Energy Absorption Mechanisms Research Articles

On the energy absorption in a novel CoFeSiB metallic‐glass fiber/epoxy resin composite under quasi‐static and dynamic compression conditions

AbstractManufacturing and investigating metallic‐glass‐fiber‐reinforced epoxies is an important new attempt to present their potential to contribute to the aviation industry. In order to explore the energy absorption in novel CoFeSiB metallic‐glass‐fiber/epoxy resin composites, CoFeSiB/epoxy resin composite cylinders with different fiber volume fractions were prepared by a hot‐pressing method. The amorphism of the metal fibers was analyzed using x‐ray diffraction. The quasi‐static compression tests were performed on different fiber oriented samples with a diameter of 3.6 mm and a height of 7.2 mm. The sample with the fiber orientation [0°/90°] has a higher energy absorption capacity, compared to the one with the fiber orientation [0°/0°]. The dynamic‐ compression tests were performed on the [0°/0°] samples with a diameter of 3 mm and height of 6 mm at different air pressures. The compression fracture surfaces were examined by scanning electron microscope. Then the energy absorption mechanism of the composites was investigated. This study is of great significance for the energy absorption in amorphous metal fiber/epoxy composites.

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

In this study, the damage and energy absorption behaviors of carbon fiber reinforced plastic (CFRP)/aluminum (Al) hybrid open-section thin-walled columns were explored. The results showed that hybrid columns exhibited tremendous merits for the energy absorption. The CFRP-Al columns could absorb 61.21 % and 44.11 % more energy than the corresponding single CFRP columns and the single Al columns with the same thickness, respectively. Furthermore, the specific energy absorption (SEA) of CFRP-Al columns was 16.29 % and 85.06 % higher than that of the corresponding single CFRP columns and the single Al columns. However, different configurations of hybrid columns underwent various damage and failure processes. In addition to Al-CFRP columns, the open-section thin-walled structure exhibited a positive hybrid interaction effect, which dissipated 45.6 % of the total energy absorption. The Al inner layer absorbed a large amount of energy by inducing the CFRP to undergo large deformation and progressive damage, thus, the CFRP-Al columns and CFRP-Al-CFRP columns dissipated more energy and had a higher energy absorption efficiency. Concurrently, the energy absorption behavior of the hybrid column could be changed by different proportions of 45° layers. The present research on damage and energy absorption mechanisms provides some guidance for the lightweight and crashworthiness design of hybrid open-section thin-walled columns.

Energy exchange mechanism between blast wave and expansion tube

The mechanical response and energy absorption characteristics of the energy-absorbing structure under blast loading are widely concerned in engineering protection, while the energy exchange mechanism remains poorly understood, thereby limiting improvements in energy absorption performance under blast loading. This paper utilizes the expansion tube structure (ETS) as a typical energy-absorbing structure to investigate the energy exchange mechanism under blast loading. Following an experimental verification, numerical simulations are conducted to investigate the effect of relevant parameters on the energy exchange characteristics. A theoretical model based on the strong-shock hypothesis is developed and validated against numerical results to predict the energy absorption efficiency of ETS under blast loading. The findings reveal that increasing the areal density of ETS positively impacts impulse transfer, but does not contribute significantly to energy exchange between the blast wave and ETS. Notably, there exists a significant negative correlation between the energy exchange efficiency and areal density. An approximately linear positive correlation is observed between the energy exchange efficiency and both peak overpressure and specific impulse of the reflected wave due to an enhanced reflection coefficient of the blast wave. Moreover, increasing equivalent strength leads to a decrease in energy exchange efficiency as it negatively correlates with effective impulse of the reflected wave. This study elucidates the underlying mechanisms governing energy exchange in expansion tube under blast loading, providing valuable insights for optimizing designs of energy-absorbing structures.

