Stabilized and efficient multi-crushing properties via face-centered hierarchical honeycomb

Investigation on the microstructure and compressive behavior of open-cell copper- Al2O3 composite foams

To enhance the mechanical performance of single fibers and reduce the cost of carbon fiber composites, a hybrid fiber thin-walled tube structure with carbon/glass fiber alternating ply design was proposed. Experimental and numerical methods revealed the failure mechanisms and energy absorption properties of alternately layered carbon/glass fiber-reinforced tubes (C/GFRP tubes) under quasi-static compression. Results demonstrated significant improvements in energy absorption without increasing costs. The energy absorption mechanism mainly includes interlayer delamination of CFRP and GFRP, FRP fronds tearing and curling, and frictional dissipation between the tube and rigid plate. Compared to single-fiber structures, C/GFRP Tube exhibited a 23.16% improvement in specific energy absorption and a 20.99% improvement in crushing force efficiency. And a novel theoretical formula for the mean crushing force of hybrid fiber thin-walled tubes was established and verified, with an error of less than 8%. In addition, the influence of different structural parameters, ply angle configurations, and fiber hybrid ratios on energy absorption characteristics was systematically analyzed, providing a theoretical basis and design reference for the design of efficient and lightweight energy absorption devices.

This work investigates the crash response of conical tubes made from different steel grades ranging from low to high strength steels using finite element (FE) simulations. The FE model was first validated against experimental results before being applied for the numerical analysis using LS DYNA software. Peak crushing load, mean load, energy absorption, crush force efficiency (CFE) and specific energy absorption (SEA) were evaluated from the cones of different steel grades and of various thicknesses. It was found that high strength steel exhibit high SEA and low CFE values. Both SEA and CFE were found to increase with increase in tube wall thickness for the five steel compared. For improved safety of the occupant, steel-CA5 is best because of higher CFE values for 1.5 mm, 2.0 mm and 2.5mm thicknesses. For better weight reduction, steel-DP600 with SEA of 10.6 kJ/kg is the best. Steel-HA3 and steel-SAP H440 with 2.5 mm thickness offer moderate CFE and SEA values. The findings of this study are useful in designing high safety performance vehicle front energy absorption components. Keywords : Conical tube; Crashworthiness; Crush force efficiency; Specific energy absorption

Damage and energy absorption behavior of CFRP/aluminum hybrid open-section thin-walled columns subjected to quasi-static loading

Crashworthiness design draws considerable attention and interest in energy absorption systems. An optimal design of circular stepped tubes based on free inversion is presented in the current work to improve and enhance the crashworthiness characteristics under axial impact loading. Circular tubes have been known to be efficient energy absorbers per unit weight, and may be considered as the main part of energy absorbing devices even for frequently impact operation like landing gear or for sudden accidents like other vehicles. The precise choice of the circular tubes' material, shape, and mechanism may save a person life or save a valuable equipment from damage. Adaptive Multiple-Objective Optimization (AMO) can obtain more light and efficient section. An optimization of variable parameters, which represent the shape of a stepped tube under axial impact, is performed using the platform of ANSYS-DESIGN-EXPLORATION linked with LSDYNA code. The analysis leads to 16% reducing in mass with corresponding 31% improving in energy absorption.

