High Velocity Impact Loading Research Articles

Effect of High-Velocity Impact Loading on Concrete Slabs Reinforced by Metallic Strips from Soft Drink Cans as Fiber

Effect of High-Velocity Impact Loading on Concrete Slabs Reinforced by Metallic Strips from Soft Drink Cans as Fiber

Optimizing an auxetic metamaterial structure for enhanced mechanical energy absorption: Design and performance evaluation under compressive and impact loading

Auxetic metamaterials, characterized by their negative Poisson’s ratio, offer promising prospects for utilization in absorbing energy during quasi-static compressive loading as well as in applications requiring impact energy absorption. The optimization of auxetic structures’ geometrical parameters can improve their performance. This research aims to optimize the design of an auxetic structure for maximum specific energy absorption and investigate its behavior under quasi-static compressive and high-velocity impact loading. The geometrical parameters of the cross-petal auxetic structure are optimized using genetic algorithm and a neural network surrogate model. The behavior of the optimized auxetic structure is examined in quasi-static compressive loading and compared with that of the basic auxetic structure using finite element simulations. The optimized auxetic structure is then evaluated in high-velocity impact loading as the core of a sandwich panel, with two plates placed in the front and rear. Simulations of projectile impacts at velocities ranging from 100 to 250 m/s reveal the sandwich panel’s behavior. Results indicate a 69.82% increase in specific energy absorption capacity for the optimized auxetic structure as compared to the basic structure in quasi-static compressive loading. In high-velocity impact, the sandwich panel with the optimal auxetic core outperforms the one with the basic core. At velocities more than the minimum perforation velocity, the core contributes about 64%–67% of the total absorbed energy by the sandwich panel.

Enhancement of the impact resistance of masonry walls using fiber-reinforced polymer composites

Many civilian structures are masonry ones. However, masonry walls are susceptible to impact loading. Despite the vulnerability, research on enhancing the impact resistance of masonry walls is substantially scarce, especially under high-velocity impact. Hence, in this study, the effect of fiber-reinforced polymer (FRP) composites on the impact resistance of masonry walls was numerically investigated, especially considering high-velocity impact loading. For this purpose, finite element analysis (FEA) was implemented deploying LS-DYNA. In modeling, the Add Erosion and the Smooth Particle Hydrodynamics options were employed to effectively represent impact behaviors of masonry walls subject high-velocity impact loading. Firstly, the developed masonry wall models were validated by comparing the numerical results with experimental ones. Using the verified numerical models, various parametric studies were performed. The main parameters were the directions and types of fiber, different velocities of an impactor, and the number of impactors. Based on the study, the near-surface-mounted (NSM) FRP method was found to be inefficient in improving the impact resistance of masonry walls. Although the externally-bonded (EB) FRP technique was more effective than the NSM FRP one, the impact behavior varied depending on the types and number of FRP. For instance, strengthening a masonry wall using one layer of high-modulus carbon FRP (HCFRP) EB sheet resulted in the perforation of the HCFRP sheet due to the low ultimate strain of HCFRP sheet. Although one layer of standard CFRP (SCFRP) EB sheet was effective to prevent a masonry wall from being perforated against one impactor, the strengthened masonry wall was penetrated by multiple impactors. It was found that two woven SCFRP EB sheets were optimum to evade the perforation of masonry walls subject to high-velocity impact loading. Furthermore, equations for correlations between the maximum impact force and impact energy are proposed.

Comparative Performance of Kevlar, Glass and Basalt Epoxy- and Elium-Based Composites under Static-, Low- and High-Velocity Loading Scenarios-Introduction to an Effective Recyclable and Eco-Friendly Composite.

In general, the majority of fiber-reinforced polymer composites (FRPs) used in structural applications comprise carbon, glass, and aramid fibers reinforced with epoxy resin, with the occasional utilization of polyester and vinyl ester resins. This study aims to assess the feasibility of utilizing recyclable and sustainable materials to create a resilient composite suitable for structural applications, particularly in scenarios involving low-velocity and high-velocity impact (LVI, HVI) loading. The paper presents a comparative analysis of the performance of E-glass, aramid, and eco-friendly basalt-reinforcing fabrics as reinforcement fibers in both thermosetting (epoxy) and recyclable thermoplastic (Elium©) resins. Given the limited research on Elium composites, especially those incorporating basalt-reinforcing fiber, there is an urgent need to expand the databases of fundamental mechanical properties for these diverse composites. This necessity is exacerbated by the scarcity of the literature regarding their performance under low- and high-velocity impact loadings. The results of this study will demonstrate the potential of basalt-reinforced Elium composite as an effective recyclable and environmentally friendly structural material system for both static and dynamic loading conditions.