Node-locked multi-cell honeycomb for efficient energy absorption

Material reconfiguration at node positions is currently a prominent method for enhancing the energy absorption capability of honeycomb structures. However, the complexity of cellar configuration poses challenges in the manufacture with cost-efficiency due to intricate preparation processes, which limits its widespread application. In this work, an innovative approach was proposed to fabricate the multi-cell honeycomb structure by nesting and assembling node-locked components with a specific shape. The stable energy absorption of multi-cell structure with node-locked design strategy was preliminarily validated by the numerical and experimental results. Additionally, the effect of the bent panels number and the cell size ratio were investigated numerically and theoretically to reveal the energy absorption mechanism of node-locked multi-cell honeycomb (NMH). It is demonstrated that the strategy by assembling node-locked components can significantly simplify preparation processes of multi-cell structure while maintaining excellent energy absorption capabilities, this offers a better balance between the cost-efficiency and superb energy absorption for multi-cell structures.

Research on the creation of new UD laminates and its ballistic performance using CSC aramid yarns via experiment and FEA analysis

In this paper, a new type of core-spun compound aramid yarn has been applied in the construction of UD fabric to investigate if the ballistic performance of the whole fabric could be positively influenced. Three types of fabrics (Fa, Fb and Fc) herein have been developed. Fa is the traditional type of UD fabric with two layers laying at the angle of 0°/90°. Fb is made by adding new CSC aramid yarns inside of Fa at the angle of 0°/90°. Fc is further developed from Fb via changing yarn-ply directions as 45°/-45°, to analyze if the yarn-ply directions would influence on the ballistic performance of new UD fabric. The result is quite positive, as it shows that Fb and Fc have apparent energy absorption capability than Fa, and Fc is the best. This indicates that the introduction of core-spun compound aramid yarns could indeed improve the ballistic performance of UD fabric, and the yarn-ply direction of 45°/-45° is better than that of 0°/90° to absorb more energy. This research has been investigated with the assistance of both the ballistic test and the FEA model. Energy absorption and penetration resistance mechanism are the two major aspects to analyze to reflect the ballistic performance of these fabrics.

Building practice of energy efficient earthquake-resistance buildings

The article discusses technologies for constructing energy-efficient, earthquake-resistant buildings that have increased rigidity and strength in their main components. These technologies utilize structures with enhanced damping and active seismic insulation systems. Practical implementations, design features, and technological aspects are examined. An analysis is conducted on the characteristics of current technologies, the conditions for production and installation, repairability, and their impact on the building's energy efficiency during operation. Technologies are systematized and categorized based on their principles of seismic protection during the analysis process. The analysis was conducted based on the following main criteria: steel consumption, suitability of repairable technologies used, possibility of implementing seismic protection during building reconstruction, ability to withstand seismic effects, feasibility of implementation, and energy efficiency. It has been determined that traditional technical solutions to increase rigidity and strength, such as introducing structures with increased damping used for buildings with precast, monolithic, and precast-monolithic frames, require a significant amount of additional resources. These solutions are characterized by accumulation of failures in individual hidden elements due to seismic loads, low maintainability, and often decrease the energy efficiency of the building. The use of seismic energy-absorbing mechanisms with high efficiency can significantly reduce resource costs for construction and increase maintainability, thus improving the overall sustainability of the structure. Based on the findings of the analysis, the following recommendations are made for conducting further studies on active protection systems in terms of design, development of construction technology, and potential application in the renovation of existing buildings.

The influences of ply interference on ballistic impact response and energy absorption behavior of multilayered woven fabrics

This paper presents a detailed experimental and numerical analysis aiming to investigate the ballistic impact response and energy absorption behavior of multilayered woven fabrics with different ply interference. Different levels of ply interference are provided by controlling the influencing factors such as angle-plying, stitching the constituent plies and spacing the adjacent plies. The three aforementioned designs were evaluated for their energy absorption capacity against ballistic impact with the impact velocities ranging from 300∼400 m/s. The energy absorption mechanism was studied through the combination of high-speed camera and numerical simulations in terms of fabric deformation, and evolution of energy absorption for each ply at different impact velocity. It was found that stitching the aligned systems showed the most pronounced beneficial effect on energy absorption, showing approximate 50 % ∼ 110 % increase than the quasi-isotropic system with a mismatched lay-up angle of 22.5º.This is probably because that thread stitching enables the panel to be more efficient in spreading energy to a more global extent, involving a more defined transverse deformation and a larger area of stress distribution, which is beneficial for energy absorption.

