Aluminum Honeycomb Structure Research Articles

Crashworthiness of Ultrathin Aluminum Honeycomb Structure

Crashworthiness of Ultrathin Aluminum Honeycomb Structure

Structural Support of Aluminum Honeycomb on Cast PBX

As the operating condition for the penetrating missile has been more advanced, the survivability of main charge has been strongly required when the warhead impacts the target. Lots of efforts to desensitize explosives such as the development of insensitive molecular explosives or optimizing plastic-bonded explosives(PBX) systems has been made to enhance the survivability of main charge. However, these efforts face their limits as the weapon system require higher performance. Herein, we suggest a new strategy to secure the survivability of main charge. We applied structurally supportable aluminum honeycomb(HC) structure to cast PBX. The aluminum HC structure reinforces the mechanical strength of cast PBX and helps it to withstand external pressure without the reaction like detonation. In this study, impact resistance character, shock sensitivity and internal blast performance of PBXs reinforced with HC structure were investigated according to the application of aluminum HC structure. The newly suggested aluminum HC structure applied to cast PBX was proved to be a promising manufacturing method available for high-tech weapon systems.

Multiscale homogenization of aluminum honeycomb structures: Thermal analysis with orthotropic representative volume element and finite element method

This study develops a thermal homogenization model for an aluminum honeycomb panel using the representative volume element (RVE) concept, considering the orthotropic nature of the structure. The RVE thermal homogenization method is a numerical approach for analyzing heterogeneous materials. It employs a constitutive model based on RVE performance to represent thermal behavior. Effective parameters are determined through averaging techniques, and the finite element method solves the thermal problem, accounting for structure topology and material behavior. The resulting heat conduction problem is solved using the finite element method (FEM) to evaluate the effective thermal characteristics. A 3D RVE is generated based on the honeycomb panel's geometry, evaluating thermal conductivity tensor and describing the medium's thermal performance. Numerical tests validate the model by comparing it with the real honeycomb structure under sinusoidal heat flux. Results show good correlation, with maximum temperatures of 1101.9 °C in the real structure and 1096.4 °C in the medium. The homogeneous medium is further used to investigate thermal performance under convective conditions with varying panel thicknesses, achieving over 77 °C temperature reduction with the thickest panel. Natural vibration behavior is considered, demonstrating strong correlation between modal responses and natural frequencies. This modeling approach efficiently analyzes thermal behavior in large honeycomb structures, reducing computational time significantly.

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

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

A Study of Aluminum Honeycomb Structures under Dynamic Loading, with Consideration Given to the Effects of Air Leakage

Aluminum honeycomb structures are used in the construction of protective materials due to the positive relationship between their mass and their energy-absorbing properties. Applying such materials in the construction of large machinery, such as military vehicles, requires the development of a new method of finite element modeling, one that considers conditions with high strain rates, because a material model is currently lacking in the available simulation software, including LS-DYNA. In the present study, we proposed and verified a method of numerically modeling honeycomb materials using a simplified Y element. Results with a good level of agreement between the full core model and the Y element were achieved. The obtained description of the material properties was used in the subsequent creation of a homogeneous model. In addition, we considered the influence of increases in pressure and the leakage of the air entrapped in the honeycomb cells. As a result, we were able to attain a high level of accuracy regarding the stress values across the entire range of progressive failure, from the loss of stability to full core densification, and across a wide range of strain rates.

Influence of the cutting tool geometry on milling aluminum honeycomb structures

Influence of the cutting tool geometry on milling aluminum honeycomb structures

Modeling machining of aluminum honeycomb structure

Modeling machining of aluminum honeycomb structure

Anti-icing and anti-frost properties of structured superhydrophobic coatings based on aluminum honeycombs

Superhydrophobic coatings have many potential applications in prevention of ice, frost, condensation, and corrosion due to their strong hydrophobicity and self-cleaning function. However, superhydrophobic coatings do not have ideal mechanical stability in engineering applications, and the coatings lose their superhydrophobic properties with wear. We propose an innovative combination of a macroscopic aluminum honeycomb structure with a superhydrophobic coating to prepare a mechanically stable, structured coating by a simple spraying process. The coating showed excellent performance in laboratory ice, frosting, and outdoor ice tests. Compared with common superhydrophobic coatings, the total ice-up time of single droplet was prolonged by 190 s on a platform at −15 °C because of the reduced heat transfer between the macro-honeycomb wall and the droplets. After 300 wear tests, the frosting amount increased by only 0.03 g when the platform was tilted to 60% at −20 °C and 75 ± 5% humidity. In the outdoor ice test, no large area of ice was observed on the surface. Our findings provide a new strategy for industrialization of superhydrophobic coating, and our strategy has potential applications in anti-icing and anti-condensation for electrical equipment, drag reduction, and anti-corrosion.

