Aluminum Honeycomb Panel Research Articles

A finite element model for analyzing curved surface sandwich panel forming

The article establishes a finite element (FE) model of sandwich panel (referred to as CSC FE model) using shell structure core and solid structure face sheet and provides a detailed derivation of the data transfer process between the shell structure and the solid structure in the FE model. In order to explore the application of CSC FE model in the curved surface sandwich panel forming, this paper studies the single curvature and double curvature sandwich panel forming in detail. Based on the maturity of the three-point bending theory, in order to facilitate theoretical verification, the article chooses the three-point bending process to study the single curvature sandwich panels forming. It is proved that the CSC FE model can be effectively applied to single curvature sandwich panel forming through three-point bending theory, numerical simulations and experiments of brazed aluminum honeycomb panel (BAHP). Low cost and efficient multi-point forming (MPF) process is used to analyze the double curvature sandwich panel forming. By MPF experiments and numerical simulations of saddle-shaped and spherical BAHPs, and with the help of 3D laser scanning technology, it is proved that the CSC FE model can accurately predict the curved surface shape of double curvature sandwich panel forming.

Thermomechanical Collaborative Design and Experimental Verification of a Sandwich Structure with a Polyimide Foam Core

This paper introduces the technology and performance of a new sandwich structure consisting of carbon fiber composite face sheets, a polyimide foam core, and an aluminum honeycomb panel with both heat insulation and load-bearing functions. The heat-resistant performance of the sandwich structure was evaluated. The vacuum thermal conductivity of the sandwich structure in the vertical direction ranges from 0.54 to 0.92 (W/[m⋅K]) with increasing temperature from −170 to 135°C. A multilayer finite element model of carbon fiber cloth, polyimide foam, and aluminum honeycomb was established. Finally, a comprehensive evaluation of the mechanical and thermal insulation performance of the sandwich structure was conducted through random vibration testing and thermal vacuum testing. The results showed that the sandwich structure had good stiffness and thermal insulation performance, successfully verifying the effectiveness of the collaborative design.

Inspection of defects in composite structures using long pulse thermography and shearography

Long pulse thermography (LPT) and shearography have been developed as primary methods for detecting debonding or delamination defects in composites due to their full-field imaging, non-contact operation, and high detection efficiency. Both methods utilize halogen lamps as the excitation source for thermal loading. However, the defects detected by the two techniques differ due to their distinct inspection mechanisms. In this study, LPT and shearography are employed to evaluate internal damage in various composite structures. The experimental results demonstrate that LPT, when combined with thermal signal processing algorithms, can clearly detect debonding defects in rubber-to-metal bonded plates, whereas excessive adhesive defects can only be identified by shearography. Flat-bottom holes in the CFRP panel can only be detected by LPT, and shearography is particularly effective for detecting composite materials with a metal skin. For the quantitative measurement of defect sizes, the average errors of the rubber-to-metal bonded plate and CFRP panel using LPT are 4.9 % and 2.2 %, respectively, whereas the average errors of the rubber-to-metal bonded plate and aluminum honeycomb panel using shearography are 15.12 % and 95.4 %, respectively. This indicates that LPT is superior to shearography in quantitatively measuring defect sizes. These two nondestructive testing methods, based on different principles, each have their own advantages and disadvantages. Employing a multi-modal inspection method can leverage their complementary advantages, preventing misdetection and leakage of internal defects in composites.

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.

Thermal and mechanical performance of cork insulated aluminum honeycomb panels exposed to corrosive environment

Thermal and mechanical performance of cork insulated aluminum honeycomb panels exposed to corrosive environment

Improving transmission through honeycomb panels through modal considerations

Recent efforts centered at Sandia National Laboratories have demonstrated transmission of power and data through continuous metal media using vibration in connection with piezoelectric tiles; however, solid metal construction may be disadvantageous in structural contexts due to the greater mass needed to achieve given stiffness characteristics. Other common structural materials, on the other hand, such as aluminum honeycomb panels, may offer poor transmission possibilities when their characteristics are not appropriated accounted for in the selection of transducers. In this study, COMSOL simulations of the aluminum honeycomb panel materials were used to select transducers with resonance frequencies in proximity to the natural modes of the panel's honeycomb cells. This enabled improved transmission through the honeycomb panels in comparison to less targeted approaches. [SNL is managed and operated by NTESS under DOE NNSA Contract No. DE-NA0003525.]

