Improved Energy Absorption Research Articles

A filling lattice with actively controlled size/shape for energy absorption

This study unveils a groundbreaking development: the chain lattice structure (CLS), a unique lattice with the capability to actively adjust its size and shape for filling diverse thin-walled structures, thereby enhancing their energy absorption characteristics. Traditional lattice structures, known for excellent energy absorption, are constrained by fixed sizes and shapes post-fabrication, limiting their adaptability to various energy-absorbing structures. The CLS introduces a revolutionary lattice structure dynamically modifying dimensions and shape. Employing selective laser sintering (SLS), we craft CLS prototypes using nylon 11 material, followed by rigorous quasi-static compression experiments. The congruence between experimental and simulation analyses validates our model's accuracy. CLS actively adjusts within varying cross-sectional thin-walled square tubes, demonstrating substantial improvements in energy absorption and compression stability compared to empty tubes (ETs). Additionally, CLS adapts to diverse cross-sectional shapes, including circular, hexagonal, and triangular tubes. Comparative assessments reveal significant enhancements in energy absorption and compression stability for CLS-filled tubes. Moreover, the pre-deformed CLS model was filled with different shapes of front rails, and its axial crashworthiness and deformation pattern stability were significantly improved compared with the unfilled front rails. In summary, CLS's flexibility in adjusting to thin-walled structures of varying dimensions and shapes holds immense promise for enhancing their performance across a wide range of applications.

Economic Optimization and Performance Enhancement of Rooftop Solar Power Systems Using Concentrated Solar Technology and Advanced Materials

Abstract: This research investigates the economic optimization and performance enhancement of rooftop solar power systems through the integration of concentrated solar technology and advanced materials. The aim is to assess the viability and effectiveness of these innovations in both residential and commercial settings. By focusing on improving energy efficiency and reducing costs, the study provides a comprehensive economic perspective on the adoption of these advanced solar technologies. Key aspects of the research include the evaluation of lifecycle costs, energy yield, and payback periods, offering insights into the long-term financial benefits and feasibility of implementing such systems. The integration of concentrated solar technology enhances the intensity of solar energy captured, thereby significantly boosting the efficiency of rooftop solar panels. Advanced materials, such as perovskites, multi-junction cells, and nanomaterials, are examined for their potential to improve energy absorption, durability, and overall performance of solar panels. The research employs simulation software to model the performance of these optimized systems under various environmental conditions, providing a detailed analysis of their energy output and efficiency.

Design of hierarchical multi-cell double circular tubes thin-walled structures for energy absorption

This study aims to investigate the crashworthiness performance of a novel hierarchical multi-cell double circular tubes (HMDC) structure under axial impact. Various dual-tube structures of different cross-sections were designed. The effects of hierarchical order, peak number of the core column, and inner circle diameter on the structure were analyzed using Abaqus finite element analysis. The results indicate that in dual-tube structures, replacing the traditional multi-cell structure with a hierarchical multi-cell structure in the interlayer significantly improves energy absorption (EA) characteristics. With the inner circle diameter of the HMDC fixed at 20 mm, the ratio of mean crushing force (MCF) to peak crushing force at the third order increased by 70.70% and 35.68% compared to the first and second orders, respectively. Experimental results and finite element results show that the initial peak value differed by 1.47%, indicating a close match between the experimental and simulation results. The parametric study shows that the inner circle diameter and the peak number of the core column significantly affect EA. The findings of this study provide effective guidance for designing multi-cell dual circular tubes with high EA efficiency.