A comparative study on the ballistic performance of aramid and aluminum honeycomb sandwich structures

This study investigated the perforation phenomenon of aramid and aluminium honeycomb sandwich structures under high-velocity impacts and compared the impact responses experimentally and numerically. The dimension of the face sheets used was 1 mm in thickness and 220 mm in diameter, and for both the honeycomb cores, the cell thickness of 0.05 mm and the cell size of 3.2 mm was used. Ballistic impact tests were conducted by employing a pneumatic air gun to study damage behavior and failure modes under different impact velocities between 35 m/s and 150 m/s using conical shaped and hemispherical shaped projectiles.Three-dimensional finite element models were implemented in ABAQUS/Explicit to model sandwich panels.The numerical model was validated with experimental data and, subsequently, the numerical study was further extended to study the effects of different geometrical parameters affecting the impact response of sandwich structures. The results showed that for the ballistic limit, sandwich structure having an aluminium honeycomb core performed better than the aramid honeycomb core by 3.09% and 2.5% against conical and hemispherical projectiles, respectively. However, the aramid honeycomb structure was proven to be more efficient than the aluminum honeycomb structure in terms of energy absorption and specific energy absorption.

Optimization of the milling process for aluminum honeycomb structures

The milling of aluminum honeycomb structures represents today an important scientific and technical research topic for many industrial applications: aerospace, aeronautic, automotive, and naval. The difficulties encountered when milling this type of materials are linked to the small thickness of the walls constituting the honeycomb cells and the ductility of the material structure. The milling of cellular composite structures requires specific and rigorous tools. In the present work, a 3D numerical modeling of the milling process of aluminum honeycombs has been developed using Abaqus Explicit software. The effect of milling parameters, such as the spindle speed, the tilt angle, and the depth of cut, has been particularly investigated in terms of cutting forces, surface integrity, and chip morphology. To properly analyze and optimize the cutting process, experimental validation was done through milling tests with different cutting conditions. The comparison between numerical simulations and experimental tests shows that the three-dimensional model correctly reproduces the milling of this type of structure.

Surface integrity quantification in machining of aluminum honeycomb structure

This work outlines an analysis of the surface integrity of aluminum honeycomb after milling using specific tools. This is the most common core material used for aircraft honeycomb structures. The machining of these materials is accompanied by some difficulties related to structural properties due to the weakness of local bending stiffness of the cell walls and the lightweight of material. This influences the surfaces quality after machining. Our analysis aims to shows the link between the surface integrity (burr, walls folding and tearing) and the machining conditions. To meet this objective a specific method based on microscopic observations is developed.

Configuration optimization of the honeycomb core in the latent heat thermal energy storage of a solar air heater: Experimental and numerical study

This article investigates the effect of embedding the aluminum honeycomb structure in latent heat thermal energy storage (LHTES) of a solar air heater (SAH) and proposes an optimal arrangement of the partial honeycomb core. The effect of placing an aluminum honeycomb core in the LHTES of a solar air heater in mass flow rates of 0.02 and 0.04 kg/s is investigated numerically. A finite volume method is utilized to solve the governing equations in the 3D domain. The phase change material's (PCM's) solid–liquid interface and temperature field are solved by the enthalpy-porosity method and validated by experimental results. The honeycomb core embedded in paraffin is simulated as a composite material with effective thermal properties and local thermal equilibrium condition. The effect of the insertion of eight different honeycomb configurations in the latent heat storage is examined, and an optimized arrangement of the honeycomb structure is proposed. The experimental setup of the SAH is designed based on the optimized honeycomb configuration and is built in the laboratory. The performance of SAH and LHTES is analyzed for three cases: (1) in the presence of a honeycomb (case 8), (2) in the absence of a honeycomb (case 1), and (3) the optimized honeycomb structure (case 2). The results indicate that the honeycomb core in LHTES reduces the melting time by over 35%. Case 2 LHTES (honeycomb in 1/3 bottom portion) is suggested as the best honeycomb structure compared with other configurations. This structure is found to increase the energy storage rate by about 50%, while the energy storage density reduces by 2%. As the thermal performance of the SAH grows after the sunset, the warm air production lasts for a longer duration.

