Honeycomb Thickness Research Articles

Experimental study on compression properties of composite aluminum honeycomb sandwich structures

AbstractThe mechanical properties of the carbon fiber and glass fiber composite honeycomb sandwich structure were studied through compression experiments. The influence of different aluminum honeycomb edge lengths, upper and lower panel thickness, aluminum honeycomb thickness, and loading speed on the compression failure load of carbon fiber composite laminates sandwich structure is analyzed. The influence of different aluminum honeycomb edge lengths and thicknesses on the compression failure load of glass fiber composite laminates sandwich structure was studied. The results show that the thickness of the panel has a significant effect on the failure load of the carbon fiber composite laminate sandwich structure, and the loading speed has a significant effect on the failure load of the carbon fiber composite laminate sandwich structure. The greater the loading speed, the greater the value of the failure load. The edge length and thickness of the aluminum honeycomb have a certain effect on the damage load of the carbon fiber composite laminates sandwich structure, but the influence on the mechanical properties of the glass fiber composite laminates sandwich structure is much greater.Highlights The compression performance of composite sandwich structures was experimentally studied. The influence of composite panel thickness was studied. The influence of aluminum honeycomb edge length and thickness was studied. The influence of loading speed was studied.

Reducing vibration and noise in honeycomb structure applied to automobile integrated water tank

This work uses modal acoustic transfer vector (MATV) technology in conjunction with vibration response analysis to determine optimal target optimization parameters for automobile integrated water tanks. The effects of square and hexagonal reinforcement honeycomb structures on the vibration damping performance of water tanks are analyzed, using an untreated smooth plane as a reference object. The study investigates the effects of honeycomb height, honeycomb length, and honeycomb thickness on the tank’s vibration damping performance. The results indicate that a hexagonal structure is more effective than a square structure in improving structural stiffness and reducing structural vibration. The height of the honeycomb structure is particularly effective in suppressing normal vibration of the structural surface, especially when the height exceeds 8 mm. A response surface model is developed based on the edge length, wall thickness, and height of the honeycomb, following the Box-Behnken central combinatorial test design principle. Considering the effect of interference of additional parts, the noise reduction is found to be most effective with a honeycomb side length L = 12 mm, height H = 4.91 mm, and wall thickness T = 2.5 mm. These parameters can be a guide for creating a new honeycomb reinforcement structure to better achieve vibration and noise reduction in automobile water tanks.

Numerical Investigations of Turbulent Flow Through A 90-Degree Pipe Bend And Honeycomb Straightener

Abstract Pipe bends are commonly used in piping systems in offshore and subsea installations. The present study explores the design considerations for the honeycomb straightener inserted downstream of a 90-degree pipe bend. The objective of the study is to evaluate the effectiveness of the honeycomb in suppressing the flow swirling for different distances from the bend outlet (Lb) and different values of the honeycomb thickness (t). The turbulent flow through the 90-degree circular pipe bend with the honeycomb straightener is investigated by carrying out numerical simulations using the Reynolds-Averaged Navier-Stokes (RANS) turbulence modeling approach. The Explicit Algebraic Reynolds Stress Model (EARSM) is adopted to resolve the Reynolds stresses. The honeycomb thickness to pipe diameter ratio (t/D) is varied between 0.1 and 1. The normalized distance from the bend outlet to the honeycomb straightener (Lb/D) is varied between 1 and 5. The disturbance in the velocity field is generated by the pipe bend with the curvature radius to pipe diameter ratio (Rc/D) of 2 and Reynolds number (Re) of 2×105. It is found that both the increase in Lb/D and t/D improves the performance of the device in removing the swirl behind the bend outlet. The best performance is observed for the honeycomb straightener with the distance Lb/D=5 and thickness t/D=0.5.