Experiment and finite element analysis of protective honeycombs based on equivalent method for ocean engineering under impact loading

Aiming at reducing damage between ship berthing and high-pressure vessels, the protective honeycomb filled with Roller Arrowhead Wings Honeycomb (RAWH) was constructed based on equivalent method. A novel Double Arrowhead Wings Honeycomb (DAWH), inspired by Tilia Platyphylloswas, was proposed for arrangement in RAWH. The analytical models were derived with size factor n for honeycomb selection and design. The mechanical properties, energy absorption, compression response, structure efficiency, and deformation mode of RAWH were investigated by Finite Element Analysis (FEA) and Experiment (EXP), comparing with Roller Hexagonal Honeycomb (RHH), Roller Re-entrant Honeycomb (RRH), and Roller Solid. With particular calculation methods, the work energy absorption, engineering strain, and engineering stress were obtained within acceptable error compared to finite element analysis. The contact force of RAWH exceeded RHH, RRH and Solid about 1.7, 5, and 0.32 times, with a maximum of 15000 N. Further, the deformation modes of RAWH were discussed and recorded with “V” mode and “U” mode appearing special characteristics of enhancement and resilience. The equivalent Poisson’s ratios for protective honeycombs were studied and described in the Morgan-Mercer-Flodin (MMF) growth model with the phenomena of “Step Fluctuation”, “Inter-layer Progression” and “Step Stability”. These results, methods, and discussions might bring significance for reducing damage from collisions in ocean engineering.

On the characteristics of natural hydraulic dampers: An image-based approach to study the fluid flow behaviour inside the human meniscal tissue

The meniscal tissue is a layered material with varying properties influenced by collagen content and arrangement. Understanding the relationship between structure and properties is crucial for disease management, treatment development, and biomaterial design. The internal layer of the meniscus is softer and more deformable than the outer layers, thanks to interconnected collagen channels that guide fluid flow. To investigate these relationships, we propose an integrated approach that combines Computational Fluid Dynamics (CFD) with Image Analysis (CFD-IA). We analyze fluid flow in the internal architecture of the human meniscus across a range of inlet velocities (0.1 mm/s to 1.6 m/s) using high-resolution 3D micro-computed tomography scans. Statistical correlations are observed between architectural parameters (tortuosity, connectivity, porosity, pore size) and fluid flow parameters (Re number distribution, permeability). Some channels exhibit Re values of 1400 at an inlet velocity of 1.6 m/s, and a transition from Darcy’s regime to a non-Darcian regime occurs around an inlet velocity of 0.02 m/s. Location-dependent permeability ranges from 20-32 Darcy. Regression modelling reveals a strong correlation between fluid velocity and tortuosity at high inlet velocities, as well as with channel diameter at low inlet velocities. At higher inlet velocities, flow paths deviate more from the preferential direction, resulting in a decrease in the concentration parameter by an average of 0.4. This research provides valuable insights into the fluid flow behaviour within the meniscus and its structural influences. 3D models and image stack are available to download at https://doi.org/10.5281/zenodo.10401592. Statement of significanceThe meniscus is a highly porous soft tissue with remarkable properties of load transfer and energy absorption. We give insight on the mechanism of energy absorption from high resolution uCT scans, never presented before, and a new method which combine CFD and image. The structure is similar to a sandwich structure with a stiff outside layer and a soft internal layer made of collagen channels oriented in a preferential direction guiding the fluid flow, enabling it to accommodate deformation and dissipate energy, making it a potentially optimized damping system. We investigate architectural/ fluid flow parameters- fluid regimes relationship, which is of interest of the readers working on designing suitable biomimetic systems that can be adopted for replacement.

Energy absorption and storage of nanofluidic solid–liquid composite material under high strain rates

Efficient energy absorption and dissipation are crucial for the development of novel protective materials under intensive dynamic loadings. Nanofluidic solid–liquid composite materials (NLCs) provide a promising pathway to engineer such materials owing to their rapid and reversible energy absorption and storage performance. In this study, we conducted systematic experiments on nanoporous SiO2 based NLCs to gain a better understanding of the dynamic mechanical behavior and the underlying energy absorption and storage mechanisms under compressions with varying strain rates. Our findings indicate that the energy absorption in terms of dissipation and storage under the repeat compressive loadings includes two stages. The initial stage indicates the maximum energy absorption capacity, which is efficiently improved by the adding electrolyte solution and the retreatment. The stable energy absorbing stage represents the reversible energy absorption and storage capacity of the NLCs. Based on the noticeable strain rate effect, a three-stage mechanism is proposed to explain the significant increase of energy absorption capacity with the varying compressive strain rates. The superior reusable energy absorption capacity of NLCs holds great promise for their use as excellent energy-absorbing materials under intensive impulsive loadings.

