Impact Resistance Characteristics Research Articles

Impact resistance characteristics of pipeline system covered with W-shape elastic-porous metallic damper

As a novel elastic-porous damping material fabricated through entangled wire mesh, W-shape elastic-porous metallic damper (W-EPMD) is considered an ideal damping element for coated pipeline system due to the micro dry friction between metal wires, which induces energy dissipation. The complex interwoven cellular formations of metallic wire mesh pose challenges in characterizing its dynamic characteristics. In this work, the dynamic properties of the pipeline system covered with W-EPMD under various impact conditions, including the acceleration response and impact isolation coefficient, were investigated by numerical simulations and experimental analysis. Constitutive models used to characterize the hysteresis behavior of W-EPMD were introduced, comprising Yeoh and Bergström-Boyce models, and parameter identification were conducted through quasi-static experiments. The reliability of the established numerical model was confirmed through drop impact experiments. The results demonstrate that there is a maximum discrepancy of 9.1 % between the simulation predictions and experimental results of the stress-strain curve. The impact isolation coefficient of the pipeline system covered with W-EPMD exhibits a fluctuating trend with the rise of the pulse peak, while the maximum compression of W-EPMD steadily increases. During the pipeline impact process, the increased density of W-EPMD reduces the impact resistance of the pipeline system, while excessively low density leads to over-compression and structural damage to W-EPMD. Furthermore, the discrepancy of the acceleration response between experimental and numerical results under various excitation signals remain within 6 %, demonstrating that the hysteresis model effectively characterizes the impact resistance characteristics of the pipeline system covered the W-EPMD.

Analyzing the strength and impact resistance characteristics of concrete with lathe machine waste as fiber

Analyzing the strength and impact resistance characteristics of concrete with lathe machine waste as fiber

Analysis of the Impact Resistance Characteristics of a Power Propulsion Shaft System Containing a High-Elasticity Coupling

In research concerning the impact resistance characteristics of ship power transmission shaft systems incorporating a high-elasticity coupling, a significant challenge lies in ascertaining the displacement compensation metrics for the high-elasticity coupling. This study constructs a finite element model of the ship power transmission shaft system with an entity equivalent model of the high-elasticity coupling. Utilizing the Dynamic Design Analysis Method (DDAM) and the time-history method, the dynamic responses of the high-elasticity coupling, the propulsion shaft system, and its critical cross-sections under explosive impact loads are analyzed. The findings indicate that the maximum impact displacement of the propulsion shafting system, as calculated by DDAM, is 22.47 mm in the vertical direction at the driven end of the high-elasticity coupling. In contrast, the maximum impact displacement determined by the time-history method is 15.23 mm in the same direction. The study corroborates the precision of the high-elasticity coupling equivalent model establishment methodology and confirms that the entity equivalent model of the power transmission shaft system with a high-elasticity coupling is capable of fulfilling the criteria for a swift evaluation of impact resistance characteristics. This provides theoretical backing for the forecasting of impact resistance performance in ship propulsion shaft systems.

Research on the impact resistance characteristics of ship side structure obstacle grid particle dampers

Research on the impact resistance characteristics of ship side structure obstacle grid particle dampers

Impact resistance of horsetail bio-honeycombs

Inspired by the ingenious cross-sectional structure of horsetail stems, a group of novel horsetail bio-honeycombs (HBHs) are firstly proposed to pursuit a superior impact resistance performance. The out-of-plane impact resistance characteristics and mechanical properties of the proposed HBHs are investigated by means of test, theoretical analysis, and finite element (FE) analysis. In the process of deriving the theoretical model of HBHs, the novel 5-panel and 7-panel membrane energy dissipation corner elements are firstly proposed and reasonable theoretical solutions for them are obtained. Theoretical results suggest that the errors between numerical and theoretical results for the majority of the HBHs are within 7 %. In addition, the studies indicate that the HBHs outperform the circular honeycomb (CH) in terms of crashworthiness while ensuring that their relative densities are the same. The complex proportional assessment method is utilized to evaluate the crashworthiness of HBH_n_6_1.5 (n represents the number of ribs, 6 represents the size of the outer diameter, and 1.5 represents the ratio (ζ) of the outer diameter to the inner diameter) under the same relative density. Furthermore, results suggest that energy absorption and crushing force efficiency of HBH_16_6_1.5 are 31.31 % and 25.54 % higher than those of CH, respectively. Subsequently, the influences of geometric parameters, including the ζ and the thickness-to-cell length ratio (TL), on the impact resistance of HBH_16_6_1.5 are investigated thoroughly. The findings show that when the ζ is within 1.2–1.5, the HBHs can exert their maximum potential, in which the inner diameter of HBHs is close to its outer diameter. Also, the findings demonstrate that the HBHs will undergo three distinct deformation modes. When the TL is roughly within 0.0200–0.0267, the deformation of HBHs will be in the transition deformation mode.

