Enhanced Impact Resistance Research Articles

Experimental investigation on the impact resistance and damage mechanism of carbon/glass unidirectional and woven hybrid laminates

AbstractThe mechanical properties of hybrid fiber composite laminates are affected by the hybrid ratio as well as the stacking sequences, to investigate the effect. In this paper, the effects of the hybrid ratio and stacking sequences on the impact resistance and residual compression properties of carbon/glass unidirectional and woven hybrid laminates are investigated. The use of acoustic emission technology enables the real‐time monitoring of the impact and compression damage processes of carbon/glass composite laminates with varying hybrid ratios and stacking sequences, thereby facilitating the elucidation of the underlying failure mechanisms and the evolution of the laminates. The findings indicated that laminates with symmetrical stacking demonstrated superior impact resistance, resilience, and residual compression properties compared to those with asymmetrical stacking when subjected to high‐energy impact. Sandwich stackings demonstrate superior energy absorption properties relative to alternate‐stacking laminates, although they exhibit diminished residual compression properties. The impact resistance of laminates with a high carbon content under a sandwich stacking sequence is poor. In the context of alternating symmetric stacking, the impact resistance of the laminate is not significantly influenced by the carbon content. The results of the acoustic emission analysis indicate that the damage is minimized when the stacking sequence is alternating symmetry and the impact side is a woven material.Highlights Enhancing impact resistance of composites through hybrid structure research. Report the optimal parameters of the effects on the impact resistance of the composite. The VMD method is used to determine the percentage of damage types in the laminate.

CFRP laminate with autonomous sensing and enhanced impact resistance by P(VDF-TrFE) nanofibers interleaving

CFRP laminate with autonomous sensing and enhanced impact resistance by P(VDF-TrFE) nanofibers interleaving

Optimal sandwich panel's core design for an enhanced impact resistance.

Despite the extensive literature revealing various core structures that can enhance the impact resistance of composite panels, a comparative study illustrating the difference in performance of the various cores under same loading conditions is missing. The aim of this study is to determine the optimal core structure and design in terms of energy absorption under low-velocity impact using both numerical simulations and experimental testing for validation. Response surface analysis was used to design the experiments and analyse the panel's behaviour. A total of 160 numerical simulations were conducted by varying the core shape, density, number of layers and panel's thickness. Drop tower tests were performed to experimentally validate the results. Additive manufacturing was used to 3D print the tested structures which simplified the manufacturing process. Results provided insights on time to perforation, stiffness of the panels showcasing an inverse relationship between recoverable strain energy and equivalent plastic strain. The number of layers within the panels were identified as a pivotal factor in the energy distribution and tendency for localized plastic deformation to occur. Both numerical and experimental results revealed the superior energy absorption capabilities of the X-frame core shaped structure. Regression models developed shed light on the relationships between core height, volume fraction, number of layers, and core topology revealing the extent of damage. Multi-objective optimization was used to yield optimal configuration for sandwich panels with highest impact resistance.

Moulded-Pulp Packaging: A Straightforward Method for Quickly Designing, Manufacturing and Testing Complex Shapes for Crash Protection Pads

Moulded-pulp packaging stands poised to replace traditional polystyrene packaging due to its eco-friendly nature and recyclability. However, optimizing the protective pins within moulded-pulp packaging has been a challenge, hindering its widespread adoption. This paper presents an innovative approach to swiftly and cost-effectively optimize pin shapes, which is crucial for enhancing impact resistance. We hereby propose a simple try and error pin optimization methodology by utilizing an hand-moulded pulp recipe and PLA 3D-printed moulds to rapidly craft tailored cardboard pins. The validation of the material fabrication was carried out with static characterization and the classification of the homemade moulded-pulp pins with impact testing analysis. This exploratory project demonstrates the feasibility of this approach, laying the foundation for future advancements in moulded-pulp packaging design.