A universal elastoplastic equivalent method for sandwich panels and its application in plastic forming

Based on Hill’48 yield criterion, a simple and universal elastoplastic equivalent method for sandwich panels was proposed. In this method, the core of sandwich panel was equivalent to an orthotropic homogeneous panel, and the elastoplastic parameters of equivalent sandwich model were quickly obtained by uniaxial tensile and pure shear numerical simulations of the mesoscopic sandwich model utilizing user-defined material subroutine (UMAT). The equivalent elastoplastic parameters of brazed aluminum honeycomb panels (BAHPs) with core heights of 9 mm (BAHP-H9) and 12 mm (BAHP-H12) were obtained, which were proved to be effective by comparison with analytical solutions and analysis of numerical simulation results. Then, the effectiveness of elastoplastic equivalent method was further demonstrated by comparing the numerical simulation results of multi-point forming (MPF) for the mesoscopic and equivalent finite element (FE) model of BAHPs. Finally, MPF experiments of cylindrical BAHPs under different target forming radii were carried out. The results showed that the elastoplastic equivalent method could be effectively applied to the plastic forming of sandwich panels.

Thermal and Structural Performance of a Small Satellite with Networked Oscillating Heat Pipes

Typically, spacecraft development is costly and time-consuming because of the many iterations usually needed to reach optimal design solutions. This paper presents an innovative approach that eliminates the need to iterate the thermal design process using a network of variable conductance oscillating heat pipes (VC-OHPs) on every structural panel. The temperatures of the panels where components are mounted would thus be maintained at constant levels by VC-OHPs, even if the instruments’ locations or heat dissipation changes. A structural thermal model was built to verify the proposed thermal and structural design in a simulated deep space environment and in a launch environment. It consisted of two VC-OHPs and six aluminum honeycomb panels. A thermal vacuum test was conducted to demonstrate the temperature control by the VC-OHPs. The test results showed that temperature control by VC-OHPs could maintain the panels operating as evaporators at stable temperatures and follow the reservoir temperature. A vibration test was conducted under the launch environment of a Japanese H2A rocket. The results confirmed that the structural thermal model met requirements for resistance to mechanical launch environment. The VC-OHPs functioned after the vibration test. The structural thermal model showed that the proposed thermal control architecture is feasible in an actual spacecraft in terms of thermal and structure design.

Numerical Investigation into In-Plane Crushing of Tube-Reinforced Damaged 5052 Aerospace Grade Aluminum Alloy Honeycomb Panels.

This paper aims to investigate the crashworthiness performance degradation of a damaged 5052 aluminum honeycomb panels under in-plane uniaxial quasi-static compression and the possibility of improving it using reinforcement tubes. The in-plane crushing behaviors and energy absorption capacities of the intact, damaged, and tube-reinforced damaged panels with different damage sizes in both X1 and X2 directions are numerically simulated by using the nonlinear FE method Abaqus/Explicit, and the crashworthiness performances are compared with each other. The validation of finite element model involves comparing the obtained simulation results with theoretical and experimental ones. Very good agreement between numerical, experimental, and theoretical results is achieved. The first maximum compressive load and the mean crushing load of the different honeycomb configurations are analyzed and compared through the load–strain curves. The energy absorption capacity of the damaged and the tube-reinforced damaged panels is calculated and then compared with their corresponding intact ones. The deformation modes are explained in detail. The obtained results show that the crashworthiness performance degradation is directly proportional to the damage size as well as the insertion of reinforcement tubes considerably improves in-plane crushing resistance of damaged honeycomb panels.

Characterization of an underwater metamaterial made of aluminum honeycomb panels at low frequencies.

This paper presents a method to characterize the effective properties of inertial acoustic metamaterial unit cells for underwater operation. The method is manifested by a fast and reliable parameter retrieval procedure utilizing both numerical simulations and measurements. The effectiveness of the method was proved to be self-consistent by a metamaterial unit cell composed of aluminum honeycomb panels with soft rubber spacers. Simulated results agree well with the measured responses of this metamaterial in a water-filled resonator tube. A sub-unity density ratio and an anisotropic mass density are simultaneously achieved by the metamaterial unit cell, making it useful in implementations of transformation acoustics. The metamaterial, together with the approach for its characterization, are expected to be useful for underwater acoustic devices.