Dynamic analysis of bird strike effect on the polymeric composite fuselage nose

A collision with a bird while in flight poses a substantial hazard to the structural integrity of aircraft. Due to these collisions, the damage occurs in the aircraft mostly in the engines, windshields, nose part, wing leading edges and other components. Reduction of bird impact is possible by carrying out suitable design and analysis using mathematical modelling and simulations. Hence, the focus of this numerical study is to analyze the high velocity impact loads from soft body projectiles on the composite structures using dynamic analysis. The analysis is carried out using LS-DYNA software. The nose part is considered as deformed target while the bird is assumed fluid during impact. The temporal pressure variations is measured on the curved plate using dynamic analysis for different bird velocities namely, 50 m/s, 100 m/s, 150 m/s, 200 m/s and 250 m/s with a nose cone thickness of 3 mm. Lagrangian method is used for finding temporal pressure variation. An increase in impact velocity of the impactor increases the impact pressure of the fuselage nose cone with respect to time.

Development of a new progressive damage model for woven fabric composites

There is no native support for the modeling of woven fabric composites within Abaqus. A new approach has been implemented within Abaqus, which is shown to be robust and capable of modeling woven composites across a range of loading conditions. This approach predicted the bending modulus and displacement at failure of woven carbon-fiber composites under three-point bending within the standard deviation of experimental results. Under high-velocity impact loading, the critical perforation velocity of woven aramid panels was predicted to within 3% of the experimental results, while the back face deformation to within the experimental error.

Numerical and experimental validation of fiber metal laminate structure for lithium-ion battery protection subjected to high-velocity impact loading

A novel structural protection based on fiber metal laminate (FML) was developed for a lithium-ion battery module to address ground impact issues in electric vehicles (EVs). To verify the battery structural protection and for experimental validation, a new high-velocity impact test methodology was proposed. FML was selected for its high strength-to-weight ratio. The design implemented was the optimum configuration identified in a prior study. Finite element models comprising FML and lithium iron phosphate batteries were developed. The numerical simulation results, which correlated well with the experiments, enabled observation of the perforation process and failure modes of the FML. In the experiment, the safety valve of the center battery in the module experienced a compression of 3.28 mm. Despite this deformation, the FML effectively protected the lithium-ion batteries, as evidenced by the stable battery voltage during the high-velocity impact test.

Poly(Ionic Liquid) Double-Network Elastomers with High-Impact Resistance Enhanced by Cation-π Interactions.

With the continuous development of impact protection materials, lightweight, high-impact resistance, flexibility, and controllable toughness are required. Here, tough and impact-resistant poly(ionic liquid) (PIL)/poly(hydroxyethyl acrylate) (PHEA) double-network (DN) elastomers are constructed via multiple cross-linking of polymer networks and cation-π interactions of PIL chains. Benefiting from the strong noncovalent cohesion achieved by the cation-π interactions in PIL chains, the prepared PIL DN elastomers exhibit extraordinary compressive strength (95.24 ± 2.49MPa) and toughness (55.98 ± 0.66MJ m-3) under high-velocity impact load (5000 s-1). The synthesized PIL DN elastomer combines strength and flexibility to protect fragile items from impact. This strategy provides a new research idea in the field of the next generation of safety and protective materials.

Numerical investigation on the high-velocity impact resistance of textile reinforced composite mesh designs inspired by spider web

The need for thin and highly deformable textile reinforcements is constant in sectors like thin composites, catching nets, and complex construction designs (like dome-shape). The conventional rectangular-patterned meshed wovens are used in thin composite structures as reinforcement at the commercial level. These woven textiles are bidirectional and exhibit approximately the same strength along both axes. However, these conventional rectangular-patterned mesh designs show poor impact stress distribution capacity. Interestingly, very thin and fine mesh designs are available in nature. One such example is the spider web structure. These structures have evolved with time and optimised their mesh pattern design for better impact damage resistance and load transfer. In this study, the basalt fibre reinforced mortar textile composites are considered for the investigation due to their growing interest in civil and construction applications. To demonstrate how the mesh geometry in textiles significantly influences the stress transfer, energy absorption, and deformation of reinforcements under various impact situations, three different geometries, (a) square shape mesh, (b) diamond-shaped mesh, and (c) bio-inspired spider web mesh, are modelled and meshed based on the reference geometry’s meshing pattern and dimensions. The results of numerical simulations show that a meshed reinforcement design inspired by spider-orb-web has improved mechanical features compared to conventional square and diamond shape mesh designs under high velocity impact loading.