Enhancing impact resistance of fiber‐reinforced polymer composites through bio‐inspired helicoidal structures: A review

AbstractOne of the primary limitations of fiber‐reinforced polymer composites, particularly carbon fiber, is their low impact resistance. Helicoidal structures, inspired by natural biological materials, are created by rotating each layer at a small angle through the thickness, forming a staircase pattern. These structures have been used as microstructure models to improve impact resistance in composite laminates. This paper provides a comprehensive review of recent progress in the impact resistance of bio‐inspired helicoidal laminates (BIHL). The review begins with an introduction to typical microstructural characteristics of helicoidal architectures, including single‐ and double‐twisted Bouligand structures. The impact damage mechanisms specific to BIHL are then elucidated, particular emphasis is placed on key parameters that affect impact performance, including different forms of helicoidal structures, constituent materials and impact factors. Furthermore, a critical discussion is conducted to highlight the advantages and limitations of manufacturing processes tailored for high‐volume production of BIHL. Finally, after identifying research gaps in the current literature, future directions for BIHL in design, fabrication and application are presented. This review may serve as a practical guide for engineers and researchers interested in developing polymer composite laminates that are highly resistant to impact loads.Highlights Helicoidal structures significantly enhance the impact resistance of composites. The damage pattern and mechanisms of BIHL are identified and summarized. Key parameters influencing the impact behavior of BIHL are discussed in detailed. The advantages and limitations of manufacturing processes for BIHL are examined Contemporary challenges and future research directions for BIHL are outlined.

Graphene origami with enhanced impact resistance and energy absorption performance

The ancient art of origami has recently shown its potential in engineering intricate three-dimensional graphene structures with unique properties. This study employs molecular dynamics simulations to investigate the dynamic mechanical behavior of graphene origami structures (GOS) under hypervelocity ballistic impact. The analysis of residual velocity, kinetic energy loss, and specific penetration energy shows that GOS exhibit superior impact resistance and energy absorption performance compared with pristine graphene. One reason for the enhancements is that highly flexible GOS can unfold to produce a conical impact zone with larger out-of-plane deformation. Another reason is that three-dimensional folded regions possess more mass, enabling them to dissipate more kinetic energy from the projectile. The impact behavior of GOS is further analyzed concerning projectile size, impact position, and surface roughness. It is found that the impact resistance and energy absorption capacity of GOS can be adjusted by altering the surface roughness, specifically the folding degree and pattern geometry. This GOS holds promise for diverse applications in impact protection, such as combat armor and spacecraft shields.

Comparative Study of Progressive Collapse Behavior of Auxetic Concrete Cellular Structures Under Low-Velocity Impact Loading

The combination of auxetic behavior with concrete offers promising advancements in structural materials, providing unique mechanical properties that enhance impact resistance and energy absorption. The study investigates the mechanical behavior of auxetic concrete cellular structures, focusing on elliptic and peanut-shaped unit cells as well as their modified stiffener configurations, under low-velocity impact loading. To compare their impact performance, traditional and stiffened models were analyzed numerically using finite element solver ANSYS/LS-DYNA. The findings indicate significant differences between traditional and stiffened models. Stiffened models, such as SEC and SPC, exhibit higher maximum impact forces compared to traditional models like TEC and TPC. The introduction of stiffeners delays the zero-force phenomenon, resulting in extended energy absorption periods. The TPC model absorbed the most significant proportion of the initial impact velocity among traditional models, whereas the SPC model exhibited the highest energy absorption in models with stiffeners. The study highlights the potential of stiffened auxetic concrete cellular structures to enhance impact resistance and energy dissipation, making them advantageous for applications requiring high structural resilience. Further research into varying impact velocities and loading directions is recommended to optimize these structures for diverse conditions.

