Papers by Keyword: Energy Absorption

Abstract: Gyroid structures are one of the most common Triply Periodic Minimal Surfaces (TPMS) with remarkable mechanical properties, including energy absorption and stress distribution. In the current study, the compressive behavior of gyroid structures fabricated through Fused Deposition Modeling (FDM) was investigated. The deformation and failure mechanisms were predicted via extensive simulations using Finite Element Analysis tools. Experimental testing using Acrylonitrile Butadiene Styrene (ABS) specimens was performed on a Universal Testing Machine (UTM), and the results compared with computational data. To predict the compressive strength and optimize the structural parameters, an Artificial Neural Network (ANN) was trained. Results indicate a good match between the experimental and simulation findings, indicating immense potential for these gyroid structures in energy absorption.

Abstract: Architected metamaterials fabricated by additive manufacturing offer deterministic geometries and tunable mechanical properties that can outperform conventional foams in energy absorption and impact mitigation. In this work, origami honeycomb and plate-lattice metamaterial concepts are unified within a common, quantitatively characterised metamaterial. An optimization-based design approach is employed to maximise absorbed energy while keeping the peak stress below a predefined threshold, using metamaterial geometric parameters as design variables. The objective function is evaluated through post-processing of Abaqus compression simulations on automatically generated designs. Owing to the high computational cost, the optimisation is performed using an evolutionary algorithm with a limited number of evaluations, yielding a best-performing design rather than a global optimum. Despite this limitation, the results elucidate the critical roles of buckling in limiting initial peak stress and of contact in enhancing post-peak energy absorption, and they highlight the significant potential for further performance gains through expanded design space exploration.

Abstract: Recently, the petroleum-based leather is focused for constituent material of wall in luxury architecture. This study examined the effect of repair processing on energy absorption of pre-crack-initiated leather for long-term use of products. Constituent materials at front and back sides of leather were, respectively, polyurethane and polyester. Tensile tests of non and pre-crack-initiated leather were conducted under constant temperature and humidity room. The crosshead speed was 100 mm/min. The repair processing was conducted by a hot-press molding method. The crack length was 4 mm. The patch size was 10 mm long and 10 mm wide. The following conclusions were obtained. Typical load-displacement curves of all leathers became nonlinear. The energy absorption of non-crack-initiated leather was higher than that of repaired leather. After some repair processing, the energy absorption of the repaired leather at bonding between polyester (Patch) and polyurethane showed the maximum value. But the fiber pull-out on fracture surface of repaired leather at bonding between polyester (patch) and polyurethane was found during tensile test. The crack initiation depends on energy absorption of leather. Therefore, the energy absorption of pre-crack-initiated leather was property affected by stress distribution and adhesion property at the repair area.

Abstract: The study presents the mechanical performance, particularly energy absorption ability, under uniaxial quasi-static compression of aluminium foams fabricated by melt processing with CaCO₃ blowing agent and B₄C+TiB₂ powder with content varied from 30 to 70%. High-strength Al6Zn2.3Mg alloy comprising brittle eutectic domains was employed for manufacture of the foam. The optimal amount of B₄C + TiB₂ powder was determined to be 50% at which it results in the highest energy absorption. The key role of identity sizes for B₄C + TiB₂ and CaCO₃ powders for the efficiency of the foaming process with the formation of certain particle configurations in the melt was examined and discussed. The results of the present study could be helpful for selecting the aluminium alloy and additives for the foaming process and providing a certain level of the mechanical properties, particularly, energy absorption ability.

Abstract: Metamaterials have emerged as promising candidates for protective structures due to their lightweight design and energy absorption capabilities. While various lattice-based architectures have been explored, further research is needed to optimize their dynamic response and computational modeling. Recent studies highlight the superior strength-to-weight ratios of lattice metamaterials over traditional foams, yet challenges remain in balancing predictive accuracy and computational efficiency.This study introduces novel computational frameworks for the design and analysis of deterministic, hybrid, and stochastic lattice architectures. Using finite element models, different unit cell configurations are evaluated under dynamic loading, comparing beam-based models for efficiency with 3D solid models for accuracy. A comparative assessment with foam materials further examines energy absorption performance.The framework developed in this study provides a versatile tool for the automatic generation and analysis of lattice structures. Moreover, this study provides critical insights into lattice topology, computational trade-offs, and impact resistance.

Abstract: This study investigates the capability of additive manufacturing (AM) technology to produce sandwich composite structures through focusing on the 3D Printing process, experimental testing, and anticipated impact as energy-absorbent elements. The growing cost of manufacturing prototypes that use conventional methods has resulted in exploring the exploration of 3D printing as a viable alternative. The research problem addresses the challenges of manufacturing sandwich composites and the need for automation in the civil, mechanical, aerospace, and aviation industries. The study aims to investigate 3D-printed hybrid sandwich composite structures made of multilayer materials, conduct finite element analysis, produce specimens, conduct flexural and impact tests, and analyze the data. The proposed methodology includes preparation of the 3D printer, 3D printing of the specimen, inspection, finite element analysis, preparing the specimen for testing, conducting different impact tests, and data collection and analysis. The expected mechanical properties of the study lie in the potential for additive manufacturing to reorganize the adoption of sandwich composite structures for energy absorption purposes, reducing costs and automating the process.

