Energy-Absorbing Capacity of Polyurethane/SiC/Glass-Epoxy Laminates Under Impact Loading

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
G. Balaganesan ◽  
V. Akshaj Kumar ◽  
V. C. Khan ◽  
S. M. Srinivasan
Keyword(s):  
Energy Absorption ◽  
Impact Loading ◽  
Composite Laminate ◽  
Failure Modes ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Fiber Failure ◽  
The Impact ◽  
Layered Target

This paper presents the energy absorption of target materials with combinations of polyurethane (PU) foam, PU sheet, SiC inserts, and SiC plate bonded to glass fiber reinforced composite laminate backing during impact loading. SiC inserts and SiC plates are bonded as front layer to enhance energy absorption and to protect composite laminate. The composite laminates are prepared by hand lay-up process and other layers are bonded by using epoxy. Low-velocity impact is conducted by using drop mass setup, and mild steel spherical nosed impactor is used for impact testing of target in fixed boundary conditions. Energy absorption and damage are compared to the target plates when subjected to impact at different energy levels. The energy absorbed in various failure modes is analyzed for various layers of target. Failure in the case of SiC inserts is local, and the insert under the impact point is damaged. However, in the other cases, the SiC plate is damaged along with fiber failure and delamination on the composite backing laminate. It is observed that the energy absorbed by SiC plate layered target is higher than SiC inserts layered target.

Low Velocity Impact Behavior of SiC/PU/GFRP Laminates

2016 ◽  
Vol 725 ◽  
pp. 122-126 ◽  
Author(s):  
Kumar V. Akshaj ◽  
Chandra Khan Vishwas ◽  
G. Balaganesan ◽  
M.S. Sivakumar
Keyword(s):  
Energy Absorption ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Low Velocity ◽  
Fiber Failure ◽  
Velocity Impact ◽  
Drop Mass ◽  
Set Up ◽  
The Impact

This paper discusses the energy absorption during low velocity impact on target with combinations of PU foam, SiC inserts/plate bonded to GFRP composite backing. SiC inserts and SiC plates are bonded as front layer to enhance energy absorption. Low velocity impact is conducted by using drop mass set-up and mild steel spherical nosed impactor is used for impact testing of target in fixed boundary conditions. Failure in the case of SiC inserts is local as only the insert under the impact is damaged and nearby areas are intact. However, in the other cases, the SiC plate is damaged along with fiber failure and delamination on the composite backing layer. It is observed that the energy absorbed by SiC plate is higher than that absorbed by SiC inserts layered target.

Low-velocity impact response of wood-strand sandwich panels and their components

Holzforschung ◽  
2018 ◽  
Vol 72 (8) ◽  
pp. 681-689 ◽  
Author(s):  
Mostafa Mohammadabadi ◽  
Vikram Yadama ◽  
LiHong Yao ◽  
Debes Bhattacharyya
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Failure Modes ◽  
Sandwich Panels ◽  
Low Velocity Impact ◽  
Insulation Material ◽  
Low Velocity ◽  
Velocity Impact ◽  
Section Modulus ◽  
The Impact

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.

Peridynamic modeling of low-velocity impact damage in laminated composites reinforced with z-pins

2018 ◽  
Vol 52 (25) ◽  
pp. 3491-3508 ◽  
Author(s):  
Forrest Baber ◽  
Vipul Ranatunga ◽  
Ibrahim Guven
Keyword(s):  
Failure Modes ◽  
Impact Damage ◽  
Impact Testing ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Identification Algorithm ◽  
Low Velocity ◽  
New Approach ◽  
Velocity Impact ◽  
The Impact

In this study, a new approach for predicting damage and specific failure modes in laminated fiber reinforced composites is presented. The new method is based on the peridynamic theory and models individual plies, and represents fiber and matrix materials in each ply explicitly. These features enable analysis of laminates with arbitrary fiber orientation in a convenient manner. Additionally, a new failure mode identification algorithm has been developed and implemented. Instead of the conventional peridynamic damage parameter, the new algorithm works with individual broken bonds, which makes identification of different failure modes including matrix cracking, fiber breakage, and delamination straight-forward and unambiguous. The new peridynamic approach is demonstrated by considering the low-velocity impact damage on composite laminates with and without translaminar reinforcements. The translaminar reinforcement technique considered in this study is z-pinning; two different geometric configurations of z-pins are explored. The impact testing and the post-impact nondestructive evaluations with ultrasonic c-scans are performed at the Air Force Research Laboratory to characterize the delaminations. The impact tests on different samples are simulated using the current peridynamic approach. The predicted impact damage failure modes are compared against the experimental measurements. The new approach is shown to capture low-velocity impact damage both quantitatively and qualitatively.

