scholarly journals Effect of Harsh Environmental Conditions on the Impact Response of Carbon Composites with Filled Matrix by Cork Powder

2021 ◽  
Vol 11 (16) ◽  
pp. 7436
Author(s):  
Marco P. Silva ◽  
Paulo Santos ◽  
João Parente ◽  
Sara Valvez ◽  
Paulo N. B. Reis
Keyword(s):  
Exposure Time ◽  
Epoxy Matrix ◽  
Mechanical Performance ◽  
Maximum Load ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Wide Range ◽  
Hostile Environments ◽  
The Impact

Composites are used in a wide range of engineering applications, as a result, exposure to hostile environments is rather common and its mechanical properties degradation is unavoidable. It is necessary to have a complete understanding of the impact of hostile environments on mechanical performance, namely critical solicitations as low velocity impacts. Therefore, this work intends to analyse the low velocity impact response of a carbon fibre/epoxy composite, and a similar architecture with an epoxy matrix filled with cork, after immersion into different solutions: diesel, H2SO4, HCl, NaOH, distilled water, seawater, and seawater at 60 °C. These solutions significantly affected the impact properties. In this context, the maximum load, maximum displacement, and restored energy behaviour were studied to understand the influence of exposure time. It was possible to conclude that such impact parameters were significantly affected by the solutions, where the exposure time proved to be determinant. The benefits of cork on the perforation threshold were investigated, and this parameter increased when the epoxy matrix was filled with cork. Finally, cork filled epoxy laminates also show less variation in maximum load and recovered energy than carbon/epoxy laminates.

Effect of Foam Core Density and Facesheet Thickness on the Low Velocity Impact Response of Foam Core Sandwich Composites

2000 ◽  
Author(s):  
M. Motuku ◽  
R. M. Rodgers ◽  
S. Jeelani ◽  
U. K. Vaidya
Keyword(s):  
Impact Energy ◽  
Maximum Load ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Foam Core ◽  
Low Velocity ◽  
Core Density ◽  
Failure Characteristics ◽  
Velocity Impact ◽  
The Impact

Abstract The effect of foam core density and facesheet thickness on the low velocity impact response and damage evolution in homogeneous foam core sandwich composites was studied. The failure characteristics, initiation and evolution of damage as well as the effect of impact energy were investigated. A Dynatup 8210 Impact Test Machine was utilized to conduct the low-velocity impact tests. Characterization of the impact response was performed by comparing the impact load histories, impact plots and failure characteristics. Fractography analysis was conducted through the use of scanning electron microscopy (SEM) and optical microscopy. Three types of foam cores with different densities, namely Airlite B12.5, Rohacell IG-71R63 and Airex R63.5 foam cores, were used to study the effect of core density. Considering four groups of facesheets made of different layers of cross-ply carbon prepregs performed the effect of facesheet thickness. For all the facesheet thicknesses (0.011-0.894-cm thick) and impact energy (11-40 J) range considered in this study, the maximum load (Pm), deflection-at-maximum load (δm) and time-to-maximum load (tm) exhibited strong influence or dependence on the type of foam core as opposed to the facesheet thickness. The energy-to-maximum load (Em), total energy absorbed (Et) and total energy-to-impact energy (Et/Eimp) ratio became less sensitive on the foam core density (or type) with increasing facesheet thickness. A transition point from foam core to facesheet controlled impact behavior as a function of impact energy level was observed. The impact parameters varied either linearly or parabolically with impact energy depending on the impact energy level, type of foam core and facesheet thickness. Excellent repeatability of impact data was generally obtained with increase in foam core density.

Effect of Impact Velocity and Impactor Mass on the Low Velocity Impact Response of Liquid Molding Vinyl Ester-350 Resin and Fiber-Reinforced Plaques

2000 ◽  
Author(s):  
M. Motuku ◽  
U. K. Vaidya ◽  
G. M. Janowski ◽  
G. Basappa ◽  
S. Jeelani
Keyword(s):  
Damage Evolution ◽  
Peak Load ◽  
Maximum Load ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact ◽  
Total Impact ◽  
Impact Duration

