  
pp. 279-284
Author(s):  
Ki Weon Kang ◽  
Jung Kyu Kim ◽  
Heung Seob Kim

The goals of the paper are to identify the impact damage and strength reduction behavior of sandwich structure, composed of carbon/epoxy laminates skin and Nomex core with two kinds of thickness (10 and 20mm). For these, low velocity impact tests were conducted using the instrumented impact-testing machine and damages are inspected by SAM. And then, subsequent static tests are conducted under flexural loading to identify the strength reduction behavior of the impacted sandwich structures. The impact damages are mainly delamination in carbon/epoxy skin and their behavior is mostly independent of core thickness. Also, their energy absorbing behavior is identified through calculating the energy absorbed by impact damage. Finally, the strength reduction behavior is evaluated through Caprino’s model, which was proposed on the unidirectional laminates.


2013 ◽  
Vol 774-776 ◽  
pp. 1242-1249 ◽  
Author(s):  
Albert U. Ude ◽  
Ahmad K. Ariffin ◽  
Che H. Azhari

This paper describes the result of an experimental investigation on the impact damage on woven natural silk/epoxy composite face-sheet and PVC foam core sandwich panel. The test panels were prepared by hand-lay-up method. The low-velocity impact response of the composites sandwich panels is studied at three energy levels of 32, 48, and 64 joule respectively. The focus is to investigate damage initiation, damage propagation, and mechanisms of failure. It was observed that absorption energy capability decreased as impact energy increased. There was deflection on each impact load configuration at some point but their margin was insignificant. Physical examination of the specimen show that damage areas increased with increase in impact load. The novelty of this research is the use of woven natural silk fabric as a reinforcement fibre.


2021 ◽  
Vol 88 (5) ◽  
Author(s):  
Mingshi Wang ◽  
Shangjun Chen ◽  
Chunping Xiang ◽  
Qinghua Qin ◽  
T. J. Wang

Abstract The dynamic behavior of sandwich columns with aluminum face-sheets and hexagonal honeycomb core under axial low-velocity impact is investigated experimentally and theoretically. In the impact tests, two typical competing cases of deformation, i.e., core shear-curling (CS-Cu) and local denting-plastic hinge (LD-PH), were observed following the first-order or higher-order global buckling. The deformation process, permanent deformation, cushioning property, energy dissipation efficiency, and factors affecting the competition of CS-Cu and LD-PH were compared and discussed in detail. It is found that, if CS-Cu occurs instead of LD-PH, an axially impacted sandwich column may perform better in both cushioning and efficiently dissipating residual energy. The theoretical analysis is carried out by extending the existing quasi-static global buckling theory of sandwich columns. A good agreement between the oscillatory plateau on the measured force–time curve and the predicted critical plastic global buckling load is found for the strain rate-insensitive face-sheet material.


2021 ◽  
Vol 893 ◽  
pp. 67-74
Author(s):  
Usha Kiran Sanivada ◽  
Gonzalo Mármol ◽  
Francisco P. Brito ◽  
Raul Fangueiro

The study of the impact energy and the composite behaviour plays a vital role in the efficient design of composite structures. Among the various categories of impact tests, it is essential to study low-velocity impact tests as the damage generated due to these loads is often not visible to the naked eye. The internal damages can reduce the strength of the composites and hence the impact behaviour must be addressed specifically for improving their applications in the transport industry. The main aim of this paper is to provide a comprehensive review of the work focusing on the assessment of biocomposites performance under low impact velocity, the different deformations, and damage mechanisms, as well the methods to improve the impact resistance.


2010 ◽  
Vol 168-170 ◽  
pp. 1149-1152
Author(s):  
Xiao Xiong Zha ◽  
Hong Xin Wang

The low velocity impact response of sandwich panels at different energy levels has been investigated by conducting drop-weight impact tests using an instrumented falling-weight impact tower. Impact parameters like maximum impact force and the extent of the damage were evaluated and compared for different types of sandwich panels. Finite elements simulations have been undertaken using the LS-DYNA software; the results of FE simulations have a good agreement with the experiments. It shows that, the impact force increased with thickness of face-sheets and foam core, the extent of the damage increased with the impact energy, sandwich panels with steel face sheet has a good impact resistance in comparison with sandwich panel with aluminum face sheets.


2019 ◽  
Vol 56 (2) ◽  
pp. 382-387
Author(s):  
Raluca Maier ◽  
Andrei Mandoc ◽  
Alexandru Paraschiv ◽  
Marcel Istrate

Low velocity impact tests were conducted on quasi-isotropic [�45/0/90o]xs laminates under drop weight impact from 0.7m, corresponding to a 30J energy. In this respect modified epoxy blends reinforced with carbon and Kevlar woven fabrics laminates were developed using autoclave technology. The four configurations developed for low velocity impact tests aimed at investigating several aspects like: the effect of fiber type, stacking sequence and mainly technological processing parameters, on the impact performances. The recorded Load-Time curves were plotted and visual inspection, high resolution laser scanner were used to observe the fracture characteristics of the impacted composite laminates. The results obtained showed that for tested configurations, both stacking sequence and processing parameters directly linked to fiber volume fraction, have a strong effect on the impact performances. The amount of absorbed energy, ductility index was calculated for each configuration under study. The results obtained showed that hybrid configuration exhibits lower stiffness and damage initiation energy amount when compared to carbon reinforced configurations. Nevertheless, their damage propagation energy amount and ductility index was the uppermost. This behaviour was already reported previously [1] and is partially attributed to the higher elastic energy absorption of carbon fibers that delays the propagation of delamination, and fiber breakage. Lower tenacity obtained on hybrid laminates was attributed to both lack of resin local rinse saturate and to the intrinsic anisotropy of para-aramid fibers.


2020 ◽  
Vol 54 (21) ◽  
pp. 2999-3007
Author(s):  
Hüseyin E Yalkın ◽  
Ramazan Karakuzu ◽  
Tuba Alpyıldız

The aim of the study is to investigate the behavior of laminated composites under low velocity impact both experimentally and numerically. With this aim, the effects of wide range impact energy values between 10 J and 60 J were evaluated experimentally and numerically for the laminate of [±45/(0/90)2]S oriented unidirectional E-glass as reinforcing material and epoxy resin for matrix material. Different impactor velocities were used to maintain the impact energy values and experimental impact tests were generated with drop weight impact testing machine at room temperature. Numerical simulations were performed using LS-DYNA finite element analysis software with a continuum damage mechanics-based material model MAT058. Contact force between impactor and laminate, and transverse deflection at the center of laminate results were obtained as a function of time and used to plot contact force–time curves, contact force–deflection curves and absorbed energy-impact energy curves. Also, delamination area was examined. Finally, numerical results were compared with experimental results and a good correlation between them was observed.


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