Study on the influence of carbon nanotube modification on the mechanical and magnetic properties of chloroprene rubber‐based magnetorheological elastomers

AbstractThis study explores the mechanical and magnetic properties of magnetorheological elastomers (MREs) based on chloroprene rubber, enhanced with carbonyl iron powder (CIP) as the primary filler. Carbon black serves as the primary reinforcing filler, with multi‐walled carbon nanotubes (CNTs) used as a secondary filler to strengthen the rubber matrix. The primary objective of this research is to examine the effects of the mixture of iron powder with reinforcing fillers and the interaction of these fillers with the rubber matrix on the mechanical and magnetomechanical performance of MREs. CNTs, tubular nanoscale carbon molecules, significantly enhance the tensile strength and fatigue resistance when combined with the MRE matrix. During mixing, CNTs form a network structure within the MRE matrix, promoting the dissipation of accumulated heat and reducing thermal fatigue loss. The addition of 20 parts of CNTs to the CR matrix significantly improved the tensile mechanical properties, with the 100% set elongation stress increasing by up to 260% and the magnetic responsiveness increasing by 30.6%. The addition of 10 parts of carboxylated CNTs most notably enhanced the magnetorheological effect, increasing the magnetic stress relaxation rate by 78%. These enhanced properties enable MREs to provide better vibration control and comfort in automotive suspension systems, improve energy absorption and damping effects in industrial damping systems, and enhance durability and sealing performance in sealant applications.Highlights Carbonyl iron powder, carbon black, and carbon nanotubes (CNTs) were used as fillers to strengthen the chloroprene (CR) matrix magnetorheological elastomers (MREs). CNTs formed a network structure, promoting the dissipation of accumulated heat and reducing thermal fatigue loss. The tensile mechanical property of MRE with 20 parts of CNTs has been significantly improved, with an increasing magnetic responsiveness of 30.6%. Magnetorheological effect of MRE with 10 parts of CNTs has notably enhanced, with the magnetic stress relaxation rate of 78%.

Improved solar still productivity using PCM and nano- PCM composites integerated energy storage

The study investigates the impact of Phase Change Material (PCM) and nano Phase Change Materials (NPCM) on solar still performance. PCM and a blend of NPCM are placed within 12 copper tubes submerged in 1 mm of water to enhance productivity. Thermal performance is assessed across four major scenarios with a fixed water level of 1 mm in the basin. These scenarios include the conventional still, equipped with 12 empty copper rods and 142 g of PCM in each tube, as well as stills with NPCM Samples 1 and 2. Sample 1 contains 0.75% nanoparticle concentration plus 142 g of PCM in the first 6 tubes, while Sample 2 features 2% nanoparticle concentration plus 142 g of PCM in the subsequent 6 tubes. Aluminum oxide (Al2O3) nanoparticles ranging in size from 20 to 30 nm are utilized, with paraffin wax (PW) serving as the latent heat storage (LHS) medium due to its 62 °C melting temperature. The experiments are conducted under the local weather conditions of Vaddeswaram, Vijayawada, India (Latitude-80.6480 °E, Longitude-16.5062 °N). A differential scanning calorimeter (DSC) is utilized to examine the thermal properties, including the melting point and latent heat fusion, of the NPCM compositions. Results demonstrate that the addition of nanoparticles enhances both the specific heat capacity and latent heat of fusion (LHF) in PCM through several mechanisms, including facilitating nucleation, improving energy absorption during phase change, and modifying crystallization behavior within the phase change material. Productivity and efficiency measurements reveal significant improvements: case 1 achieves 2.66 units of daily production and 46.23% efficiency, while cases 2, 3, and 4 yield 3.17, 3.58, and 4.27 units of daily production, respectively. Notably, the utilization of NPCM results in a 60.37% increase overall productivity and a 68.29% improvement in overall efficiency.

Analysis of low-velocity impact responses in bidirectional gradient double-arrow auxetic metamaterials

In this paper, we propose double-arrowed auxetic metamaterials (DAMs) featuring bidirectional wall thickness gradients. Their crushing behavior under low-velocity impact is systematically investigated using a validated finite element (FE) model. The results show that the bidirectional gradient design effectively improves the transverse necking effect observed in uniform DAMs. The bidirectional gradient configuration contributes to improved energy absorption and impact strength. Specifically, there is a 60.7% increase in specific energy absorption (SEA) and a 40.5% improvement in plateau stress, compared to uniform DAMs. Furthermore, the bidirectional gradient configuration reduces the initial peak stresses generated during the dynamic crushing process and exhibits higher crash load efficiency (CLE).