Study on Thermal Properties of Epoxy-Adhesive Film for Aluminum Sandwich Composite Structure

Among many composite material structures, honeycomb sandwich composites have been used in various ways. The honeycomb sandwich is adhered by polymer resin adhesive and the stiffness of honeycomb sandwich structures is determined by adhesive characteristics. This study is intended to evaluate adhesive characteristics after surface treatment and lateral compressive characteristics before and after thermal treatment when using adhesive films between aluminum skin (5J32) and honeycomb of aluminum honeycomb panel.

Sparsity enhancement post-nonlinear blind deconvolution method and its application to aluminum honeycomb panel cabin structure

In this paper, we propose a method for post-nonlinear blind source separation. The method divides the separation process of post-nonlinear mixed signals into two independent stages: the nonlinear compensation stage and the linear blind source separation stage. The nonlinear compensation stage is achieved by taking sparsity enhancement as the optimization objective. The L1-norm is taken as the objective function and is combined with the fast iteration based on the gradient descent method to realize the fast nonlinear compensation of the mixed signals. In the stage of linear blind source separation, the blind deconvolution algorithm with reference signals is used to process the compensated signals to realize the separation of the source signals. The separation performance of the method is verified by simulation, and the superiority of the method is tested by comparison. The proposed method is also investigated by the excitation experiment of the aluminum honeycomb panel cabin structure, which simulates the satellite structure.

Boundary condition identification of a clamped honeycomb sandwich panel based on thin-layer element

The stiffness of boundary conditions in mechanical structures is difficult to represent. An approach on high fidelity modeling of the clamped boundary condition is proposed in this paper. Firstly, the normal and tangential stiffness of the contact surface of the clamped boundary condition is parameterized by using thin-layer element with isotropic material. Secondly, the material parameter is identified by minimizing the discrepancy between the calculated results and the experimental data, and parameter identification can be treated as an optimization problem. Experimental investigation is undertaken to verify the proposed method by employing an aluminum honeycomb panel, the numerical model of which is constructed by using the equivalent theory. Thin-layer elements with different properties are used to simulate the mechanical properties in different area of the boundary conditions, and the experimental modal data is adopted to identify the material parameters. Results show that the weighted matrix is a crucial option in the parameter identification procedure, and the width to thickness ratio of the thin layer element has a great influence on the identification results. After parameter identification, the error of the first three order of the modal frequencies is less than 2.7 %, the thin-layer element can accurately reflect the mechanical performance of clamped boundary condition.

Damage Mitigation of a Steel Column Subjected to Automobile Collision Using a Honeycomb Panel

AbstractThis study investigates the performance and design of an aluminum honeycomb panel attached to the face of a steel column for reducing local damage caused by vehicle collision. The dynamic p...

Stiffness identification of boundary conditions by using thin-layer element for parameterization

The stiffness of boundary conditions in mechanical structures is difficult to represent. A method is proposed to model the mechanical performance of the clamped boundary condition based on thin-layer element. Firstly, the contact surface of clamped boundary condition is parameterized by using isotropic thin-layer element to model the normal and tangential contact stiffness. Secondly, material parameter of thin-layer element is identified by using experimental modal data, parameter identification is transformed as an optimization problem. Experimental investigation is undertaken to verify the proposed method by employing an aluminum honeycomb panel, the numerical model of which is constructed by using the equivalent theory. Thin-layer elements with different properties are used to simulate the mechanical properties in different area of the boundary conditions, and the experimental modal data is adopted to identify the material parameters. Results show that the width to thickness ratio of the thin layer element has a great influence on the identification results.

Life Cycle Assessment Contribution in the Product Development Process: Case Study of Wood Aluminum-Laminated Panel

The benefits of aluminum lamination in improving the physical and mechanical properties of wood-based composites is now well documented. This paper shows the contribution of life cycle assessment (LCA) as a tool to assess and compare the environmental footprint in the development of laminated panels. SimaPro 9.0 software, using Ecoinvent database was used to analyze the environmental impacts associated with the manufacturing of wood aluminum-laminated (WAL) panels and aluminum honeycomb panel (AHP). The impact 2002+ method was used to estimate environmental impacts. The LCA results show that the WAL panels manufacturing had a lower environmental impact than AHP manufacturing. In term of product, wood-based composites were the best choice as a core in laminated panel manufacturing. Wood-based composite manufacturing showed environmental advantages in all damage categories except in ecosystem quality. Aluminum alloy sheets manufacturing played an important role in the generation of environmental impacts for laminated panel development.