Abstract The influence of test conditions on the low velocity impact (LVI) response and damage evolution in neat resin plaques was investigated and documented. Specifically, the effect of impactor mass, velocity, and corresponding impact energy on the LVI response and damage evolution in unreinforced DERAKANE vinyl ester 411-350-resin system was studied. An instrumented drop weigh test machine was used to conduct the low velocity impact tests. The room temperature response of the material to impact loading and damage evolution was investigated using the impact load histories, impact plots and fractography analysis. This study is built upon previous work by the authors on LVI of neat resin systems, particularly those that have emerged as a new class of resins in liquid molding process. The study was motivated by the need for data and understanding of the failure characteristics of the individual constituents of a composite material such as in modeling of damage propagation and failure criteria analysis. For constant impact velocity, the time-to-maximum load (tm), total impact duration (tt), and the energy-to-maximum load to total energy absorbed (Em/Et) ratio increased, and energy absorbed after peak load (Ep) decreased with the mass of the impactor. For constant impactor mass, the time-to-maximum load and total impact duration decreased, the Em/Et ratio remained fairly the same, and energy absorbed after peak load increased with velocity; i.e., the impact velocity and mass had opposing effects on the time-to-maximum load, the total impact duration, Em/Et and energy absorbed after peak load. A single layer of plain-weave S2-glass fabric was incorporated in some of the unreinforced plaques in order to analyze the influence of reinforcement on the impact response and damage evolution. Insertion of a fabric layer aided in containment of the damage within the bounds of the specimen and to isolate the failure characteristics, which enabled further analysis of the impact response and damage evolution.

Characterization and Scaling of Low Velocity Impact Response of Structures With Local Plastic Deformation: Implications for Design

2012 ◽  
Author(s):  
Andreas P. Christoforou ◽  
Ahmet S. Yigit ◽  
Majed Majeed
Keyword(s):  
Boundary Conditions ◽  
Early Stage ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Model Parameters ◽  
Analytical Prediction ◽  
Low Velocity ◽  
Adequate Model ◽  
Wide Range ◽  
The Impact

This paper presents a methodology for the characterization and scaling of response of structures having different shapes, sizes, and boundary conditions that are under impact by blunt objects through a characterization diagram. The diagram is constructed from an analytical functional relationship of the normalized maximum impact force and three non-dimensional parameters, namely the ‘Relative Stiffness’, ‘Relative Mobility,’ and ‘Effective Mass Ratio’. The efficacy of this diagram, which is developed using simple structural models, is demonstrated by FE simulations of more complicated and realistic structures and boundary conditions (clamped, stiffened plates and cylindrical panels). All the necessary parameters needed for characterization are determined using FE models simulating real-world experiments. The characterization method is validated for a wide range of impact parameters that cover the entire dynamic spectrum. It is expected that by determining the model parameters for various engineering structural elements and support conditions, the impact response and subsequent damage may be predicted in an early stage using the characterization diagram. The diagram can also be used to assess the accuracy of simple lumped parameter models and to provide clear guidelines for the choice of an adequate model for a given impact situation. As a result, the characterization diagram and simple models can be used for both the evaluation of finite element and other solutions, and as guides in the design of experiments and in scaling experimental results. The characterization diagram can be used as a powerful analytical prediction tool in various stages of design of complex structures subject to impact such as, initial design, testing and commissioning.

scholarly journals EFFECT OF THE STACKING SEQUENCE ON THE IMPACT RESPONSE OF CARBON-GLASS/EPOXY HYBRID COMPOSITES

2020 ◽  
Vol 18 (1) ◽  
pp. 069
Author(s):  
Hafiz Tauqeer Ali ◽  
Roya Akrami ◽  
Sakineh Fotouhi ◽  
Farzad Pashmforoush ◽  
Cristiano Fragassa ◽  
...  
Keyword(s):  
Hybrid Composites ◽  
Glass Fibers ◽  
Maximum Load ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Stacking Sequence ◽  
Low Velocity ◽  
Impact Performance ◽  
Hybrid Laminates ◽  
The Impact

This paper investigates low-velocity impact response of Quasi Isotropic (QI) hybrid carbon/glass fiber reinforced polymer composites with alternate stacking sequences. Cross-ply woven carbon and glass fibers were used as reinforcing materials to fabricate sandwiched and interlayer hybrid composites. For comparison, the laminates containing only-carbon and only-glass fibers were also studied. Drop weight test was used to impact the samples. The images captured by a normal camera demonstrated that localized damages (delamination) existed within plies. The hybrid laminates had smaller load drops, smaller maximum deflection, and higher maximum load compared to the single fiber laminates. In addition, carbon outside interlayer hybrid laminate showed the highest maximum load and energy absorption, showing the significant dependence of the impact performance on hybridization and stacking sequence. It was concluded that a hybrid composite would help improve impact performance of laminated composites compared to non-hybrid composites if they are properly designed.