ARCHITECTURAL DESIGN OF SOCIAL AND PROTECTED HOUSING FROM VOLUME BLOCKS

Purpose. Application of a systematic approach to the design of social and safe housing for the population in the form of residential buildings of rapid construction with constructive measures regarding the requirements of inclusivity. The project of a 9-story residential building using Speedstac modules with external insulation from KingSpan thermal insulation boards is proposed. Methodology. The possibility of developing design solutions for a residential building made of three-dimensional blocks with the use of insulation of facades with KingSpan slabs was considered. The advantages of block construction were analyzed and design solutions were developed for the facade, arrangement of the roof, entrances and constructive elevators in the building for people with limited physical abilities, protective premises made of steel fiber concrete. Findings. A 9-story, 54-apartment residential building is designed, which is made of three-dimensional blocks. The external walls were insulated with KingSpan plates. Originality. Application of a complex approach to the architectural design of social and safe housing. Practical value. On the example of a designed typical residential section, the following questions are considered: economical and quick-build mass housing construction in the form of buildings from volumetric blocks, energy efficiency issues are solved by the use of effective heat-insulating panels, for protection against artillery fire, the option of arranging premises made of monolithic reinforced concrete structural elements from steel fiber concrete, which has increased impact resistance characteristics, for people with physical disabilities and mobility restrictions, a solution is proposed in the form of a separate entrance to the residential section with the use of a ramp and a lift to the common corridor and elevator.

Research on the comparison of impact resistance characteristics between energy absorption and conventional hydraulic columns in fluid–solid coupling

Rock burst disaster affects underground mining safety. The energy-absorbing hydraulic support for preventing tunnel impact has been implemented in rock burst mines. In order to compare the impact resistance characteristics of conventional columns and energy-absorbing columns, based on the derivation of energy theory, the CEL fluid–solid coupling simulation algorithm is used to simulate the process of static load 1000 kN superimposed impact load 1500 kN on φ180 mm type conventional column and energy-absorbing column. Combined with the static-dynamic combined test of the 6500 kN impact testing machine on the column, the accuracy and reliability of the CEL simulation column impact response are verified. The results showed that compared with conventional columns, the reaction force of energy-absorbing columns is reduced by 32.55%. The stress and expansion of the cylinder are significantly reduced. The acceleration of the mass movement has been reduced by 59.46%. The addition of the energy-absorbing device enhances the system's energy absorption by 33.46%, thereby reducing the energy absorption of the column itself to 23.58%. Additionally, the deformation of the energy-absorbing device increases the effective displacement by 239.45%. This also prolongs the impact duration, ensuring sufficient time for the safety valve to open, safeguarding the support from damage, and enhancing the overall integrity of the tunnel.

