Energy Absorption Capability Research Articles

A Footpad Structure with Reusable Energy Absorption Capability for Deep Space Exploration Lander: Design and Analysis

The footpad structure of a deep space exploration lander is a critical system that makes the initial contact with the ground, and thereby plays a crucial role in determining the stability and energy absorption characteristics during the impact process. The conventional footpad is typically designed with an aluminum honeycomb structure that dissipates energy through plastic deformation. Nevertheless, its effectiveness in providing cushioning and energy absorption becomes significantly compromised when the structure is crushed, rendering it unusable for reusable landers in the future. This study presents a methodology for designing and evaluating structural energy absorption systems incorporating recoverable strain constraints of shape memory alloys (SMA). The topological configuration of the energy absorbing structure is derived using an equivalent static load method (ESL), and three lightweight footpad designs featuring honeycomb-like Ni-Ti shape memory alloys structures and having variable stiffness skins are proposed. To verify the accuracy of the numerical modelling, a honeycomb-like structure subjected to compression load is modeled and then compared with experimental results. Moreover, the influence of the configurations and thickness distribution of the proposed structures on their energy absorption performance is comprehensively evaluated using finite element simulations. The results demonstrate that the proposed design approach effectively regulates the strain threshold to maintain the SMA within the constraint of maximum recoverable strain, resulting in a structural energy absorption capacity of 362 J/kg with a crushing force efficiency greater than 63%.

Nonlinear parametric excitation and dynamic stability of auxetic honeycombs core with CNTRC face sheets sandwich plate

This study aims to analyze the Nonlinear vibration and instability of a sandwich plate with an Auxetic Honeycomb core and a Carbon Nanotube Reinforced Composite (CNTRC) face layer on a viscous elastic foundation under parametric excitation. In the analytical model, the Hamilton principle and nonlinear strain-displacement relations determined by Von Karman theory and the first shear deformation plate theory (FSDT) are used. The governing equations are solved using the Galerkin method, which involves expanding the displacement field based on orthogonal functions. Once the displacement field has been expanded, a multiple-scale method is used to solve the equation of motion. The results show that the bifurcation diagrams and stability of sandwich plates depend on several parameters, including the geometric dimension of the honeycomb core, the material properties of the CNTRC face layer, and the temperature increment. The results of this study will likely be helpful in optimizing the design of sandwich plates for engineering applications, including the aerospace and automotive industries, where sandwich structures are widely utilized because of their high strength-to-weight ratios and excellent energy absorption capabilities.

Quasi‐static axial crushing of multi‐tubular foam‐filled carbon fiber reinforced composite structures

AbstractIn automotive design, a key aspect in limiting injuries in the event of collision is the ability of vehicle's structures to absorb high quantities of energy. Recently, automobiles have been designed with materials such as carbon fiber‐reinforced polymers to replace the conventional metallic materials, to boost structural safety and fuel efficiency. In this study, various combinations of carbon fiber‐reinforced plastic and Kevlar‐reinforced polymer composite tubes were assembled to form multi‐tubular composites and their crushing properties were investigated under quasi‐static axial compression. A total of five different combinations were designed and tested. The results showed that the addition of intermediate tubing system in the hollow composite tubes significantly improved the load‐bearing and energy absorption capabilities of the composite tubes. In addition, these configurations were also filled with polyurethane (PU) foam. It was shown that, apart from specific energy absorption (SEA), all the other parameters, such as peak load, mean load, crushing force efficiency, and overall energy absorption ability, were enhanced with the addition of foam. The SEA parameter showed inconsistent behavior, and this was attributed to the weight addition caused by the addition of foam in the composite tubes.Highlights This study examined the crashworthiness properties of multi‐tubular structures. Placing of intermediate tubing showed great improvement in absorption capacity. The system with carbon‐based intermediate tubes performed the best. Filling PU foam within the structures also improved the load‐bearing properties. The SEA was seen to reduce with the addition of PU foam.

