Numerical and experimental investigations on sandwich panels made with eco-friendly components under low-velocity impact

2021 ◽  
pp. 109963622110204
Author(s):  
Pablo Oliveira ◽  
Sebastian Kilchert ◽  
Michael May ◽  
Tulio Panzera ◽  
Fabrizio Scarpa ◽  
...  

A low-velocity impact characterisation of a sustainable sandwich panel based on upcycled bottle caps as circular honeycomb is conducted. The recycled core aims to develop an alternative route of reusing waste bottle caps disposed in landfills. Ecological alternatives to skin (recycled PET foil) and adhesive (bio-polyurethane) are also compared with classic components (aluminium skin and epoxy polymer). A low-cost reinforcement (cement particles) is also proposed to enhance the mechanical strength of the panel. The samples are tested at several levels of impact energy, according to the type of skin, to observe their effect on mechanical behaviour. Metal skins achieve higher impact loads and energy absorption compared to PET foil. The bio-adhesive leads to a similar or enhanced maximum impact load and energy absorption compared to the epoxy adhesive. Specific properties highlight the promising performance of the bio-based adhesive with aluminium skins, reaching increments of up to 378%. The cement increases the maximum load and reduces the duration of the impact event, leading to lower energy absorption. The unreinforced epoxy polymer shows a visible adhesive peeling off from aluminium skin, while particle inclusions lead to reduced overall delamination. Biopolymer exhibits marginal adhesive debonding and stable deformation, revealing a progressive failure. In general, PET samples show core shear failure due to rupture of the skin. Crack propagation in PET samples made with biopolymer adhesive is reduced at lower energy levels. The results evidence the promising application of bottle caps in a more sustainable honeycomb core to build eco-friendly structures.

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4416
Author(s):  
Yanyan Lin ◽  
Huaguan Li ◽  
Zhongwei Zhang ◽  
Jie Tao

The weak interface performance between metal and composite (IPMC) makes the composite materials susceptible to impact load. Aluminum/glass fiber/polypropylene (Al/Gf/PP) laminates were manufactured with the aluminum alloy sheets modified by nitrogen plasma surface treatment and the phosphoric acid anodizing method, respectively. FEM models of Al/Gf/PP laminates under low-velocity impact were established in ABAQUS/Explicit based on the generated data including the model I and II interlaminar fracture toughness. Low-velocity impact tests were performed to investigate the impact resistance of Al/Gf/PP laminates including load traces, failure mechanism, and energy absorption. The results showed that delamination was the main failure mode of two kinds of laminates under the impact energy of 20 J and 30 J. When the impact energy was between 40 J and 50 J, there were metal cracks on the rear surface of the plasma pretreated specimens, which possessed higher energy absorption and impact resistance, although the integrity of the laminates could not be preserved. Since the residual compressive stress was generated during the cooling process, the laminates were more susceptible to stretching rather than delamination. For impact energy (60 J) causing the through-the-thickness crack of two kinds of laminates, plasma pretreated specimens exhibited higher SEA values close to 9 Jm2/kg due to better IPMC. Combined with the FEM simulation results, the interface played a role in stress transmission and specimens with better IPMC enabled the laminates to absorb more energy.


2016 ◽  
Vol 838 ◽  
pp. 29-35
Author(s):  
Michał Landowski ◽  
Krystyna Imielińska

Flexural strength and low velocity impact properties were investigated in terms of possibile improvements due to epoxy matrix modification by SiO2 nanoparticles (1%, 2%, 3%, 5%, 7%wt.) in glass/epoxy laminates formed using hand lay-up method. The matrix resin was Hexion L285 (DGEBA) with Nanopox A410 - SiO2 (20 nm) nanoparticle suspension in the base epoxy resin (DGEBA) supplied by Evonic. Modification of epoxy matrix by variable concentrations of nanoSiO2 does not offer significant improvements in the flexural strength σg, Young’s modulus E and interlaminar shear strength for 1% 3% and 5% nanoSiO2 and for 7% a slight drop (up to ca. 15-20%) was found. Low energy (1J) impact resistance of nanocomposites represented by peak load in dynamic impact characteristics was not changed for nanocompoosites compared to the unmodified material. However at higher impact energy (3J) nanoparticles appear to slightly improve the impact energy absorption for 3% and 5%. The absence or minor improvements in the mechanical behaviour of nanocomposites is due to the failure mechanisms associated with hand layup fabrication technique: (i.e. rapid crack propagation across the extensive resin pockets and numerous pores and voids) which dominate the nanoparticle-dependent crack energy absorption mechanisms (microvoids formation and deformation).


Holzforschung ◽  
2018 ◽  
Vol 72 (8) ◽  
pp. 681-689 ◽  
Author(s):  
Mostafa Mohammadabadi ◽  
Vikram Yadama ◽  
LiHong Yao ◽  
Debes Bhattacharyya

AbstractProfiled hollow core sandwich panels (SPs) and their components (outer layers and core) were manufactured with ponderosa and lodgepole pine wood strands to determine the effects of low-velocity impact forces and to observe their energy absorption (EA) capacities and failure modes. An instrumented drop weight impact system was applied and the tests were performed by releasing the impact head from 500 mm for all the specimens while the impactors (IMPs) were equipped with hemispherical and flat head cylindrical heads. SPs with cavities filled with a rigid foam insulation material (SPfoam) were also tested to understand the change in EA behavior and failure mode. Failure modes induced by both IMPs to SPs were found to be splitting, perforating, penetrating, core crushing and debonding between the core and the outer layers. SPfoams absorbed 26% more energy than unfilled SPs. SPfoams with urethane foam suffer less severe failure modes than SPs. SPs in a ridge-loading configuration absorbed more impact energy than those in a valley-loading configuration, especially when impacted by a hemispherical IMP. Based on the results, it is evident that sandwich structure is more efficient than a solid panel concerning impact energy absorption, primarily due to a larger elastic section modulus of the core’s corrugated geometry.


