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This paper aims to evaluate the effect of temperature on impact damage resistance of glass/epoxy laminates. A series of impact tests were performed using an instrumented impact-testing machine at temperature ranging from -40°C to +80°C. The resulting impact damage was measured using back light method. The impact resistance parameters were employed to understand the damage resistance. It was observed that temperature has a little effect on the impact responses of composite laminates. The damage resistance of glass/epoxy laminates is somewhat deteriorated at two opposite extremes of the studied temperature range and this behavior is likely due to the property change of glass/epoxy laminates under extreme temperatures

The rapid growth in the usage of polymers/polymer composites demands innovative welding techniques for joining. In this research work, Polypropylene (PPE) is chosen as the thermoplastic matrix and the filler selected is Spheri Glass 3000 (SGE) at 2.5wt.%. In this work, Friction Vibration Joining (FVJ) is used for joining PPE/SGE composites. The FVJ experiments were carried out according to Taguchi ${\text{L}}_{27}$ orthogonal array with input parameters as (i) Tool Profile (TP), (ii) Frequency of Vibrating Tool (FVT) and (iii) Feed Rate of Workpiece (FRW). The joints were analyzed mechanically (tensile strength, impact strength and shore D hardness) and metallurgically (scanning electron microscope). Analysis of Variance (ANOVA) is used for studying the significance of the input factors over output factors. The mechanical characteristics of FVJ joints were optimized by Technique for Order Preference by Similarity to Ideal Solution (TOPSIS).

For diamond coating, natural fragile property easily leads to fracture, delamination and peeling, which seriously inhibits the applications in many industrial fields. In order to prolong the lifetime, improving the toughness under impact load is essential for diamond coating. In this work, a novel method was proposed by the conventional CVD diamond technique combining with the particles, with which the nanocrystalline diamond (NCD) coating with W particles (W-NCD) was fabricated to evaluate the impact behavior. The pure NCD coating was also produced for comparison. Repeating impact testing was performed to evaluate the impact resistance of the as-deposited NCD coatings. The results showed that the diamond coating can be fabricated on the substrate with W particles. The indentation scar revealed that the W-NCD coating had the stronger impact resistance than the NCD coating. Ratcheting effect was employed to discuss the impact properties of NCD coating for the first time. The coating integrity played a vital role in ratcheting displacement. Repeating impact can make the NCD and W-NCD coatings soft, and the W particles can accelerate the softening process. Hence, embedding particles can provide a potential and valid method to enhance the impact resistance of diamond coating that was very important for the fragile coating.

Fundamental principles controlling the deflection behavior of a simply supported beam responding to the impact action of a solid object is revealed in this paper. The significant mitigating effects that the mass of the beam have upon its impact resistant behavior have been illustrated with examples. It is a myth that the static resistance of the beam is indicative of its impact resistance. The important effects of "cushioning" and the higher modes phenomenon have also been identified by the analytical study presented herein. Hand calculations and computer analysis methods are introduced and evaluated by comparison with results obtained from finite element analyses using LS-DYNA.

In this study, the impact damage resistance of carbon/basalt hybrid fiber reinforced polymer pipes was experimentally investigated under low velocity impact loading. The composite pipes, composed of thin plastic liner of HDPE wrapped with eight layers of plies at constant winding angle of [$\pm$55${}^{\circ }$/90${}_2^{\circ }$/$\pm$55${}^{\circ }$/90${}_2^{\circ }$], were fabricated through filament winding technique. Eight pipe configurations with different stacking sequence and fiber content proportion were studied. Specimens cut from the original pipes were tested in a drop weight impact machine under two levels of impact energies, 50J and 100J, in order to predict the impact response and induced damage resistance of the pipe. The damage of the tested pipes was assessed based on the force-displacement, force-time histories, the energy absorption mechanism, as well as the micrographs captured by scanning electron microscope (SEM) for the specimens. The results indicate that the impact resistance behavior was highly affected by the stacking sequence of the layers and partly affected by the fiber content ratio. Positioning the basalt fiber on the impacted side enhances the energy absorption mechanism for both levels of imposed energies, while improving the impact resistance. The addition of 50% basalt fiber can slightly increase the impact resistance compared to the addition of 25% basalt fiber. However, specimens with 25% basalt fiber showed lower peak force, lower damage area and lower energy absorption.

This study attempts to propose innovative multi-layer cement-based composites to have high impact resistance which could be used for runway. In this paper, the performances of two innovative multi-layer composite runway pavements using asphalt concrete-high strength concrete-cement-treated aggregate and asphalt concrete-high strength concrete-cement mortar in surface-base-subbase layer were evaluated under impact loads. ABAQUS/Explicit software was used to simulate loading condition and nonlinear stabilized runway pavement layers characteristics. In addition, a detailed parametric study was also carried out to explore the effects of the selected materials and load-related parameters in changing the performance of multi-layer composites. The findings of the study will be helpful to introduce protective multi-layer composite runway pavement and consequently to reduce the maintenance work of runway pavement.