Dynamic behavior of polyethylene terephthalate (PET) foam under compressive loads: Experimental and numerical study

The behavior of PET foam under quasi-static and dynamic compressive loads is analyzed. An experimental study is performed to evaluate its mechanical behavior and energy absorption characteristics at different strain rates. Also, a numerical model is developed to reproduce the dynamic compression behavior of the PET foam. Differences between the properties obtained in the quasi-static and dynamic tests show that the strength, stiffness and energy absorption efficiency are dependent on strain rate. The evolution of the Poisson ratio with strain and strain ratio is studied. A decrease in the Poisson ratio is observed as the strain rate increases.

Constitutive modeling and simulation of polyethylene foam under quasi-static and impact loading

In this paper, quasi-static and dynamic compression experiments were carried out on polyethylene foam by a universal material testing machine and a drop tower impact device. The mechanical response characteristics and energy absorption capacity of polyethylene foam under quasi-static and moderate strain rate (4 × 10−3–102s−1) loading conditions were obtained. An improved constitutive model of strain-rate term coupling strain and strain rate was established based on the Sherwood–Frost phenomenological constitutive model and Johnson–Cook constitutive model. Low Density Foam model combined in the finite element software ABAQUS with the improved constitutive model was used as the parameter definition of polyethylene foam material in the simulation. The drop-tower impact tests at different heights were simulated, and the simulation results were compared with the actual drop tower impact test results. The results showed that the peak acceleration errors between simulation and experiment were less than 7.1%, verifying the accuracy of the constitutive model. This study provides a method of constitutive models and finite element simulation to the performance of polymer foams.

Structural design and crashworthiness analysis of expanding-splitting circular tubes

The use of expanding-splitting circular tubes was proposed to improve crashworthiness and overcome their deficiencies in terms of low energy absorption and poor stroke efficiency in a single deformation mode. Quasi-static experiments and finite element simulations were conducted to study the force–displacement response of circular tubes under combined deformation modes. A theoretical model of the circular tube during expanding-splitting deformation was established to reveal the coupled expanding-splitting deformation and energy-absorbing mechanism of the circular tube. Furthermore, the factors influencing key parameters were analyzed using the finite element model. The results showed that the behavior changed smoothly from splitting deformation to curling deformation when adding preformed notches to the circular tube, and the final platform force of the circular tube decreased when increasing the transitional radius. Compared with the traditional expansive structure, the combined energy absorber offers better energy absorption with a 78% increase in platform force.

Analytical modeling and analysis of the low-velocity penetration and non-penetration behaviors of fiber-reinforced composite cylindrical shells based on critical impact velocity criterion

An analytical model is developed to predict the impact characteristic parameters of composite cylindrical shells when low-velocity penetration and non-penetration damage are considered. The critical impact velocity criterion for judging the penetrating failure of such structures is also proposed. The impact contact force, displacement, and load-displacement curve of the structure subjected to oblique non-penetrating impact loading are solved using the improved Hertz contact theory, cumulative damage theory, stiffness degradation method, etc. Based on the formula derivation of critical impact velocity, the key impact parameters are solved, such as the residual velocity of the projectile and damage area of the structure with penetrating impact, which takes into account three energy absorption mechanisms, such as delamination, laminating crushing and linear momentum transfer. A series of non-penetrating and penetrating impact tests are conducted using a low-velocity drop hammer rig and a light gas gun. The prediction results of the proposed model are compared to both experimental and literature results. One can find out that the largest prediction errors of the peaks of impact contact force and displacement deformation are 12.3 and 9.2 %, respectively, and the counterparts of residual velocity and damage area are 12.0 and 6.2 %, respectively. Hence, the present model is trustworthy for predicting these impact parameters. Moreover, it is advised to adopt an appropriate stacking sequence, a high ratio of structural thickness to radius, a large oblique impact angle of the projectile, and a small mass ratio of the projectile to such a structure to enhance its impact resistance or reduce impact response. In addition, it is worth noting that the current model probably has a big prediction error of the high-velocity impact behaviors involving the material heating and soft effects caused by penetration damage since high strain rate and temperature effects are not considered.

