Low-Velocity Impact Response of Discontinuous Kirigami Cruciform Sandwich Panel

2019 ◽  
Vol 11 (05) ◽  
pp. 1950046 ◽  
Author(s):  
Caihua Zhou ◽  
Chaoxiang Xia ◽  
Shizhao Ming ◽  
Xiangjun Bi ◽  
Tong Li

Cruciform structures have desirable energy absorption capacity. However, the engineering application is limited by the difficulties in the manufacturing process. In this paper, a kirigami approach is introduced to simplify the manufacturing process. Based on the kirigami strategy, a structure referred to as a discontinuous kirigami cruciform sandwich panel (DKC), is investigated to validate the mechanical performance in energy absorption. Experiments and numerical simulations were carried out to investigate the impact resistance of DKC under four levels of impact energy and the energy–absorption performance is evaluated by comparing to a typical energy–absorption device, pyramidal truss sandwich panel (PT). In order to reduce the initial impact force and the displacement of the bottom surface on the protected objective, the DKC is further optimized by introducing an additional cutout at the opposite end in each component plate. With the new design, the displacement of the bottom surface on the sandwich structure is reduced by 13.9%, together with a decrease of impact peak force and an increase of energy absorption.

2018 ◽  
Vol 22 (4) ◽  
pp. 929-947 ◽  
Author(s):  
LL Yan ◽  
B Yu ◽  
B Han ◽  
QC Zhang ◽  
TJ Lu ◽  
...  

In this study, a closed-cell aluminum foam was filled into the interspaces of a sandwich panel with corrugated cores to form a composite structure. The novel structure is expected to have enhanced foam-filled cores with high specific strength and energy absorption capacity. An out-of-plane compressive load under low-velocity impact was experimentally and numerically carried out on both the empty and foam-filled sandwich panels as well as on the aluminum foam. It is found that the empty corrugated sandwich panel has poor energy absorption capacity due to the core member buckling compared to that of the aluminum foam. However, by the filling of the aluminum foam, the impact load resistance of the corrugated panel was increased dramatically. The loading-time response of the foam-filled panel performs a plateau region like the aluminum foam, which has been proved to be an excellent energy absorption material. Numerical results demonstrated that the aluminum foam filling can decrease the corrugated core member defects sensitivity and increase its stability dramatically. The plastic energy dissipation of the core member for the foam-filled panel is much higher than that of the empty one due to the reduced buckling wavelength caused by the aluminum foam filling.


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.


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.


Author(s):  
Joseph M. Gattas ◽  
Zhong You

Honeycomb core sandwich shells are used for many applications, but available unit architectures and global curvatures are limited. Numerous origami-core sandwich shells, known as foldcores, have been proposed as alternatives, but studies into their mechanical performance are few. This paper conducts a preliminary investigation into the impact resistance and energy absorption of single-curved foldcore sandwich shells that utilise Miura-derivative patterns as their core geometry. A numerical analysis on three Miura-derivative core patterns, the Arc-Miura (AM), Non-Developable Miura (ND), and Non-Flat Foldable Miura (NF) patterns, shows that ND and AM-type shells have similar impact resistance to each other, and superior impact resistance to NF-type shells. Prototypes of aluminium ND and AM-type foldcores are constructed and used to validate numerical models. Numerical models were then used to draw comparisons with an over-expanded honeycomb (OX-core) sandwich shell. It was seen that the OX-core had a better energy absorption capacity than either of the foldcores. However the AM-type foldcore possessed superior initial strength, and the ND-type possessed superior response uniformity, attributes that might be exploitable with future research. A brief parametric study on ND-type shells suggested that in general, for a given design radius and density, a foldcore shell configuration with a lower unit cell area-to-height ratio will have a higher energy absorption capability.


2017 ◽  
Vol 21 (6) ◽  
pp. 2127-2153 ◽  
Author(s):  
Zohreh Asaee ◽  
Farid Taheri

The main objective of the present study is to examine the level of enhancement in performance of three-dimensional fiber metal laminates (3DFML) under low velocity impact, when reinforced by different types of reinforcing face-sheets (i.e. fiberglass or carbon). Three layup configurations of the fabrics are considered in this investigation. The impact response of each of these configurations is assessed numerically using ABAQUS/Explicit, a commercially available finite element software. Specifically, each configuration’s impact capacity, deformation, contact time, and energy absorption capacity are evaluated. The numerical results are validated by comparison against experimental results. Moreover, a semi-empirical equation is developed for evaluating the impact capacity of such panels, as a function of impact energy, capable of accounting the influence of any type of reinforcement. Finally, the most efficient reinforced three-dimensional fiber metal laminates are identified based on their impact strength with respect to their overall weight and cost.


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.


2019 ◽  
Vol 8 (4) ◽  
pp. 6002-6006

Filament winded composite pipes are used in various environments conditions for different applications. In this study filament winded hybrid (Glass/Carbon/Epoxy) composite pipes with interwoven (CG90/CG60) orientation were tested under various low velocity impact conditions for two different thickness. Internal diameter as 50 mm with various thicknesses such as 4 mm, 6mm are used to study the effect of impact. The impact test conducted at three different energy levels as 20 J, 25 J and 30 J. Effect of impact on these pipes were measured by the comparison of energy absorption, force and deformation values. The results shows that increasing thickness of specimens increase maximum load carrying capacity and reduces the energy absorption and deformation of impacted specimens


2018 ◽  
Vol 53 (12) ◽  
pp. 1717-1734 ◽  
Author(s):  
M Ravandi ◽  
U Kureemun ◽  
M Banu ◽  
WS Teo ◽  
Liu Tong ◽  
...  

This work investigates the effects of interlayer hybrid fiber dispersion on the impact response of carbon-flax epoxy hybrid laminates at low carbon volume fractions, and benchmarks the mechanical performance enhancement against the non-hybrid flax epoxy. Five hybrid laminate stacking sequences with similar carbon-to-flax weight ratio were fabricated and subjected to low-velocity impact at three different energy values, generating non-perforated and perforated damage states. A virtual drop-weight impact test that models intralaminar failure based on continuum damage mechanics approach, and delamination using cohesive elements, was also implemented to evaluate the material behavior and damage development in the composites. Simulation results were then verified against experimental data. Results suggested that positioning stiffer carbon plies at the impact face does not necessarily lead to enhancement of the hybrid's impact properties. On the contrary, flax plies at the impacted side lead to significant improvement in impact resistance compared to the non-hybrid flax composite with similar thickness. Results of finite element analysis showed that carbon plies play a significant role in the hybrid laminate's energy absorption characteristics due to lower failure strain.


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