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The multi-layer armor shell structure of the scaly-foot snail has been proven to be resistant to penetration and perforation. Inspired by the special structure, a novel ceramic-composite impact-resistant structure was proposed. We developed a user-defined subroutine (VUMAT) of the finite element software ABQUS to analyze the progressive damage process and energy dissipation mechanism under impact. It is found that the novel structure features rigid-flexible coupling, both soft and hard layers play a key role in the impact resistance process. Compared with the traditional sandwich structure, the novel structure has better impact resistance under the impact energy of 20 J–80 J. [ABSTRACT FROM AUTHOR]

Basalt fiber-reinforced composite (BFRC) is extensively used in various fields such as rail transportation and aerospace. However, how to design the structure of BFRC to optimize its impact resistance remains a great challenge. Herein, inspired by the double-twisted Bouligand structure of coelacanth scales, a biomimetic BFRC is prepared. Significantly, the peak impact force of double-twisted BFRC (DT-BFRC) is 3408.12 N, which increases by 48.56% compared with unidirectionally laminated BFRC (UL-BFRC). The maximum residual elastic modulus of DT-BFRC reaches 7.88 J, which is 236.75% higher than that of UL-BFRC. This work offers a promising way to efficiently develop impact resistant BFRC. [ABSTRACT FROM AUTHOR]

To address the technical challenge that automobile wheels made of lightweight materials are prone to failure under dynamic impact loads, an integrated multi-objective optimization approach is proposed to determine the optimal design with enhanced impact resistance without reducing other structural performance. The shape-morphing technique, hybrid surrogate-based modelling approach, multi-objective particle swarm optimization algorithm, and a novel identification approach combining the modified technique for order preference by similarity to ideal solution and modified comprehensive objective weighting method are used separately to parameterize a model of the wheel, construct approximation models, solve the optimization process and determine the optimal trade-off design. The robustness and effectiveness of the identification method are demonstrated by analysing the effects of different optimization strategies on the optimal trade-off solutions. According to the optimized results, the impact resistance of the wheel is evidently enhanced while its total mass remains almost unchanged and other mechanical performance metrics are improved to varying degrees. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical properties of Polyurethane Bark Gum (PBG) reinforced with Solid Glass Beads (SGBs) of varying diameters and content. The tensile analysis demonstrates that a 1% SGB volume fraction maximizes tensile stress and fracture elongation due to synergic composite effects, with smaller SGBs enhancing interfacial adhesion and reducing microcrack formation. The impact analysis revealed that the addition of SGB reduced the impact strength due to interface delamination and energy dissipation mechanisms, with optimal impact resistance observed at a particle size of 0.4–0.6 mm and a content of 5%. Morphological characterization was conducted using optical microscopy, scanning electron microscopy, and synchrotron radiation CT scanning techniques, highlighting the role of SGB in toughening, crack bridging, and stress shielding. This study provides insights into the performance of PBG/SGB composite materials and guides the material design for specific applications. [ABSTRACT FROM AUTHOR]

Fused filament fabrication (FFF) is a rapidly growing additive manufacturing technique. It is widely used in various industrial applications due to its ability to efficiently produce functional parts with complex geometrical features. Estimating the mechanical properties and dimensional accuracy is essential for the functional testing of objects fabricated using the FFF process. Several process variables influence the mechanical qualities and dimensional accuracy of objects manufactured using FFF technology. Selecting the optimal set of parameters is crucial for achieving the desired properties in the final parts. This research investigated the influence of four crucial process variables, layer thickness, extrusion temperature, printing speed, and extrusion width, on the impact resistance and shear strength of polycarbonate parts printed using the fused filament fabrication (FFF) technique. A hybrid modelling approach involving dimensional analysis (DA)–based mathematical modelling and regression-based machine learning (ML) modelling was adopted to predict the two output responses and determine the correlation between the process parameters and mechanical properties. A comparison based on various error metrics and the performance of the models suggested that ML models have higher prediction performance and accuracy than DA models. The developed prediction models exhibited significant agreement with the observed values and may be used to forecast the mechanical characteristics of FFF components while manipulating the input parameters. The findings revealed that a maximum impact strength of 66.37 J/m and shear strength of 50.43 MPa were obtained when the layer height, extrusion temperature, printing speed, and extrusion width were 320 µm, 280 °C, 20 mm/s, and 0.56 mm, respectively. [ABSTRACT FROM AUTHOR]

Intelligent impact‐protection wearable devices often require intricate circuitry to operate, which hinders the timely display of impact‐related injuries. Consequently, it is imperative to develop intelligent protective materials that are self‐sufficient and capable of visualization. In this work, the impact protection material shear‐stiffening gel (SSG) is combined with the mechanoluminescent (ML) material ZnS:Cu/PDMS@SiO2 to create ML‐SSG. This material embodies various protective features, including impact protection, force visualization, flame resistance, and long‐distance passive control, making it ideal for intelligent wearable devices. In light of the significant shear stiffening effect of SSG, ML‐SSG effectively dissipates up to 80% of the impact energy and exhibits excellent impact resistance. Concurrently, ML‐SSG is also capable of visualizing impact injuries, displaying and warning in real‐time via mechanoluminescence, and assessing the impact force based on the intensity of mechanoluminescence. The incorporation of SiO2 and ZnS:Cu has resulted in ZnS:Cu/PDMS@SiO2 with remarkable flame‐retardant property. This innovative material significantly improves the performance of ML‐SSG in complex environments. In addition, ML‐SSG realizes human–computer interaction through neural network based on mechanoluminescence display characteristics. This research significantly expands the potential applications of multifunctional protective materials in various complicated environments, thereby promoting the development of wearable protective devices. [ABSTRACT FROM AUTHOR]

Magnetorheological elastomers (MREs) are innovative materials composed of ferromagnetic particles embedded within a polymer matrix, enabling real‐time tunability of mechanical properties through external magnetic fields, thereby generating pronounced mechanical‐magnetic coupling effects. However, the mechanical performance of MREs, particularly their load‐bearing capacities under dynamic conditions, remains constrained by the limitations of conventional matrix materials. In this study, shear‐stiffening gel (SSG), exhibiting viscoelastic mechanical behavior, is incorporated into magnetorheological elastomers to develop magnetorheological shear‐stiffening elastomer (MSSE) through a high‐temperature and high‐pressure vulcanization process. The mechanical‐magnetic coupling behavior of these composites is systematically evaluated utilizing a series of mechanical experiments across varying strain rates. Notably, the interaction between carbonyl iron particles (CIPs) and the molecular chains within the shear‐stiffening matrix significantly enhanced the magnetorheological effects of MSSEs, particularly under dynamic impact loadings. Leveraging the adjustable modulus of MSSEs and drawing inspiration from the microstructural characteristics of beetle exoskeletons, a beam‐structured 3D buffer device is designed. This device demonstrates superior energy absorption capacity, underscoring its potential for advanced flexible protection applications. [ABSTRACT FROM AUTHOR]