Izod impact resistance of 3D printed discontinuous fibrous composites with Bouligand structure

The Bouligand structure found in the dactyl club of mantis shrimps is known for its impact resistance. However, Bouligand-inspired reinforced composites with 3D shapes and impact resistance characteristics have not yet been demonstrated. Herein, direct ink writing was used to 3D print composites reinforced with glass microfibers assembled into Bouligand structures with controllable pitch angles. The energy absorption levels of the Bouligand composites under impact were found to surpass those of composites with unidirectional microfiber alignment. Additionally, the Bouligand composites with a pitch angle of 40° exhibited a maximum energy absorption of 2.4 kJ/m2, which was 140% higher than that of the unidirectional composites. Furthermore, the characterization of the topography of the fractured surface, supplemented with numerical simulations, revealed a combination of crack twisting and crack bridging mechanisms. Flexural tests conducted on the composites with a pitch angle of 40° revealed that these composites had the strongest properties, including a flexural strength of 36.9 MPa, a stiffness of 2.26 GPa, and energy absorption of 8 kJ/m2. These findings are promising for the microstructural design of engineered composites using direct ink writing for applications in aerospace, transportation, and defense.

Effect of infill pattern of polylactide acid (PLA) 3D-printed integral sandwich panels under ballistic impact loading

This paper investigates the effect of the infill pattern of polylactide acid (PLA) 3D-printed sandwich panels under ballistic impact loading. Fused deposition modeling (FDM) technique is used to manufacture the PLA 3D-printed integral sandwich panels with four infill patterns: cubic, grid, gyroid, and honeycomb. The ballistic data acquisition system is collected the experimental results with three impact velocities: 109.65, 173.97, and 209.48 m/s. It was revealed that the 3D-printed sandwich panel with cubic infill pattern reached the highest maximum impact load than the other three infill patterns. Moreover, it was highlighted that the sandwich panel with cubic and gyroid infill patterns absorbed 1.41 and 1.15 J and provided better impact resistance characteristics. It is highlighted that the infill pattern plays a vital role in the impact resistance of 3D-printed sandwich structures. Furthermore, it is recommended the three-dimensional (3D) infill pattern, e.g., cubic, gyroid, 3D honeycomb, can provide better impact performance than the two-dimensional (2D) infill pattern.

Study on impact resistance and parameter optimization of patch‐repaired plain woven composite based on multi‐scale analysis

AbstractPatch‐repaired plain woven composite structures were exposed to internal damage caused by impact during service, which reduced mechanical properties. A multi‐scale modeling strategy was proposed to study the impact resistance characteristics of patch‐repaired plain woven carbon‐fiber‐reinforced‐polymer (CFRP) laminates. The micro representative volume element (RVE) was extracted from the yarn; a local homogenization method was used to obtain the equivalent cross‐ply laminate (ECPL) cells corresponding to the mesoscale RVE. The finite element model (FEM) of patch‐repaired plain woven laminate was established by extending the ECPL cells. The FEM was checked by the low‐velocity impact (LVI) tests, and the impact parameter errors were within 10%. Furthermore, impact resistance of repaired specimens under different impact conditions (e.g., the impact energy was 3 ~ 20 J) was studied. Finally, patch parameters (patch thickness, patch size, off‐axis angle) of the repaired specimen were optimized by multi‐objective optimization based on the surrogate model and response surface method (RSM). After multi‐objective function optimization, the optimal patch parameter configuration (the thickness of the patch was 0.87 mm, the diameter was 66 mm, and the off‐axis angle was 44.2°) reduced the absorbed energy value of the repaired specimen from 4.9089 to 4.1640 J, and the delamination area of the repaired specimen from 605 to 280 mm2. All the results provide a reference for patch repair of plain woven composites.

Improving the Properties of Biodegradable PLA via Blending with Polyesters for Industrial Applications

Polylactic acid (PLA) is a biodegradable polymer obtained from the fermentation of renewable resources, which can also be used in industrial areas. The employment of PLA is restricted by its brittle nature at room temperature. This study, it is aimed to prepare PLA blends with PBT (Polybutylene terephthalate) to overcome this drawback. Thus, it can be provided new raw materials to many sectors, especially textile, automotive and electronic products, by preparing biodegradable, environmentally friendly materials with better performance properties. PLA/PBT blends containing 5%, 10%, and 15% PBT by weight were produced in a twin screw extruder using with using maleic anhydride grafted ethylene/butyl acrylate (EBA-g-MAH) as a compatibilizer. For comparison studies, blends of PLA/PBT without compatibilizer were also prepared. Examinations on the flow, viscoelastic properties, and rheologic characteristics of prepared samples were carried out by using Melt Flow Index values and Rotational Rheometer measurements. Mechanical and impact resistance characteristics were identified in accordance with the relevant standards. Physical properties of blends such as molding shrinkage, density, and hardness values were also determined. Degradation or cross-linking-induced changes in the chain structure was not observed during the investigation via using a rotational rheometer for PBT samples at 240 °C /15 min., and PLA samples at 260 °C /15 min. Notched izod impact test results show that adding compatibilizer increases 16% impact resistance of PLA/PBT blends. The tensile modulus values of the blends containing compatibilizer decreased by 2% approximately. These results show the transition from brittle to ductile behavior of PLA for compatibilized blends.