Experimental study of energy absorption capability in the lattice structures based on the octagonal bipyramid unit cell

Experimental study of energy absorption capability in the lattice structures based on the octagonal bipyramid unit cell

Optimizing the performance of the ZnO-based varistors using the neural networks technique

This study aimed to propose a scientific method depending on neural networks technique to determine the optimal proportions of some impurities (Bi2O3, Nb2O5, MnO2, Co3O4, Cr2O3, NiO, La2O3, Ce2O3) used in manufacturing the ZnO-based varistors. The technique enables obtaining varistors with high structural homogeneity, high performance, and surge energy absorption capability. A nonlinear neural model between the nonlinear coefficient and the proportion of each impurity was accurately created. Subsequently, the neural models have been trained to approximate the correlation factor to the optimum value (R = 1), which proves the accuracy of the models. Then, using the optimization toolbox in MATLAB, the proportion of each impurity producing the highest nonlinear coefficient was determined. Afterwards, a nonlinear neural model representing the relationship between the most influential impurities combined (MnO2, NiO, Ce2O3, La2O3) and the nonlinear coefficient was built. Through training the neural model, the correlation factor was R = 0.99516, and the mean square error was MSE = 0.1078, proving the model's accuracy. Depending on the optimal solutions based on the Lagrange-Newton algorithm in MATLAB, the optimal proportions of impurities combined corresponding to the highest value of the nonlinear coefficient were determined. The accuracy of the proposed method was practically confirmed by preparing a varistor according to the optimal proportions and performing the measurements. The relative error between the theoretical value (α = 99.7522) and the practical value (α = 99.41) of the nonlinear coefficient was RE = 0.0035. That confirms that the proposed method has high reliability and accuracy to be adopted.

Optimizing Infill Parameters for Improved Mechanical Performance and Cost Savings in Additive Manufacturing

In this study, compression tests were performed on the samples produced with PLA filament with different infill parameters and infill densities by additive manufacturing method and their mechanical performances & static energy absorption capabilities were evaluated. According to the results obtained, it was determined that the samples with triangular and tri-hexagonal infill parameters performed better and it has been shown that time, material and energy can be saved without losing materials mechanical performance.

Suture Interface Inspired Self-Recovery Architected Structures for Reusable Energy Absorption.

Designing materials and structures with high energy absorption and self-recoverability remains a challenge for reusable energy absorption, particularly in aerospace engineering applications (i.e., planetary landers). While the prevalent design methods of reusable energy absorbers mainly use the mechanical instability of tilted and curved beams, the limited energy absorption capabilities and low strength of tilted or curved beams limit performance improvement. In nature, Phlorodes diabolicus has evolved extreme impact resistance, in which the suture interface structure plays a key role. Herein, we propose a convex interface slide design strategy for reusability and energy absorption through friction interface, geometry, and bending elasticity, inspired by the elytra of Phlorodes diabolicus. Convex interfaces slide to achieve a more than 270% higher energy absorption capacity per unit volume than the curved beams. The convex interface slide design can be easily integrated with other structures to achieve multiple functions, such as various shapes and self-recoverability. Furthermore, we developed a theoretical model to predict the mechanical behavior and energy absorption performance. Our strategy opens up a new design space for creating reusable energy-absorbing structures.

Bending performance and failure mechanism of 3D-printed hybrid geometry honeycombs with various poisson’s ratios

By utilizing 3D printing technology, experimental three-point bending (TPB) tests, and finite element analysis, six honeycomb structures with a variety of overall Poisson’s ratios (PR) are studied and compared in terms of bending properties and failure mechanisms. Four novel honeycombs that are designed by hybridizing hexagonal and re-entrant units outperform benchmark conventional honeycombs in terms of load-carrying capacity. Architected hybrid geometry honeycombs with zero PR show excellent specific energy absorption capability in comparison to benchmark honeycombs, absorbing approximately 136.9% and 475.1% more energy under TPB. 3D-printed honeycombs consisting of hexagonal units face layer separation damage mode under bending, while honeycombs with re-entrant cells in their lattice fail with joint shear due to the angle of their struts towards loadings. Designing honeycombs with a hybrid geometry lattice can enhance the load-carrying capacity, specific energy absorption, flexibility, and flexural modulus of the structure under bending. Due to their superior performance, the proposed architected hybrid geometry honeycombs with various Poisson’s ratios own promising applications in automotive, protective, and construction industries.