Various strategies are developed to engineer aligned hierarchical architectures in polymer hydrogels for enhanced mechanical performance. However, chain alignment remains impeded by the presence of hydrogen bonds between adjacent chains. Herein, a facile sacrificial micelle‐assisted‐alignment strategy is proposed, leading to well‐aligned, strong and tough pure chitosan hydrogels. The sacrificial sodium dodecyl sulfate micelles electrostatically interact with the protonated chitosan chains, enabling chain sliding and alignment under uniaxial forces. Subsequently, sacrificial micelles can be easily removed via NaOH treatment, causing the reforming of H‐bond in the chain networks. The strength of the pure chitosan hydrogels increases 140‐fold, reaching 58.9 ± 3.4 MPa; the modulus increases 595‐fold, reaching 226.4 ± 42.8 MPa. After drying‐rehydration, the strength and modulus further rise to 70.3 ± 2.4 and 403.5 ± 76.3 MPa, marking a significant advancement in high‐strength pure chitosan hydrogel films. Furthermore, the designed multiscale architectures involving enhanced crystallinity, well‐aligned fibers, strong interfaces, robust multilayer Bouligand assembly contribute to the exact replica of lobster underbelly with impact resistance up to 6.8 ± 1.0 kJ m−1. This work presents a promising strategy for strong, tough, stiff and impact‐resistant polymer hydrogels via well‐aligned hierarchical design. [ABSTRACT FROM AUTHOR]

The hybrid sandwich structures possessing composite faces and an aluminum foam (ALF) core exhibit lightweight and superior impact resistance. However, limited studies pay attention to the mechanical behavior of hybrid sandwich beams with various ALF densities. The present article has focused on the influence of foam densities on the quasi‐static and low‐velocity impact (LVI) behaviors of hybrid sandwich beams with aramid‐fiber‐reinforced polymer (AFRP) faces and ALF core. The failure mode, loading response, and energy absorption of sandwich beams have been obtained experimentally and the failure map with a wide range of dimensional configurations has been established theoretically. Increasing core density significantly enhances the load‐carrying capacity of the sandwich beam, and the enhanced effect becomes more obvious for a thicker core. The medium‐density ALFs provide the maximum specific energy absorption, while the high‐density ALFs offer the highest energy absorption for hybrid sandwich beams. The applicability of core densities in hybrid sandwich structures is provided. Highlights: Normal strain distribution under quasi‐static loading is analyzed using DIC.AFRP face microbuckling provides higher impact resistance than core failure.The applicability of core density in hybrid sandwich structures is given. [ABSTRACT FROM AUTHOR]

Aluminium foam sandwich panels (AFSPs) have a high impact resistance and are suitable for a wide range of engineering applications. To improve corrosion resistance, this paper proposes an anti-corrosion sandwich panel with stainless steel as the upper sheet. Drop hammer impact tests were performed on a total of ten AFSPs to investigate their dynamic response and failure patterns. To assess the deformation performance of AFSPs, a laser displacement meter was used to obtain the bottom centre displacement. The effects of the impact energy and the thickness of each component of AFSPs on the peak impact force and deformation performance were studied. Test results showed that the thickness of each component had notable effects on the impactor and bottom displacements. In addition, the effect of the unit mass of the components in AFSPs on decreasing the bottom displacement was discussed. Compared to increasing the aluminium foam and lower sheet thicknesses, increasing the upper sheet thickness was more effective in decreasing the bottom displacement. A finite element model of AFSPs was developed to conduct parameter analysis, indicating that impactors with larger diameters resulted in higher peak forces and reduced deformation of AFSPs. [ABSTRACT FROM AUTHOR]

The traditional Miura-ori was optimized to Miura-ori with platforms by geometric parameters. Two types of impactors were used to conduct low-velocity impact experiments at two specific sites. The damage morphology, response characteristics, and failure mechanism under various energy were systematically investigated. The results reveal that the impact resistance of the node is better than that of the base due to crushing absorbing energy. The impact resistance of the Miura-ori with platforms sandwich structures to the flat-ended impactor is better than that of the hemispherical impactor at the node. Still, the performance at the base is the opposite. [ABSTRACT FROM AUTHOR]

To enhance the impact resistance of hydraulic columns, a theoretical analysis method was employed to develop a dynamic characteristic analysis model for conventional columns under impact loads. This model facilitated the derivation of key parameters such as equivalent stiffness, maximum retraction amount, and impact duration. A fluid-solid coupling model for the conventional column was constructed using finite element and coupled Eulerian-Lagrangian (CEL) methods. Subsequently, numerical simulation results were compared and analyzed against theoretical predictions. Based on this analysis, an energy-absorbing column was designed, and its fluid-solid coupling model was established to investigate its mechanical response under static and dynamic impact loads.The findings indicate that under a static load of 2000 kN, when superimposed with impact loads of 200 kJ, 400 kJ, and 800 kJ respectively, the peak impact forces on energy-absorbing columns are 89.20%, 91.72%, and 98.42% lower than those on normal columns. The yield displacements of energy-absorbing columns increase by 142.26%, 109.15%, and 108.41% compared to normal columns. Energy absorption in energy-absorbing columns is 152.11%, 171.80%, and 145.18% higher than in normal columns. Furthermore, initial velocities of energy-absorbing columns are consistently lower compared to normal columns. After reaching initial velocity, energy-absorbing columns exhibit reduced oscillations due to interactions between the energy absorber, column, and hydraulic fluid system under impact loads. Unlike normal columns, energy-absorbing columns mitigate stress concentration at the column head through interactions between the energy absorber, emulsion, and column. Additionally, the impact resistance time of energy-absorbing columns is 2.19, 1.64, and 1.85 times longer than that of normal columns.Energy-absorbing columns outperform conventional columns across six metrics: peak impact force, column yield displacement, energy absorption, column movement speed, stress distribution, and impact resistance time, demonstrating superior mechanical properties in impact resistance. [ABSTRACT FROM AUTHOR]