Response and failure modes of biaxial warp-knitted flexible composite subject to low-velocity impact

2021 ◽  
pp. 152808372110154
Author(s):  
Ziyu Zhao ◽  
Tianming Liu ◽  
Pibo Ma
Keyword(s):  
Impact Energy ◽  
Linear Density ◽  
Failure Modes ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Minor Effect ◽  
Low Velocity ◽  
Velocity Impact ◽  
Flexible Composites ◽  
The Impact

In this paper, biaxial warp-knitted fabrics were produced with different high tenacity polyester linear density and inserted yarns density. The low-velocity impact property of flexible composites made of polyurethane as matrix and biaxial warp-knitted fabric as reinforcement has been investigated. The effect of impactor shape and initial impact energy on the impact response of flexible composite is tested. The results show that the initial impact energy have minor effect on the impact response of the biaxial warp-knitted flexible composites. The impact resistance of flexible composite specimen increases with the increase of high tenacity polyester linear density and inserted yarns density. The damage morphology of flexible composite materials is completely different under different impactor shapes. The findings have theoretical and practical significance for the applications of biaxial warp-knitted flexible composite.

Low Velocity Impact Resistance of CPVC Pipes Exposed to Natural Outdoor Weathering Conditions

2012 ◽  
Vol 445 ◽  
pp. 959-964
Author(s):  
Z. Khan ◽  
Necar Merah ◽  
A. Bazoune ◽  
S. Furquan
Keyword(s):  
Impact Resistance ◽  
Outdoor Exposure ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Pipe Material ◽  
Low Velocity ◽  
Impact Energies ◽  
The Impact ◽  
Impact Events ◽  
Outdoor Weathering

Low velocity drop weight impact testing of CPVC pipes was conducted on 160 mm long pipe sections obtained from 4-inch (100 mm) diameter schedule 80 pipes. Impact test were carried out for the base (as received) pipes and after their exposure to out door natural weathering conditions in Dhahran, Saudi Arabia. The results of the impact testing on the natural (outdoor exposure) broadly suggest that the natural outdoor exposures produce no change in the impact resistance of CPVC pipe material for the impact events carrying low incident energies of 10 and 20J. At the impact energies of 35 and 50J the natural outdoor exposures appear to cause appreciable degradation in the impact resistance of the CPVC pipe material. This degradation is noted only for the longer exposure periods of 12 and 18 months.

Low Velocity and Compression-After-Impact Response of Pin-Reinforced Sandwich Composites

1999 ◽  
Author(s):  
Uday K. Vaidya ◽  
Mohan V. Kamath ◽  
Mahesh V. Hosur ◽  
Anwarul Haque ◽  
Shaik Jeelani
Keyword(s):  
Impact Testing ◽  
Low Velocity Impact ◽  
Sandwich Composites ◽  
Low Velocity ◽  
Static Compression ◽  
Velocity Impact ◽  
Transverse Stiffness ◽  
Impact Studies ◽  
Compression After Impact ◽  
The Impact

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.

Effect of SiO2 Nanoparticles on the Mechanical and Low Velocity Impact Properties of Epoxy/Glass Composites

2016 ◽  
Vol 838 ◽  
pp. 29-35
Author(s):  
Michał Landowski ◽  
Krystyna Imielińska
Keyword(s):  
Flexural Strength ◽  
Energy Absorption ◽  
Impact Energy ◽  
Epoxy Matrix ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Nanoparticle Suspension ◽  
Impact Properties ◽  
Velocity Impact ◽  
The Impact

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).

scholarly journals Mechanical Behavior of Entangled Metallic Wire Materials under Quasi-Static and Impact Loading

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3392 ◽  
Author(s):  
Yiwan Wu ◽  
Lei Jiang ◽  
Hongbai Bai ◽  
Chunhong Lu ◽  
Shangzhou Li
Keyword(s):  
Energy Absorption ◽  
Impact Loading ◽  
Absorption Rate ◽  
Maximum Load ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Metallic Wire ◽  
Maximum Deformation ◽  
Air Damping ◽  
Stiffness And Damping

In this paper, the stiffness and damping property of entangled metallic wire materials (EMWM) under quasi-static and low-velocity impact loading were investigated. The results reveal that the maximum deformation of the EMWM mainly depends on the maximum load it bears, and that air damping is the main way to dissipate impact energy. The EMWM can absorb more energy (energy absorption rate is over 60%) under impact conditions. The EMWM has excellent characteristics of repetitive energy absorption.

scholarly journals Ultrasonic Analysis of Damage in CFRP Resulting from Static Indentation and Low Velocity Impact

1993 ◽  
Vol 2 (3) ◽  
pp. 096369359300200
Author(s):  
H. Kaczmarek
Keyword(s):  
Impact Testing ◽  
Low Velocity Impact ◽  
Ultrasonic Tomography ◽  
Transverse Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Testing Procedures ◽  
Damage Initiation ◽  
Static Indentation ◽  
The Impact

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.

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