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1 – 10 of over 1000Dixon M Correa, Timothy Klatt, Sergio Cortes, Michael Haberman, Desiderio Kovar and Carolyn Seepersad
The purpose of this paper is to study the behavior of negative stiffness beams when arranged in a honeycomb configuration and to compare the energy absorption capacity of these…
Abstract
Purpose
The purpose of this paper is to study the behavior of negative stiffness beams when arranged in a honeycomb configuration and to compare the energy absorption capacity of these negative stiffness honeycombs with regular honeycombs of equivalent relative densities.
Design/methodology/approach
A negative stiffness honeycomb is fabricated in nylon 11 using selective laser sintering. Its force-displacement behavior is simulated with finite element analysis and experimentally evaluated under quasi-static displacement loading. Similarly, a hexagonal honeycomb of equivalent relative density is also fabricated and tested. The energy absorbed for both specimens is computed from the resulting force-displacement curves. The beam geometry of the negative stiffness honeycomb is optimized for maximum energy absorption per unit mass of material.
Findings
Negative stiffness honeycombs exhibit relatively large positive stiffness, followed by a region of plateau stress as the cell walls buckle, similar to regular hexagonal honeycombs, but unlike regular honeycombs, they demonstrate full recovery after compression. Representative specimens are found to absorb about 65 per cent of the energy incident on them. Optimizing the negative stiffness beam geometry can result in energy-absorbing capacities comparable to regular honeycombs of similar relative densities.
Research limitations/implications
The honeycombs were subject to quasi-static displacement loading. To study shock isolation under impact loads, force-controlled loading is desirable. However, the energy absorption performance of the negative stiffness honeycombs is expected to improve under force-controlled conditions. Additional experimentation is needed to investigate the rate sensitivity of the force-displacement behavior of the negative stiffness honeycombs, and specimens with various geometries should be investigated.
Originality/value
The findings of this study indicate that recoverable energy absorption is possible using negative stiffness honeycombs without sacrificing the high energy-absorbing capacity of regular honeycombs. The honeycombs can find usefulness in a number of unique applications requiring recoverable shock isolation, such as bumpers, helmets and other personal protection devices. A patent application has been filed for the negative stiffness honeycomb design.
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Xiaokun Zhou, Suming Xie, Maosheng He, Tingting Fu and Qifeng Yu
This study aims to reduce the weight of the door, improve the operating efficiency and ensure the safety of vehicle operation.
Abstract
Purpose
This study aims to reduce the weight of the door, improve the operating efficiency and ensure the safety of vehicle operation.
Design/methodology/approach
Based on traditional aluminium alloy doors, a new type of honeycomb composite material was developed. Tests were conducted to determine the honeycomb compression resistance, honeycomb and skin shear performance, plate bending, thermal conductivity and environmental protection. Eight doors were developed based on the full-side open structure, and static strength and stiffness analyses were performed simultaneously. To solve door vibration problems, modal analysis and test were carried out.
Findings
The test results showed that the weight of the door was reduced by more than 40% whilst ensuring the strength and stiffness of the vehicle. The first–sixth-order test mode of the door was increased by more than 14% compared with existing aluminium alloy doors.
Originality/value
A new type of honeycomb composite material was used in this study. The test results showed that the weight of the door was reduced by more than 40% whilst ensuring the strength and stiffness of the vehicle. The 1st-to-6th order test mode of the door was increased by more than 14% compared with the existing aluminium alloy door.
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Solomon O. Obadimu and Kyriakos I. Kourousis
Honeycombs enjoy wide use in various engineering applications. The emergence of additive manufacturing (AM) as a method of customisable of parts has enabled the reinvention of the…
Abstract
Purpose
Honeycombs enjoy wide use in various engineering applications. The emergence of additive manufacturing (AM) as a method of customisable of parts has enabled the reinvention of the honeycomb structure. However, research on in-plane compressive performance of both classical and new types of honeycombs fabricated via AM is still ongoing. Several important findings have emerged over the past years, with significance for the AM community and a review is considered necessary and timely. This paper aims to review the in-plane compressive performance of AM honeycomb structures.