The capacity to withstand challenges posed by complex environments is crucial for developing advanced high‐performance protective materials with mechanically adjustable nature. By constructing long‐range hierarchical network of shear‐stiffening gel‐carbon nanotube‐cellulose nanofiber (SCC) embedded within epoxy resin (ER), this work engineers a nacre‐inspired variable‐stiffness SCC‐ER composite (SCCE). Lightweight SCC scaffold attenuates falling impact force from 2.23 to 0.46 kN, and reaches 60 °C within 20 s under 1 sun exposure. Additionally, owing to the rigid ER matrix, SCCE exhibits 4.03 GPa elastic modulus, outperforming numerous conventional engineering materials in puncture resistance. Specific energy absorption of nacre‐mimetic SCCE presents 1.91 MJ m−3 while that of random structural SCCE is only 0.50 MJ m−3. More importantly, SCCE features representative photothermal‐induced reversible rigidity whose storage modulus varies from 9.85 MPa at 30 °C to 11.61 kPa at 116 °C under light stimulation. It also presents shape‐programmability, capable of adhering complex structural surfaces for protection. Eventually, SCCE‐based semi‐active adjustable protectors are constructed that leverage contactless photothermal effect to modulate rigidity. 5 mm‐thick smart SCCE‐protectors resist 163.93 m s−1 ballistic impact while 15‐mm commercial kneepads are penetrated at lower speed of 136.98 m s−1. This bio‐inspired semi‐active strategy proposes a promising avenue for enhancing personal protective equipment. [ABSTRACT FROM AUTHOR]

Engineered Cementitious Composites (ECC) are highly regarded in construction owing to their tensile ductility and crack control capabilities, making them suitable for various structural applications. The accumulation of multi-walled carbon nanotubes (MWCNTs) further enhances their mechanical properties. However, there’s a significant knowledge gap concerning MWCNTs-ECC impact resistance. The objective of this study is to tackle the challenges associated with evaluating, optimizing, and predicting MWCNTs-ECC impact resistance to ensure its safe and widespread use in critical infrastructure by applying response surface methodology (RSM). Moreover, the 13 mixtures of ECC combined with several quantities of PVA fiber and MWCNTs as input elements were utilized to calculate the first (E1) and final (E2) impact energies. The findings demonstrated that the MWCNTs-ECC combinations’ impact resistance improved as the input ingredient concentrations increased. Besides, the optimum E1 and E2 of ECC combined with 1% of PVA fiber were noted by 1398 Joules and 12,956 Joules at 0.065% of MWCNTs on 28 days respectively. Furthermore, Response prediction models for E1 and E2 were created, and after being validated with an analysis of variance (ANOVA), it was determined that they had high R2 readings of 99.30% and 99.07%, correspondingly. The optimization process produced an ideal number of input variables for MWCNTs and PVA fiber, respectively, of 0.066% and 1%, with a desirability value of 100%. Moreover, it is recommended that the usage of 0.066% of MWCNTs in ECC combined with 1.0–1.50% PVA fiber provides optimum results for the construction industry. [ABSTRACT FROM AUTHOR]

During the past decade, a lot of study has been conducted in the favor of biomimicry and its applications in our daily lives. Fish scales, specifically, are being investigated with quite a lot of detail, and there are several species which possess an impressive mechanical property when under impact loadings and these impact loadings are naturally observed on the fish scale of the prey by the sharp teeth of predator fish when under attack. Considering such a reputation of fish scales, this article provides a concise look into the structural dependability of a fish scale from a species called Arapaima Gigas, which is a freshwater fish species found in the Amazon River. [ABSTRACT FROM AUTHOR]

The use of alternative materials in concrete creation has increased recently because of the mixture's advantages, both economically and technically. Incorporating some industrial waste in the concrete sector produce initiative that are sustainable in addition to developing concrete. This study focuses on the compressive, flexural, impact behavior, and attained sustainability of concrete that has glass powder (GP) and fly ash (FA) in place of some cement. Ordinary Portland Cement was used with partially replaced by FA and GP in the range of 0.0-10.10% (FA, GP), which represented by five concrete mixes. Concrete samples were subjected to testing for impact resistance, flexural strength, and compressive strength. The findings shown that while activated FA and GP reduce strengths at earlier ages (7 and 14 days), they improve compressive flexural strengths after 28 days of age. According to strength, the activated FA and GP performed best at 10% and 0% substitutes, respectively, at age 28 days. At 90 days, the best mixture performed best with ratios 10% and 10% FA and GP, respectively, also acquired maximum impact resistance. In term of sustainability, the findings demonstrated that substituting up to 20% of these wastes for cement in concrete led to a reduction in CO2 emission of up to 25% when compared to references combination. [ABSTRACT FROM AUTHOR]

Biochar is a well‐known sustainable and effective additive used in mortar/concrete to improve its mechanical properties. However, its potential to improve the impact resistance of concrete is still unexplored. This paper investigates biochar's effectiveness in improving the strength and impact performance of alkali‐activated slag concrete (AASC). Five AASC samples with 0%, 2%, 4%, 6%, and 8% rice husk biochar (RB) were employed in an experimental program. The strength and the impact resistance were tested, and the latter was assessed over a drop‐weight test conforming to the ACI Committee 544 guidelines. The crack propagation of the impact‐tested samples was examined using micro‐CT images. The results showed that adding RB up to 6% improved, notably the 28‐day compressive strength of AASC. At 6% RB, the strength enhancement was 44.6%, whereas no additional gain was observed at the 8% RB blend. More importantly, except for the 8% RB sample, the impact resistance was considerably augmented with the RB level increment. The increment in the impact number at the first crack and the failure in the 6% RB sample were as high as 185% and 180%, respectively. The reduction in the solution/binder ratio of the mix with the addition of biochar and the internal curing effect of biochar were deemed to be responsible for these improvements. However, possibly due to biochar's brittle characteristics, the increase in RB dosage from 6% to 8% reduced the impact resistance drastically. [ABSTRACT FROM AUTHOR]

Abstract Aluminium foam sandwich panels (AFSPs) have a high impact resistance and are suitable for a wide range of engineering applications. To improve corrosion resistance, this paper proposes an anti-corrosion sandwich panel with stainless steel as the upper sheet. Drop hammer impact tests were performed on a total of ten AFSPs to investigate their dynamic response and failure patterns. To assess the deformation performance of AFSPs, a laser displacement meter was used to obtain the bottom centre displacement. The effects of the impact energy and the thickness of each component of AFSPs on the peak impact force and deformation performance were studied. Test results showed that the thickness of each component had notable effects on the impactor and bottom displacements. In addition, the effect of the unit mass of the components in AFSPs on decreasing the bottom displacement was discussed. Compared to increasing the aluminium foam and lower sheet thicknesses, increasing the upper sheet thickness was more effective in decreasing the bottom displacement. A finite element model of AFSPs was developed to conduct parameter analysis, indicating that impactors with larger diameters resulted in higher peak forces and reduced deformation of AFSPs.