Effects of length-thickness ratio on the dynamic calculation accuracy of the honeycomb panel equivalent models

In order to improve the numerical calculation accuracy of the hexagonal aluminum honeycomb panel, the influence of the length-thickness ratio on the dynamic calculation accuracy of the equivalent models is studied. The modal frequencies of the equivalent models and the entity model are compared to analyse the influence of the length-thickness ratio on the dynamic calculation accuracy of the equivalent models. The results show that the first 10 order errors of sandwich panel theory model and honeycomb panel theory model are less than 20% for medium thickness panel with length-thickness ratio less than 10.3, so the equivalent effect is ideal. When the ratio of length to thickness of Reissner theory model and honeycomb panel theory model is about 10.3 and 13.7 respectively, the calculation accuracy is low and the error peak appears. The sandwich panel theory model has lower accuracy than other equivalent models for thick panel.

Numerical and experimental comparative study of Aluminum and hybrid mounting interfaces of launch vehicle avionics for weight reduction

Weight is a paramount parameter for launch vehicle applications. Avionics are used for command, control and guidance of launch vehicle. Interface brackets are used for mounting of these avionic packages to the launch vehicle chassis. Dynamic loads and vibration responses dominate the design criteria for these interface brackets. The weight sensitivity on range is more prominent for the upper stages of the launch vehicle. To improve the performance of launch vehicle, employment of light weight hybrid (Aluminum honeycomb panel made up of honeycomb core with face sheets at top and bottom) bracket instead of comparatively heavy conventional all metallic aluminum alloy bracket, for a particular case of mounting two of the launch vehicle avionic packages is explored in this study. Comparable vibration responses are obtained along all three axes for the two bracket configurations (aluminium alloy vs hybrid) with packages mounted for the standard random vibration inputs. Sufficient static margin of safety is achieved for high deceleration re-entry flight loads as well. It is concluded that tremendous weight saving on mounting interfaces can be gained without compromising on factor of safety and amplification of vibration responses.

Thermal damage of aluminum honeycomb panel irradiated by continuous laser

Thermal damage of aluminum honeycomb panel (AHP) irradiated by continuous laser is studied in this paper. Firstly, facula radius and power density caused by defocusing are considered to model thermal damage of continuous laser. An accurate simulation model is established to calculate the shape of a damage hole. The relative errors of entrance hole and exit hole are less than 15 percent. The simulation results are in good agreement with the experimental results. Then, the effects of laser parameters on damage are experimentally investigated, and the damage rule of AHP irradiated by continuous laser is obtained. The experimental results show that edge diameters of entrance hole and exit hole increase with the use of higher laser power and smaller incident angle. A larger defocusing amount decreases edge diameter of entrance hole and increases the diameter on the edge of exit hole.

Mechanical design and analysis of a gripper for non-cooperative target capture in space

Space grippers are the key devices for accomplishing space non-cooperative target capture, which has a great significance for satellite services and space debris removal. This article proposes a novel mechanical gripper device for the capture of aluminum honeycomb panels of non-cooperative satellites. The gripper was modeled and assembled in the three-dimensional modeling platform UGNX. The model was imported into the simulation software ADAMS. ADAMS is capable of analyzing the kinematic feasibility of the gripper model. Collision and penetrating power analysis of the mechanical claws into an aluminum honeycomb plate were carried out in LS-DYNA. Through non-vertical piercing experiment, the maximum approaching angle tolerance is 10°. The established rigid connection can withstand a destructive force greater than 1000 N. A prototype of the mechanical gripper is built. A ground test was carried out with this prototype, in which a test-platform simulated the space microgravity environment. The results certified that the prototype could reach the target at a relative speed of 0.5 m/s and then quickly complete the grabbing motion and establish a rigid connection. The experiment shows that this mechanical gripper can accomplish the task of repeatedly capturing the surface of non-cooperative space satellites.