A novel method to eliminate the bending-induced collapse of hexagonal honeycomb

A novel grooving method for eliminating the bending-induced collapse of hexagonal honeycombs has been proposed, which lies in determining the appropriate grooving parameters, including the grooving spacing, angle, and depth. To this end, a framework built upon the experiment-based, machine learning approach for grooving parameters prediction was presented. The continuously grooved honeycomb bending experiments with various radii, honeycomb types, and thicknesses were carried out, and then the deformation level of honeycombs at different grooving spacing was quantitatively evaluated. A criterion for determining the grooving spacing was proposed by setting an appropriate tolerance for the out-of-plane compression strength. It was found that as the curvature increases, the grooving spacing increases due to the deformation level of honeycombs being more severe at a smaller bending radius. Besides, the grooving spacing drops as the honeycomb thickness increases, and the cell size has a positive effect on the grooving spacing, while the relative density has a negative effect on the grooving spacing. Furthermore, the data-driven Gaussian Process (GP) was trained from the collected data to predict the grooving spacing efficiently. The grooving angle and depth were calculated using the geometrical relationship of honeycombs before and after bending. Finally, the grooving parameters design and verification of a honeycomb sandwich fairing part were conducted based on the proposed grooving method.

Entropy analysis and thermal energy storage performance of PCM in honeycomb structure: Effects of materials and dimensions

This manuscript focuses on comprehensive investigation of entropy analysis and improve energy storage of phase change material (PCM) using a honeycomb material. In the last decade, the honeycomb structure has quickly emerged as a major tool for improving heat transfer rate, particularly for the back of solar radiation PV panels. The aim of this study was to investigate the effect of honeycomb cell wall thickness (0.2 - 2 mm), cell diameter (2 - 16 mm), and honeycomb material types (cellulose, graphite, polyethylene, stainless steel, magnesium alloy, aluminum, and copper) on heat transfer rate of paraffin. These parameters have significant impact on paraffin's energy storage. The variables were optimized numerically using the CFD techniques according to phase change behavior, kinetic energy storage, and total energy storage of composite/paraffin. The results showed that the embedded metal cage had no effect on the total heat storage capacity of paraffin (27.89 W) for 0.33 mm wall thickness of honeycomb. The other optimal geometrical specifications of a honeycomb were determined to be 10mm cell diameter, and stainless-steel material. The ideal honeycomb cell has a uniform distribution of temperature and phase change in all cells at the same time. The entropy study confirmed that the phase transition of PCM with stainless steel honeycomb fins happened homogeneously and promptly. Furthermore, the heat transfer can be improved with changing the geometry of honeycomb structure, and addition fins inside cell.

Comparative and parametric study of aluminium honeycomb sandwich composites and GRP

Sandwich composites are a special class of material because of distinctive properties such as lightweight, high damping and high energy absorbing capacity, which in turn make this material highly suitable for the shipbuilding industry. The traditionally used materials for hull construction in the shipbuilding industry are steel, Glass Reinforced Plastic (GRP) and wood which is prone to problems such as weight and strength reduction due to water absorption over a period of time. This manuscript presents a comparative study of specific energy absorption (SEA) of GRP sheets and two different aluminium honeycomb sandwich composites one of which has aluminium honeycomb core and aluminium face sheet/skin and the other has aluminium honeycomb core and GRP face sheet. Experiments are carried out on the GRP sheet and sandwich composite with aluminium honeycomb core and aluminium as face sheet using Charpy ASTM E-23 machine. The experimental results are compared with the numerical results obtained from Abaqus and are found to be in good agreement. Further, the numerical simulation has been carried out on sandwich composites and GRP sheets varying several parameters such as foil thickness of honeycomb in sandwich composites, and skin of sandwich composites (aluminium sheet and GRP). Failures have been discussed based on stress theories and the deformation patterns of sandwich composites and GRP sheets (obtained from the numerical and experimental investigation) have been compared. The maximum impulse force has also been presented by using the impulse-momentum equation. It has been found in the study that the aluminium honeycomb sandwich composites with aluminium as face sheet possess high energy absorption to mass ratio than the pure GRP sheets and the aluminium honeycomb sandwich composites with GRP sheet as skin. Further parametric study reveals that the energy absorption to mass ratio increases with increase in foil thickness in both type of honeycomb sandwich composites.