Flexible materials to achieve deformable wing technology requires high mechanical properties of flexible materials，the existing research on chiral structures as flexible materials to drive deformable wings is based on the case of linear small deformations. In order to investigate the mechanical properties of chiral structures under large deformation conditions，five common chiral system negative Poisson's ratio structures，such as tri-chiral，anti-trichiral，tetra-chiral，anti-tetra-chiral，and hex-chiral structures are taken as the object of study. Based on the theory of cellular structural mechanics，the effect of topological structure and cellular element geometrical parameter on the in-plane compression and energy absorption characteristics of chiral system negative Poisson's ratio structures of the intrinsic model of ideal plastic materials are compared and analysed. The results show that the elastic modulus，plateau stress and energy absorption capacity of the chiral structure are inversely proportional to the cell element parameter α and positively proportional to the cell element parameter β. The topology affects the energy-absorbing properties of chiral structures significantly，i.e.，the energy-absorbing capacity of chiral structures with the same single-cell geometrical parameter is significantly enhanced with the increase in the number of ligaments.

Abstract To enhance the impact resistance of hydraulic columns, a theoretical analysis method was employed to develop a dynamic characteristic analysis model for conventional columns under impact loads. This model facilitated the derivation of key parameters such as equivalent stiffness, maximum retraction amount, and impact duration. A fluid-solid coupling model for the conventional column was constructed using finite element and coupled Eulerian-Lagrangian (CEL) methods. Subsequently, numerical simulation results were compared and analyzed against theoretical predictions. Based on this analysis, an energy-absorbing column was designed, and its fluid-solid coupling model was established to investigate its mechanical response under static and dynamic impact loads.The findings indicate that under a static load of 2000 kN, when superimposed with impact loads of 200 kJ, 400 kJ, and 800 kJ respectively, the peak impact forces on energy-absorbing columns are 89.20%, 91.72%, and 98.42% lower than those on normal columns. The yield displacements of energy-absorbing columns increase by 142.26%, 109.15%, and 108.41% compared to normal columns. Energy absorption in energy-absorbing columns is 152.11%, 171.80%, and 145.18% higher than in normal columns. Furthermore, initial velocities of energy-absorbing columns are consistently lower compared to normal columns. After reaching initial velocity, energy-absorbing columns exhibit reduced oscillations due to interactions between the energy absorber, column, and hydraulic fluid system under impact loads. Unlike normal columns, energy-absorbing columns mitigate stress concentration at the column head through interactions between the energy absorber, emulsion, and column. Additionally, the impact resistance time of energy-absorbing columns is 2.19, 1.64, and 1.85 times longer than that of normal columns.Energy-absorbing columns outperform conventional columns across six metrics: peak impact force, column yield displacement, energy absorption, column movement speed, stress distribution, and impact resistance time, demonstrating superior mechanical properties in impact resistance.

Abstract Engineered Cementitious Composites (ECC) are highly regarded in construction owing to their tensile ductility and crack control capabilities, making them suitable for various structural applications. The accumulation of multi-walled carbon nanotubes (MWCNTs) further enhances their mechanical properties. However, there’s a significant knowledge gap concerning MWCNTs-ECC impact resistance. The objective of this study is to tackle the challenges associated with evaluating, optimizing, and predicting MWCNTs-ECC impact resistance to ensure its safe and widespread use in critical infrastructure by applying response surface methodology (RSM). Moreover, the 13 mixtures of ECC combined with several quantities of PVA fiber and MWCNTs as input elements were utilized to calculate the first (E1) and final (E2) impact energies. The findings demonstrated that the MWCNTs-ECC combinations’ impact resistance improved as the input ingredient concentrations increased. Besides, the optimum E1 and E2 of ECC combined with 1% of PVA fiber were noted by 1398 Joules and 12,956 Joules at 0.065% of MWCNTs on 28 days respectively. Furthermore, Response prediction models for E1 and E2 were created, and after being validated with an analysis of variance (ANOVA), it was determined that they had high R2 readings of 99.30% and 99.07%, correspondingly. The optimization process produced an ideal number of input variables for MWCNTs and PVA fiber, respectively, of 0.066% and 1%, with a desirability value of 100%. Moreover, it is recommended that the usage of 0.066% of MWCNTs in ECC combined with 1.0–1.50% PVA fiber provides optimum results for the construction industry.

Abstract Hydraulic actuated quadruped robots have bright application prospects and significant research values in unmanned area investigation, disaster rescue and other scenarios, due to the advantages of high payload and high power to weight ratio. Among these fields, inevitable collision of robots may occur when contact with unknown objects, step on empty objects, or collapse, all of which have an impact on the working hydraulic system. To overcome the unknown external disturbances, this paper proposes an active disturbance rejection control (ADRC) strategy of double vane hydraulic rotary actuators for the hip joints of the quadruped robots. Considering the order of the valve-controlled actuator model, a three-stage tracking differentiator, a four-stage extended state observer, and a state error feedback controller are designed relatively, and the extended state observer is adopted to observe and compensate the uncertainty of external load torque of the system. The effectiveness of the ADRC method is verified in simulation environment and a single joint experimental platform. Moreover, the impact experiments of the limb leg unit are carried out after introducing the proposed ADRC strategy into hip joint, the limb leg unit of quadruped robots presents better impact resistance ability.