Flexural and low‐velocity behavior of GFPP/DP980 honeycomb sandwich structure inspired by fiber metal laminates

AbstractWith the rapid development of electric vehicles, a hybrid composite structure has been designed for the battery pack bottom guard to enhance impact resistance and reduce weight. The glass fiber‐reinforced polypropylene (GFPP)/DP980 honeycomb sandwich structure consists of GFPP panels with a polypropylene honeycomb core. DP980 advanced high‐strength steel plate is encapsulated within the structure, inspired by fiber metal laminates. A lightweight and high‐strength sandwich composite lay‐up solution was determined through equivalent bending stiffness theory, finite element simulation and experiment. An asymmetric sandwich structure with the steel plate on the impacted side enhanced flexural strength and ductility, demonstrating different failure sequences and a higher bending strength of 77.64 MPa compared to 50.18 MPa when the steel plate was on the unimpacted side. As impact energy increased from 100 to 200 J, the sandwich structure showed higher peak impact load, deeper craters, and increased bulge height, with significant delamination up to 175 J, while gravel impact tests revealed minimal flexural strength reduction (4.92%) even after repeated impacts. This study confirms that the use of thermoplastic sandwich structures is a viable and promising option for crash safety and the lightweight design of battery pack bottom guards.Highlights The thermoplastic honeycomb sandwich structure is polypropylene‐based. The use of advanced high strength steel is inspired by fiber metal laminates. Both thickness and surface density are considered in the structural design. The steel plate placed on the impacted side improves the flexural behavior. The sandwich structure has excellent impact resistance and lightweight level.

Low-Velocity Impact Analysis in Composite Plates Incorporating Experimental Interlaminar Fracture Toughness.

Reliable performance of composite adhesive joints under low-velocity impact is essential for ensuring the structural durability of composite materials in demanding applications. To address this, the study examines the effects of temperature, surface treatment techniques, and bonding processes on interlaminar fracture toughness, aiming to identify optimal conditions that enhance impact resistance. A Taguchi experimental design and analysis of variance (ANOVA) were used to analyze these factors, and experimentally derived toughness values were applied to low-velocity impact simulations to assess delamination behavior. Sanding and co-bonding were identified as the most effective methods for improving fracture toughness. Under the identified optimal conditions, the low-velocity impact analysis showed a delamination area of 319.0 mm2. These findings highlight the importance of parameter optimization in enhancing the structural reliability of composite adhesive joints and provide valuable insights for improving the performance and durability of composite materials, particularly in aerospace and automotive applications.

Enhancing the flexural capacity of RC beams under various loading rates through strengthening with ultra-high-performance fiber-reinforced concrete

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.

Additive manufactured 3D re-entrant auxetic structures for enhanced impact resistance

Abstract This study presents a novel exploration of the geometric parameters within a 3D re-entrant auxetic lattice structure, specifically focusing on their unique impact energy absorption properties, which were systematically evaluated through drop weight impactor testing. Each lattice configuration was additively manufactured using stereolithography, allowing for precise control over strut thickness (t), re-entrant angle (θ), and the aspect ratio (h/l) of unit cells during both low and high energy impact scenarios. This study found that the overall auxetic behavior is predominantly controlled by the aspect ratio of the cell ribs, while the modulus is governed by rib thickness. A finite element model was subsequently developed to simulate the experimental impact loading conditions and was used to examine a wider range of parameters that were not experimentally tested. The simulated dynamic test results displayed the deformation trends and changes to the Poisson's ratio. Among the studied parameters, experimental results highlighted that a lattice structure with t = 1.6 mm, θ = 65°, and a h/l ratio = 1.8 exhibited the highest specific energy absorption (SEA) under uniaxial impact deformation with 5 Joules of impact energy. Conversely, when employing 20 Joules of impact energy revealed the greatest SEA at t = 1.0 mm, θ = 65°, and an h/l ratio of 2.2. The results demonstrate unique deformation mechanism of auxetic structures under impact loading and the capacity to adapt the 3D re-entrant lattice structure for applications requiring tailored impact energy absorption.