Investigation of the Fracture Characteristics of a Cement Mortar Slab under Impact Loading Based on the CDEM

For brittle and quasi-brittle materials such as rock and concrete, the impact-resistance characteristics of the corresponding engineering structures are key to successful application under complex service environments. Modeling of concrete-like slab fractures under impact loading is helpful to analyze the failure mechanism of an engineering structure. In this paper, simulation models of impact tests of a cement mortar slab were developed, and a continuum-discontinuum element method (CDEM) was used for dynamic analysis. Concretely, the cracking simulations of a mortar slab when considering the hammer shape and impact velocity were conducted, and the impact process and failure results of the slab structure were analyzed. The results showed that the top fracture area of the mortar slab was significantly smaller than that of slab bottom under impact loadings of the drop hammer. The impact velocity was an important factor that affected the mortar slab's cracking. With the increase in the initial impact velocity, the effective fracture area of the slab structure increased significantly; the impact force and rupture degree of the mortar slab also showed a linear growth trend. The shapes of the impact hammerhead also had a significant effect on the crack model of the mortar slab. The effective fracture zones of slab structures were close under circular and square hammers, while the effective fracture zone was significantly larger under a rectangular hammer impact. The peak value (45.5 KN) of the impact force under a circular hammer was significantly smaller than the peak value (48.7 KN) of the impact force under the rectangular hammer. When considering the influence of the stress concentration of the impact hammerhead, the maximum impact stress of the rectangular hammer was 147.3 MPa, which was significantly greater than that of the circular hammer impact (maximum stress of 87.5 MPa). This may have meant that the slab structures were prone to a directional rupture that mainly propagated along the long axis of the rectangular hammerhead. This impact mode is therefore more suitable for rehabilitation and reconstruction projects of slab structures.

Investigation on energy-absorption-based protection mechanism of polyurea-coated aluminum alloy composite (PCAA) plate under impact loading by K9 glass projectile

To investigate the dynamic response and anti-impact characteristics of polyurea-coated aluminum alloy (PCAA) plates, impact experiments by the K9 glass projectile were first carried out with a light-gas gun. Based on the experiments, numerical simulations were conducted and validated using LS-DYNA software. After validation, the effect of polyurea coating thickness on the composite response as the impact surface under the same substrate conditions was discussed. The transverse diffusion effect and glassy transition effect were proposed in this study, and the results demonstrate better energy absorption characteristics and protective mechanisms of composite structures. The impact load is dispersed to a wider area due to the existence of polyurea coating on the impact surface characterized by the transverse diffusion effect, which will reduce the impact stress but deform a larger area plastically. In addition, our findings reveal that the glassy transition effect of polyurea determined by the average loading rate plays a significant role in improving the impact resistance characteristics of the composite structure. Finally, for the metal substrate with fixed thickness, this study demonstrates the existence of an optimal thickness of the coating as the impact surface of the PCAA plate to achieve the highest energy absorption efficiency under projectile impact conditions. The results and findings in this study provide a deep insight into the deformation and energy-absorption-based protective mechanism of PCAA targets under impact loading and may contribute to the future design of protective structures.

