Impact Resistance Of Materials Research Articles

A numerical approach for response of whipple shields with coated and monolithic front bumper to hypervelocity impact by spherical projectiles

Orbital debris in space offers a constant threat to spacecraft, satellites, and the International Space Station (ISS). There is a growing concern as the number of satellites and other space objects keep increasing year-on-year with advancements in space exploration and orbital activities. The threat posed by the small debris or MMODs (micrometeoroid orbital debris) to satellites and spacecraft can be prevented using Whipple shields made of impact-resistant materials. In the current work, a numerical approach has been utilized to simulate hypervelocity impact of spherical projectiles of diameter 4 mm on monolithic and coated whipple shields to determine the extent of damage, and the deformation behaviour. The simulations were conducted at 3.5 km/s and 5.5 km/s. The computational work was carried out using AUTODYN® module of ANSYS® finite element software.

Study on Bone-like Microstructure Design of Carbon Nanofibers/Polyurethane Composites with Excellent Impact Resistance.

It is a challenge to develop cost-effective strategy and design specific microstructures for fabricating polymer-based impact-resistance materials. Human shin bones require impact resistance and energy absorption mechanisms in the case of rapid movement. The shin bones are exciting biological materials that contain concentric circle structures called Haversian structures, which are made up of nanofibrils and collagen. The "soft and hard" structures are beneficial for dynamic impact resistance. Inspired by the excellent impact resistance of human shin bones, we prepared a sort of polyurethane elastomers (PUE) composites incorporated with rigid carbon nanofibers (CNFs) modified by elastic mussel adhesion proteins. CNFs and mussel adhesion proteins formed bone-like microstructures, where the rigid CNFs are served as the bone fibrils, and the flexible mussel adhesion proteins are regarded as collagen. The special structures, which are combined of hard and soft, have a positive dispersion and compatibility in PUE matrix, which can prevent cracks propagation by bridging effect or inducing the crack deflection. These PUE composites showed up to 112.26% higher impact absorbed energy and 198.43% greater dynamic impact strength when compared with the neat PUE. These findings have great implications for the design of composite parts for aerospace, army vehicles, and human protection.

Recycling of waste tire rubber as aggregate in impact-resistant engineered cementitious composites

With the development of modern transportation, the recycling and reusing of waste tires have gradually become a global concern. This paper was indented to develop impact-resistant engineered cementitious composites (ECC) with the application of waste tire rubber as the aggregate. The local PVA fibers, as well as the rubber crumb derived from waste tire with the replacement ratio up to 40 %, were applied to make ECCs. The basic mechanical behaviors of rubber-modified ECC were first investigated with uniaxial compressive and tensile tests. The impact tests of rubber-modified ECC were further conducted under different environmental temperatures ranging from −50 ℃ to 150 ℃, as well as different impact heights from 100 mm to 500 mm. It was concluded that the rubber-modified ECCs are more suitable to be applied as impact-resistant material in cold regions, as the rubber-modified ECC has higher energy dissipation capacity than normal ECC, especially under cold temperatures.

Insights into impact interaction between graphene and High-speed atomic oxygen for aerospace protection application

Graphene has great potential in aerospace applications but is inevitably influenced by the high-speed atomic oxygen (AO) in the low earth orbit. So far, the understanding of the impact interaction between AO and graphene as well as the protection mechanisms in the literature are still inconsistent and obscure, jeopardizing the practical application of graphene in this field. Herein, by using first-principles calculation combined with experiments, we explored the interaction process between high-speed AO and graphene based on actual aerospace conditions. The ab-initio molecular dynamics simulations show that the high-speed AO will either be scattered or adsorbed by graphene, which is strongly correlated to the impacting sites and incident angles. The AO-bonding condition of different sites on graphene is the most significant determinant affecting the impacting results. Moreover, the experimental results show that scattering AO is a better protection strategy than trapping AO on the graphene surface. To achieve higher probability of scattering, it is desired that graphene directly, rather than obliquely, faces to vertical AO impact. These findings revealed useful insights into the interaction mechanisms between AO and graphene and provide a guide for using graphene as an AO impact-resistant material in aerospace applications.