Nowadays, hybrid structures, which combine low‐density composites with low‐cost thin‐walled metals, have shown great effect in enhancing the performance of automotive body structures, especially the energy absorber components. This study focuses on the experimental and numerical investigation of the bending energy absorption behavior of CFRP/aluminum hybrid double hat‐section beams used in the side part of the car body. In the experimental section, two types of double hat‐section beams were fabricated: aluminum and Al/CFRP. These beams were then subjected to quasi‐static three‐point bending tests. The results demonstrated that the hybrid beam exhibited superior energy absorption capabilities compared to the single beam. Subsequently, a finite element model was developed using LS‐Dyna software and was validated by comparing the experimental and numerical load–displacement results. In‐depth numerical analyses were conducted to investigate the influence of various design parameters, including CFRP‐reinforcement configuration, numbers of CFRP layers, CFRP ply‐angle, CFRP reinforced length, and aluminum/CFRP mass, on crashworthiness indicators. The numerical findings indicate that the hybrid beam with , ply‐angles exhibited better crash force efficiency (CFE) and specific energy absorption (SEA) compared to other ply‐angles, respectively. Furthermore, increasing the number of CFRP layers within the total beam's mass improved its energy absorption capacity. It was also revealed that the CFRP length on the upper and lower hats could be considered as 42.5% of the total aluminum beam length, as opposed to the full CFRP length, providing enhanced energy absorption capabilities.Highlights Bending behavior of the Al and Al/CFRP double hat section beams. Effects of variable thickness and identical mass on the double hat section beam. Effects of variable ply angle and number of CFRP layers on the hybrid beams. Discrete effect of CFRP reinforcement configurations and inner CFRP lengths.

Energy-absorbing characteristics of hollow-cylindrical hierarchical honeycomb composite tubes inspired a beetle forewing

Three-dimensional (3D) parts are widely gaining popularity in industries like automotive, aerospace, medical healthcare, consumer goods, and electronics. The properties and performance of these parts vary depending on the parameters chosen at the design and manufacturing stages. This study experimentally evaluates the impact of topology on energy absorption and structural stability of eight strut-based lattice topologies fabricated using Fused Deposition Modeling (FDM) with Polylactic Acid (PLA). Quasi-static compression tests were conducted in accordance with ASTM D695. Specific Energy Absorption (SEA), crush force efficiency (CFE), and newly defined metrics—Peak-to-Plateau Load Ratio (PPLR) and Structural Efficiency (SE)—were used to determine collapse behavior and load stability. All lattices were manufactured within a narrow relative density range (0.29–0.30) to ensure topology-driven assessment. The Double Octagon lattice showed superior performance, achieving a maximum SEA of 6653.18 J kg⁻¹ , total absorbed energy of 57.55 J, and the highest structural efficiency among the investigated configurations. Substantial energy dissipation and trustworthy collapse mechanisms were shown by the Hex Truss and Kelvin cell; however, the Face Centered and Face Diagonal structures showed comparatively lower energy absorption. The proposed PPLR metric quantifies initial peak load severity relative to sustained collapse response, complementing conventional SEA and CFE measures. The findings highlight the critical role of topology optimization in balancing stiffness, weight, and energy absorption in guiding lightweight crashworthy lattice design.

Mechanical properties and energy absorption of 3D printed double-layered helix honeycomb under in-plane compression

This study presents a series of novel mirrored multi-cell square tubes (NMST) developed through the application of various evolutionary designs and mirror settings to traditional multi-cell square tubes. Numerical simulations were performed using validated models to assess their crashworthiness under conditions of uniform wall thickness and mass. The findings indicate that the implementation of mirror settings significantly enhances the crashworthiness of the structure, with strategy E demonstrating a particularly marked improvement. Under conditions of equal wall thickness, NMSTE4 exhibited increases in specific energy absorption (SEA) and crush force efficiency (CFE) of 47.15% and 24.15%, respectively, when compared to NMSTE1. Under equal mass conditions, these values increased by 24.84% and 25.53%, respectively. Parametric studies revealed that both an increase in wall thickness and the incorporation of additional mirror settings contribute positively to the energy absorption performance of the structure. The integration of the design characterized by strategy D with those of other strategies further enhances the impact resistance of the original structure, with the AD combination yielding the most substantial improvement. Specifically, compared to NMSTA4, NMSTAD demonstrated increases in energy absorption (EA), SEA, and CFE of 43.85%, 21.91%, and 13.20%, respectively. A comparative analysis was conducted, revealing that compared to non-mirrored design structures, NMSTD4 achieved SEA and CFE improvements of up to 106.38% and 32.43%, respectively.