Recent Experimental Advances in Solid–Liquid Composites for Impact and Blast Mitigation

The development of high-performance composites for mechanical energy dissipation during impact or explosive events is of vital importance for the safety of personnel and infrastructures. Solid–liquid composites are an emerging class of energy absorbers where a liquid-phase filler is seamlessly integrated into a solid matrix to enhance the impact resistance of the protection target. This innovative approach leverages the distinct properties of both phases and the unique interactions between them to achieve superior performance under high-impact conditions. This paper aims to review the liquid-phase materials used in solid–liquid composites, ranging from neat liquids to complex fluids, including liquid nanofoam and shear-thickening fluids, to provide an in-depth analysis of the fundamental physics underpinning the resulting solid–liquid composites, and to explore how their unique properties contribute to enhanced impact resistance and energy absorption. Furthermore, this paper evaluates the advantages and limitations of these solid–liquid composites and offers insights into future directions for the development of solid–liquid composites in various fields, including personal protective equipment, automotive safety systems, and structural protection.

Analysis of failure modes and impact resistance factors of PDC cutters

The service life of PDC cutters directly affects the overall drilling performance. In hard and heterogeneous formations, PDC cutters often fail prematurely due to dynamic impacts, leading to short footage and slow penetration rates. Enhancing the dynamic impact resistance of PDC cutters is crucial for achieving one-run drilling and reducing costs. This paper systematically studies the main factors influencing and optimizing the impact resistance of PDC cutters. First, the failure modes of hundreds of returned PDC drill bits were statistically analyzed, revealing that dynamic impact failure, wear failure, thermal damage, and erosion are the primary failure modes. Among these, dynamic impact failure is the most prevalent, with dynamic impact load being the main cause. Following the successful practices of leading international drill bit companies, a set of dynamic impact test and evaluation devices for PDC cutters was designed, and corresponding testing standards were established. Based on this, 19 types of PDC cutters were tested for impact resistance, exploring the effects of cutter diameter, diamond layer thickness, chamfer, cobalt removal, and cutter design on impact resistance. An optimized design methodology to enhance impact resistance was summarized, leading to the proposal of a new arch-axe cutter design. Indoor impact test data verified the superiority of this cutter. The research results indicate that cutter design (non-standard cutters) can significantly improve the dynamic impact resistance of PDC cutters. Additionally, increasing the cutter diameter and chamfer size while reducing the diamond layer thickness also enhances the dynamic impact resistance of PDC cutters. Through the optimization of the arch-ridge design, the independently developed arch-axe cutter improved the dynamic impact resistance by 106.45% and 71.43% compared to flat circular cutters and axe-shaped cutters, respectively.

Fireproof Cavity Structure with Enhanced Impact Resistance and Thermal Insulation toward Safeguarding.

Developing devices emphasizing safety protection is becoming increasingly important due to the widespread occurrence of impact damage and thermal hazards. Herein, the F-SSG/TPU-based circular cavity structure (FC) is developed through a convenient and efficient template method, which can effectively achieve anti-impact and thermal insulation for protection. The flame-retardant shear stiffening gel/thermoplastic urethane (F-SSG/TPU) is synthesized through the dynamic interaction between the SSG, TPU, and modified ammonium polyphosphate (APP@UiO-66-NH2) by thermo-solvent reactions. The developed FC can dissipate the impact force from 4.19 to 0.99 kN at 45 cm impacting heights, indicating good anti-impact performance. Moreover, the thermal insulation test demonstrates that the FC achieves a temperature drop of 76 °C at 160 °C attributed to the unique cavity structure design. Under the continuous shock of high-temperature flame, FC remains intact, and its performance is almost undamaged. These results elaborate that the designed FC can effectively resist various damage, such as high-temperature shock and collision. Then, a wearable wristband integrated with FC is developed which exhibits superior impact resistance and heat insulation properties compared with commercial wristbands. In short, this cavity structure based on high-performance F-SSG/TPU material shows promising potential applications in the protection field.