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 ◽  
Author(s):  
Karmanya Ratra

Carbon fiber bicycle wheels were tested under low velocity impact to monitor the damage evolution of the impact event. A wheel model designed by KQS Inc. (industrial partner) with eight different configurations, including spoke tension, number of spokes, and location of impact on the rim were investigated. IR thermography combined with PCA was used to monitor the damage during impact. Results showed that wheels in line with spokes had 16% higher impact energy absorption compared to those impacted in between spokes on average (58.9 J vs 70.2 J). The 20 spoked wheels had a slightly higher (6%) impact energy absorption than the 24 spoked wheels. The added stiffness due to the extra spokes reduced the impact energy absorption of rim. Wheels with higher spoke tension also had slightly improved impact energy absorption (4%). The test protocol established in this study provides a good understanding of the wheel’s impact damage evolution.


2014 ◽  
Vol 564 ◽  
pp. 406-411
Author(s):  
Parnia Zakikhani ◽  
R. Zahari ◽  
Mohamed Thariq Hameed Sultan

Impact simulation with finite element analysis is an appropriate manner to reduce the cost and time taken to carry out an experimental testing on a component. In this study, the impact behavior of the composite hemispherical shell induced by low velocity impact is simulated in ABAQUS software with finite element method. To predict the responses of Kevlar fabric/polyester, glass fabric/polyester and carbon fabric/polyester in the form of a hemisphere, once as one layer and then as a three-layered composite under applied force by an anvil. The sequences of layers are changed, to investigate and compare the occurred alternations in the amount of energy absorption, impact force and specific energy absorption (SEA). The comparison of results showed that the highest and the lowest quantity of energy absorption and SEA belong to Carbon/Glass/Kevlar (CGK) and Kevlar/Carbon/Glass (KCG) respectively.


CARALL hybrid material has been extensively used in the aircraft structure due to their competitive impact strength. Low velocity impact test is utilized to evaluate the impact and damage properties for such material. It is also employed to observe complex damage mechanisms. A numerical modelling is an alternative way for impact assessment. This paper investigates the impact and damage properties under low velocity impact using numerical modeling and experimental work. A three-dimensional (3D) finite element (FE) model was devolved and validated with two studies from the literature. This model was meshed with solid elements. It was subjected to 2.4 m/s impact velocity and to 10 J impact energy. Absorbed energy, penetration, impact load and damage morphology were obtained. The impact energy was efficiently absorbed by the material. Both aluminum alloy layers underwent plastic deformation whereas the fiber layer failed. A macroscopic cross-sectional morphology was presented using the FE model. An agreement between the numerical and the experiment results were achieved and discussed.


2016 ◽  
Vol 852 ◽  
pp. 23-28
Author(s):  
S. Subha ◽  
Battu Sai Krishna ◽  
Dalbir Singh ◽  
R. Gokulnath

In this study, an attempt has made to explore the low-velocity impact response of a Carbon/epoxy laminate (CFRP) and E-Glass/epoxy laminates (GFRP). The composite was reinforced with Graphene Nanoplatelets (GnPs) and impact energy absorption capacity was studied. The plain GFRP and plain CFRP were served as a baseline for comparison. These composite laminate plates were fabricated using hand layup technique. The tests were carried out on the laminate plate as per ASTM D5628 FD. Impact tests were performed using a specially designed vertical drop-weight testing machine with an impactor mass of 1.926 kg. The result shows that laminate plate reinforced with GnPs reinforcement enhances the impact energy absorption capacity of the composites almost 4.5 % in the case Carbon/epoxy laminate and 3.5 % in the case of and E-glass/epoxy laminate. The enhanced impact resistance could be attributed to increased interlaminar fracture toughness of the fibres.


2017 ◽  
Vol 52 (8) ◽  
pp. 1005-1016 ◽  
Author(s):  
Patryk Jakubczak ◽  
Jarosław Bienias ◽  
Barbara Surowska

The objective of this study was to assess the influence of fibre orientation in hybrid fibre metal laminates based on aluminium and carbon fibres on the impact of low-velocity impact. The analysis was conducted on the basis of fibre metal laminate impact resistance criteria, including impact force, energy absorption, bending stiffness, damage area and failure. To assess the resistance of various aluminium–carbon laminates, qualitative and quantitative evaluation criteria were employed, including the shape of the force–time curve, characteristic impact forces, energy absorption, bending stiffness, damage area and external failure analysis. Among others, authors concluded that no explicit influence of the composite layer fibre orientation on the shape and value of characteristic forces was observed. It was found that the fibre orientation and the changing number of interfaces of low durability show no explicit influence on the size and shape of delaminations.


2021 ◽  
Author(s):  
Karmanya Ratra

Carbon fiber bicycle wheels were tested under low velocity impact to monitor the damage evolution of the impact event. A wheel model designed by KQS Inc. (industrial partner) with eight different configurations, including spoke tension, number of spokes, and location of impact on the rim were investigated. IR thermography combined with PCA was used to monitor the damage during impact. Results showed that wheels in line with spokes had 16% higher impact energy absorption compared to those impacted in between spokes on average (58.9 J vs 70.2 J). The 20 spoked wheels had a slightly higher (6%) impact energy absorption than the 24 spoked wheels. The added stiffness due to the extra spokes reduced the impact energy absorption of rim. Wheels with higher spoke tension also had slightly improved impact energy absorption (4%). The test protocol established in this study provides a good understanding of the wheel’s impact damage evolution.


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