scholarly journals Evaluation of the Impact Resistance of Various Composite Sandwich Beams by Vibration Tests

2011 ◽  
Vol 18 (6) ◽  
pp. 789-805 ◽  
Author(s):  
Amir Shahdin ◽  
Joseph Morlier ◽  
Laurent Mezeix ◽  
Christophe Bouvet ◽  
Yves Gourinat
Keyword(s):  
Structural Integrity ◽  
Impact Damage ◽  
Glass Fibers ◽  
Damping Ratio ◽  
Impact Resistance ◽  
Experimental Tests ◽  
Sandwich Beams ◽  
Low Velocity ◽  
Composite Sandwich ◽  
The Impact

Impact resistance of different types of composite sandwich beams is evaluated by studying vibration response changes (natural frequency and damping ratio). This experimental works will help aerospace structural engineer in assess structural integrity using classification of impact resistance of various composite sandwich beams (entangled carbon and glass fibers, honeycomb and foam cores). Low velocity impacts are done below the barely visible impact damage (BVID) limit in order to detect damage by vibration testing that is hardly visible on the surface. Experimental tests are done using both burst random and sine dwell testing in order to have a better confidence level on the extracted modal parameters. Results show that the entangled sandwich beams have a better resistance against impact as compared to classical core materials.

A Smart Polymer Composite for Repeatedly Self-Healing Impact Damage in Fiber Reinforced Polymer (FRP) Vessels

2011 ◽  
Author(s):  
Jones Nji ◽  
Guoqiang Li
Keyword(s):  
Polymer Composite ◽  
Impact Damage ◽  
Glass Fibers ◽  
Shape Memory Polymer ◽  
Impact Resistance ◽  
Three Dimensional ◽  
Polymer Composite Material ◽  
Self Healing ◽  
Repeated Impact ◽  
The Impact

This paper investigated the impact properties of a novel polymer composite material with a potential to repeatedly self-heal impact damage in FRP vessels. The composite was fabricated by first dispersing copolyster thermoplastic particles in a shape memory polymer (SMP) matrix, and then reinforcing the material with three-dimensional (3D) woven glass fibers. Specimens of the reinforced composite with dimensions of 152 mm × 101 mm × 12.7 mm were produced by machining and divided into two groups (G1 and G2). G1 specimens were subjected to several impact/healing test cycles with 42 J of impact energy. G2 specimens were subjected to repeated impact test cycles with no healing at the same energy level. A third group of specimens without thermoplastic particles (G3), with identical dimensions as G2 was also produced and tested in a similar manner as G2 to evaluate the effects of thermoplastic particles on impact resistance. G2 specimens were perforated at the 40th impact while G3 specimens were perforated at the 27th impact. G1 specimens lasted an additional 9 rounds of impact to a total of 49 impacts compared to G2 specimens.

scholarly journals Experimental and numerical study of the response to various impact energy levels for composite sandwich plates with different face thicknesses

2019 ◽  
Vol 21 (5) ◽  
pp. 1654-1682
Author(s):  
Moeen S Rajput ◽  
Magnus Burman ◽  
Fredrik Forsberg ◽  
Stefan Hallström
Keyword(s):  
Impact Energy ◽  
Impact Damage ◽  
Energy Levels ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Absorbed Energy ◽  
Low Velocity ◽  
Composite Sandwich ◽  
The Impact ◽  
Dent Depth

Composite sandwich structures find wide application in the aerospace sector thanks to their lightweight characteristics. However, composite structures are highly susceptible to low-velocity impact damage and therefore thorough characterization of the impact response and damage process for the used material configurations is necessary. The present study investigates the effect of face-sheet thickness on the impact response and damage mechanisms, experimentally and numerically. A uni-directional, non-crimp fabric is used as reinforcement in the face-sheets, and a closed cell Rohacell 200 Hero polymer foam is used as core material. Low-velocity impact tests are performed in a novel instrumented drop-weight rig that is able to capture the true impact response. A range of impact energies are initially utilized in order to identify when low level damage (LLD), barely visible impact damage (BVID) and visible impact damage (VID) occur. A thorough fractography investigation is performed to characterize the impact damage using both destructive and non-destructive testing. The damage from the impacts in terms of dent depth, peak contact force, deflection and absorbed energy is measured. The results show bilinear responses in dent depth vs. impact energy and absorbed energy vs. impact energy. It is found than the BVID energy works well as an indication for the onset of excessive damage. Fractography reveals that there is a failure mode shift between the LLD and the VID energy levels, and that delaminations predominantly grow along the fiber direction and rotate in a spiral pattern through the thickness, following the laminate ply orientations. Finally, a progressive damage finite element model is developed to simulate both the impact response and the delamination extent, incorporating both intra-laminar and inter-laminar damage modes. The simulation shows good agreement with the experiments.