Dynamic response mechanism of layered coatings under impacts: Insights from the perspective of stress wave

Precision machining operations often lead to the failure of protective coatings on cutting tools due to common issues such as cracking, delamination, and peeling from cyclic impacts. While material selection and structural design are crucial for enhancing impact resistance, they primarily focus on static performance with limited consideration from the dynamic sights. This paper presents a novel dynamic design method for coatings, viewed through the lens of stress waves. We investigate the propagation behavior of stress waves in TaN/TiN and CrN/TiN coatings with layered structures. Our findings indicate that the attenuation of stress waves is dominated by the physical properties on both sides of the interface and the stride length. For interfaces with similar physical properties, the attenuation of stress waves is insensitive to the stride length, while for interfaces with different physical properties, the attenuation is regulated by the ratio of single-layer thickness to the full width at half maximum of the stress wave. These insights offer a strategy for extending the life of coatings and improving process safety under dynamic shocks.

Recycled PET foam core sandwich panels with reinforced hybrid composite facesheets: A sustainable approach for enhanced impact resistance

This research explores the Low-Velocity Impact behavior of thermoplastic composite sandwich panels with 100% recycled Polyethylene Terephthalate (PET) foam sourced from post-consumer plastic water bottles. Being recognized as a reliable technique, hybridization using stainless-steel mesh layers was employed to reinforce the panels’ composite facesheets of sandwich panels accessible for modular housing, cold storage rooms and cargo trucks. Adequate impregnation of the reinforcement metallic mesh layer alongside proper skin-to-core adhesion was accomplished by optimizing a two-phase compression molding method. The effect of hybridization on impact response of sandwich panels with two different PET foam core thicknesses, and stacking sequence were evaluated. It was revealed that reinforcing the impacted surface of the composite sandwich panels significantly increased the perforation threshold. Moreover, analyzing the post-impact section view of the samples indicated that hybridization modified the damage propagation response of the PET foam core sandwich composites, through which the energy absorption capacity was improved.

Enhanced Impact Resistance, Oxygen Barrier, and Thermal Dimensional Stability of Biaxially Processed Miscible Poly(Lactic Acid)/Poly(Butylene Succinate) Thin Films.

This study investigates the crystallization, microstructure, and performance of poly(lactic acid)/poly(butylene succinate) (PLA/PBS) thin films processed through blown film extrusion and biaxial orientation (BO) at various blend ratios. Succinic anhydride (SA) was used to enhance interfacial adhesion in PLA-rich blends, while blends near 50/50 formed co-continuous phases without SA. Biaxial stretching and annealing, adjusted according to the crystallization behavior of PLA and PBS, significantly influenced crystallinity, crystallite size, and molecular orientation. Biaxial stretching induced crystallization and ordered chain alignment, particularly at the cold crystallization temperature (Tcc), leading to a 70-80-fold increase in impact resistance compared to blown films. Annealing further enhanced crystallinity, especially at the Tcc of PLA, resulting in larger crystallite sizes. BO films demonstrated reduced thermal shrinkage due to improved PLA crystalline structure, whereas PLA-rich blown films showed higher shrinkage due to PLA's lower thermal resistance. The SA-miscibilized phase reduced oxygen transmission in blown films, while BO films exhibited higher permeability due to anisotropic crystal orientation. However, the annealing of BO films, especially at high temperature (Tcc of PLA), further lowered oxygen permeability by promoting the crystallization of both PLA and PBS phases. Overall, the combination of SA compatibilization, biaxial stretching, and annealing resulted in substantial improvements in mechanical strength, dimensional stability, and oxygen barrier properties, highlighting the potential of these films for packaging applications.