Efficacy of various structural forms of disentangled polyethylene laminates against low velocity impact

Filament-based unidirectional laminates of para-aramid and ultra-high molecular weight polyethylene exhibit excellent impact resistance performance. This research explored the possibility of using disentangled polyethylene (DPE) tape, instead of filaments, as an alternative impact resistant material. The effects of laminate structure, binding resin content and processing temperature on the tensile and impact properties of cross-ply laminates prepared from DPE tape was investigated. Three types of cross-ply laminates prepared from tape, woven fabric of untwisted tape and woven fabric of twisted tape were explored. Tensile properties and low velocity impact resistance of laminates were evaluated. Laminate made from woven untwisted tape showed much lower impact energy absorption than cross-ply laminate, while the woven twisted tape based laminate performed the worst. Cross-ply laminates made with low resin content showed better tensile and impact resistance performances. Cross-ply laminates prepared at higher moulding temperature showed significantly enhanced impact energy absorption than its counterpart prepared at a lower temperature. Therefore, cross-ply laminate of DPE tape with low resin content is ideal for impact resistance applications.

Coupled Effect of Polypropylene Fibers and Slag on the Impact Resistance and Mechanical Properties of Concrete.

The disposal of steel slag leads to the occupation of large land areas, along with many environmental consequences, due to the release of poisonous substances into the water and soil. The use of steel slag in concrete as a sand-replacement material can assist in reducing its impacts on the environment and can be an alternative source of fine aggregates. This is the very first paper that seeks to experimentally investigate the cumulative effect of steel slag and polypropylene fibers, particularly on the impact resistance of concrete. Various concrete mixes were devised by substituting natural sand with steel slag at volumetric replacement ratios of 0%, 10%, 20%, 30%, and 40%, with and without fibers. Polypropylene fibers of 12 mm length were introduced into the steel slag concrete at 0%, 0.5%, and 1.0% by weight of cement as a reinforcing material. Performance evaluation of each mix through extensive experimental testing indicated that the use of steel slag as partial substitution of natural sand, up to a certain optimum replacement level of 30%, considerably improved the compressive strength, flexural strength, and tensile strength of the concrete by 20.4%, 23.8%, and 17.0%, respectively. Furthermore, the addition of polypropylene fibers to the steel slag concrete played a beneficial role in the improvement of strength characteristics, particularly the flexural strength and final drop weight impact energy, which had a maximum rise of 48.1% and 164%, correspondingly. Moreover, integral structure and analytical analyses have also been performed in this study to validate the experimental findings. The results obtained encourage the use of fiber-reinforced steel slag concrete (FRSLC) as a potential impact-resistant material considering the environmental advantages, with the suggested substitution, of an addition ratio of 30% and 1.0% for steel slag and polypropylene fibers, respectively.

Topological Interaction among Molecular Cluster Assemblies Affords Tunable Viscoelasticity.

In the assemblies of subnanoscale polyhedral oligomeric silsesquioxane, topological interaction makes the dominant contribution to their viscoelasticity with broad tunability. The assembly molecules are designed with dumbbell, triangular, and tetrahedral shapes, and they demonstrate an intrinsic glassy feature with neither long-range ordering nor supramolecular assembly formation in their bulk. Their viscoelasticity can be broadly tuned through the tailoring of molecular topologies, while the trimer and tetramer assemblies afford elastic moduli comparable to those of rubbers (∼0.5 MPa) even 80 K above their glass transition temperatures. Molecular dynamics studies reveal the topological constraints resulting from the topology-disrupted cooperative dynamics among the cluster assemblies, and this finally leads to the typical caging dynamics of the structural units and the elasticity of the bulk materials. Further broadband dielectric spectroscopy studies uncover the unique hierarchical relaxation dynamics, inspiring the strategy for the decoupling of mechanical strengths and toughness for the design of impact resistant materials.

Does speed kill or make friction better?—Designing materials for high velocity sliding

Many modern applications rely on the safe operation of components sliding at high speeds, e.g., in the fields of e-mobility, high-speed manufacturing, or impact-resistant materials. While the impact of mechanical energy and heat on the friction and wear behavior of dry metallic interfaces has been the focus of extensive research in the past, the effect of extreme speeds on the near-surface deformation mechanisms in polycrystalline metals has remained poorly understood. In this work, we have tackled this crucial issue by exploring sliding velocities ranging from 10 to 2560 m/s via large-scale molecular dynamics simulations to identify three distinct deformation regimes in CuNi alloys. The microstructural response does not vary much for any of the considered systems up to sliding velocities of 40 m/s, but then evolves drastically up to a maximum value located between 320 and 1280 m/s depending on the composition. We observe that the degree of plastic deformation at the highest sliding speeds drops down to a level almost as low as for the lowest sliding speeds. We attribute this behavior to a sharp increase in the contact temperature at these high sliding speeds, approaching or even exceeding the bulk melting temperature, which goes hand in hand with a decline in the contact area and the resistance to sliding. Our characterization of the non-linear and non-monotonic material response to increasing sliding velocities will aid the systematic selection of materials and the design of robust components for a variety of high-speed sliding and wear applications.