Compression and Three-Point Bending Analyzes of Aerospace Sandwich Composites produced with Polymeric Core Materials with ANSYS

Honeycomb materials are widely used in aircraft structures. However, these structures have disadvantages in longitudinal compression forces. While aluminum is generally used as the face material in sandwich composites used in aircraft structures, Nomex honeycomb or aluminum honeycomb structures are used as the core material, depending on the design. The reduced interface area between the core and the surface layer also increases the probability of separation of the surface and core under an applied load. In this study, attention is drawn to the combination of polymeric foam - honeycomb structure as a potential material to eliminate or minimize these disadvantages of honeycomb core structures. In this study, polyurethane foam filled PLA (polylactic acid) honeycomb core sandwich composite with carbon fiber faces was subjected to compression and three-point bending tests in ANSYS. The results obtained show that this new material can be used in aerospace materials.

Genetic algorithm based design optimization of crashworthy honeycomb sandwiched panels of AA7075-T651 aluminium alloy for aerospace applications

Crashworthiness studies, for decades have been an area of tremendous interest in aerospace and automotive sectors, as ensuring the safety of the occupants in the vehicle is a primary goal. Honeycomb sandwich panels are generally used for building floor, ceiling and other important fuselage parts in a commercial airliner to make the structures shock-resistant. In this work, optimization of the design of crashworthy sandwiched honeycomb structure was carried out using a non-dominated sorting genetic algorithm (NSGA) . The stated algorithm had actively monitored the variation of the geometric parameters. To study the shape effect of the cells which absorb impact energy, three cellular shapes namely hex-grid, ortho-grid and iso-grid structures were considered for analyzing their deformation behavior under impact loading. A multi objective function in the genetic algorithm was implemented in MATLAB, where the objectives were to minimize weight and to maximize the absorbed impact energy while constraining the maximum transmitted force and displacement due to crushing. Sandwiched aluminum (AA7075-T651) honeycomb structures were modeled in ABAQUS using python scripts , with the number of core cells and the wall thickness of each core cell being optimized through genetic algorithm in MATLAB using an interactive mechanism. Significant improvements were observed in terms of reduction of weight and increase in the ability to absorb the specific energy during crushing in the sandwiched panels after 450 iterations of optimization cycles. A novel methodology in the domain of crash analysis of aerostructures was established with design optimization of honeycomb sandwiched panels.

Axial crushing responses of aluminum honeycomb structures filled with elastomeric polyurethane foam

In this study the energy absorption of elastomeric foam-filled aluminum honeycomb under quasi-static compression loading and low velocity impact was experimentally investigated. Commercially available Al honeycomb made of Al5052 H38 filled with elastomeric polyurethane foam was used as the specimens. Pure polyurethane had a shore hardness of 30A and to make it foam, different volume fraction of glass microballoon was added to it and a novel material was synthesized that simultaneously had the properties of elastomers and foams Energy absorption of the specimens were evaluated by different parameters such as peak load, crushing load and absorbed energy. Also, the effective failure mechanisms were fully discussed. The results showed that the addition of polyurethane to the honeycomb cells had no significant effect on energy absorption enhancement. However, the addition of glass microballoon particles to the elastomer considerably raised the maximum load, mean crushing load, and total absorbed energy and unlike conventional filled structures, it had been significantly less deformed and could act as an energy absorber against impact many times.

A new and lean finite element model to predict the out of plane crash behaviour of aluminium honeycomb structures

Aluminium honeycombs are well-known anisotropic structures which are commonly used as energy absorber units. In the past decades, several researchers have focused on developing finite element models credible enough to predict the crash behaviour of honeycomb structures. A number of modelling methodologies have been developed and validated to closely represent the structural behaviour under various boundary conditions. Due to the limitations with modelling the structure accurately as well as the adhesive failure and trapped air, presents a serious challenge to predict the crushing behaviour of honeycomb structures. This paper introduces multiple simplified FE models and the results from simulations are compared with experimental data to evaluate the most effective model. The results have also been compared with our existing article which used LSDYNA for numerical analysis. The techniques proposed in this paper show good correlation with the mentioned experimental data and the LSDYNA model. Thus, the simplified FE models are regarded as validated and credible enough to predict out-of-plane crash behaviour of aluminium honeycomb. Altair’s HyperMesh and HyperCrash were used to create the FE models and the dynamic explicit code RADIOSS to solve the models.