Abstract: Carbon and glass fabric reinforced polymer (C/GFRP) composites are extensively used in aerospace and sports industry because of their exceptional properties. However, during service, static and dynamic bending loads can ensue damage in composites affecting their strength, stiffness and energy absorption. Carbon fiber composites, being inherently brittle, are prone to sudden catastrophic fracture without ductile-like behavior of metals. This study investigates mechanical behavior and damage mechanisms of woven C/GFRP composites in on- and off-axis orientations during bending. Initially, bending tests with quasi-static loading were performed, followed by dynamic ones using an Izod impact testing apparatus. Results showed distinct behavior in on-axis CFRP laminates with brittle fracture. Off-axis CFRP samples and both on- and off-axis GFRP laminates showed signs of damage and non-linear behavior, yet they retained their ability to bear loads. Significantly, off-axis specimens of both types and on-axis GFRP laminates exhibited enhanced energy absorption capabilities without experiencing fracture, undergoing pseudo-ductile deformation. CFRP specimens were analyzed with micro-computed tomography (micro-CT), provided insights into prevalent damage modes such as matrix mircocracking, debonding of tows, delamination and breakage of fabric. While on-axis CFRP laminates experienced brittle fracture, off-axis specimens exhibited a ductile-like response attributed to matrix plasticity, cracking and fiber trellising before eventual failure.

Abstract: Many industries and automotive companies use thin-walled cylinders as energy-absorbing devices. Researchers have previously investigated various parameters related to thin-walled cylinders and their behavior under impact loads. When the impactor hits the thin-walled cylinder from the axial direction, it causes the bending of the cylinder wall on an axisymmetric or non-axisymmetric pattern, depending on the ratio of diameter divided by wall thickness. In addition, the length of the specimen influences the deformation mode that occurs. This study discusses how installing ribs on the cylinder walls affects energy absorption capabilities. We conducted the research by making modeling based on the finite element method by making various specimens according to the experimental scenarios. We experimented with an aluminum alloy cylinder with a diameter of 50 cm, a thickness of 1.5 mm, and a length of 200 mm. Then, successively, we installed ribs with a length of 2 mm and a thickness of 3.5 mm, one rib, two ribs, three ribs, four ribs, and five ribs. The impactor hits the specimen from the axial direction to one end at high speed while the other is given fixed support. The results obtained from the experiment are total deformation, reaction force, absorbed energy, and deformation pattern. The experimental results show that adding ribs changes the deformation pattern from previously non-axis-symmetric to axis-symmetric. The total deformation decreases, the reaction force becomes smaller, and the ability to absorb energy equals the total kinetic energy. This result is a recommendation for manufacturing in an energy absorption structural system. Keywords: rib, deformation mode, wall thickness, energy absorption, reaction force.

Abstract: The study presents mechanical performance metrics, especially, energy absorption, of aluminium foams fabricated by melt processing with CaCO₃ blowing agent without Ca additive. Relatively ductile Al1Mg0.6Si alloy and high strength Al6Zn2.3Mg alloy comprising brittle eutectic domains were employed for the foams manufacture and then examined in conditions of uniaxial quasi-static compression. It was recognized that mechanical response of the foams and energy absorption is radically defined by the mechanism of cell collapse which, in turn, depends on the nature of structural constituents of the cell wall material. In particular, the presence of brittle eutectic domains in the cell wall material of foam based on Al6Zn2.3Mg alloy results in reducing the compressive strength and energy absorption compared to those of foam processed with Al1Mg0.6Si alloy, both deviate markedly from the theoretical predictions. In spite of this experimental verification of foams cell collapse is considered to be strongly required before their engineering application.

Abstract: In automotive applications, replacing heavy and expensive materials with light and cheap natural fiber leads to noise reduction, strength enhancement and fuel management. Enhancing the absorption of energy, controlling the failure style of composite thin shell tube and utilizing it instead of thin-walled steel columns in vehicle structural parts can provide more protection for occupants during collisions. This research investigates the possibility of gradually replacing metallic materials with natural and hybrid fibers in industries. The hand layup technique is utilized to study the performance of fiber reinforced epoxy composite tubes under static crushing to examine the jute fiber effect with different fibers types on the failure mechanism. The research studies the effect of using different fibers types on stress and strain after determining the tubes load-displacement curves. Total of 48 specimens are fabricated at room temperature and tested with a constant speed 1.5 mm/sec using one resin (epoxy) type and three fibers types (Glass, Kevlar, Jute). Two circular and square geometries with three heights (200 mm,250 mm,300 mm) including two circular diameters and two square side lengths are used to investigate the crashworthiness parameters. The Kevlar and glass fiber tubes showed low and unstable behavior. Replacing two layers of Kevlar or Glass fiber by two layers of natural jute fiber enhanced the crash worthiness parameters particularly, failure type. The hybrid jute with Kevlar accomplished desirable and best results followed by hybrid jute with glass.