Frequency domain analyses of low-velocity impact loading of elastomeric foams

Frequency analyses can reveal spectral features otherwise concealed within the time domain data. Such analyses are imperative to gain more insights into the undergoing dynamics in structures and materials, especially those with strong time dependence, such as elastomeric foams. This study aims to extend the applicability to data analysis from low-velocity impact scenarios by transforming into the frequency-domain, concurrently reporting crucial attributes of the dynamic loading and materials properties. Elastomeric polyurea foams with different densities were impacted at four different energies, ranging from 1.71 J to 7.09 J, to simulate low-velocity impact scenarios relevant to dynamic loading at different strain rates. In each impact test, a flattop drop mass was released from a preset height to control the impact velocity and energy while recording the impact and transmitted forces using impactor-mounted and base-mounted force sensors. The time-domain data of the primary impact was transformed into the frequency-domain using fast Fourier analysis. In the transformed domain, impact scenario characteristics, including acceleration and strain rate, and viscoelastic properties, i.e., storage and loss moduli, were extracted and benchmarked to time domain results. The impact characteristics agreed with previous reports based on time domain analysis while revealing the frequency-dependence of the acceleration and strain rate on the foam density and impact energy. The extracted viscoelastic properties were also in reasonable agreement with previously reported properties while consistent with linear viscoelastic principles. The robustness of the demonstrated method unlocks the potential for more in-depth data analysis from other dynamic mechanical experimental setups, including high-velocity impact and shock loading.

Structural Performance of Ferrocement Panels under Low- and High-Velocity Impact Load.

The primary objective of this experimental study is to examine the response and energy absorption capacity of ferrocement panels exposed to low- and high-velocity impact loads. The panels are reinforced with two different types of mesh layers, namely, welded wire grid (WWG) and expanded wire grid (EWG), with varying percentages of steel fibers (SF). The ferrocement panel system is made up of cement mortar reinforced with 0-2% SF with an increment of 1% and wire grid layers arranged in three different layers 1, 2, and 3. A consistent water-cement ratio (w/c) of 0.4 is maintained during mortar preparation, and all panels are subjected to a 28-day curing process in water. The study utilized square-shaped ferrocement panels measuring 290 mm × 290 mm × 50 mm. The panels are exposed to repeated impact blows from a 2.5 kg falling mass dropped from a height of 0.80 m. The count of blows necessary to commence the first crack formation and the cause of ultimate failure are recorded for each panel. The study reports that an increase in SF content and the number of wire grid layers increased the number of blows needed for both the first crack and the ultimate failure. In the high-velocity impact test, 7.62 mm bullets are fired at the panels from a distance of 10 m with a striking velocity of 715 m/s. The study observed and analyzed the extent of spalling, scabbing, and perforation. The results showed that an increase in fiber content and the number of wire grid layers led to a decrease in the area of scabbing and spalling compared with the control specimens. It was also possible to see the mode of failure and crack pattern for impacts with low and high velocities.

Fibre-metal laminate structures: High-velocity impact, penetration, and blast loading – A review

Fibre-metal laminate structures: High-velocity impact, penetration, and blast loading – A review

Estimation of non-linear mechanical properties of rubber using Split Hopkinson pressure bar

The material non-linearity is a very important phenomenon in the behavior of the materials subjected to high strain rate loading. Rubber is a material which has high damping properties due to which it is more vulnerable in applications that involve absorption of vibration and shock; generally, these damping materials are subjected to high strain rate loading while absorbing the load. In the present work, various types of rubbers are subjected to very high-velocity impact due to which a very high strain rate loading is applied on the rubber specimens through the usage of Split Hopkinson Pressure Bar apparatus. The behavior of the rubber specimens at this high-velocity impact loading is studied through the variation of stress, strains, and strain rate with time. A comparison is drawn between various rubbers and the best rubber for the impact applied, is evolved and the same is presented in the work.

Effects of steel fiber and target thickness on the penetration resistance of UHPC under high velocity small projectile impact loading

Ultra high performance concrete (UHPC) with significant compressive strength and elastic modulus is expected to perform well under high–velocity impact loading. This paper introduces a study on the penetration resistance of UHPC based on variables including the thickness, fiber volume ratio, and striking velocity. The maximum striking velocity reaches approximately 1150 m/s. The results indicate that although the addition of steel fiber insignificantly improves the resistance, its effect on restraining the development of damage is non–negligible when the fiber volume ratio increases from 0.5% to 2%. The target thickness substantially influences the residual velocity and depth of penetration. Through computed tomography (CT) scanning, the damage can be divided into two parts: central damage (cratering, penetration tunnel, and scabbing) and interior cracks (radiate cracks, incomplete spalling cracks, and asymmetrical horn–shaped cracks). According to Forrestal's and the authors' previous models, satisfactory prediction results are obtained based on the suggested penetration resistance and modified cratering height.