Analysis of fracture mechanisms of ultrathin glass for flexible cover window under pen drop conditions

AbstractThe fracture mechanism of a chemically strengthened ultrathin glass (UTG) for the cover window of flexible display devices was investigated under pen loading conditions for the first time to better understand the UTG impact resistance characteristics. High‐speed camera analysis, fracture fragment analysis, and finite element modeling were employed to investigate the fracture mechanism of the UTG under pen drop conditions. A pen‐on‐plate (POP) test was also employed to examine the fracture characteristics under static loading condition, and its results were compared with those of the pen drop test (PDT) to find a correlation between the static and dynamic loading conditions. The correlation found between the POP and PDT tests indicates that a quantitative estimation of contact displacement under PDT can be obtained by measuring the first ring crack size, to more easily determine the impact resistance characteristics of UTG.

Analysis of pressure regulating characteristics of safety valve in hydraulic system of offshore oil production equipment

The hydraulic system is used to control the oil production equipment in China ' s seabed oil exploitation. When the oil production equipment is subjected to a small impact, the safety valve may not open for unloading, resulting in damage to the oil production equipment. In this study, a two-stage safety valve that combines a direct acting valve and a differential valve is designed and tested. First a simulation model of the valve is developed using MATLAB/Simulink modules. The impact resistance characteristics of the safety valve under the impact are simulated and analysed. Then, a hydraulic circuit of the oil production equipment is created. Finally, an impact test system is built to perform an impact test on the developed hydraulic circuit. The simulation results are similar to the experimental results. When the pressure of the hydraulic system of the oil production equipment increases, the two-stage safety valve exhibits the favourable dynamic response characteristics of opening, unloading, overflowing and closing and effectively adjusts to ensure the pressure stability of the hydraulic system. This study provides a theoretical basis and experimental reference for the design of offshore oil production equipment safety valves.

Low-velocity impact behavior of carbon woven laminates after exposure to varying temperatures

The present study reports the low-velocity impact (LVI) performance of carbon woven reinforced polymer (CWRP) composites with varying temperatures. The fabrication of carbon woven lamina and carbon woven reinforced two-layered laminate (named CWRP-1 and CWRP-2) was done using a vacuum-assisted resin transfer molding (VARTM) process. CWRP-1 samples were tested at varying impact velocities of 1, 2, 3, and 4 m/s at −25, 25, and 50 °C for each incident velocity. CWRP-2 samples were tested at room temperature at varying incident velocities to determine the effect of multiple woven layers. The impact resistance of the first-crack load, peak impact load, and absorbed energies were recorded and evaluated under different loading conditions. In addition, the Weibull probability method is adapted to forecast failure behavior as a function of load. Visual inspection, optical microscopy, and scanning electron microscope (SEM) images were used to assess the damage pattern and failure morphologies in forecasting the failure phases during LVI. The low-velocity impact behavior of CWRP-1 at −25 °C with various velocities was shown to be random due to the polymer matrix freezing condition. The softening of the resin matrix at 50 °C is responsible for the difference in damage tolerance. The relevance of multiple layered composites for better impact resistance characteristics was demonstrated during testing of CWRP-2 at room temperature. Overall, the results of this experiment showed that CWRP lamina and laminates are highly sensitive to the impact velocities and external temperatures.

Impact Damage Analysis of Fiber Reinforced Plastic Structure with Rib

Fiber reinforced plastic (FRP) is a widely used structural form in engineering. FRP ribs can absorb most of the impact energy to protect the structure from damage. The purpose of this study is to obtain the impact resistance of FRP ribs by test and simulation. Taking glass fiber reinforced plastic (GFRP) oil sump as the object, the damage degree of structure under different impact angles, impact velocity, and impactor masses is compared and analyzed by material test, impact test, and simulation. It can be seen from the test results that the design of surface ribs has a great influence on the energy absorption effect of the shell. The constitutive parameters of the shell material are obtained by testing, and the failure mode of the ribs is analyzed by finite element simulation. The impact effects of flying stones with different incident angles, velocities, kinetic energy, and geometric dimensions on the shell are compared and analyzed. The results show that, at the same impact energy, the impact resistance characteristics change regularly under different working conditions. Under a certain incident angle, the damage effect caused by flying stones in a specific mass range is greater. Beyond a certain incident angle, the damage begins to occur, and the larger the incident angle is, the greater the damage effect is. Combined with the actual situation and road standards, the defense of medium quality flying stones is a major concern in the design of oil pan. The results are helpful for designing reasonable ribs to improve the reliability of FRP structures.