Improving the compressive response of bio-polymeric additively manufactured cellular structures via foam-filling: An experimental and numerical investigation

Additive Manufacturing is effective at addressing advanced innovative design requirements for functional applications. Lattice structures and lightweight composites are the result of engineering designs for enhanced mechanical and structural properties. Inspired by nature, this work investigates the static and cyclic compressive response of 3D-printed Triply-Periodic-Minimal-Surface cellular structures made of Poly-(Butylene-Adipate-co-Terephthalate) (PBAT) biopolymer functionalized with Poly-Urethane foam. The plateau stress of the hybrid structure is 30% higher and the specific energy absorption capability 18% higher than the empty structure due to interaction between the two phases. A finite-element model is developed as a supporting tool to analyze, predict, and optimize structural behavior, as well as improve understanding of the deformation mechanisms. In addition, PBAT proves to be the ideal candidate for greener manufacturing, combining good mechanical properties with biodegradability, paving the way for a range of new applications.

Auxetic response of additive manufactured cubic chiral lattices at large plastic strains

Auxetic lattices exhibit a negative Poisson’s ratio and excellent energy absorption capability. Here, we investigate the compressive performance of auxetic cubic chiral structures. By utilising finite element analysis (FEA) verified by interrupted mechanical testing and x-ray computed tomography, the auxeticity and failure mechanisms at the large strain deformation have been evaluated. The FEA results show that the initial elastic–plastic response agrees with the prediction of the classic scaling laws of bending-dominated lattices. At increasing plastic deformation, the energy absorption and auxeticity are dependent on relative density, i.e., the slenderness ratio, of the constitutive struts. In the plastic regime, the auxeticity decreases with relative density. Ductile fracture precedes densification in relative densities above 1.2%, thus dictating a new scaling law for the variation of the maximum energy absorbed with density. The numerical model predicts the scaling of mechanical properties, fracture strains, and energy absorption of the constitutive unit cell and finite-sized specimens in the relative density ranging from 0.3% to6.5%. However, to accurately model the failure mechanism, geometrical imperfections should be included. The scaling laws derived from this work may aid the design of next generation auxetic lattices with tailored mechanical properties.

3D printing thermoplastic polyurethane hierarchical cellular foam with outstanding energy absorption capability

3D printing thermoplastic polyurethane hierarchical cellular foam with outstanding energy absorption capability

Compressive behavior and energy absorption analysis of casting skin-wrapped aluminum foams

The mechanical properties are an indispensable factor affecting the energy absorption capability of aluminum foam. In the past few decades, various aluminum foam sandwich structures, including casting skin-wrapped aluminum foams (CWFs), have been developed and proven to be effective in enhancing the integral mechanical properties. This study investigates how adding casting skin affects the compressive behavior and energy absorption of closed-cell aluminum foam. The aluminum foams were produced using the melt route and then used as the core material for manufacturing CWFs through counter-gravity casting solution after pre-heating. Axial and radial compressions were applied to columnar CWFs with pores falling within two size ranges and three ratios (D/T) of outer diameter to casting skin thickness. The failure mode of CWFs was dominated by brittle fracture of casting skin and progressive crush of foam core. Adding casting skin significantly enhanced the mechanical properties in axial compression, while it had no significant effect in radial compression, with both types of compression varying depending on D/T values. Samples with smaller pore sizes exhibited better overall performance. The influence of the addition of mass on the specific energy absorption should be considered in the design of lightweight crashworthy components.

In‐Plane Crushing Behaviors of Hexagonal Honeycombs with Hollow‐Circle Joint under Different Compressive Velocities

The in‐plane crushing behaviors of hierarchical hexagonal honeycombs, structured by replacing every three‐wall vertex of both the conventional and reentrant hexagonal honeycombs with a small hollow‐circle, are investigated herein. The finite element (FE) models are first verified by an empirical formula from the literature and then further used to simulate the in‐plane crushing behaviors of the honeycombs under different compressive velocities. The deformation mode, plateau stress, and specific energy absorption (SEA) are studied based on the FE simulations. With respect to the conventional hierarchical honeycombs, the reentrant hierarchical honeycombs, in most instances, are found to exhibit higher plateau stress but lower SEA. It is remarkable that the hierarchical hexagonal honeycombs exhibit higher plateau stress and SEA than the basic hexagonal ones, which indicates that the hierarchical design is effective in improving both the impact resistance and energy absorption capabilities of the honeycombs.