Construction of soft polyurethane cushioning composites based on integral fabric air layer: Reaching new levels in compression and cushioning behaviors

AbstractIn order to prepare a cushioning composite with good resilience and compressibility, the 3D fabric was perforated into a hexagonal honeycomb, high elasticity porous polyurethane foam was used as substrate, and the air layer structure was encapsulated with the packaging film. By changing the hexagonal side length and wall thickness of the honeycomb structure, the integral fabric air layer polyurethane buffer composite was prepared. The properties of the structure were studied, and its compressive capacity under different compressive strains was analyzed. The results show that the mechanical properties of polyurethane foam were improved after adding the integral fabric air layer structure. When the composite HPU‐R1L2 (polyurethane cushioning composites with 1 cm side length and 2 cm wall thickness of hexagonal honeycomb) was compressed to 75%, its compressive capacity was 8.24 times that of PU (Polyurethane foam with 2.5% bentonite). The prepared composite HPU‐R1L1 (Polyurethane cushioning composites with 1 cm side length and 1 cm wall thickness of hexagonal honeycomb) absorbed 96.7% of the energy in the dynamic impact test, indicating that the composite cushioning performance was stronger than that of polyurethane foam. The HPU composites based on the synergistic reinforcement strategy of polyurethane foam and monolithic fabric air‐layer structures are an excellent candidate in the field of commodity packaging and personal protection.

Dynamic compressive behaviour of shear thickening fluid-filled honeycomb

Shear thickness fluid (STF) is considered an ideal filler to enhance the mechanical behaviour of in-plane honeycomb due to its special rheological properties. In order to investigate the dynamic compressive behaviour of STF-filled honeycomb, a comparative study between a STF-filled honeycomb and an empty honeycomb is numerically carried out after the fluid-structure coupled model has been validated against experimental testings. It is shown that the addition of STF in the honeycomb cells results in significant improvement in the energy absorption of the STF-filled honeycomb, which in turn, effectively prevents the premature collapse of the honeycomb cell walls. Furthermore, a parametric study of STF-filled honeycomb is conducted to investigate the contributions of each component to the total energy. It is found that the honeycomb plastic deformation is the predominant mechanism of energy absorption during impact, whilst the proportion of viscous energy contribution to the total energy is significantly reduced when the honeycomb wall thickness is increased. Additionally, the mean crushing force of STF-filled honeycomb has a power law relation to the honeycomb wall thickness for each specific loading velocity. Moreover, the mean crushing force contributed by STF is proportional to loading velocity and the increase in velocity significantly improves the percentage of viscous energy to the total energy. Meanwhile, optimal honeycomb thickness and weight fraction of STF are crucial to avoid earlier plastic densification of the honeycomb during the loading process. The results of this paper provide useful insights for future design and optimization of STF-filled structures.

Crushing behavior of curved Nomex honeycombs under combined shear-compression loads

This paper investigated the initial yield behavior of curved honeycombs under combined shear-compression loads with particular attention to the curvature, loading angle, and honeycomb thickness effects. A detailed finite element model was introduced to analyze the mechanical response and deformation mechanism of curved honeycombs and then verified through experiments using a specially designed set-up. It was found that the curvature had a significant effect on the crushing response. As the curvature increased, the initial peak stress reduced by 16.20%. The out-of-plane loading angle ranging from 0º to 15º had little effect on the crushing behavior, whereas it became more pronounced for the angles larger than 15º. In comparison, the effect of in-plane loading angle fluctuating between 0º and 60º was more significant. Based on the obtained data, a macroscopic yield criterion for the initial yield stress of curved honeycombs was proposed. A novel inverse parameter identification approach for curved honeycombs was proposed to determine the induced parameters conveniently. The current study gave insight into the performance change of honeycombs with specific curvature and could be used to develop its constitutive models under complex loads.