The high‐speed impact‐resistanct materials are of great significance while their development is hindered by the intrinsic tradeoff between mechanical strength and energy dissipation capability. Herein, the new chemical system of molecular granular material (MGM) is developed for the design of impact‐resistant materials from the supramolecular complexation of sub‐nm molecular clusters (MCs) and hyper‐branched polyelectrolytes. Their hierarchical aggregation provides the origin of the decoupling of mechanical strengths and structural relaxation dynamics. The MCs' intrinsic fast dynamics afford excellent high‐speed impact‐resistance, up to 5600 s−1 impact in a typical split‐Hopkinson pressure bar test while only tiny boundary cracks can be observed even under 7200 s−1 impact. The high loadings of MCs and their hierarchical aggregates provide high‐density sacrificial bonding for the effective dissipation of the impact energy, enabling the protection of fragile devices from the direct impact of over 200 m s−1 bullet. Moreover, the MGMs can be conveniently processed into protective coatings or films with promising recyclability due to the supramolecular interaction feature. The research not only reveals the unique relaxation dynamics and mechanical properties of MGMs in comparison with polymers and colloids, but also develops new chemical systems for the fabrication of high‐speed impact‐resistant materials. [ABSTRACT FROM AUTHOR]

Hydraulic actuated quadruped robots have bright application prospects and significant research values in unmanned area investigation, disaster rescue and other scenarios, due to the advantages of high payload and high power to weight ratio. Among these fields, inevitable collision of robots may occur when contact with unknown objects, step on empty objects, or collapse, all of which have an impact on the working hydraulic system. To overcome the unknown external disturbances, this paper proposes an active disturbance rejection control (ADRC) strategy of double vane hydraulic rotary actuators for the hip joints of the quadruped robots. Considering the order of the valve-controlled actuator model, a three-stage tracking differentiator, a four-stage extended state observer, and a state error feedback controller are designed relatively, and the extended state observer is adopted to observe and compensate the uncertainty of external load torque of the system. The effectiveness of the ADRC method is verified in simulation environment and a single joint experimental platform. Moreover, the impact experiments of the limb leg unit are carried out after introducing the proposed ADRC strategy into hip joint, the limb leg unit of quadruped robots presents better impact resistance ability. [ABSTRACT FROM AUTHOR]

The fractal theory can effectively describe the complexity and multi-scale of concrete under impact load and provide a scientific basis for evaluating concrete's impact resistance. Therefore, based on the fractal theory, this study carried out the fragmentation size analysis by weighing the quality of SFRRAC fragments, disclosed the distribution characteristics of impact fragmentation size of steel fiber reinforced recycled aggregate concrete (SFRRAC) specimens under different recycled coarse aggregate (RCA) replacement ratio, different steel fiber (SF) contents and different impact pressures. The results indicate that the fractal dimension can describe the degree of fragmentation of the specimen. The greater the fractal dimension, the more the amount of fragmentation of the specimen subjected to impact load, the lesser the fragmentation size, and the greater the degree of fragmentation. Under the impact load, the fractal dimension of SFRRAC is between 1.36 and 2.28. As the impact pressure increases, the energy consumption increases, and the fractal dimension decreases. With the growth in replacement ratio, the fractal dimension gradually increases, and the energy consumption is negatively correlated with the fractal dimension. Along with the growth of SF content, the energy consumption gradually increases, and the fractal dimension continuously decreases. A new metric angle is provided to explore the inherent law between the impact-crushing characteristics of SFRRAC and the dynamic load, thereby offering foundational support for the application of SFRRAC in practical engineering. [ABSTRACT FROM AUTHOR]

Wireless communication technology is indispensable in our daily lives, but it also results in serious electromagnetic radiation pollution. Hence, developing smart electromagnetic interference shielding materials with adjustable electromagnetic wave (EMW) responses holds significant promise for future electromagnetic shielding devices. In this study, we propose an electromagnetic shielding switch (ESS) characterized by tunable electromagnetic shielding performance achieved by fabricating a three-dimensional (3D) carbon nanotube-based spacer fabric (CNT-SF) and modifying CNT-SF with chemical vapor deposition (CCNT-SF). The CCNT-SF displays direction-dependent electrical conductivity by manipulating the warp and weft density, measuring 128 S/m transversely and 447 S/m vertically. This characteristic allows the CCNT-SF to transmit or shield EMW by adjusting the angle of EMW incidence through fabric rotation, resulting in anisotropic electromagnetic shielding performance (33 dB transversely and 87 dB vertically). This feature enables switchable shielding with an on/off ratio of 2.64. Furthermore, the unique 3D structure confers excellent mechanical properties on the fabric, with compressive strength reaching 120 kPa. As a flexible, lightweight, and mechanically robust ESS, the CCNT-SF holds promising prospects for mitigating the challenges of increasingly severe and intricate electromagnetic environments. [ABSTRACT FROM AUTHOR]

Concrete is the second most common material demanded over the world. Recently, a trending issue is the vast tracking in constructing infrastructure to ensure traffic movement and life quality. Concrete types such as self and rolled compacted concrete offer magical solutions ensuring vast infrastructure and life quality. However, these structures must be assessed using non-destructive testing methods to observe the difference between the concrete types. Several studies have used recycled waste, specifically the crumb rubber extracted from old tires, as a potential replacement for natural aggregate in concrete manufacturing. However, limited research has been devoted to nondestructive testing of produced concrete to further evaluate existing concrete elements containing crumb rubber. This study investigates the self and rolled compacted concrete in comparison with normal ones, in addition to using chopped rubber as recycled materials. This study examines the concrete manufactured destructively by evaluating its compressive, tensile, and flexural strength, in addition to impact resistance, and correlates those results with the non-destructive such as Schmit hammer and Ultrasonic Pulse (UPV) for extended utilization of the concrete produced and data publication. The results showed unique performance and a high potential for data contribution to the extensive utilization of self-compacted rubberized concrete and rolled compacted concrete. [ABSTRACT FROM AUTHOR]

AbstractAs known, ceramics possess desirable strength, hardness and low density, which have been extensively applied in engineering fields. However, the inherent brittleness makes the ceramics present poor toughness and consequently impact resistance as well. In recent decades, some ingenious architectures of biomaterials employed to improve the mechanical properties of brittle bulk materials, such as laminate and brick-mud, have become increasingly popular. Here, in order to further enhance the impact resistance of ceramics, a kind of hybrid ceramic-based composite structure is designed according to the gradient feature in dactyl club of mantis shrimp. The impact resistance performances of bulk, laminate, brick-mud and hybrid structures are investigated by finite element simulation. The results show that the hybrid structure can effectively avoid catastrophic failure, thereby having large scope of deformation area to store energy. Moreover, the damage mass of impactor for the hybrid plate is the largest due to the beginning hard collision between impactor and target plate and long cumulative damaging time of impactor. As a result, with the highest internal energy and eroding kinetic energy of impactor simultaneously, the hybrid structure dissipates the most energy of impactor. Further, under extreme working conditions of oblique and high velocity impact, the hybrid structure still exhibits optical impact resistance performance. [ABSTRACT FROM AUTHOR]