Exploring the effect of nanoclay addition on energy absorption capability of laterally loaded glass/epoxy composite tubes

AbstractThe energy absorption capability of laterally loaded glass fiber reinforced polymer (GFRP) tubular components containing montmorillonite clay (MC) was explored in this article. GFRP components filled with 0, 1, 2, 3, and 4 wt% of MC were created using wet‐wrapping by hand lay‐up techniques. For the laterally loaded tubes, the crushing load and the energy absorption versus displacement responses were presented. In addition, deformation histories were tracked. The energy absorption analysis was carried out by evaluating the initial peak load (), total energy absorption, and specific absorbed energy. Also, a mathematical regression models were built to predict the energy absorption indicators. Furthermore, the optimal MC wt% is determined using a multi‐attribute decision making method called complex proportional assessment. Overall results demonstrated that the suggested GFRP tubes containing 4 wt% of MC exhibited unique energy absorption capability.Highlights The designed tubes, that is, GFRP tubes filled with 0, 1, 2, 3, and 4 wt% of montmorillonite clay (MC) were created using wet‐wrapping by hand lay‐up techniques. The fabricated tubes were subjected to lateral compression loads to investigate their energy absorption capability. The crushing load and energy absorption versus displacement curves were accessible. Furthermore, the deformation histories were traced. Regression models were built to predict the energy absorption indicators. In addition, complex proportional assessment (COPRAS) is used to find the optimum MC wt%.

Compressive Behavior of a Novel Hexagonal Nodes-Based 3D Chiral Auxetic Structure

The energy absorption capacity of materials with negative Poisson’s ratio (NPR) is attracting interest from both industry and academia due to the excellent impact resistance of the local shrinkage of materials. However, understanding the compressive behavior of 3D auxetic structures at different strain rates and developing design methods are challenging tasks due to the limited literature and insufficient data. This paper presents a study on the behavior of Poisson’s ratio of an advanced 3D chiral structure, which is formed of two orthogonally positioned 2D hexagonal nodes-based chiral structures. Firstly, both theoretical analysis and numerical simulations are conducted to identify the Poisson’s ratio of 2D chiral structures. The same theoretical value of −1 is obtained for 2D chiral structures with a bending-dominated ligaments assumption. Thereafter, the Poisson’s ratio of 3D chiral structures is determined numerically using a low-speed loaded model composed of 5 × 5 × 8 3D unit cells for eliminating the boundary effects. The results show that impact velocity can strongly affect the energy absorption and deformation behavior of the proposed 3D chiral structure. Increasing the beam radius results in reduced energy absorption capability. However, the energy absorption capability of the 3D chiral structure is not sensitive to the yield strength of nodes. Impact direction affects the energy absorption performance of the 3D chiral structure, depending on the crushing strain. The research results could be used to optimize the design of the proposed novel 3D chiral honeycombs for various applications, such as impact energy absorbers and vibration-resistant dampers.

Triangulated cylindrical origami: Design and experimental investigation

Origami-based mechanical metamaterials have emerged in multiple technologies, such as vehicle and wearable equipment industries, thanks to their appealing mechanical performances. The excellent energy absorption capability, multi-stability, tunable stiffness, and stretchability of origami metamaterials enable them to adapt easily to different working requirements. Among all the origami metamaterial structures, triangulated cylinder origami (TCO) has been one of the most useful ones. In this research paper, a parametric study based on experiments and data analysis is performed to explore the effect of design parameters on the strain and strength of the TCOs. It was revealed that while the relative orientation of units in each column has no significant impact on the mechanical properties of the TCOs, the number of units in each column, n, plays an important role. It was discovered that a hexagon TCO with n of 6 offers higher strain and strength compared to an octagon TCO with n of 8. This study aims to pave the road for later optimization of TCOs for building materials and foldable structures applications.