Using highly porous aluminum alloys and honeycomb structures in spacecraft landing gear

Highly porous aluminum alloys and honeycomb structures may be utilized as single-use shock absorbers in landing gear and other elements of spacecraft thus ensuring safety of the landing process. This paper presents the results of studies that make it possible to estimate mechanical properties and shock-absorbing characteristics of highly porous aluminum alloys and honeycomb aluminum alloy structures, the initial average densities of said alloys and structures ranging from 330 to 2250 kg/m³. We list analogs that correspond with different stages found on stress-strain curves of highly porous aluminum alloys and honeycomb structures. The paper also provides the foundations of calculating the specific and effective energies of shock absorption.

On Aluminum Honeycomb Impact Attenuator Designs for Formula Student Competitions

The use of impact attenuators (IA) is important for vehicles as they absorb the kinetic energy exerted from the car crashes to protect the drivers from any possible injuries. Under the framework of the Formula Student (FS) competition, we investigate various designs of IA made of aluminum honeycomb material. Specifically, the crushing behavior of the honeycomb structure is investigated from the theoretical point of view and later verified with numerical simulations. To achieve the desired crushing behavior of the aluminum honeycomb structure, apart from the so-called pre-crushing method, another way to pre-process the aluminum honeycomb is proposed. Modification on the aluminum honeycomb is done in a symmetric manner to ensure the same uniform crushing behavior on the two sides of the mirror plane of the car. Different variations presented in this paper shed a light on future aluminum honeycomb IA designs in the context of FS competitions.

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ МЕТАЛЕВИХ ЛОПАТЕЙ НЕСУЧОГО І РУЛЬОВОГО ГВИНТІВ ВЕРТОЛЬОТА

Analysis of the foreign and domestic work experience, manufacturing and operation of the helicopters with metal blades of the main (MR) and tail (TR) rotors is performed. General requirements for the helicopter MR and TR blades design are formulated. Structural arrangement of the helicopter MR metal blade is reviewed, features of the construction materials for the metal blades are noted. Features of the MR and TR metal blades design with the pressed spar and aluminum honeycomb core are given. Parametric modeling technique of the helicopter MR metal blade is presented. The manufacturing rout technology and the method of the surface strengthening of the metal blade tip are presented. The scheme and the manufacturing rout technology of the pressed aluminum spar are given; the geometrical twist features, the surface strengthening and the assembling of the spar with the blade tip are re- viewed. The features of the electric-heating patch bonding on the spar leading edge are shown. Following technological steps of the blade metal rear area manufacturing are reviewed: the rolled aluminum foil degreasing; the aluminum honeycomb structures manufacturing; the aluminum honeycomb core butt milling. The features of the blade rear area assembling and metal blade assembling by bonding in the jig are presented; the content of works outside of the jig for metal blade of the helicopter main rotor is given.

High-velocity impact loading in honeycomb sandwich panels reinforced with polymer foam: a numerical approach study

The employment of lightweight structures is one of the most important goals in various industries. The lightweight sandwich panel is an excellent energy absorber and also a perfect way for decreasing the risk of impact. In this paper, a numerical study of high-velocity impact on honeycomb sandwich panels reinforced with polymer foam was performed. The results of numerical simulation are compared with the experimental findings. The numerical modeling of high-velocity penetration process was carried out using nonlinear explicit finite-element code, LS-DYNA. The aluminum honeycomb structure, unfilled honeycomb sandwich panel, and the sandwich panels filled with three types of polyurethane foam (foam 1: 56.94, foam 2: 108.65, and foam 3: 137.13 kg/m3) were investigated to demonstrate damage modes, ballistic limit velocity, absorbed energy, and specific energy absorption (SEA) capacity. The numerical ballistic limit velocity of sandwich panels, filled with three types of foam, was more than that of a bare honeycomb core and unfilled sandwich panel. In addition, the numerical results showed that the sandwich panel filled with the highest density foam could increase the strength of sandwich panel and the numerical specific energy absorption of this structure was 23% more than that of unfilled. Finally, the numerical results were in good agreement with experimental findings.