Since acrylate‐based materials are widely used in dentistry, their drawbacks such as low impact resistance and hardness, require continuous research in the field of materials science in order to avoid sudden fracture caused by chewing or fall. In this study, auto‐polymerizing poly(methyl methacrylate) (PMMA), commonly used as denture base material, was reinforced with poly(4‐styrenesulfonic acid‐co‐maleic anhydride) sodium salt (PSSMA) and strontium titanate (STO), with the aim of improving impact behavior and microhardness. Morphological analysis confirmed formation of phase‐separated and co‐continuous microscopic structures of PSSMA in PMMA, without visible agglomerates of STO nanoparticles, indicating that PSSMA‐STO interaction contributed to a better distribution of nanoparticles. Fourier transformed infrared spectroscopy revealed that PSSMA and STO did not interfere in the polymerization of methyl methacrylate. This was further supported by thermal analysis, which also showed that the addition of PSSMA and STO had no significant influence on thermal degradation. On the other side, PSSMA and STO significantly enhanced mechanical performance of PMMA. The modulus of elasticity increased by up to 48.6%, total absorbed impact energy improved by up to 108.4%, and microhardness increased by up to 272.8% when PSSMA was combined with STO for reinforcing denture PMMA. These results demonstrate the significant potential of PSSMA, which could be combined with other ceramic nanoparticles for denture reinforcement in the future. Highlights: This research presents novel dental hybrid composite.Influence of strontium titanate (STO) and poly(4‐styrenesulfonic acid‐co‐maleic anhydride) sodium salt (PSSMA) on poly(methyl methacrylate) (PMMA) was investigated.PSSMA/STO improved modulus of elasticity, microhardness and impact resistance.Sample with 5 wt% PSSMA and 1 wt% STO showed the highest improvement compared to PMMA.Presented hybrid composite could use as denture base material. [ABSTRACT FROM AUTHOR]

In the present study, nylon waste fibers (NWF) were utilized for the first time to improve the impact resistance of self-compacting concrete (SCC) slabs against pistol shooting. Six ratios of NWF were used in the range of (0.25- 1.5 at an increment of 0.25) % with three different lengths (50, 70, and 90) mm for each ratio. The fresh properties, compressive strength, and Utara sonic pulse velocity (UPV) of SCC were also measured. The results indicate the positive role of NWF in improving compressive strength. However, the fresh properties are affected negatively by using NWF. The best impact resistance of the slab occurred when 1% of NWF with a length of 90 mm was utilized. [ABSTRACT FROM AUTHOR]

Sandwich structures are widely used in engineering fields, but their connection and assembly problems become more and more prominent, especially for combat equipment under strong dynamic loads. How to design connection joints to improve the reliability and maintainability of the structure is a hot research topic at present. Aimed at the connection and assembly problem of honeycomb sandwich protection structures in typical combat environment, a quick assembly joint locked by square tubes was designed, and the dynamic responses of the connection structure under different impulses were obtained by foam projectile impact tests. Then the finite element method was used to simulate the impact test, and the simulation results agree well with the experimental results. On this basis, the effects of geometric parameters such as wall thicknesses and connection unit widths on the peak deflections of the structure under the foam projectile impacts were further discussed with the finite element model. The results indicate that, the thinner wall thickness (tt/tf≤0.375) of the square tube makes the connection structure prone to collapse, leading to a significant increase in peak deflections. However, a smaller width (2a/W≤0.267) of the connection unit causes the panel tensile strength to decrease, thereby weakening the impact resistance of the connection structure. In addition, as the connection unit width increases, the peak deflection of the connection structure will first decrease and then increase. This is due to the competition mechanism between the effective cross-sectional area of the connection unit and the mechanical interlocking contact area. The proposed quick assembly connection joint can effectively resist dynamic impact loads, has good impact energy absorption abilities, and easy maintenance and replacement. It is hopeful to be applied to the connection of various types of main combat equipment protection structures, and provides reference for the impact resistance design of sandwich connection structures. [ABSTRACT FROM AUTHOR]

The packaging materials with cushioning performance are used to prevent the internal contents from being damaged by the impact and vibration of external forces. The polyurethane microcellular elastomers (PUMEs) can absorb energy through cell collapse and molecular chain creep. In this study, PUMEs with different densities were investigated by scanning electron microscopy, dynamic mechanical analysis and dynamic compression tests. PUMEs exhibited significant impact resistance and the maximum peak stress attenuation ratio reached 73.33%. The protective equipment was made by PUME with the optimal density of 600 kg/m3, and then the acceleration sensing device installed with the same protective equipment fell from a height of 3, 5 and 10 m to evaluate the energy-absorbing property and reusability of PUMEs. The results showed that PUMEs equipment reduced the peak acceleration of the device by 93.84%, with a maximum deviation of 9% between actual test and simulation, and shortened the impact time of first landing by 57.39%. In addition, the equipment PUMEs equipment could effectively reduce the stress on the protected items. [ABSTRACT FROM AUTHOR]

This study examines the stress characteristics and deformation modes of masonry walls under flood loads in a 500kV substation project in Xinyang City, Henan Province. A simplified finite element model of substation masonry walls is developed in ABAQUS, considering dynamic water loads, the stress characteristics and deformation modes of masonry walls under flood loads are studied. Flood depth, water velocity, and erosion depth are selected as variables to carry out the parametric analysis of masonry enclosure walls under flood load, to investigate the dynamic response of walls under various parameters, and to examine the damage mechanism of the wall. The research findings suggest that stress levels are elevated at critical locations, such as the bottom center of the wall, the junction between the inner wall and structural column, and the connection between the foundation and structural column during flood loading. The safety of a masonry wall is significantly compromised when flood depth exceeds 0.8 m, water velocity exceeds 2.3 m/s, or erosion depth reaches 0.4 m. A proposed measure aims to enhance the performance of masonry walls by improving stress distribution and reducing stress concentrations, thereby significantly augmenting their load-bearing capacity. [ABSTRACT FROM AUTHOR]