The deformation mechanism, energy absorption behavior and optimal design of vertical-reinforced lattices

As a typical hybrid lattice, vertical-reinforced lattices, i.e., adding vertical struts to traditional lattices, have not been extensively studied, especially from the aspects of deformation mechanism, energy absorption performance and structural optimization. In this paper, body-centered cubic (BCC), face-centered cubic (FCC), as well as vertical-reinforced BCC and FCC (VBCC and VFCC) lattices were established and fabricated by the selective laser melting technique to elucidate the influence of the vertical struts on the mechanical behavior of the lattices. Uniaxial quasi-static compression tests were conducted on lattice samples made of stainless steel 316L. Moreover, numerical simulations were performed to facilitate analysis of the deformation modes of the specimens and further optimization designs. The results show that the VBCC and VFCC lattices exhibit stronger stiffness and higher initial strength compared to the BCC and FCC lattices. Typically, the effective specific energy absorption of the vertical-reinforced lattices can be increased by about 60%–75% compared with those of non-reinforced lattices, since more plastic hinges are formed in the lattice via adding vertical struts to dissipate energy. The present study also demonstrates that increasing the diameter of the vertical struts plays a vital role in improving energy absorption capabilities of the vertical-reinforced lattice, and the highest effective specific energy absorption of optimized VBCC and VFCC lattices are 21.7 J/g and 27.9 J/g, notably far above the general trend of most metal lattices.

Adaptive enhancement design of triply periodic minimal surface lattice structure based on non-uniform stress distribution

The Schwarz primitive triply periodic minimal surface (P-type TPMS) lattice structures are widely used. However, these lattice structures have weak load-bearing capacity compared with other cellular structures. In this paper, an adaptive enhancement design method based on the non-uniform stress distribution in structures with uniform thickness is proposed to design the P-type TPMS lattice structures with higher mechanical properties. Two types of structures are designed by adjusting the adaptive thickness distribution in the TPMS. One keeps the same relative density, and the other keeps the same of non-enhanced region thickness. Compared with the uniform lattice structure, the elastic modulus for the structure with the same relative density increases by more than 17%, and the yield strength increases by more than 10.2%. Three kinds of TPMS lattice structures are fabricated by laser powder bed fusion (L-PBF) with 316L stainless steel to verify the proposed enhanced design. The manufacture-induced geometric deviation between the as-design and as-printed models is measured by micro X-ray computed tomography (µ-CT) scans. The quasi-static compression experimental results of P-type TPMS lattice structures show that the reinforced structures have stronger elastic moduli, ultimate strengths, and energy absorption capabilities than the homogeneous P-TPMS lattice structure.

Crashworthiness analysis of a novel bioinspired hexagonal honeycomb under out-of-plane crushing

In this paper, a novel bioinspired hexagonal honeycomb (NBHH) is proposed. Different from the conventional honeycomb (CH), the core wall of the NBHH has a saw-tooth corrugated shape. Firstly, LS-DYNA R11.0 is used to construct a finite element model and conduct experimental verification; then, a comparative analysis is carried out with the CH and the bionic honeycomb sandwich panel (BHSP) with sinusoidal curves, and the proposed NBHH exhibits excellent energy absorption capability under dynamic impact. In particular, compared with the CH and the BHSP with the same wall thickness, the specific energy absorption of the NBHH is 58.60% higher than that of the CH. Compared with the BHSP, the specific energy absorption of the NBHH has increased by 7.23%. Finally, parametric research is carried out on the NBHH.

Low-velocity impact responses of composite structures incorporating shear thickening fluid tubes under various temperatures

This study proposes a novel approach to enhance the impact resistance of carbon fiber reinforced polymer (CFRP) composite plates by incorporating an additional layer consisting of shear thickening fluid (STF)-filled tubes, resulting in a hybrid composite referred to as STF hybrid composite (STFC). The proposed STFC plates were subjected to low-velocity impact tests under varying impact energies and temperatures to consider realistic operating conditions for practical applications. It was found that the insertion of STF-filled tubes into the composite structure led to lower contact forces during impact and reduced residual velocities of the impact striker at temperatures ranging from 25 to 100 °C, thereby improving the impact resistance of the structure. Specifically, the STFC plates exhibited enhanced energy absorption capabilities, with energy absorption increasing by up to 38.10% at 25 °C under the impact energy of 2 J, potentially mitigating secondary damages within the composite structure. These results suggest that the proposed STFC hybrid composite is a promising solution for applications requiring high energy absorption capabilities.