Dynamic structural responses of high-performance fiber-reinforced cement composites panels subjected to high-velocity projectile impact loadings

Dynamic structural responses of high-performance fiber-reinforced cement composites panels subjected to high-velocity projectile impact loadings

Review of mechanical properties and impact response of PLA auxetic structures

In this paper, mechanical properties under quasi-static loading conditions and low to high-velocity impact response of Poly-lactic acid (PLA) material produced by the Fused Deposition Modeling (FDM) 3D printing method, having auxetic and non-auxetic geometric structures are critically assessed. Specifically, the load–displacement curve under various loads and parameters, such as energy absorption and the existence of the NPR effect with varying applied loads, are investigated. The effect of a large collection of material parameters, process parameters, and geometrical effects on load–displacement curves, strength, stiffness, and energy absorption are discussed in detail. The in-depth studies on auxetic structures of PLA, for quasi-static compressive load and low to high-velocity impact load, have shown that its impact resistance is superior to that of its non-auxetic counterparts. Also, a method for predicting peak load and maximum displacement for low-velocity impact derived from quasi-static loading data is discussed.

An experimental study on shear behaviour of fully grouted rock bolt under static and dynamic loading conditions

This paper aims to enhance the understanding of conventional rock bolt performance subjected to shear loading under static and in particular dynamic loading conditions. For this purpose, thirteen sets of static tests were undertaken using 16 mm smooth and 18 mm ribbed rock bolts aiming; 1) to examine the effect of internal confinement, and 2) to evaluate the energy absorption of the system subjected to static shear loading. The dynamic response of the conventional 18 mm ribbed rock bolt was assessed by using the drop hammer to generate high-intensity dynamic loading. The results showed that using perforated steel tubes inside concrete blocks as internal confinement in the vicinity of the shear planes prevents axial as well as radial cracking in the concrete, which enabled the rock bolt to go through more shear rather than tension. Furthermore, the shear performance of the conventional rock bolt under high-velocity impact load was found to be 70 % of that in static loading conditions, which tallies well with past experimental studies as well as mathematical approaches.

A unified elasto-viscoplastic peridynamics model for brittle and ductile fractures under high-velocity impact loading

Peridynamics (PD), as an alternative formulation of classical continuum mechanics, is a powerful method for predicting the spontaneous initiation and propagation of cracks. In this paper, a unified elasto-viscoplastic peridynamics model, named the Bodner-Partom theory-based Peridynamics (BPPD) model, is proposed to describe the whole deformation-damage-fracture process for both brittle and ductile materials under impact loadings. It defines the bond-wise elasto-viscoplastic deformation by incorporating the Bodner-Partom's (B-P) constitutive theory into the ordinary state-based PD framework. In BPPD model, the bond deterioration is introduced as an intrinsic variable coupled with the modified B-P theory and the bond fracture is realized by the critical bond stretch model. The proposed BPPD model permits the natural development of plastic deformation and material deterioration, which shares the same vision as PD theory. Equipped with the elastic short-range force contact model, the present study further investigates the modelling capacity of the BPPD model under various impact loadings. Simulations for brittle drop-ball test, Taylor impact test and ballistic penetration test show a good agreement between numerical results and experiment data. The proposed BPPD model can accurately capture the whole deformation processes of various impact fractures and thus contribute a new diversity to the development of PD theory and a new perspective to the understanding of material fracture mechanism.

Impact on Vectran/Epoxy composites: Experimental and numerical analysis

AbstractThe aim of this paper is to present a plane-stress damage model based on the Classical Lamination Theory (CLT), developed for polymer fibre-based composite. The proposed numerical model utilises a damage mechanics methodology coupled with fracture mechanics to predict composite failure, particularly under quasi-static and dynamic loadings. In addition, the proposed constitutive equations consider a single secant modulus to describe its tensile and compressive modulus, as opposed to the physically proposed tier models for polymer fibres which possesses a ‘skin-core’ structure. The result of single element and coupon-level modelling showed excellent correlation with the experimental results. In addition, it was also found that the proposed numerical model showed considerable accuracy on the response of the composite under low and high velocity impact loadings.

Modelling of woven CFRP plates subjected to oblique high-velocity impact and membrane loads

In this work, an analytical model was employed to model the perforation of woven plates made of AS4/8552 (carbon/epoxy) laminates exposed to oblique impact and preload in plane. The model assumed six mechanisms for the absorption of the kinetic energy of projectile: the laminate acceleration, elastic deformation of fibres, fibres failure, shear plugging, delamination and matrix cracking. The model was validated with numerical and experimental data from previous works and, was used to determine the influence of an oblique and perpendicular impacts on laminates with and without the in-plane preload.