Design/methodology/approach
This paper provides a state-of-the-art review focussing on the in-plane compressive performance of AM honeycomb structures, covering both polymers and metals. Recently published studies, over the past six years, have been reviewed under the specific theme of in-plane compression properties.
Findings
The key factors influencing the AM honeycombs' in-plane compressive performance are identified, namely the geometrical features, such as topology shape, cell wall thickness, cell size and manufacturing parameters. Moreover, the techniques and configurations commonly used for geometry optimisation toward improving mechanical performance are discussed in detail. Current AM limitations applicable to AM honeycomb structures are identified and potential future directions are also discussed in this paper.
Originality/value
This work evaluates critically the primary results and findings from the published research literature associated with the in-plane compressive mechanical performance of AM honeycombs.
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Rafid Hussein, Sudharshan Anandan, Myranda Spratt, Joseph W. Newkirk, K. Chandrashekhara, Misak Heath and Michael Walker
Honeycomb cellular structures exhibit unique mechanical properties such as high specific strength, high specific stiffness, high energy absorption and good thermal and acoustic…
Abstract
Purpose
Honeycomb cellular structures exhibit unique mechanical properties such as high specific strength, high specific stiffness, high energy absorption and good thermal and acoustic performance. This paper aims to use numerical modeling to investigate the effective elastic moduli, in-plane and out-of-plane, for thick-walled honeycombs manufactured using selective laser melting (SLM).
Design/methodology/approach
Theoretical predictions were performed using homogenization on a sample scale domain equivalent to the as-manufactured dimensions. A Renishaw AM 250 machine was used to manufacture hexagonal honeycomb samples with wall thicknesses of 0.2 to 0.5 mm and a cell size of 3.97 mm using 304 L steel powder. The SLM-manufactured honeycombs and cylindrical test coupons were tested using flatwise and edgewise compression. Three-dimensional finite element and strain energy homogenization were conducted to determine the effective elastic properties, which were validated by the current experimental outcomes and compared to analytical models from the literature.
Findings
Good agreement was found between the results of the effective Young’s moduli ratios numerical modeling and experimental observations. In-plane effective elastic moduli were found to be more sensitive to geometrical irregularity compared to out-of-plane effective moduli, which was confirmed by the analytical models. Also, it was concluded that thick-walled SLM manufactured honeycombs have bending-dominated in-plane compressive behavior and a stretch-dominated out-of-plane compressive behavior, which matched well with the simulation and numerical models predictions.
Originality/value
This work uses three-dimensional finite element and strain energy homogenization to evaluate the effective moduli of SLM manufactured honeycombs.
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Nattapon Chantarapanich, Apinya Laohaprapanon, Sirikul Wisutmethangoon, Pongnarin Jiamwatthanachai, Prasert Chalermkarnnon, Sedthawatt Sucharitpwatskul, Puttisak Puttawibul and Kriskrai Sitthiseripratip
The purpose of this paper was to investigate the feasibility on design and production of a three-dimensional honeycomb based on selective laser melting (SLM) technique for use in…
Abstract
Purpose
The purpose of this paper was to investigate the feasibility on design and production of a three-dimensional honeycomb based on selective laser melting (SLM) technique for use in aeronautical application.
Design/methodology/approach
Various polyhedrons were investigated using their mechanical property, i.e. strain energy density (SED), by means of finite element (FE) analysis for the suitability of use in aerospace application; the highest SED polyhedron was selected as a candidate polyhedron. From the FE analysis, the truncated octahedron (three-dimensional honeycomb) structure was considered to be the potential candidate. Polyhedron size and beam thickness of the open-cellular three-dimensional honeycomb structure were modelled and analysed to observe how the geometric properties influence the stiffness of the structure. One selected model of open-cellular honeycomb (unit cell size: 2.5 mm and beam thickness: 0.15 mm) was fabricated using SLM. The SLM prototypes were assessed by their mechanical properties, including compressive strength, stiffness and strength per weight ratio. To investigate the feasibility in production of airfoil section sandwich structure, NACA 0016 airfoil section with three-dimensional honeycomb core was constructed and also fabricated using SLM.