A wave forecasting method based on probabilistic diffusion LSTM network for model predictive control of wave energy converters

Accurate long-term prediction of wave excitation forces is critical for optimizing wave energy converters, enabling enhanced control, and improving energy absorption efficiency. Traditional prediction models often employ deterministic conservative approaches, overlooking uncertainties. This paper introduces a novel prediction method based on the probabilistic diffusion model, offering a more precise prediction while accounting for uncertainty. Notably, our approach goes beyond previous works by simultaneously achieving control objectives for maximizing energy absorption, contrasting with methodologies solely focused on prediction and control tasks. The proposed method utilizes long short-time memory to extract temporal information from historical wave excitation observation. The hidden features are then processed through a diffused probabilistic-based unit. Subsequently, a time-scale neural network is developed for wave excitation moment prediction, followed by the application of nonlinear model predictive control to maximize the energy absorption. The methodology is validated on the 1:20 Wavestar prototype devices through numerical simulations. Results indicate that the predicted excitation moment closely align with measured values. In cases 4, 5, 6, the proposed method yields a substantial improvement in maximum control energy absorption–22%, 16%, and 31%, respectively–compared to traditional prediction methods. The proposed approach not only achieves a more accurate wave excitation moment prediction with uncertainty consideration but also introduces advanced control strategies in a full-scale plant application. This work contributes significantly to the field by bridging the gap between precise prediction and effective control in wave energy conversion systems.

Electroplating Additively Manufactured Honeycomb Structures to Increase Energy Absorption Under Quasi-Static Crush

Honeycomb (HC) has been used in energy absorption applications due to its high stiffness and low density. Metallic HC are used for energy absorption applications, however, these metallic structures can be challenging to manufacture if complex geometric features designed to improve energy absorption are used, which motivates the use of additive manufacturing (AM). Metal AM methods include powder bed fusion (PBF) and direct energy deposition (DED). In addition to capital equipment cost, these processes possess challenges that include a required inert environment, powder handling, final part porosity, residual stresses, and nonuniform surface finish. These concerns can be alleviated through the use of polymer AM, however, polymeric parts exhibit brittle failure and have a lower stiffness than metallic HC structures. In this study, a low-cost 3D polymer printing method, stereolithography (SLA), is combined with a conventional electroplating process to fabricate a metal-plastic composite HC structure with energy absorption capability much greater than of a plastic HC structures of the same nominal volume. SLA parts have a smooth surface, so that the surface finish is at least as uniform after electroplating as the SLA part. The energy absorption characteristics of the electroplated HC is studied to determine how these energy absorbing materials can be manufactured at reduced cost. Our study confirms that the metal-plastic composite HC increases both the crush strain range and the mean crush stress of these samples, resulting in metal-plastic composite HC structures with substantially increased energy absorption. This study also examines how buckling initiators (BIs), or diamond shaped holes located at 50, 75, and 100% of the height of the hexagonal cell vertices, can influence energy absorption performance. This study shows that it is feasible to fabricate electroplated HCs, using an SLA preform, to achieve a substantial increase in energy absorption over using SLA alone.

