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 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.

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.

Theoretical and experimental analysis for the impact response of glass fibre reinforced aluminium honeycomb sandwiches

2016 ◽  
Vol 20 (1) ◽  
pp. 42-69 ◽  
Author(s):  
Vincenzo Crupi ◽  
Emre Kara ◽  
Gabriella Epasto ◽  
Eugenio Guglielmino ◽  
Halil Aykul
Keyword(s):  
Experimental Data ◽  
Sandwich Structures ◽  
Low Velocity Impact ◽  
Balance Model ◽  
Model Parameters ◽  
Low Velocity ◽  
Internal Damage ◽  
Limit Loads ◽  
Load Carrying ◽  
The Impact

Honeycomb sandwich structures are increasingly used in the automotive, aerospace and shipbuilding industries where fuel savings, increase in load carrying capacity, vehicle safety and decrease in gas emissions are very important aspects. The aim of this study was to develop the theoretical methods, initially proposed by the authors and by other researchers for the prediction of low-velocity impact responses of sandwich structures. The developed methods were applied to sandwich structures with aluminium honeycomb cores and glass-epoxy facings for the assessment of impact parameters and for the prediction of limit loads. The values of model parameters were compared with data reported in literature and the predictions of the limit loads were validated by means of the experimental data. Good achievement was obtained between the results of the theoretical models and the experimental data. The failure mode and the internal damage of the sandwich panels have been investigated using 3D computed tomography, which allowed the evaluation of parameters of energy balance model, and infrared thermography, which allowed the detection of the temperature evolution of the specimens during the tests. The experimental and theoretical results demonstrated that the use of glass-epoxy reinforcement on aluminium honeycomb sandwiches enhances the energy absorption and load carrying capacities.

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.

scholarly journals Numerical Modelling of Ballistic Impact Response at Low Velocity in Aramid Fabrics

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2087 ◽  
Author(s):  
Norberto Feito ◽  
José Antonio Loya ◽  
Ana Muñoz-Sánchez ◽  
Raj Das
Keyword(s):  
Numerical Model ◽  
Mechanistic Model ◽  
Computation Time ◽  
Impact Angle ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Computational Time ◽  
Low Velocity ◽  
Aramid Fabrics ◽  
The Impact

In this study, the effect of the impact angle of a projectile during low-velocity impact on Kevlar fabrics has been investigated using a simplified numerical model. The implementation of mesoscale models is complex and usually involves long computation time, in contrast to the practical industry needs to obtain accurate results rapidly. In addition, when the simulation includes more than one layer of composite ply, the computational time increases even in the case of hybrid models. With the goal of providing useful and rapid prediction tools to the industry, a simplified model has been developed in this work. The model offers an advantage in the reduced computational time compared to a full 3D model (around a 90% faster). The proposed model has been validated against equivalent experimental and numerical results reported in the literature with acceptable deviations and accuracies for design requirements. The proposed numerical model allows the study of the influence of the geometry on the impact response of the composite. Finally, after a parametric study related to the number of layers and angle of impact, using a response surface methodology, a mechanistic model and a surface diagram have been presented in order to help with the calculation of the ballistic limit.

The Effect of the Impactor Diameter and Boundary Conditions on Low Velocity Impact Composites Behaviour

2007 ◽  
Vol 7-8 ◽  
pp. 217-222 ◽  
Author(s):  
Ana M. Amaro ◽  
Paulo N.B. Reis ◽  
A.G. Magalhães ◽  
Marcelo F.S.F. de Moura
Keyword(s):  
Boundary Conditions ◽  
Damage Model ◽  
Testing Machine ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Energies ◽  
The Impact

The aim of present work is to study the influence of the impactor diameter and boundary conditions on low velocity impact on carbon-fibre-reinforced epoxy laminates. Experimental tests were performed on [04,904]s laminates, using a drop weight-testing machine. Circular plates were tested under low velocity impacts for two diameters of the hemispherical impactor, 12.7 mm and 20 mm, and considering similar impact energies, 2.6 J for the first impactor and 3 J for the second one. Rectangular and square plates were analysed under low velocity impacts with different boundary conditions. The impacted plates were inspected by X-radiography. Numerical simulations were also performed considering interface finite elements compatible with three-dimensional solid elements including a cohesive mixed-mode damage model, which allows to model delamination between layers. The impact tests showed that both the impactor’s diameter and boundary conditions have influence on the delaminated area. Good agreement between experimental and numerical analysis for shape, orientation and size of damage was obtained.

Multi-layer polymer beam reinforced by graphene platelets on low velocity impact response

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammed Salih Hassan ◽  
Haideer Taleb Shomran ◽  
Abbas Allawi Abbas ◽  
Bashar Dheyaa Hussein Al-Kasob ◽  
Manar Hamid Jasim ◽  
...  
Keyword(s):  
Contact Force ◽  
Separation Of Variables ◽  
Weight Fraction ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Conservation Of Energy ◽  
Content Type ◽  
Graphene Platelets ◽  
The Impact

Purpose The purpose of this paper is to investigate the effect of graphene platelets (GPLs) on the low-speed contact between a mass and surface of a multi-layer polymer beam. Design/methodology/approach This problem is primarily organized by first-order shear deformation beam theory and nonlinear Hertz rule. GPLs are distributed along the beam thickness direction. The Halpin–Tsai micromechanics model is applied for computing the effective Young’s modulus of the GPLs/polymer composites. In the formulation process, the principle of conservation of energy is first used and the histories of results are extracted using the separation of variables and Runge–Kutta method. Findings In comparing the responses with the available data, a good agreement is observed. The effects of the weight fraction and distribution pattern on the impact response of polymer beam reinforced with GPLs are studied. Results show that contact force is increased, contact time and beam recess are decreased with increasing of weight fraction of GPLs. Also, among the different distribution patterns, the contact force depended on value of GPLs at the point of contact. Originality/value The effects of GPLs addition on the multi-layer polymer beam has a novelty in impact problems.

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.

scholarly journals Impactor Shape Effect on Low Velocity Impact Response of Woven Glass Epoxy Composites

2012 ◽  
Vol 21 (5) ◽  
pp. 096369351202100 ◽  
Author(s):  
Bulent Murat Icten ◽  
Binnur Gören Kıral
Keyword(s):  
Energy Levels ◽  
High Energy ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Shape Effect ◽  
Test Machine ◽  
Low Velocity ◽  
Impact Characteristics ◽  
The Impact ◽  
Maximum Contact

This study deals with the effect of impactor shape on the impact response of plain woven glass-epoxy laminates. Impact tests were performed by using Fractovis Plus test machine with seven different impactor noses grouped as hemispherical, conical and flat. Specimens were impacted at low (5 J) to high energy levels (45 J) enough to obtain perforation of the composite at the room temperature. Variation of the impact characteristics such as maximum contact load, maximum deflection, total contact time and absorbed energy versus impact energy are depicted in Figs. Results indicated that the projectile shape highly affects the impact response of composite materials.

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