Findings
According to the result, the three-dimensional honeycomb has elastic modulus of 63.18 MPa and compressive strength of 1.1 MPa, whereas strength per weight ratio is approximately 5.0 × 103 Nm/kg. The FE result presented good agreement to the mechanical testing result. The geometric parameter of the three-dimensional honeycomb structure influences the stiffness, especially the beam thickness, i.e. increase of beam thickness obviously produces the stiffer structure. In addition, the sandwich structure of airfoil was also successfully manufactured.
Originality/value
This work demonstrated the production of sandwich structure of airfoil using SLM for aeronautical engineering. This investigation has shown the potential applications of the three-dimensional structure, e.g. aircraft interior compartment components and structure of unmanned aerial vehicles.
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Myranda Spratt, Sudharshan Anandan, Rafid Hussein, Joseph W. Newkirk, K. Chandrashekhara, Misak Heath and Michael Walker
The purpose of this study is to analyze the build quality and compression properties of thin-walled 304L honeycomb structures manufactured by selective laser melting. Four…
Abstract
Purpose
The purpose of this study is to analyze the build quality and compression properties of thin-walled 304L honeycomb structures manufactured by selective laser melting. Four honeycomb wall thicknesses, from 0.2 to 0.5 mm, were built and analyzed.
Design/methodology/approach
The density of the honeycombs was changed by increasing the wall thickness of each sample. The honeycombs were tested under compression. Differences between the computer-assisted design model and the as-built structure were quantified by measuring physical dimensions. The microstructure was evaluated by optical microscopy, density measurements and microhardness.
Findings
The Vickers hardness of the honeycomb structures was 209 ± 14 at 50 g load. The compression ultimate and yield strength of the honeycomb material were shown to increase as the wall thickness of the honeycomb samples increased. The specific ultimate strength also increased with wall thickness, while the specific yield stress of the honeycomb remained stable at 42 ± 2.7 MPa/g/cm3. The specific ultimate strength minimized near 0.45 mm wall thickness at 82 ± 5 MPa/g/cm3 and increased to 134 ± 3 MPa/g/cm3 at 0.6 mm wall thickness.
Originality/value
This study highlights a single lightweight metal structure, the honeycomb, built by additive manufacturing (AM). The honeycomb is an interesting structure because it is a well-known building material in the lightweight structural composites field but is still considered a relatively complex geometric shape to fabricate. As shown here, AM techniques can be used to make complex geometric shapes with strong materials to increase the design flexibility of the lightweight structural component industry.
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Vijayanand Rajendra Boopathy, Anantharaman Sriraman and Arumaikkannu G.
The present work aims in presenting the energy absorbing capability of different combination stacking of multiple materials, namely, Vero White and Tango Plus, under static and…
Abstract
Purpose
The present work aims in presenting the energy absorbing capability of different combination stacking of multiple materials, namely, Vero White and Tango Plus, under static and dynamic loading conditions.
Design/methodology/approach
Honeycomb structures with various multi-material stackings are fabricated using PolyJet 3D printing technique. From the static and dynamic test results, the structure having the better energy absorbing capability is identified.
Findings
It is found that from the various stacking combinations of multiple materials, the five-layered (5L) sandwich multi-material honeycomb structure has better energy absorbing capability.
Practical implications
This multi-material combination with a honeycomb structure can be used in the application of crash resistance components such as helmet, knee guard, car bumper, etc.