Sandwich panel is a widely used protective component, this paper designs Bidirectionally Arranged Bionic sandwich Panel (BABP) and Unidirectionally Arranged Bionic sandwich Panel (UABP) according to the appendage of Odontodactylus scyllarus. Meanwhile, Triangular sandwich Panel (TP), Corrugated sandwich Panel (CP) and Elliptical arc sandwich Panel (EP) are accordingly designed as a comparison. Hyperworks and LS-DYNA are used to simulate the impact conditions, and the drop-weight test shows that the finite element simulation is reliable. Bionic sandwich panels have excellent protective effect at the impact velocity of 6–14m/s. UABP has the best comprehensive impact resistance by comparing the deformation, specific energy absorption (SEA) and peak force (PF) of the five kinds of sandwich panels under five impact velocities. Parameter analysis and response surface optimization work based on orthogonal experiments are carried out for UABP, the results are that the wall thickness $T$ and the triangle-width ratio ${\lambda }_2$ have extremely significant influences on the SEA, and the order of influence is $T>{\lambda }_2$; the wall thickness $T$ and the arc-width ratio ${\lambda }_1$ have extremely influences on PF, and the triangle-width ratio ${\lambda }_2$ has a significant influence on PF, and the order of influence is $T>{\lambda }_1>{\lambda }_2$. Both the errors about SEA and PF of the optimal solutions are less than 5%. The comprehensive evaluation index of the optimal UABP is larger than that of sandwich panels by 29.15%, 52.61%, 65.64%, 40.5%. This research is expected to provide new perspectives on the design of sandwich panels.

Polyvinyl butyral (PVB) laminated glass is widely used in architectural structures and automotive glass due to its remarkable cushioning and cohesive properties, and its lamination thickness has a significant effect on the overall impact resistance of the glass. In this paper, two conventional laminated glass thicknesses of 0.76 mm and 1.52 mm were selected to study the dynamic performance and damage morphology of laminated glass under three different impact velocities using light gas gun impact tests combined with industrial CT scanning-3D reconstruction techniques. The results showed that the PVB sandwich thickness had a significant positive correlation with the energy absorption effect, but under different impact velocities and glass thickness, the sandwich thickness and impact resistance showed a differentiated “marginal effect”. At moderate impact velocities, the impact resistance was most sensitive to the change in sandwich thickness. With the increase in glass thickness, the sensitivity of impact resistance to the change of sandwich thickness decreased. According to the characterization of full-dimensional cracks under medium-velocity impact conditions, it could be seen that the sandwich had the function of buffering dissipation and gathering recovery in different stress directions, and the thickness of the sandwich was a key functional parameter to reduce the flying of glass fragments. Therefore, the results of this study can provide a reference for the analysis and design of the impact resistance of PVB laminated glass.

One-dimensional impact response of graded cellular rods with monotonously increasing density distribution, which benefits in buffering the impact object in proximal end, is investigated by using shock models and cell-based finite element models. Based on the rigid–plastic hardening (R-PH) idealization, a theoretical model of the shock front propagation behavior in graded cellular rods subjected by impact is developed and solved numerically with a fourth-order Runge–Kutta scheme. Finite element analysis is performed using 2D random Voronoi technique, and the comparisons illustrate that the theoretical predictions and finite element results are in good agreement. The anti-impact responses of graded cellular materials with different gradient parameters are carried out, and it is demonstrated that the design indicators, including support stress, critical length and maximum deceleration of the object, are highly related to the gradient parameters of graded cellular materials. A design strategy for the impact alleviation of graded cellular materials is proposed. Thus, the gradient parameters can be finally determined to meet the requirement of the actual design indicators and it can also offer an optimal critical length for final graded cellular materials.

A biped robot that has a high impact resistant is required to extend the range of application in various fields such as hazardous disaster site, industrial plants, and living environments. To realize a high impact resistant or lightweight biped robot, we applied flexible struts to the body of the robot.We proposed two impact resistance tests for the biped robot by dropping a weight and by dropping the body itself. Through several experimental results, we showed the two impact tests are inherently correspond with. According to the experiments of falling robot, our biped robot composed of flexible struts is available after falling down from the height that is two times of the entire height of the robot.

Hot forming technology can not only improve the impact resistance and safety performance of the car, but also reduce its weight, so it has become a popular research topic in China and abroad. Hot forming steel is divided into uncoated hot forming steel and coated hot forming steel. Hot stamping parts of coated hot forming steel do not need shot blasting treatment and have better corrosion resistance compared with uncoated hot forming steel, so coated hot forming steel has been used more widely. Al-Si coating is the most mature coating for hot forming steel, and the Zn coating hot forming steel is still in the research stage because of the narrow process window. This paper focuses on Masteel Al-Si coating hot forming steel, whose coating composition, matrix microstructure and mechanical properties before and after hot stamping is studied. The research shows that Masteel Al-Si coating hot forming steel has good performance, and it can meet the requirements of mainstream car manufacturers.