Mechanical behavior of twinning-induced plasticity (TWIP) steel fibre reinforced cementitious composite under impact loading

Twinning-induced plasticity (TWIP) steel fibre is a supermaterial known for its outstanding impact resistance. This paper, for the first time, applied TWIP steel fibre to increase the impact resistance of cementitious composites. The mechanical properties behaviours of TWIP steel fibre-reinforced cementitious composites (T-SFRCC) were investigated and compared with conventional SFRCC with normal steel fiber. The fractal theory was utilized to analyze the deterioration of damage in various SFRCCs subjected to impact loads, displaying TWIP steel fiber could prevent the cracks propagation and fewer fractal dimension compared with others. Results demonstrate that T-SFRCC has comparable compressive strength to SFRCC while exhibiting higher flexural strength. When subjected to impact loading, T-SFRCC demonstrates markedly improved energy absorption and impact toughness, such as better impact force and displacement. Specifically, the energy absorption capacity of T-SFRCC can exceed five times that of SFRCC with corrugated steel fiber, particularly evident when the drop height reaches 1200 mm. The influences of different fiber types and hammer drop methods on the impact resistance of SFRCCs were also discussed, which can provide reference for TWIP steel fiber in the field of cementitious composite materials.

Quantitative assessment of impact damage in stitched foam‐filled Aluminium honeycomb Sandwich panels by experimental and machine learning methods

AbstractNovel Stitched Foam‐filled Honeycomb Sandwich (SFHS) panels have been fabricated using vacuum‐assisted resin transfer molding to address the weak interfaces between the face sheets and the core in the Foam‐filled Honeycomb Sandwich (FHS) panel. The SFHS panels have shown better load‐bearing capacity and performance characteristics compared to FHS panel after Low‐Velocity Impact (LVI) tests. After the LVI test, MATLAB image processing was used to analyze the impact damage areas and failure mechanisms. In addition, Machine Learning regression algorithms were employed to predict the optimal amount of energy absorbed during low‐velocity impact testing of fabricated panels with a maximum impactor drop height of 700 mm. The results indicated that nylon yarn stitching significantly improved energy absorption and interfacial behavior compared to unstitched honeycomb panels. This research also revealed that SFHS1 panels with adjacent honeycomb cell stitching are more impact resistant, provide increased load carrying capacity, and are cost‐effective. These panels can be utilized by modern engineers to increase economy, durability, and functionality in industrial, automotive, and construction applications.Highlights Stitched Foam Filled Honeycomb Sandwich (SFHS) panels, manufactured via resin transfer molding, and eliminates weak interfaces between the face sheets and core. SFHS panels outperformed unstitched panels in load‐bearing and energy absorption during low‐velocity impact, as confirmed by MATLAB image analysis showing reduced damage and failure. Machine learning algorithms particularly polynomial regression model predicted maximum absorption energy precisely with 99.9% accuracy, close to experimental results. SFHS panels can be used in automotive and industrial applications due to their through‐thickness stitching.

Effect of solutionizing heat treatment on the structure and mechanical properties of silicon bronze (Cu-10wt%Si-2wt%Ni)

The effect of solutionizing temperature, soaking time, and quenching media on the structure and mechanical properties of silicon bronze (Cu-10wt%Si-2wt%Ni) has been examined. The samples were produced using the sand casting technique, machined to the required dimensions, and solutionized at temperatures of 700 oC, 800 oC, and 900 oC for 0.5, 1.5, 2.5, and 3.5 hrs and quenched in brine and oil respectively. The prepared as-cast and solution heat-treated samples were subjected to mechanical tests (hardness, and impact strength tests) as well as microstructural analysis. The results of the microstructural analysis revealed the presence of coarse grains and coarse sparse distribution of Ni2Si precipitate in the as-cast sample while the surface morphology of the heat-treated samples consisted of fine grains of intermetallic compounds evenly dispersed in the copper matrix. It was also observed that the microstructures of samples solutionized at lower temperatures (700 oC) revealed finer grains with better grain distributions compared with samples solutionized at higher temperatures (800 oC and 900 oC). These microstructural changes led to the improvement of the hardness and impact strength of the alloy. The hardness value of the as-cast sample 48.5 HRB, increased to 53.7 HRB and 57.8 HRB after solid solution heat treatment at 700 oC for 3.5 h and cooled in brine and oil, respectively. It was also observed that the hardness of the brine-cooled samples increased further to 72.45 HRB after 3.5 h at 900 oC. The results obtained also showed that the solid solution heat-treated samples gave an optimum impact strength value of 214 J/m3 and 183 J/m3 from the samples solutionized at 900 oC and 800 oC for 3.5 h and 1.5 h and cooled in brine and oil respectively. This was concluded to be a result of solid solution alpha and beta phases formed which improve energy absorption in the alloy.