Analyzing melting process of paraffin through the heat storage with honeycomb configuration utilizing nanoparticles

To intensify the charging rate of thermal storage, new honeycomb configuration has been utilized in this work. The various material were utilized for solid structure namely: Stainless steel (SS); Aluminum-6061-T4 (Al-6061) and pure aluminum (Al). The holes were filled with mixture of paraffin (RT82) and Al2O3 nanoparticles. To create various configurations of holes with honeycomb shape, the geometric factor (b2) has three levels and another geometric factor was calculated to reach the equal volume of paraffin in all geometries. Characteristics of NEPCM were measured based on homogeneous model. The two dimensional laminar melting process was simulated based on finite volume approach. The size of mesh and value of time step have been optimized to decrease the computing price and precision of code was tested with matching the data with exist published article. With decrease of b2, the thickness of honeycomb reduces and number of holes increases. When b2 = 1 mm, the required time decreases around 90.87% and 24.28% with changing the material from SS to Al and Al-6061. With utilize of Al, the melting time decreases around 27.96% with reduce of b2. The lowest period is about 6.548 min which belongs to case with pure aluminum and b2 = 1 mm.

Influence of HT on energy absorption in CLS compression process

ABSTRACT Paper honeycomb and EPE are widely used in the field of packaging protection and safety transportation. Given the cushioning and protective function of unilateral and bilateral composite layered structures (CLSs) including polyethylene foam (EPE) and paper honeycomb, this work focused on analyzing the energy absorption (EA) and compression deformation of honeycomb thickness (HT) CLS under diverse drop impact (DI) status. Experimental observation showed that the increase of HT can improve the impact resistance of EPE and its CLSs. For the CLS with the HTs of 10, 15, 20, and 25 mm, the increase of paper HT may reduce the EA at low impact energy, while enhancing the EA capability at high impact energy. However, the EA of CLSs with a large HT of 70 mm is relatively poor. For the same drop weight mass or impact energy, the stroke efficiency (SE) and specific energy absorption (SEA) of the unilateral CLS with the same HT are, respectively, increased by 39.1% and 16.2%, so the EA of the unilateral CLS is superior to the bilateral CLS.

MANUFACTURING OF RAPID PROTOTYPES OF MECHANICAL PARTS USING REVERSE ENGINEERING AND 3D PRINTING

This article focuses on the design and manufacture of mechanical parts that have complicated shapes using the technique of reverse design using a scanner or an MMT for data acquisition in the form of a point cloud, using CAD software (CATIA). The digital model created is used for a virtual representation of the final product. Then we get the physical model on a 3D printer (also called additive manufacturing process) for later use in sand moulds. To have the imprint in the sand mould, we go through the fusion of the physical model (part). The use of this technique in the industry, allows us to save a lot of time in terms of model preparation and simple to implement, especially if it is mechanical parts that do not have a definition drawing, or they are worn out, then structural analysis was applied on the model using FE based software and tools to prove the quality of the product. Von Mises equivalent strains and stresses were predicted and decreased with increasing areas and honeycomb thickness. The objective of this article is to give an overview of this relatively modern technology and its various applications.

Experimental and numerical study on the constrained bending-induced collapse of hexagonal honeycomb

This study aims to analyze the deformation behavior of hexagonal honeycomb and classify the collapse modes during constrained bending for forming curved sandwich structures. To this end, the experiments with various bending radiuses and honeycomb thicknesses were carried out, and a finite element model (FEM) was developed to simulate the bending operation. To evaluate the honeycomb’s buckling level, a novel quantitative approach was proposed based on the extracted deformed configuration of the honeycomb top surface. The FEM model was validated by comparing predicted deformation modes and quantities with experimental results and then used to analyze the honeycomb deformation. The buckling evolution, as well as its dependence on the honeycomb thickness and imperfection, has been extensively explored. It was found that the cell wall thickness variance has the most significant influence on the bending behavior. Furthermore, this study revealed two distinct honeycomb collapse patterns during the constrained bending process along the transverse direction (WD). The likelihood of each collapse pattern varies with bending radius and sample thickness. Besides, a snap-through buckling mechanism at the cell scale was proposed for the collapse onset and evolution. These achievements pave the way for the development of curved honeycomb sandwich structures.