Experimental and computational analysis of energy absorption characteristics of three biomimetic lattice structures under compression

The objective of this study is to evaluate the mechanical properties and energy absorption characteristics of the gyroid, dual-lattice and spinodoid structures, as biomimetic lattices, through finite element analysis and experimental characterisation. As part of the study, gyroid and dual-lattice structures at 10% volume fraction were 3D-printed using an elastic resin, and mechanically tested under uniaxial compression. Computational models were calibrated to the observed experimental data and the response of higher volume fraction structures were simulated in an explicit finite element solver. Stress-strain data of groups of lattices at different volume fractions were studied and energy absorption parameters including total energy absorbed per unit volume, energy absorption efficiency and onset of densification strain were calculated. Also, the structures were characterized into bending-dominant and stretch-dominant structures, according to their nodal connectivity and Gibson-and-Ashby's law. The results of the study showed that the dual-lattice is capable of absorbing more energy at each volume fraction cohort. However, gyroid structures showed higher energy absorption efficiency and the onset of densification at higher strains. The spinodoid structure was found to be the poorest structure in terms of energy absorption, specifically at low volume fractions. Also, the results showed that the dual-lattice was a stretch dominated structure, while the gyroid structure was a bending dominated structure, which may be a reason that it is a better candidate for energy absorption applications.

The 3D Printing of Novel Honeycomb-Hollow Pyramid Sandwich Structures for Microwave and Mechanical Energy Absorption.

Honeycomb sandwich (HS) structures are important lightweight and load-bearing materials used in the aerospace industry. In this study, novel honeycomb-hollow pyramid sandwich (HPS) structures were manufactured with the help of fused deposition modeling techniques using PLA and PLA/CNT filaments. The microwave and mechanical energy absorption properties of the HPS structures with different geometry parameters were studied. Compared with the HS structure, the HPS structure enhanced both microwave absorption and mechanical properties. The HPS structures possessed both broadband and wide-angle microwave absorption characteristics. Their reflection loss at 8-18 GHz for incident angles of up to 45° was less than -10 dB. As the thickness of the hollow pyramid increased from 1.00 mm to 5.00 mm, the compressive strength of the HPS structure increased from 4.8 MPa to 12.5 MPa, while mechanical energy absorption per volume increased from 2639 KJ/m3 to 5598 KJ/m3. The microwave absorption and compressive behaviors of the HPS structures were studied.

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

The undesirable resistance to multi-crushing loads limits the development of regular honeycomb structures in advanced engineering fields. Therefore, a novel hierarchical strategy, namely face-centered hierarchical strategy, is proposed to improve the multi-crushing properties of honeycombs. The honeycombs with the face-centered hierarchical network are manufactured by selective laser melting to test their energy absorption mechanism against the oblique crushing load. The multi-crushing properties of face-centered hierarchical honeycomb (FCHH) are explored by a numerical investigation. The carrying capacity and energy absorption of the FCHH decrease with the increasing crushing angle. The parameter configuration design indicates that the hierarchy order has a positive effect on the multi-crushing resistance of the FCHH. The face-centered hierarchical network not only provides the strong lateral support, improving the collapse of the honeycomb, but also reduces the folding wavelength, improving its material utilization. Specifically, the specific energy absorption and crushing force efficiency of the FCHH improve by 27.65 % and 30.83 % respectively as the hierarchy order increases from 1 to 3 at the crushing angle of 30°. Furthermore, when the thickness gradient factor is close to 1, the FCHH obtains a more reasonable material distribution to resist the oblique crushing load. Compared with other hierarchical honeycombs for the oblique crushing resistance, the FCHH demonstrates a more stable carrying process and more efficient energy absorption. This research expects to propose a promising reinforcement strategy to guide the design of multi-crushing properties for honeycombs.