Energy absorption characteristics of a bio-inspired prepreg carbon fiber crash box under quasi-static axial compression

Reducing vehicle weight is crucial for enhancing fuel efficiency and reducing emissions in transportation. Traditional composite materials offer improved energy absorption over metals yet are limited by brittleness. This study introduces an innovative approach, inspired by the mantis shrimp's natural defense mechanisms, to enhance the crashworthiness and energy absorption of composite structures, optimizing safety and performance. Utilizing a bio-inspired design, we developed corrugated Carbon Fiber Reinforced Polymer (CFRP) crash box structures, aiming to optimize their energy absorption capabilities and crash force efficiency (CFE) for potential applications in transportation safety. Through a series of quasi-static axial compression tests, the corrugated structures' performance was evaluated against traditional crash box designs. The experimental results demonstrate that the bio-inspired configurations improved crashworthiness characteristics. Strategic manipulation of layer numbers and corrugations led to superior CFE values, indicative of safer, more controlled collision behavior. The “7N-6L” configuration featuring seven corrugations with six layers of CFRP demonstrated the highest efficacy, achieving an optimal CFE of 1.08. This configuration demonstrated a Specific Energy Absorption (SEA) of 1.56 J/g and an Energy Absorption (Ea) of 42.56 J. Furthermore, compared to conventional steel crash boxes, the CFRP crash box with 7N-6L corrugated structure showcased competitive energy absorption capabilities with significantly reduced mass, absorbing 2850 J with a CFE of 0.91, nearly matching the ideal CFE and highlighting its superior lightweight performance. These results underline the potential of integrating bio-inspired designs to develop robust, lightweight structures for improved crashworthiness, paving the way for safer and more sustainable transportation solutions.

Enhancing impact resilience of thermal battery through honeycomb-structured aluminum buffering devices: Insights from large-scale gas-gun tests and simulations

Modern warfare relies heavily on electronic equipment, necessitating reliable energy sources like thermal batteries. Assessing their impact resilience, a study employed honeycomb-structured Al plates as buffering devices in a large-scale gas gun simulating artillery fire. Comparison between peak curves from gas-gun tests and simulations with varying honeycomb wall thicknesses revealed unique patterns, attributed to the buffering device's deformation-restoration process. Different honeycomb wall thicknesses led to varying deformation behavior and impact deceleration, complicating effective energy absorption assessment. Stepped honeycomb wall designs aimed to balance compression, extending energy absorption and reducing deceleration peaks. Prototype honeycomb buffering devices showed improved energy absorption and reduced deceleration during gas-gun tests. Gas-gun tests highlighted complexities in energy absorption assessment, with designs proposing improved energy absorption and reduced deceleration. The actual gas-gun test launched a projectile equipped with a thermal battery and buffering device, resulting in slight casing deformation, while battery cells remained intact, exceeding the standard discharge time (1 h).