scholarly journals Effect of Uniaxial Fatigue Aging and Fabric Orientation on Low Impact Velocity Response of Glass Fibers/Elium Acrylic Composite Laminates

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4089
Author(s):  
Tomasz Libura ◽  
Rodrigue Matadi Boumbimba ◽  
Alexis Rusinek ◽  
Zbigniew L. Kowalewski ◽  
Tadeusz Szymczak ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Impact Energy ◽  
Composite Structures ◽  
Glass Fibers ◽  
Impact Resistance ◽  
Woven Fabric ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Engineering Structures ◽  
The Impact

Impact resistance is one of the most critical features of composite structures, and therefore, its examination for a new material has a fundamental importance. This paper is devoted to the characterization of the fully recyclable thermoplastic ELIUM acrylic resin reinforced by glass fabric woven, which belongs to a new category of materials requiring advanced testing before their application in responsible elements of engineering structures. Its high strength, low weight as well as low production cost give excellent opportunities for its wide application in the automotive industry as a replacement of the thermoset-based laminates. The study presents an experimental work concerning the effect of damage due to low and high cyclic fatigue aging of two groups of specimens, first with the woven fabric orientations of [0°/90°]4 and secondly with [45°/45°]4, on the low impact velocity properties. The impact resistance was measured in terms of load peak, absorbed energy, penetration threshold and damage analysis. The low velocity impact results indicate that the uniaxial cyclic loading (fatigue aging) of the material leads to the reduction of impact resistance, especially at the high impact energy levels. Scanning Electron Microscopy (SEM) and Computed Tomography (CT) scan observations reveal that the damage area grows with the increase of both strain amplitude and impact energy.

Experimental Research on Dynamics Characteristics and Damage of ALC Wallboard

2012 ◽  
Vol 535-537 ◽  
pp. 1780-1784
Author(s):  
Yan Min Yang ◽  
Hao Zhang
Keyword(s):  
Structural Damage ◽  
Performance Test ◽  
Lightweight Concrete ◽  
Damping Ratio ◽  
Impact Resistance ◽  
Wall Material ◽  
Composite Sandwich ◽  
Building Wall ◽  
Resistance Performance ◽  
The Impact

The new building wall material ALC ( Autoclaved Lightweight Concrete) wallboard is solid composite sandwich panel. The existing standard requires that the ALC wallboard must meet resistance performance when it is laid into the wall. The evaluation index is determined and exists error. In order to guarantee the ALC board has better suitability，and make up the deficiency of the current specification. Through the impact resistance performance test of the ALC wallboard， study the dynamics characteristics under impact loading. Do some further analysis of the ALC wallboard dynamic characteristics damage problems through the change of frequency and the damping ratio. In turn， these changes can be the basis of structural damage evaluation. Laying a foundation for the ALC wallboard can better applied in practical projects.

TEMPERATURE EFFECT OF LOW VELOCITY IMPACT RESISTANCE OF GLASS/EPOXY LAMINATES

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2657-2663 ◽  
Author(s):  
KI-WEON KANG ◽  
HEUNG-SEOB KIM ◽  
TAE-JIN CHUNG ◽  
SEUNG-KEE KOH
Keyword(s):  
Composite Laminates ◽  
Impact Damage ◽  
Testing Machine ◽  
Impact Resistance ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Effect Of Temperature ◽  
Low Velocity ◽  
Damage Resistance ◽  
The Impact

This paper aims to evaluate the effect of temperature on impact damage resistance of glass/epoxy laminates. A series of impact tests were performed using an instrumented impact-testing machine at temperature ranging from -40°C to +80°C. The resulting impact damage was measured using back light method. The impact resistance parameters were employed to understand the damage resistance. It was observed that temperature has a little effect on the impact responses of composite laminates. The damage resistance of glass/epoxy laminates is somewhat deteriorated at two opposite extremes of the studied temperature range and this behavior is likely due to the property change of glass/epoxy laminates under extreme temperatures

Effect of temperature on the low-velocity impact response of environmentally friendly cork sandwich structures

2021 ◽  
pp. 109963622110354
Author(s):  
Claudia Sergi ◽  
Fabrizio Sarasini ◽  
Pietro Russo ◽  
Libera Vitiello ◽  
Enrique Barbero ◽  
...  
Keyword(s):  
Sandwich Structures ◽  
Impact Damage ◽  
Impact Resistance ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Effect Of Temperature ◽  
Low Velocity ◽  
High Performing ◽  
The Impact