Review of Potential Capabilities of 3D Printed Parts Reinforced with a Non- Newtonian Fluid for Enhancing Impact Resistance

This theoretical paper presents a comprehensive review of the promising prospects offered by the integration of non-Newtonian fluids in 3D printed parts to enhance impact resistance. Non-Newtonian fluids exhibit unique rheological behavior, and their ability to alter mechanical properties makes them an intriguing candidate for reinforcing 3D printed objects. The paper delves into the underlying principles of non-Newtonian fluid mechanics and how these fluids can be effectively utilized to augment the impact resistance of 3D printed structures. By surveying recent advancements and emerging applications, this review explores the potential benefits and challenges associated with the incorporation of non-Newtonian fluids in additive manufacturing. Furthermore, it offers valuable insights into the design, material selection, and manufacturing processes crucial for achieving robust, impact-resistant 3D printed components. This paper aims to provide a foundation for further research and development in the field, shedding light on the transformative possibilities of non-Newtonian fluid reinforcement in 3D printing.

Bioinspired Bouligand-Structured Cellulose Nanocrystals/Poly(vinyl alcohol) Composite Hydrogel for Enhanced Impact Resistance.

Impact-protective materials are gaining importance because of the widespread occurrence of impact damage. Hydrogels have emerged as promising candidates owing to their lightweight and flexible nature. However, achieving soft impact-resistant hydrogels with exceptional stiffness, strength, and toughness remains a challenge. Inspired by the Bouligand structure found in the smasher dactyl club of stomatopods, we propose a straightforward multiscale hierarchical structural design strategy. This strategy integrates self-assembly and salting-out techniques to enhance the impact resistance of soft hydrogels. Rigid cellulose nanocrystals (CNCs) self-assemble into Bouligand-like structures within soft poly(vinyl alcohol) (PVA) matrix via supramolecular interactions. This rational structural design combines the CNC Bouligand structure with a cross-linked network of soft PVA crystalline domains, resulting in a composite hydrogel with impressive mechanical properties: high tensile fracture strength (30.2 MPa), elastic modulus (62.7 MPa), and fracture energy (75.6 kJ m-2), surpassing those of other tough hydrogels. Moreover, the multiscale hierarchical structure facilitates various energy dissipation mechanisms, including crack twisting, tortuous crack paths, and PVA chain orientation, resulting in notable force attenuation (80.4%) in the composite hydrogel. This biomimetic design strategy opens new avenues for developing soft and lightweight impact-resistant materials.

Enhancing impact resistance in E‐glass fabric composites through shear thickening fluids and functionalized polyethylene glycol

AbstractIn this study, we delved into innovative strategies to make neat E‐glass fabrics (NGFs) more impact‐ and tensile‐resistant by using shear‐thickening fluids (STFs). To achieve this goal, the polyethylene glycol (PEG) in STFs has been modified. Subsequently, the STF‐impregnated fabric composites were prepared from unmodified PEG and functionally modified PEGs using malonic and tartaric acids, V/S/GF, M/S/GF, and T/S/GF composites, respectively. Fourier‐transform infrared spectroscopy (FTIR) analysis was conducted to confirm the chemical modification of PEGs. The rheological tests showed a significant improvement in the peak viscosity of modified STFs compared with virgin STF. Dynamic rheological analysis also studied media‐particle interaction, revealing improved media‐particle interaction in STFs due to abundant H‐bonding. In addition, a series of experimental tests, namely compressive impact resistance and strip tensile strength tests, have been conducted to investigate the effect of STF modification on the NGF. The results revealed notable improvements in tensile strength and energy dissipation in the T/S/GF and M/S/GF composites compared with V/S/GF and NGF. Importantly, this improvement extended to the impact performance of single, triple, and quintuple layers. Notably, we found that the peak load of 5 T/S/GF was 37.71%, 18.57%, and 11.87% lower than that of 5NGF, 5 V/S/GF, and 5 M/S/GF, respectively. The idea that made these improvements possible came from PEG functionalization, which helps hydrogen bonds form between the dispersed phase and the dispersion medium, leading to higher viscosity. This, in turn, increases inter‐yarn friction, effectively enhancing the spring‐like properties of T/S/GF and M/S/GF compared with V/S/GF. A two‐step artificial intelligence regression analysis underpinned these findings, elucidating the interplay of molecular mechanisms in high‐performance fabric composites.