Effect of Stacking Arrangement and Reinforcement Ratio on Impact Behavior of Novel Thermoplastic Embedded Hybrid Composites

Light weight and enhanced impact resistance characteristics are the principal drivers to invent advanced materials for structural and armor applications. In this article, the dynamic transient impact response of hybrid composites developed from glass fabric, polycarbonate (PC) sheet with different relative volume fractions and different stacking arrangements is discussed. The dynamic tests are performed for evaluating the impact resistance of novel hybrid composites at an equal level of impact energy (55 J), impact velocity (4.56 m/s) and impactor mass (5.26 kg). Neat composite is prepared and tested for comparison. The hand-lay-up method with compression molding technique is employed for preparing all the laminates. Contribution of the thermoplastic sheet in conventional glass fiber reinforced composites toward improvisation of impact resistance is assessed and reported. Load–energy–deflection–time curves are plotted to understand the transient behavior of the composite plates. The results indicated that thermoplastic phase in the novel composite enhanced impact resistance in terms of load-carrying capability, energy absorption. Further, it reduced the degree of damage extent and damage area. The density reduction of 12.5–22.5% is noted for hybrid laminates on comparison with neat composite. The damage assessment carried using the vision measuring system revealed that the cone formation due to plastic deformation of PC along with fiber fracture and matrix cracking is the main reason for impact resistance enhancement.

Role of Size of Rubber Particles on Failure Mode and Impact Resistance Characteristics of PC/ABS Blends and their ABS Constituents with a Higher Rubber Content

This study presents an experimental study on failure modes and resistances of polycarbonate (PC)/Acrylonitrile Butadiene Styrene (ABS) blends and their ABS constituents under a drop weight impact test (DWIT). Failure modes and impact resistances such as impact strength and impact toughness of such blends are generally influenced by molecular weight of the PC, rubber content and size of rubber particle in ABS system. A preliminary study on ABS materials using a DWIT showed that size of rubber particle not only determined their failure modes but also influencing their resistance characteristics. However, in a previous study performed using the similar DWIT on PC/ABS blends with a 10 wt% rubber content, it was revealed that size of rubber particle did not significantly influence their resistances. Their failure modes were even macroscopically very difficult to be distinguished. This study, hence, is aimed to further explore role of the size of rubber particle on failure mode and impact resistance characteristics of the PC/ABS blends and their ABS constituents with a higher rubber content. The impact test results have revealed that with a 20 wt% rubber content, size of rubber particle only influenced the resistances of the PC/ABS blends. It did not significantly contribute to affect failure mode of the PC/ABS blends. Whilst, it significantly influenced failure modes and resistances of the ABS. The DWIT results also re-confirmed that blending a brittle ABS into PC led to produce a tougher PC/ABS blend.

Evaluation of concrete containing waste plastic shredded fibers: Ductility properties

AbstractApplication of concrete for pavement and barrier purposes demands ample energy absorption capacity and impact resistance characteristics. These attributes were investigated for concrete produced by using waste plastic shredded fibers (WPSF), which were obtained by shredding waste plastic bags. The WPSF were incorporated in concrete at an amount of 0, 0.5, 1.0, 2.0, 3.0, and 5.0% by weight of concrete. The strength (compressive and impact), and the ability to absorb the energy of concrete samples incorporating WPSF were evaluated. Additionally, empirical relations were also developed between WPSF fraction and compressive strength; WPSF fraction and impact energy for the first crack; WPSF fraction and impact energy for final failure; and WPSF fraction and energy absorption capacity using regression analysis method. The outcomes of the tests showed that there was a systematic decline in compressive strength of concrete on the inclusion of WPSF. However, superior energy absorption capacity and higher resistance to impact of concrete specimens were observed on the inclusion of WPSF. It was thus concluded that WPSF could be incorporated in concrete up to certain level for producing sustainable concrete pavement and barrier.