Impact events are common in every-day life and can severely compromise the integrity and reliability of high-performing structures such as sandwich composites that are widespread in different industrial fields. Considering their susceptibility to impact damage and the environmental issues connected with their exploitation of synthetic materials, the present work aims to propose a bio-based sandwich structure with an agglomerated cork core and a flax/basalt intraply fabric as skin reinforcement and to address its main weakness, i.e. its impact response. In-service properties are influenced by temperature, therefore the effect of high (60 °C) and low (−40°C) temperatures on the impact behavior of the proposed structures was investigated and a suitable comparison with traditional (polyvinyl chloride) (PVC) foams was provided. The results highlighted the embrittlement effect of decreasing temperature on the impact resistance of the sole cores and skins and of the overall structures with a reduction in the perforation energy that shifted, in the last case, from 50–60 J at – 40 °C up to more than 180 J at 60 °C. A maleic anhydride coupling agent in the skins hindered fundamental energy dissipation mechanisms such as matrix plasticization, determining a reduction in the perforation threshold of all composites. In particular, neat polypropylene (PP) skins displayed a perforation energy of 20 J higher than compatibilized (PPC) ones at 60 °C, while agglomerated cork sandwich structures at 60 °C were characterized by a perforation threshold higher of at least 50 J.

Impact Damage Resistance of Glass/Epoxy Laminates with Embedded Shape Memory Alloy

2007 ◽  
Vol 345-346 ◽  
pp. 1529-1532 ◽  
Author(s):  
Ki Weon Kang ◽  
H.J. Kim ◽  
J.H. Kim ◽  
Heung Seob Kim ◽  
Yong Su Kim ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Impact Damage ◽  
Testing Machine ◽  
Impact Resistance ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Damage Resistance ◽  
The Impact

This paper deals with the damage resistance of glass/epoxy laminates with embedded shape memory alloy (SMA) subjected to low-velocity impact at various temperatures. For this goal, the impact tests were performed by using an instrumented impact-testing machine at three temperatures: +20°C, -10°C and -40°C. And the resultant damages were inspected through the scanning acoustic microscope (SAM). Also, based on the impact force history and the damage configuration, the impact resistance parameters were employed to evaluate damage resistance of laminates with embedded SMA wires. As results, it was found that the damage resistance of glass/epoxy laminates with embedded SMA wires is dependent on the service temperature.

scholarly journals Impact Resistance of Composite Materials under Biaxial Preloading

2011 ◽  
Vol 482 ◽  
pp. 39-48 ◽  
Author(s):  
Christian Garnier ◽  
Toufik Djilali ◽  
Romain Brault ◽  
Sébastien Mistou
Keyword(s):  
Axial Load ◽  
Impact Damage ◽  
Impact Resistance ◽  
Fatigue Loading ◽  
Low Energy ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Low Velocity ◽  
The Impact ◽  
Non Destructive

The first aim of this study is to analyze the impact behavior of pre-loaded composite. Indeed, a bi-axial load is applied to the composite specimen, in order to keep in touch with a real case of composite fuselage. Then, this pre-loaded specimen is impacted by a pendulum. The used energy and velocity are weak in order to be in the case of low-energy and low-velocity impact. The second aim of this study is to develop and design a pendulum device to be integrated to the bi-axial fatigue loading. Moreover, two Non Destructive Inspections (Sonoscan and InfraRed Thermography) is used in order to establish links between pre-load and induced impact damage.

Static and dynamic response of sandwich beams with lattice and pantographic cores

2021 ◽  
pp. 109963622110338
Author(s):  
Yury Solyaev ◽  
Arseniy Babaytsev ◽  
Anastasia Ustenko ◽  
Andrey Ripetskiy ◽  
Alexander Volkov
Keyword(s):  
Mechanical Performance ◽  
Lattice Structure ◽  
Unit Length ◽  
Experimental Tests ◽  
Plane Geometry ◽  
Sandwich Beams ◽  
Static Tests ◽  
Three Point Bending ◽  
The Core ◽  
The Impact

Mechanical performance of 3d-printed polyamide sandwich beams with different type of the lattice cores is investigated. Four variants of the beams are considered, which differ in the type of connections between the elements in the lattice structure of the core. We consider the pantographic-type lattices formed by the two families of inclined beams placed with small offset and connected by stiff joints (variant 1), by hinges (variant 2) and made without joints (variant 3). The fourth type of the core has the standard plane geometry formed by the intersected beams lying in the same plane (variant 4). Experimental tests were performed for the localized indentation loading according to the three-point bending scheme with small span-to-thickness ratio. From the experiments we found that the plane geometry of variant 4 has the highest rigidity and the highest load bearing capacity in the static tests. However, other three variants of the pantographic-type cores (1–3) demonstrate the better performance under the impact loading. The impact strength of such structures are in 3.5–5 times higher than those one of variant 4 with almost the same mass per unit length. This result is validated by using numerical simulations and explained by the decrease of the stress concentration and the stress state triaxiality and also by the delocalization effects that arise in the pantographic-type cores.

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