Shock wave propagation in carbon honeycomb nanostructure and effect of cell vacancies

• Investigates the shock wave propagation and attenuation in CHC via MD simulation. • Explores the effects of vacancies and temperature on the shock wave propagation in CHC. • Calculates the critical shock wave intensity of CHC. Due to its periodic porous structure and high mechanical strength, carbon honeycomb (CHC), a new carbon allotrope, possesses a high energy absorption capability and thus great potential for the design and fabrication of advanced impact-resistant materials. In this work, the propagation and attenuation of shock waves in CHC are investigated for the first time via molecular dynamics simulation. The simulation results indicate that the propagation speed of shock waves in CHC is highly anisotropic and the shock wave energy decays with the propagation distance exponentially regardless of the direction. In addition, the energy decay is accelerated at elevated temperatures. When vacancies are introduced into CHC, the shock wave propagation in it is significantly impeded due to the large deformations of the vacancies in the form of shrinkage and expansion caused by the shock wave. The calculation of the critical shock wave intensity at which structure failure of CHC initiates shows that the cell axis direction of CHC can sustain a high shock wave intensity which is over two times higher than those for the other two directions. The simulation results obtained in this work are helpful for the design, fabrication, and application of CHC-based and other porous impact-resistant materials.

PENERAPAN METODE QUALITY FUNCTION DEPLOYMENT (QFD) DALAM UPAYA PENINGKATAN KUALITAS PRODUK PADA TOKO SIBAYAK KETAREN ROTAN

Sibayak Ketaren Rotan store is a furniture store that offers home furnishings where synthetic patio chairs are the customer's favorite product. Each customer certainly has a different desire for these products. So that the Sibayak Ketaren Rotan store needs to improve the quality of synthetic patio chairs, but because there is no system capable of managing the process of measuring product quality levels based on customer desires, this creates a problem for the company and has the potential to reduce customer interest in buying the product. Anticipation and solutions to this problem is an application that can measure product quality based on customer wishes (voice of customer) so that companies can improve product quality. Product improvements or enhancements can trigger customer interest in buying the product. The method used to measure product quality in planning the repair of synthetic patio chairs is quality function deployment (QFD). The results of the web-based application produce the highest rise factor report, namely the chair is made of sturdy and impact-resistant materials.

Extreme strain rate deformation of nacre-inspired graphene/copper nanocomposites under laser-induced hypersonic micro-projectile impact

Design and fabrication of impact resistant metal materials under extreme strain rate conditions is of great importance, especially in the field of collision protection of satellites and spacecraft. As inspired by the ‘brick-and-mortar’ microstructure induced excellent impact resistance in natural nacre, coupling with extraordinary intrinsic impact resistance of graphene (Gr), in this work a nacre-inspired Gr/Cu nanocomposite is fabricated, and its anisotropic extreme strain rate (at a level of ∼108/s) deformation behaviors are studied by using laser-induced microprojectile impact tests (up to a speed of ∼2.5 Km/s). Such extreme impact loading together with pinning effect of graphene can lead to highly stabilized high-density deformation twins and stacking faults at impact front even in the ultrafine grained Cu matrix. As the loading direction perpendicular to the composite layers, volume of severely-deformed region and the density of twinning and stacking faults at impact front is one third and half of that in the parallel impact direction, respectively. Such discrepancies indicate the capacity to dissipate impact energy in the perpendicular direction is ∼6 times higher than that of the parallel one, in spite of only ∼0.9 vol% graphene incorporated in the bio-inspired composites, evidencing architecture design plays an important role in impact resistance of materials under extreme dynamic conditions.

In situ determination of the extreme damage resistance behavior in stomatopod dactyl club.

The structure and mechanical properties of the stomatopod dactyl club have been studied extensively for its extreme impact tolerance, but a systematic in situ investigation on the multiscale mechanical responses under high-speed impact has not been reported. Here the full dynamic deformation and crack evolution process within projectile-impacted dactyl using combined fast 2D X-ray imaging and high-resolution ex situ tomography are revealed. The results show that hydration states can lead to significantly different toughening mechanisms inside dactyl under dynamic loading. A previously unreported 3D interlocking structural design in the impact surface and impact region is reported using nano X-ray tomography. Experimental results and dynamic finite-element modeling suggest this unique structure plays an important role in resisting catastrophic structural damage and hindering crack propagation. This work is a contribution to understanding the key toughening strategies of biological materials and provides valuable information for biomimetic manufacturing of impact-resistant materials in general.