The equine hoof wall has outstanding impact resistance, which enables high-velocity gallop over hard terrain with minimum damage. To better understand its viscoelastic behavior, complex moduli were determined using two complementary techniques: conventional (∼5 mm length scale) and nano (∼1 µm length scale) dynamic mechanical analysis (DMA). The evolution of their magnitudes was measured for two hydration conditions: fully hydrated and ambient. The storage modulus of the ambient hoof wall was approximately 400 MPa in macro-scale experiments, decreasing to ∼250 MPa with hydration. In contrast, the loss tangent decreased for both hydrated (∼0.1–0.07) and ambient (∼0.04–0.01) conditions, over the frequency range of 1–10 Hz. Nano-DMA indentation tests conducted up to 200 Hz showed little frequency dependence beyond 10 Hz. The loss tangent of tubular regions showed more hydration sensitivity than in intertubular regions, but no significant difference in storage modulus was observed. Loss tangent and effective stiffness were higher in indentations for both hydration levels. This behavior is attributed to the hoof wall's hierarchical structure, which has porosity, functionally graded aspects, and material interfaces that are not captured at the scale of indentation. The hoof wall's viscoelasticity characterized in this work has implications for the design of bioinspired impact-resistant materials and structures. The outer wall of horse hooves evolved to withstand heavy impacts during gallop. While previous studies have measured the properties of the hoof wall in slowly changing conditions, we wanted to quantify its behavior using experiments that replicate the quickly changing forces of impact. Since the hoof wall's structure is complex and contributes to its overall performance, smaller scale experiments were also performed. The behavior of the hoof wall was within the range of other biological materials and polymers. When hydrated, it becomes softer and can dissipate more energy. This work improves our understanding of the hoof's function and allows for more accurate simulations that can account for different impact speeds. [Display omitted] [ABSTRACT FROM AUTHOR]

Traditional cement epoxy pavements suffer from inherent limitations such as terrible tribological properties, poor wear resistance, and weak impact resistance, presenting significant challenges to ensure the safety and continuous operation of urban roads. As a solution, high-performance cement epoxy composite grouting materials have emerged as the preferred option for engineering construction and road maintenance. In this study, CSP/epoxy cement (CSEC) composite materials were prepared by emulsion polymerization. The thermal properties of the materials were characterized, revealing that CSP enhances the thermal properties of epoxy cement (EC) to a certain extent. Furthermore, the frictional properties of CSEC composite materials and pure epoxy cement under different normal loads were investigated. The results indicated that the CSEC composite material exhibited a slight increase in friction coefficient and a notable decrease in wear rate compared to pure epoxy cement (EC). Specifically, the wear rate of CSEC decreased by 14.4% at a load of 20 N, highlighting the enhanced frictional performance facilitated by CSP. Mechanistic analysis attributed the improvement to the unique core-shell structure of CSP, which imparted higher impact resistance and eliminated alleviate residual stresses at the friction interface. This structural advantage further enhanced the wear resistance of materials, making it a promising choice for improving the durability and safety of urban road surfaces. [ABSTRACT FROM AUTHOR]

The TNM alloy, a βo-phase-containing TiAl alloy, has been withdrawn from use as a last-stage turbine blade in commercial jet engines as it suffered frequent impact fractures in service, raising doubts regarding the necessity of the βo-phase in practical TiAl alloys. Here, we evaluate the practical properties required for jet engine blades for various TiAl alloys and investigate the effects of the βo-phase thereupon. First, we explore the influence of the βo-phase content on the impact resistance and machinability for forged Ti–43.5Al–xCr and cast Ti–46.0Al–xCr alloys; the properties deteriorate significantly at increasing βo-phase contents. Subsequently, two practical TiAl alloys—TNM alloy and TiAl4822—were prepared with and without the βo-phase by varying the heat treatment temperature for the former and the Cr concentration for the latter. In addition to impact resistance and machinability, the creep strength is significantly reduced by the presence of the βo-phase. Overall, these findings suggest that the βo-phase is an undesirable phase in practical TiAl alloys, especially those used for jet engine blades, because, although the disordered β-phase is soft at high temperatures, it changes to significantly more brittle and harder βo-phase after cooling. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Structural materials such as ceramics, metals, and carbon fiber‐reinforced plastics (CFRP) are frequently threatened by large compressive and impact forces. Energy absorption layers, i.e., polyurethane and silicone foams with excellent damping properties, are applied on the surfaces of different substrates to absorb energy. However, the amount of energy dissipation and penetration resistance are limited in commercial polyurethane foams. Herein, a distinctive nacre‐like architecture design strategy is proposed by integrating hard porous ceramic frameworks and flexible polyurethane buffers to improve energy absorption and impact resistance. Experimental investigations reveal the bioinspired designs exhibit optimized hardness, strength, and modulus compared to that of polyurethane. Due to the multiscale energy dissipation mechanisms, the resulting normalized absorbed energy (≈8.557 MJ m−3) is ≈20 times higher than polyurethane foams under 50% quasi‐static compression. The bioinspired composites provide superior protection for structural materials (CFRP, glass, and steel), surpassing polyurethane films under impact loadings. It is shown CFRP coated with the designed materials can withstand more than ten impact loadings (in energy of 10 J) without obvious damage, which otherwise delaminates after a single impact. This biomimetic design strategy holds the potential to offer valuable insights for the development of lightweight, energy‐absorbent, and impact‐resistant materials. [ABSTRACT FROM AUTHOR]

In this paper, a new type of foldcore sandwich panel (tentatively called X‐type foldcore sandwich panel) is proposed by combining the X‐type corrugated sandwich panel and the Miura‐ori sandwich panel. The experimental specimens are prepared by using a glass fiber‐reinforced polymer. To systematically reveal the low‐velocity response mechanism and impact resistance of sandwich panels, a hemispherical impactor is used to impact panels. The effects of impact energy, impact position, diameter of tup, and impact mass on low‐velocity impact performance of X‐type foldcore sandwich panels are considered. The damage morphology, response process, and failure mechanism are analyzed under different working conditions. The results show that under the impact of 75 and 125 J, the impact resistance of the node is better than that of the base. Under 200 J impact, the impact resistance of the base is better than that of the node. Compared with the traditional foldcore sandwich panel, the new configuration reduces the impact resistance difference between two positions (node and base). Highlights: A new foldcore sandwich panel is proposed.The impact effect of energy, mass, position, and tup diameter is investigated.Damage morphology, response process, and impact resistance are analyzed.The new structure reduces differences in impact resistance. [ABSTRACT FROM AUTHOR]