Dynamic cushioning energy absorption of paper composite sandwich structures with corrugation and honeycomb cores under drop impact

The paper composite sandwich structure with corrugation and honeycomb cores has been widely used in civil and national defense industries, and the cushioning energy absorption characteristic is a key indicator to evaluate the performance of this composite structure. Therefore, this paper is focused on the influences of honeycomb thickness on the shock acceleration response and deformation characteristics to analyze cushioning energy absorption performance of the composite structure by various experimental tests. The experimental result shows that the paper corrugation layer firstly comes into crushed, and then the paper honeycomb layer is crushed. Additionally, the large honeycomb thickness may cause the secondary collapse of paper honeycomb layer. Under the same impact energy or impact mass, the cushioning energy absorption of the single-sided composite sandwich structure is better than that of the double-sided structure with the same honeycomb thickness. However, the impact resistance of the double-sided composite structure is better than that of the single-sided structure. For the paper composite sandwich structures with the honeycomb thicknesses 10, 15, 20, and 25 mm, the increase of honeycomb thickness would decrease the cushioning energy absorption of the whole structure under the drop impact with low energy. However, under the drop impact with high energy, the influence of honeycomb thickness on cushioning energy absorption is contrary. For the paper composite sandwich structure, the specific energy absorption, unit volume energy absorption, and stroke efficiency for the honeycomb thicknesses 10, 15, 20, and 25 mm are higher than those for the honeycomb thickness 70 mm. Therefore, the low honeycomb thickness is more advantageous for the cushioning energy absorption of paper composite sandwich structure.

Impact penetration through spacecraft honeycomb panels analytical, numerical and experimental study

Abstract Sandwich panels owing its high bending stiffness and low density are widely used in space and aerospace industry [1].Sandwich panel consists of two thin face sheet separated by the core material. Core geometry and material properties determine the strength and stiffness of the sandwich panel. In the aerospace industry, foam and metal cores are used. Honeycomb core is widely used in the satellite. In this paper, the impact resistance of metallic honeycomb is studied analytically. Analytical formulation discusses the resistance force,energy dissipation and damage in the metallic honeycomb. Analytical formulation discusses the perforation velocity of the projectile as function cell size and a wall thickness of honeycomb. The quasi-static test was done on various size of the honeycomb to study penetration and perforation by a spherical projectile. Analytical Formulation was compared with the impact experimental on metallic honeycomb by Goldsmith et al. [3], A.Alavi Nia et al. [4] and H.Zhao et al.[5]. Full 3D F.E model of the metallic honeycomb and projectile was developed in Abaqus 6.14 . Material and Geometric Nonlinearity has been modeled for the metallic honeycomb in the explicit simulation. Continuum damage modeling technique is used to compare the analytical, experimental and numerical results

Static cushioning energy absorption of paper composite sandwich structures with corrugation and honeycomb cores

In view of cushioning energy absorption of paper composite sandwich structures with sinusoidal corrugation and hexagonal honeycomb cores, the static yield strength and compression deformation were firstly analyzed by experiments, then the unit volume energy absorption, unit area energy absorption, and specific energy absorption were evaluated. Further, the influences of static compression rate, corrugation types, and honeycomb thickness on the cushioning energy absorption were respectively studied. The experimental observations show that the paper composite sandwich structures are crushed layer by layer due to the difference in the yield strength of sandwiches, and the honeycomb core is crushed after the collapsing of corrugation core. The three evaluation indices of cushioning energy absorption have similar change rule with the compression rate, corrugation types, and honeycomb thickness. The influence of static compression rate on the yield strength and cushioning energy absorption of the paper composite sandwich structure is not obvious. The composite sandwich structures consisting of paper corrugation sandwich with large inertia moment and honeycomb sandwich with large thickness have more excellent cushioning energy absorption, the B-corrugation can increase the unit volume energy absorption of paper composite sandwich structures by up to 18% than C-corrugation, and the 3-honeycomb can increase the unit volume energy absorption of paper composite sandwich structures by up to 32% than 2-honeycomb.