Finite Element Analysis of Energy-Absorbing Floors for Reducing Head Injury Risk during Fall Accidents

Energy-absorbing floor (EAF) has been proposed as one of several biomechanically effective strategies to mitigate the risk of fall-related injuries by decreasing peak loads and enhancing system energy absorption. This study aims to compare the protective capacity of four commercially available EAF products (Igelkott Floor, Kradal, SmartCells, and OmniSports) in terms of head impacts using the finite element (FE) method. The stress–strain curves acquired from mechanical tests were applied to material models in LS-Dyna. The established FE models were then validated using Hybrid III or hemispheric drop tests to compare the acceleration–time curves between experiments and simulations. Finally, the validated FE models were utilized to simulate a typical pedestrian fall accident scenario. It was demonstrated that EAFs can substantially reduce the peak forces, acceleration, and velocity changes during fall-related head impacts. Specifically, in the accident reconstruction scenario, SmartCells provided the largest reduction in peak linear acceleration and skull fracture risk, while Igelkott Floor provided the largest reduction in peak angular velocity and concussion risk. This performance was caused by different energy absorption mechanisms. Consequently, the results can contribute to supporting the implementation of EAFs and determine the effectiveness of various protective strategies for fall-related head injury prevention.

Performance of Carbon Fiber-Reinforced Polymer Plates Against Impact Loading

The carbon-fiber laminated composites are widely used in various industrial sectors due to their magnificent mechanical and engineering properties. While designing the structures of strategic importance, the impact perforation study and prediction of impact performance of such composites are of utmost importance. This work basically concentrates on two major areas of impact perforation study, determining impact perforation characteristics and understanding the perforation process. The objective has been achieved through experimental as well as numerical investigations. Microstructural analysis have also been carried out to understand different energy-absorbing mechanisms. The pneumatic gun setup is utilized to fire the projectile. In addition, square-shaped carbon fiber laminates and projectiles are modeled in ABAQUS/Explicit. The carbon fiber laminates of different thicknesses and layup sequences are impacted with three different types of projectiles. The cross ply, angle ply and quasi-isotropic layup sequences are considered in this study. The conical, blunt and ogive nose with caliber radius head (CRH) 1.5 projectiles are modeled as analytical rigid. Hashin criteria are adopted to replicate the behavior of carbon fiber laminates. The experimental and numerical calculations are compared and are found to be in good agreement. The different perforation features are calculated and the influence of ply orientations, thickness, projectile shape and impact velocities on the performance of targets against impact are discussed. An efficient and better laminate configuration under various ballistic conditions has been sought.

Impact Response of Monolithic and Laminated Polycarbonate Panels: An Experimental and Numerical Investigation.

This study aimed to investigate the impact resistance of monolithic and laminated polycarbonate plates for windshields in motorsport applications through a coupled experimental-numerical study. Both low- and high-velocity impact tests were performed by using a drop tower and a gas gun, respectively, considering a sharp-edged projectile impacting on flat panels. The response of the polycarbonate plates was evaluated in terms of the failure mode, perforation velocity threshold, and energy absorption mechanism. The experiments allowed for the assessment and the generalization of a 3D finite element modeling approach originally developed for supersonic application based on different state-of-the-art constitutive theories, including temperature-dependent and rate-dependent von Mises plasticity coupled with ductile damage, Mie-Grüneisen equation of state, and temperature variation due to energy dissipation under adiabatic assumptions. The approach was completed with a cohesive zone model for a laminate plate and studies were performed to highlight the relevancy of different aspects of material characterization. The tests and numerical analyses performed at different velocity ranges highlight the importance of viscoplastic behavior in a polycarbonate windshield. The numerical approach showed its capability to model the different failure modes for monolithic and laminated panels and capture the perforation velocity thresholds with appreciable accuracy, which were actually found to be quite similar for the two types of panels in the test conditions considered. A numerical investigation suggests that the development of delaminations could lead to the improved energy absorption of laminated polycarbonate. To further assess the numerical model, it was used to successfully predict the penetration threshold velocity of a polycarbonate windshield subjected to a gas gun impact test.