Size Effect in the Split Hopkinson Pressure Bar Experiment

For many structures, their service environment is very strict, and the requirements for the impact resistance of materials are very high. Therefore, the dynamic testing method has important scientific significance and application value for practical engineering. Split Hopkinson pressure bar (SHPB) is one of the most common experimental methods for obtaining dynamic mechanical properties of materials. However, there is no uniform standard for the size of the bars and specimens used in the test. Theoretically, the size has little influence on the experimental results, but it has not been proved by experiments. This paper mainly studies the influence of device/specimen sizes of split Hopkinson pressure bar through experiments, it is demonstrated that the sizes of bars and specimen have little effect on experimental results.

Low-energy impact behavior of ambient cured engineered geopolymer composites

Engineered geopolymer composite (EGC) is a new kind of fiber reinforced geopolymer composite with tensile strain-hardening behaviors. This paper was intended to investigate the low-energy impact behaviors of EGC. To further reduce the carbon footprint and material cost of EGC, the feasibility of developing ambient cured EGC with cheap local PVA fiber was discussed according to the micromechanics-based analytical models. The compressive, tensile and impact tests of EGC, engineered cementitious composites (ECC), pure geopolymeric matrix and cementitious matrix were conducted and compared. It was found that the EGC specimens have similar tensile behaviors with ECC and the ultimate tensile strain of EGC can be as high as 7.5%. Under impact load, it was found that the PVA fibers could effectively restrict the crushing and spalling of geopolymeric matrix. Also, the dissipated energy of pure geopolymeric matrix is 3.8 times higher than that of cementitious matrix, indicating that it is recommendable to develop impact-resistant material based on geopolymeric matrix. The influences of NaOH molarity on the impact behaviors of EGC and geopolymeric matrix were discussed. It was found that the impact-resistance of EGC improved with the increase of NaOH molarity, while the threshold of NaOH molarity for geopolymeric matrix was recommended as 12 mol/L. Even though the compressive strength of EGC is lower than ECC, it can be concluded that EGC could have comparable or even higher impact-resistance than ECC under different low-velocity impact conditions.

Hybrid Composite Material Reinforced with Carbon Nanolaminates for Gradient Stiffness: Preparation and Characterization.

Currently, the procurement of lightweight, tough, and impact resistant materials is garnering significant industrial interest. New hybrid materials can be developed on the basis of the numerous naturally found materials with gradient properties found in nature. However, previous studies on granular materials demonstrate the possibility of capturing the energy generated by an impact within the material itself, thus deconstructing the initial impulse into a series of weaker impulses, dissipating the energy through various mechanisms, and gradually releasing undissipated energy. This work focuses on two production methods: spin coating for creating a granular material with composition and property gradients (an acrylonitrile–butadiene–styrene (ABS) polymer matrix reinforced by carbon nanolaminates at 0.10%, 0.25%, and 0.50%) and 3D printing for generating viscoelastic layers. The aim of this research was to obtain a hybrid material from which better behaviour against shocks and impacts and increased energy dissipation capacity could be expected when the granular material and viscoelastic layers were combined. Nondestructive tests were employed for the morphological characterization of the nanoreinforcement and testing reinforcement homogeneity within the matrix. Furthermore, the Voronoï tessellation method was used as a mathematical method to supplement the results. Finally, mechanical compression tests were performed to reveal additional mechanical properties of the material that had not been specified by the manufacturer of the 3D printing filaments.

Nitinol wire-reinforced GLAREs as a novel impact resistant material: An experimental study

Glass-fiber-reinforced aluminum layers (GLARE) are one of the excellent impact resistant materials, benefited from both the metal and glass fibers properties. Owing to their high impact damping properties, the shape memory alloys have been also considered as useful materials for arming the conventional impact-exposed materials. In the present paper, the shape memory wires were integrated with GLARE laminate and its response to the Charpy low-velocity impact was experimentally studied. The current study is aimed to determine the effects of three parameters (pre-strain percentage of shape memory alloy (SMA), glass fibers angle and the location of SMA wires within the novel fiber metal laminate) for the first time. Hybrid GLARE specimens of this study were planned by Taguchi design of experiments (DOE) method and contained Nitinol shape memory alloy wires. The results showed that the pre-strain and the angle of glass fibers are the most effective parameters on the impact energy absorption at accepted levels of confidence. Regarding the innovations in the construction of this type of impact-resistant hybrid composites, this study could be used in design of aerospace bodies.