Quantized energy absorption of sandwiched origami ring

Origami cores are increasingly recognized as effective structures for energy absorption in sandwich plates. However, as most origami sandwich cores are made of tessellations of orthotropic unit cells, their free edges may hinder the formation of plastic hinges and reduce energy absorption capacity. To eliminate such free edges, in this work, by trimming the popular Miura-ori unit cells to form ring-shaped loops, we create a new origami sandwich plate with improved energy absorption efficiency. We study the energy absorption characteristics of these origami ring cores through a combination of theory, numerical simulations, and experiments. Both simulations and experiments verify that the origami ring cores possess quantized energy absorption capacity, related to the number of additional plastic hinges derived from strong local buckling of origami creases. We develop a theoretical model that effectively captures the formation of plastic hinges and predicts their absorbed energy. In summary, the origami ring cores present a novel and promising sandwich plate design approach, characterized by quantized energy absorption performance. This innovation holds significant potential for diverse engineering applications across sectors such as the aeronautic and marine industries and infrastructure development.

Energy absorption performance of woven metallic lattices with orthogonal spiral wires under quasi-static compression

Woven metallic lattice (WML) structures are gaining attention for their beneficial mechanical properties, such as low weight and special energy absorption capability. They hold potential for diverse applications, including energy absorption components in aerospace. Drawing inspiration from the traditional double-arrow lattice, this study proposes a novel WML design featuring multi-plateau stresses. The deformation behavior of this structure under compression was investigated using finite element analysis and experimental methods. Three gradient structures defined by the different layer arrangements along load direction associated with specific structure variables, namely positive gradient (PG), negative gradient (NG), and hybrid gradient (HG), were introduced, along with an examination of their mechanical properties. The study explored the influence of key parameters of the cell structure on compression characteristics. Findings suggest that enhancing cell vertex angle and wire diameter can improve energy absorption, while the opposite holds true for cell base angle. Among the gradient structures analyzed, the PG WML structure demonstrates optimal energy absorption due to its dual-plateau stress characteristics. The NG WML structure is noteworthy for its uniform lattice deformation during initial compression stages, which is crucial for precision engineering with subtle deformation control strategies. Lastly, the deformation pattern of the HG WML structure during compression progresses from low to high strength.

Compression behavior of lightweight corrugated composite Sandwich panels with smart facesheets reinforced by shape memory alloy wires: an experimental study

AbstractThis paper presents an experimental examination of the compression demeanor of lightweight corrugated core composite (CCC) sandwich panel and corrugated core smart composites (CCSC) sandwich panels subjected to quasi‐static edgewise compression loading. The existence of shape memory alloy (SMA) wires and pre‐strain percentages of SMA are the indicators studied in this article. The fabrication procedure presented and the appraisement of the mechanical properties of the CCC and CCSC sandwich panels are expressed. The core geometry of samples is trapezoid corrugated made of aluminum. The facesheets are four layers of woven glass fiber/ epoxy laminated composite. For evaluation of the efficacy of the presence of SMA wires on mechanical specifications of sandwich panels, three SMA wires with various pre‐strain percentages (0%, 3%, and 6%) are embedded in each composite facesheet. Mechanical properties of all types of CCC and CCSC sandwich panels such as maximum force, critical damage force, specific strength, absorb energy, specific toughness, Young's modulus, and specific stiffness were evaluated. Results showed that the CCC sandwich panel has higher mechanical specifications than the CCSC sandwich panels with 0% and 3% pre‐strain. Also, increasing pre‐strained SMA wires improves all mechanical parameters of CCSC sandwich panels. CCSC sandwich panel with 6% pre‐strain has the highest compression properties than other sandwich panels. Maximum Force, Critical Damage Force, Specific Strength, Absorbed Energy, Specific Toughness, Young's Modulus, and Specific Stiffness of CCSC sandwich panel with 6% pre‐strain are 14.73 kN, 13.6 kN, 9.55 MPa/g, 26.61 kJ, 0.346 MJ/m3g, 4395 MPa and 0.61 kN/mm g, respectively.Highlights Lightweight CCC sandwich panel and CCSC sandwich panel manufactured. Compression behavior of CCC sandwich panel and CCSC sandwich panel evaluated. Pre‐strained SMA wires improves energy absorption of CCSC sandwich panels. Higher specific toughness was obtained with 6% pre‐strain SMA. Presence of SMA wires with no pre‐strain cannot improve the specific strength.