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.

Energy absorbed ability and damage analysis for honeycomb sandwich material of bio-inspired micro aerial vehicle under low velocity impact

2020 ◽  
pp. 095440622097542
Author(s):  
Jianxun Du ◽  
Peng Hao ◽  
Mabao Liu ◽  
Rui Xue ◽  
Lin’an Li
Keyword(s):  
Honeycomb Structure ◽  
Low Velocity Impact ◽  
Parameter Study ◽  
Low Velocity ◽  
Micro Aerial Vehicle ◽  
Thin Walled Structures ◽  
Wide Range ◽  
Aerial Vehicle ◽  
Thin Walled ◽  
The Impact

Because of the advantages of light weight, small size, and good maneuverability, the bio-inspired micro aerial vehicle has a wide range of application prospects and development potential in military and civil areas, and has become one of the research hotspots in the future aviation field. The beetle’s elytra possess high strength and provide the protection of the abdomen while being functional to guarantee its flight performance. In this study, the internal microstructure of beetle’s elytra was observed by scanning electron microscope (SEM), and a variety of bionic thin-walled structures were proposed and modelled. The energy absorption characteristics and protective performance of different configurations of thin-walled structures with hollow columns under impact loading was analyzed by finite element method. The parameter study was carried out to show the influence of the velocity of impactor, the impact angle of the impactor and the wall thickness of honeycomb structure. This study provides an important inspiration for the design of the protective structure of the micro aerial vehicle.

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 Impact Analysis of Carbon/Glass/Epoxy Hybrid Composite Pipes

2019 ◽  
Vol 8 (4) ◽  
pp. 6002-6006
Keyword(s):  
Energy Absorption ◽  
Impact Analysis ◽  
Energy Levels ◽  
Maximum Load ◽  
Low Velocity Impact ◽  
Internal Diameter ◽  
Low Velocity ◽  
Glass Carbon ◽  
Composite Pipes ◽  
The Impact

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

Dynamic response of a size-dependent nanobeam to low velocity impact by a nanoparticle with considering atomic interaction forces

2019 ◽  
Vol 233 (18) ◽  
pp. 6640-6655 ◽  
Author(s):  
Mohammad Noroozi ◽  
Majid Ghadiri ◽  
Asghar Zajkani
Keyword(s):  
Nonlocal Parameter ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Strain Gradient Theory ◽  
Atomic Interaction ◽  
Gradient Theory ◽  
Low Velocity ◽  
Velocity Impact ◽  
Size Dependent ◽  
The Impact

In the present paper, low velocity impact response of a size-dependent nanobeam in a thermal field with uniform temperature distribution has been investigated. The van-der Waals interaction force based on description of Lennard–Jonses is considered as the impact force between nanoparticle and nanobeam. According to third-order shear deformation beam theory, the governing equations are obtained using Hamilton's principle based on nonlocal strain-gradient theory. The Galerkin's method was adopted to solve the differential equations of nanobeam with simply supported and clamped boundary conditions. Afterward, the system of time-dependent equations by applying the fourth-order Runge–Kutta method is solved. The parametric study is presented to examine the effect of particle radius, initial velocity, temperature environment, the nonlocal parameter, and the length-scale parameter on the impact response of nanobeam.

Effect of interlayer carbon fiber dispersion on the low-velocity impact performance of woven flax-carbon hybrid composites

2018 ◽  
Vol 53 (12) ◽  
pp. 1717-1734 ◽  
Author(s):  
M Ravandi ◽  
U Kureemun ◽  
M Banu ◽  
WS Teo ◽  
Liu Tong ◽  
...  
Keyword(s):  
Damage Mechanics ◽  
Mechanical Performance ◽  
Hybrid Composites ◽  
Weight Ratio ◽  
Material Behavior ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Fiber Dispersion ◽  
Velocity Impact ◽  
The Impact

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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