In this study, we investigate the mechanical energy absorption performance of reusable 3D-printed honeycomb structures fabricated using fused deposition modeling with three thermoplastic polyurethane variants: TPU 70A, TPU 85A, and TPU 95A. Prior to manufacturing, the mechanical properties of the TPU filaments were analyzed as a function of printing temperature to optimize tensile strength and layer adhesion. Four honeycomb configurations, including hexagonal and circular cell geometries, both with and without a 30° twist, were subjected to out-of-plane compression testing to evaluate energy absorption efficiency, specific energy absorption, and crushing load efficiency. The highest energy absorption efficiency, 47%, was achieved by the hexagonal honeycomb structure fabricated from TPU 95A, surpassing the expected values for expanded polystyrene and approaching the performance reported for high-cost advanced lattice structures. Additionally, twisted honeycomb configurations exhibited improved crushing load efficiency values (up to 73.5%), indicating better stress distribution and enhanced reusability. Despite variations in absorbed energy, TPU 95A demonstrated the best balance of elasticity, structural integrity, and reusability across multiple compression cycles. These findings suggest that TPU-based honeycomb structures could provide a viable, cost-effective alternative for energy-absorbing applications in impact protection systems, automotive safety, and sports equipment.

Crashworthiness design of novel hierarchical hexagonal columns

The selection of the appropriate materials and structures for enhanced energy absorption is paramount in the design of protective gear, regardless of the final application. This research addresses a long‐standing academic debate regarding the effectiveness of auxetic structures in mitigating impacts relative to open‐cell foam counterparts by developing a comparative, energy‐based framework to conclusively establish auxetic structures as the superior option. The framework calculates the energetic performance across the elastic, plateau, and densification regions, utilizing consistent bulk material: polyurea, irrespective of the type of cellular solid (open‐cell foam vs. re‐entrant auxetic). The material properties were found to play a major role in the mechanical performance of open‐cell foams; therefore, they were investigated parametrically. Furthermore, the study examines the critical effect of the auxetic structure's characteristic re‐entrant angle on its energy absorption mechanisms. The results demonstrate that the auxetic structures significantly outperform the open‐cell foams, reporting a four‐fold increase in specific energy absorption. This outcome definitively concludes the discussion in favor of auxetic metamaterials. Crucially, amplifying the initial auxetic angle resulted in a significant seven‐fold increase in energy absorption across the explored re‐entrant range (50° to 85°), providing mechanical designers with a powerful new tool for tailoring energy absorption properties.

Effect of the cross-sectional shape of hat-type cross-sections on crash resistance of an “S”-frame

Enhancing energy absorption in mechanical metamaterials has been a focal point in structural design. Traditional methods often include introducing heterogeneity across unit cells. Herein, we propose a straightforward ribbed strategy to achieve exceptional energy absorption. We demonstrate our concept through modified body-centered cubic (BCC) and face-centered cubic (FCC) ribbed truss-lattice metamaterials (BCCR and FCCR). Using stainless-steel 316L samples, compression tests indicate a 111% and 91% increase in specific energy absorption (SEA) for BCCR and FCCR, respectively, along with an enhancement in compression strength by 61.8% and 40.7%. Deformation mechanisms are comprehensively elucidated through both finite element analysis and theoretical calculations. The mitigation of stress concentration at nodes, redistribution of load transfer pathways within struts, and introduction of multiple plastic hinges collectively contribute to increased energy absorption and higher compression strength. Using rein-based polymer samples, the ribbed truss-lattice metamaterials also exhibit exceptional damage tolerance, experiencing only a 15% loss in maximum strength after cyclic compression at 20% strain, while maintaining a 73% higher SEA compared to their non-ribbed counterpart. This strategy extends beyond the discussed structures, presenting itself as a generic approach to enhance plateau strength and SEA.