A Bioinspired Design of Protective Al2O3/Polyurethane Hierarchical Composite Film Through Layer-By-Layer Deposition.

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

Mechanical performance of interpenetrating phase composites with multi-sheet lattice structures

Interpenetrating phase composites (IPCs), as a novel type of composite material, offer advantages such as lightweight, high strength, and superior energy absorption. This study proposed a multi-sheet lattice structure based on the Gyroid surface, which was initially designed and then fabricated via TC4 laser powder bed fusion (LPBF). Through the infiltration of epoxy resin, a composite material with interpenetrating phases was achieved. Subsequently, the mechanical properties of the IPCs were comprehensively investigated using experimental and numerical simulation methods. In quasi-static compression tests, the IPCs demonstrated higher strength and improved energy absorption characteristics compared to original lattice structures. However, under dynamic loading conditions, while the strength of the IPCs showed significant enhancement, the improvement in energy absorption characteristics of the composite structures was constrained by temperature rise, thermal softening effects, and the glass transition of the epoxy resin induced by elevated temperatures. Thus, while the proposed IPCs exhibited high strength under both quasi-static and dynamic loads, it is imperative to consider material properties and the influence of temperature on energy absorption to prevent overestimation of performance under dynamic loading conditions. Therefore, this study not only highlights the novelty of utilizing a multi-sheet lattice structure based on the Gyroid surface for creating IPCs, but also underscores the importance of carefully considering temperature effects on material properties when evaluating their performance under dynamic conditions.

Biaxial porosity gradient and cell size adjustment improve energy absorption in rigid and flexible 3D-printed reentrant honeycomb auxetic structures

This paper compares different uniaxial and biaxial graded designs of auxetic reentrant honeycomb structures to enhance their mechanical properties, especially the specific energy absorption under compressive load. The lattice structures were 3D printed using the vat photopolymerization masked-stereolithography technique from two different materials – tough (OR) and flexible (FR). The results were evaluated from a material and structural point of view, investigating the effect of porosity, cell number, size, graded design, and fracture mode. The universally best energy-absorbing performance was found in a biaxially graded structure with a center-wise location of the highest local porosity. Depending on the used resin, its energy absorption capacity was up to 2–3 times enhanced compared to a reference uniform-porosity auxetic design. The presented data constitutes a fundamental understanding of auxetic structures and identifies practical approaches for tuning the auxetic structures’ performance regarding their mechanical response. Finally, this study demonstrates the potential of shape versatility offered by 3D printing and other additive manufacturing techniques.

Crushing Performances of Kenaf Fibre Reinforce Composite Tubes

The quest for sustainable and eco-friendly materials has led to a burgeoning interest in natural fibers as reinforcements in composite materials. Kenaf fiber, derived from the Hibiscus cannabinus plant, presents a promising avenue for enhancing the mechanical and energy absorption properties of composite tubes. This study focuses on the fabrication of composite tubes using a combination of kenaf fiber and epoxy resin. The composite tubes were then subjected to compressive testing to evaluate their energy absorption performances. The fabrication process involved the impregnation of kenaf fibre with epoxy resin, followed by winding and curing to form composite tubes. Different configurations of kenaf fiber content were utilized to investigate their impact on the structural integrity and energy absorption capabilities of the tubes. Compressive testing was conducted to assess the energy absorption behaviour under axial loading conditions. The results revealed that the incorporation of kenaf fiber significantly influenced the energy absorption capabilities of the composite tubes. Higher kenaf fiber content demonstrated improved energy absorption performance, showcasing the potential of kenaf fiber as an efficient energy-absorbing reinforcement. The findings of this study offer valuable insights into the use of sustainable and renewable resources, such as kenaf fiber, in enhancing the mechanical and energy absorption properties of composite structures, thereby contributing to the development of eco-friendly and high-performance materials.