Investigation of low velocity impact behaviors of honeycomb sandwich composites

Honeycomb sandwich composites are used as significant structural members in advanced engineering applications. Thus, it is critical to determine how they behave under impact loading, in addition to other loads. In this study, low velocity impact loading behaviors of honeycomb sandwich composites were experimentally investigated. Almost all of the design parameters of honeycomb sandwich composites were investigated. The results indicated that the core thickness of honeycomb had no effect on the strength of the composite, and the parameter influencing the impact behavior of the specimen the most was the face sheet thickness. When the face sheet thickness of the specimen was increased, the most apparent strength increase was observed in the models using carbon fiber-reinforced composite face sheets. For all face sheet types subject to impact energy of 10 Joules, the upper face sheets of 0.5 mm-thick specimens were perforated.

Numerical investigation of honeycomb filled crash box for the effect of honeycomb's physical parameters on crashworthiness constants

ABSTRACTThe current research focuses on investigation of crashworthiness of the high-strength steel (HSS) columns filled with aluminium honeycomb. In this study, five variants of honeycomb thickness; Thickness-1, Thickness-2, Thickness-3, Thickness-4, Thickness-5 and six variants of honeycomb cell size; CellSize-1, CellSize-2, CellSize-3, CellSize-4, CellSize-5 and CellSize-6 are considered. Numerical analysis is performed for sandwich honeycomb separated by steel plates in HSS crash box and by inducing V-Notch triggers in the honeycomb. It was perceived that energy absorption (EA), specific energy absorption (SEA) and crush force efficiency (CFE) of Thickness-5 increased by 77%, 19% and 60% respectively compared to Thickness-1 and for CellSize-1, increased by 51%, 24% and 38% respectively compared to CellSize-6. Similarly, the crash box filled with V-Notch triggered honeycomb is increased by 10%, 17% and 4% respectively compared to crash box filled with regular honeycomb and 17%, 55% and 7% respectively compared to crash box filled with sandwich honeycomb.

Design and Manufacturing of Variable Stiffness Mattress

Sleep quality are found to be decreased in the past decades from several surveys. And researches conducted that uncomfortable mattress can be one of the important reasons causing sleeping problems. This paper presents the design and manufacturing of variable stiffness mattress with cellular structure to maintain uniform body support. The relation between the hexagonal honeycomb thickness and stiffness is studied and tested. The author applies image analysis technique to extract and digitize the information from the body load distribution map. Voxelization is used to determine the thickness of each unit hexagon. A comparison between the designed mattress and current existing mattress is given based on their deformation under same load. With the study of the unit cell and voxelization technique, our designed mattress has less variation on deformation compare to the uniform mattress which indicates we have more control on the deformation with this proposed methodology.

Investigation on the static and dynamic behaviors of non-pneumatic tires with honeycomb spokes

Non-pneumatic tires (NPTs) have wide application prospects due to their advantages of no run-flat, no need of air pressure maintenance, and low rolling resistance. In this paper, the static and dynamic behaviors of NPTs with different honeycomb spokes were investigated. Based on the static behavior of three types of NPTs with the same cell wall thickness of honeycomb or the same reference load carrying capacity, it is shown that the maximum stresses in spokes and tread of a NPT are much lower than that of traditional pneumatic tires, but its load carrying capacity is higher than the latter. In comparison with the dynamic behavior of three types of NPTs designed with the same load carrying capacity, it is found that the stress level in spokes and tread under dynamic loading are higher than that under static loading. The rolling resistance of NPTs with the smallest cell expanding angle is lowest, which is due to the lowest mass and smallest deformation of honeycomb spokes. Taking all these factors into account, it is suggested that an optimal NPT in applications is one with a small cell expanding angle and wall thickness.