The safety of airport runways is important to guarantee aircraft taking-off, landing, and taxiing, and the comparison of the mechanical response of pavement structures under dynamic and static loading by LS-DYNA has rarely been studied. The purpose of this work is to separate two analysis methods to investigate the mechanical response of rigid airport pavements. Firstly, a tire–road coupling model of an airfield was established to evaluate the suitability of dynamic and static analyses. Then, the effects of landing pitch angles, sinking speeds, and tire pressures on the effective stress, effective strain, and z-displacement of the runway were investigated for both dynamic and static analysis. Finally, the significance of influence factors was analyzed by regression analysis in Statistical Product and Service Solutions (SPSS). The results indicated that the effective stress, effective strain, and z-displacement of the runway increased with a decrease in the landing pitch angle, which also increased with an increase in the sinking speed and tire pressure. It was demonstrated that the difference in pavement mechanical response between dynamic and static analyses progressively widened at high tire pressure and sinking speed. In other words, the static analysis method can be adopted to assess the dynamic mechanical behavior when the landing pitch angle is large and the tire pressure is small. Among the various factors of mechanical response, the effect of tire pressure was the most obvious, followed by sinking speed and landing pitch angle. The work proposes a new approach to understanding the mechanical behavior of runways under complicated and varied conditions, evaluates the applicability of the dynamic and static mechanical analysis methods, identifies key factors in the dynamic and static mechanical analysis of rigid runways, and provides technical support for improving and maintaining the impact resistance of pavement facilities. [ABSTRACT FROM AUTHOR]

This study investigates the enhancement of impact resistance in reinforced concrete (RC) beams using ultra-high-performance fiber-reinforced concrete (UHPFRC). Three types of steel fibers and two fiber volume fractions (0.75% and 1.5%) were considered. UHPFRC-strengthened RC beams exhibited an increase in flexural strength by approximately 6% at a fiber volume fraction of 1.5% compared to plain RC beams, due to effective crack suppression. Steel fibers in the UHPFRC strengthening layer inhibited the deep propagation of cracks into the compressive zone, resulting in a more gradual decrease in the neutral axis depth of RC beams. Under impact loading, UHPFRC-strengthened beams showed up to 7% lower deflection, with straight steel fibers providing superior impact resistance. RC beams strengthened with UHPFRC including straight steel fibers demonstrated improved residual flexural strength at higher fiber volumes. This highlights UHPFRC's effectiveness in enhancing impact resistance of RC beams according to the fiber type and volume fraction.

Dynamic mechanical behavior and size-related impact resistance of CNT films are studied by employing laser-induced projectile impact test (LIPIT) and coarse-grained molecular dynamics (CGMD) simulation. The energy dissipation mechanisms of the CNT films are investigated via CGMD simulations. An evident anomalous thickness-dependent effect is directly observed in the experiment, consistent with simulation phenomena. The mechanisms underlying this anomalous thickness-dependent effect are investigated at the atomic scale. The disparities between experiments and simulations are discussed. Our analysis of energy dissipation modes, deformation behaviors during impact, and impact area reveals that kinetic energy change predominantly governs the deformation mode. Meanwhile, a plugging failure mode near the exit face of CNT film is identified at high impact velocity (∼160 m/s), leading to a deterioration in impact resistance and a corresponding reduction in SEA with increasing CNT film thickness. These findings provide a feasible strategy for the protection design of CNT film in broaden protective application scenarios.

This study critically examines the composite material's mechanical properties and performance for 3D-printed shin guards. It contains a thermoplastic polymer matrix with short carbon fibre reinforcement. Shin guard stress and deformation under impact loading were modelled using FEA models. The composite material was 3D-printed and tested for tensile, flexural, and impact properties. The entire cycle of FEA models and careful mechanical testing allows for the development and evaluation of new composite materials and designs. The finite element analysis, such as maximum von Mises stress, is 2890.5 MPa. The carbon fibre-reinforced composite's mechanical properties, including tensile strength, flexural strength, and impact resistance, showed a considerable improvement over those of the unreinforced polymer. The solid design could be heavier and less adaptable than the pattern. Compared to unreinforced polymers, carbon fibre improves strength, stiffness, and impact resistance for the 3D-printed composite. This result thus proves that 3D-printed carbon fibre-reinforced composites could make superior sports protective equipment like shin guards. The FEA calculations and extensive mechanical testing provide a dependable framework for creating and testing these new composite materials and systems.

Abstract Various strategies are developed to engineer aligned hierarchical architectures in polymer hydrogels for enhanced mechanical performance. However, chain alignment remains impeded by the presence of hydrogen bonds between adjacent chains. Herein, a facile sacrificial micelle‐assisted‐alignment strategy is proposed, leading to well‐aligned, strong and tough pure chitosan hydrogels. The sacrificial sodium dodecyl sulfate micelles electrostatically interact with the protonated chitosan chains, enabling chain sliding and alignment under uniaxial forces. Subsequently, sacrificial micelles can be easily removed via NaOH treatment, causing the reforming of H‐bond in the chain networks. The strength of the pure chitosan hydrogels increases 140‐fold, reaching 58.9 ± 3.4 MPa; the modulus increases 595‐fold, reaching 226.4 ± 42.8 MPa. After drying‐rehydration, the strength and modulus further rise to 70.3 ± 2.4 and 403.5 ± 76.3 MPa, marking a significant advancement in high‐strength pure chitosan hydrogel films. Furthermore, the designed multiscale architectures involving enhanced crystallinity, well‐aligned fibers, strong interfaces, robust multilayer Bouligand assembly contribute to the exact replica of lobster underbelly with impact resistance up to 6.8 ± 1.0 kJ m−1. This work presents a promising strategy for strong, tough, stiff and impact‐resistant polymer hydrogels via well‐aligned hierarchical design.

This study focuses on investigating the mechanical behavior of a set of new chemically-treated crosslinked Ultra-High Molecular Weight Polyethylene (UHMWPE) plain-weave fabrics with varying areal densities, and impregnated with a shear thickening fluid (STF). The evaluation of the materials performance included tensile, bias-extension (shear), puncture, and drop tower tests under low rates of loading. For comparison purposes, three different sample groups were considered: untreated fabrics, crosslinked fabrics, and crosslinked fabrics with STF. The STF impregnation was composed of fumed silica nanoparticles (NPs) suspended in a polyethylene glycol (PEG) medium. Both the individual and combined effects of the chemical crosslinking and STF impregnation on the UHMWPE fabrics were explored. Additionally, the impact of strain rate on the tensile and shear behavior of various material groups was examined. The findings revealed that the addition of the crosslinker and shear thickening fluid significantly improves the puncture resistance of the base UHMWPE fabric, by as high as 92 %. The energy absorption and specific energy absorption of the UHMWPE fabric also increased up to 55 % and 16 %, respectively, with the addition of both STF and crosslinker.