Supersonic impact resilience of nanoarchitected carbon.

Architected materials with nanoscale features have enabled extreme combinations of properties by exploiting the ultralightweight structural design space together with size-induced mechanical enhancement at small scales. Apart from linear waves in metamaterials, this principle has been restricted to quasi-static properties or to low-speed phenomena, leaving nanoarchitected materials under extreme dynamic conditions largely unexplored. Here, using supersonic microparticle impact experiments, we demonstrate extreme impact energy dissipation in three-dimensional nanoarchitected carbon materials that exhibit mass-normalized energy dissipation superior to that of traditional impact-resistant materials such as steel, aluminium, polymethyl methacrylate and Kevlar. In-situ ultrahigh-speed imaging and post-mortem confocal microscopy reveal consistent mechanisms such as compaction cratering and microparticle capture that enable this superior response. By analogy to planetary impact, we introduce predictive tools for crater formation in these materials using dimensional analysis. These results substantially uncover the dynamic regime over which nanoarchitecture enables the design of ultralightweight, impact-resistant materials that could open the way to design principles for lightweight armour, protective coatings and blast-resistant shields for sensitive electronics.

Design and analysis ergonomic adjustable baby chair

Baby chairs are important equipment in the early stages of child care. An ergonomic, comfortable, and safe baby chair is the most important point that is expected by a customer. An ergonomic and safety baby chair will provide better comfort for the baby since the higher need for affection and emotional bonds. The research aimed to investigate and develop an ergonomic baby chairs design with considering comfort and regulatory safety standards. The initial step was product design scoring based on customer voice using simple decision matrices. Optimization of the structure material selection parameters was carried out by using a numerical simulator based on the factor of safety. The research shows that a baby chair need to have safety features such as castors with brake, 5-points restrain system, adjustable or recline seat, detachable tray. Durability features are also important, such as high tensile strength, wear and impact-resistant material, and lightweight aluminium structure. As a result, a hollow aluminium pipe with a diameter of 26 mm for the chair structure is the most economic choice with a factor of safety 4.8.

Manufacturing Technology of Some Impact Resistant Materials

In this paper impact resistance is a key parameter for composite materials. Composite structures can experience impact loads either accidentally in the designed life or in an anticipated hostile service environment. That is why the manufacturing technology is very important. For materials manufacture were established: the type of polymer matrix, the types of fabrics and additives which will be used to improve impact resistance and also analysis of mechanical properties of formed composite materials (bending and tensile tests). Knowledge of the mechanical properties of polymeric materials is necessary in all areas of their applicability. Thus, rigidity and mechanical strength are key properties for most applications in which polymeric matrix composites are used.

РАЗРАБОТКА СОСТАВА УДАРОПРОЧНОЙ ПОЛИМЕРНОЙ КОМПОЗИЦИИ АБС/ПК ДЛЯ АВТОМОБИЛЬНОЙ ПРОМЫШЛЕННОСТИ

Polymer and composite materials are becoming more and more widely used in the Russian automotive industry. The Russian market of polymer materials for automotive components is characterized by an insufficiently developed production of some types of such materials. And, as a result, the use of imported materials. Styrene plastics are one of the innovative materials for the automotive industry. Using them in a car makes the product more attractive to customers. The use of this type of plastics allows to create a new look for the car. This applies to both the interior and exterior. The aim of this work is to develop the composition of a polymer composition based on ABS plastic from domestic raw materials. In addition, the new mixed composition should replace imported mixed compositions or contain a minimum amount of imported components of the composition, which will significantly reduce the cost of products and accordingly the car. The article analyzes the polymer materials used in the automotive industry. The disadvantages of using these materials in their pure form are revealed. The selection of the components of the composition of the impact-resistant material with the development of its formulation has been made. The composition of an impact-resistant polymer composition based on ABS plastic and PC has been developed, which is not inferior in terms of the complex of properties to the imported material. The influence of the composition of ABS-plastic, various grades of polycarbonate, their ratio in the polymer composite material on the physical, mechanical and technological properties of the obtained composition has been investigated. It is shown that the best set of properties is possessed by a material based on 2020-30 ABS-plastic and PC-3S polycarbonate with a component ratio of 70%:30%.