Originality/value
Through experimental work, various multi-material honeycomb structures and impact resistance of single material clearly indicated the inability to absorb impact loads which experiences a maximum force of 5,055.24 N, whereas the 5L sandwich multi-material honeycomb structure experiences a minimum force of 1,948.17 N, which is 38.5 per cent of the force experienced by the single material. Moreover, in the case of compressive resistance, 2L sandwich multi-material honeycomb structure experiences a maximum force of 5,887.5 N, whereas 5L sandwich multi-material honeycomb structure experiences a minimum force of 2,410 N, which is 40.9 per cent of the force experienced by two-layered (2L) sandwich multi-material honeycomb structure. In this study, the multi-material absorbed most of the input energy and experienced minimum force in both compressive and impact loads, thus showing its energy absorbing capability and hence its utility for structures that experience impact and compressive loads. A maximum force is required to deform the single and 2L material in terms of impact and compressive load, respectively, under maximum stiffness conditions.
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Hui Wang, Tianyu He and Chunjie Wang
In the field of planetary exploration, the legged-type lander is a common landing buffer device. There are two important performance metrics for legged-type landers: the energy…
Abstract
Purpose
In the field of planetary exploration, the legged-type lander is a common landing buffer device. There are two important performance metrics for legged-type landers: the energy absorption capacity and landing stability. In this paper, a novel method is proposed to optimize the honeycomb buffer of a legged-type lander. Optimization design variables are the dimension parameters of honeycomb and the objective functions are the evaluation parameters of the above two performance metrics.
Design/methodology/approach
A multi-body dynamic model of a lander and a finite-element model of the metal honeycomb are established. Based on the simulation results of the finite-element model and the quartic polynomial, the surrogate models are established to evaluate the energy absorption capacity of honeycomb. Considering both the multi-body dynamic model and the surrogate models, the study designed the optimization flow of dimension parameters of honeycomb. Besides, the non-dominated sorting genetic algorithm II is used for iterative calculation.
Findings
Images of surrogate models show the monotonous functional relationship between the honeycomb’s energy absorption characteristics and its dimension parameters. Optimization results show an apparent contradiction among the objective functions. Besides, according to the simulation results, this method can significantly improve the comprehensive performance of the lander.
Originality/value
The novel method can effectively reduce the cost of honeycomb compression tests and improve the lander’s design. Therefore, it can be used for optimizing buffers of other types of legged-type landers.
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Hossein Goodarzi Hosseinabadi, Reza Bagheri and Volker Altstädt
Hexagonal honeycombs with meso-metric cell size show excellent load bearing and energy absorption potential, which make them attractive in many applications. However, owing to…
Abstract
Purpose
Hexagonal honeycombs with meso-metric cell size show excellent load bearing and energy absorption potential, which make them attractive in many applications. However, owing to their bend-dominated structure, honeycombs are susceptible to deformation localization. The purpose of this study is to provide insight about shear band propagation in struts of 3D-printed honeycombs and its relation to the achieved macroscopic mechanical behavior.
Design/methodology/approach
Hexagonal honeycombs and unit cell models are 3D-printed by fused deposition modeling (FDM). The samples are exposed to compression loading and digital image correlation technique and finite element analyses are incorporated.
Findings
It is found that the strain contours, which are obtained by finite element, are in agreement with experimental measurements made by DIC. In addition, three stages of shear band propagation in struts of 3D-printed honeycombs are illustrated. Then the correlation between shear band propagation stages and the achieved macroscopic mechanical responses is discussed in detail.
Originality/value
For the first time, a hierarchical activation of different modes of shear band propagation in struts of a 3D-printed honeycomb is reported. This information can be of use for designing a new generation of honeycombs with tailor-made localization and energy absorption potential.
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S. Kelsey, R.A. Gellatly and B.W. Clark
Simple expressions for upper and lower limits to the shear modulus of honeycomb sandwich cores are obtained by application of the Unit Displacement and Unit Load methods in…
Abstract
Simple expressions for upper and lower limits to the shear modulus of honeycomb sandwich cores are obtained by application of the Unit Displacement and Unit Load methods in conjunction with simplifying assumptions as to the strain and stress systems respectively in the core. The theory is given for cores built up from foil ribbons to form cells of general honeycomb form. Test methods for the experimental determination of the shear modulus are also discussed. Of these, the three‐point bending test on sandwich beams is considered most satisfactory and results of such tests on steel and aluminium foil honeycombs show good agreement with the theory.