Honeycomb Sandwich Composite Structures Research Articles

Development of Deployable Reflector Antenna for the SAR-Satellite: Part 1. Design and Analysis of the Main Reflector Using Honeycomb Sandwich Composite Structure

The deployable reflector antenna based on the synthetic aperture radar is a satellite component that consists of a unit structure in the form of a folded reflector. During the launch process, this satellite antenna is in the stowed condition to improve storage efficiency. It is then deployed to perform the space mission in the on-orbit condition. Due to these structural characteristics of the deployable reflector antenna, the reflector is possible to be loaded in the limited volume of the launch vehicle with the reduced size. Additionally, because the deployable reflector antenna is made by the lightweight material of the carbon fiber reinforced polymer and honeycomb core, it can reduce the launching cost and improve the revisit interval. In this paper, the conceptual design of the main reflector of the deployable reflector antenna was conducted. The main reflector was designed as the honeycomb sandwich composite structure. To design the main reflector, the stacking sequence of the composite material and honeycomb core was investigated to maximize the structural stiffness and minimize the antenna’s mass. Subsequently, finite element analyses including modal, quasi-static, structural–thermal coupling, and transient response were performed to numerically evaluate the structural performance of the lightweight composite reflector antenna.

Characterization of wave propagation in complex composite structures (CCS) using a robust inverse analysis method

This paper presents the application of wave propagation characterization for complex composite structures through the Algebraic K-space Identification technique in the Cartesian coordinate system (AKSI-C). The proposed method is a novel development since the developed methodology uses adequate partial differential algebraic operations to provide a robust and low-cost framework for identifying wave propagation parameters of the structures with multidimensional signals for the first time. Additionally, the proposed method has been experimentally applied to identify the complex wave propagation phenomenon of different complex composite structures: (i) honeycomb sandwich composite structure: variability of orthotropic behavior and damping properties with frequency and direction is identified by wavenumber space, 3D dispersion curves, and damping loss factor surface. Then, the contribution of individual layer properties on the changes in dynamic behavior is studied by estimating transition frequency; (ii) locally resonant meta-structure: the effect of the local resonator-induced band gap on the wave attenuation is investigated; (iii) periodic rib-stiffened composite plates: the inner resonance phenomena and their remarkable elastic wave manipulation ability are explored by designing 3D-printed resonators and identifying the mixed-resonance-induced band gap. The proposed method has been compared with other inverse methods to assess its reliability under complex conditions.

Experiment and Numerical Simulation on Damage Behavior of Honeycomb Sandwich Composites under Low-Energy Impact

It is well-established that the honeycomb sandwich composite structures are easily prone to damage under low-energy impact. Consequently, it would lead to a dramatic decrease in structural load-bearing capacity and a threat to overall safety. Both experimental and numerical simulations are carried out to investigate the impact damage behavior of honeycomb sandwich composite specimens. The damage mode, damage parameters, and contact force-time curves of three types of panel materials with T300, T700, and T800 are obtained under different impact energies of 10 J, 20 J, and 40 J by the drop-weight impact experiment. Moreover, digital image correlation (DIC) tests are used to measure the deformation and strain of the lower panel. The experimental results reveal that the degree of damage increases with increasing impact energy. Particularly, the T300 panel specimen exhibits visible fiber fracture when subjected to an impact energy of 40 J. The impact process involves matrix cracking, fiber fracture, and delamination of the upper panel occurring first, followed by immediate crush damage to the honeycomb core and, finally, slight fiber damage to the lower panel. Due to its higher strength, the T800 panel specimen exhibits the highest damage resistance compared to the T700 and T300 panel specimens. To consider the microscopic failure criteria and various types of contact during the impact process, a finite element model of honeycomb sandwich composites is established, and numerical simulation analysis of low-energy impact is performed to determine the damage mode, damage size, and contact-force curves. Comparative analysis demonstrates good agreement between the simulation and experimental results. The findings of this study provide valuable technical support for the widespread application of honeycomb sandwich composites in the aviation field.

Mechanical Properties and Optimization Analysis on Battery Box with Honeycomb Sandwich Composite Structure

Mechanical Properties and Optimization Analysis on Battery Box with Honeycomb Sandwich Composite Structure

Experimental and Numerical Study on Residual Strength of Honeycomb Sandwich Composite Structure after Lightning Strike

Honeycomb sandwich composite structures are widely used in various aircraft structures due to their unique performance. However, honeycomb sandwich composite structures are prone to lightning damage that threatens the structure safety. Therefore, it is necessary to assess the residual mechanical properties of honeycomb sandwich composite structures after a lightning strike. In this study, simulated lightning strike tests were first conducted for honeycomb sandwich panels with and without carbon nanotube film (CNTF) to obtain different damage scenarios and study the protection effect of CNTF. Then, the residual compressive strength of the panels with lightning strike damage was predicted using a progressive damage analysis method and verified with the experimental results. It was found that the numerical prediction results agree with the experimental results. The size and extent of lightning damage have an important effect on the compression damage mode of honeycomb sandwich panel with closed edges.

Investigation of carbon nanotube reinforcement to polyurethane adhesive for improving impact performance of carbon fiber composite sandwich panels

In this study, the development of a polyurethane adhesive by using carbon nanotubes (CNT) to enhance the low-velocity impact behavior of aluminum honeycomb sandwich composite structures was investigated. The interaction of CNT and polyurethane for the impact behavior of sandwich composite panels is the main originality of this paper. The fabrication of carbon fiber reinforced composite (CFRC) sandwich structures was conducted using different polyurethane (PU) adhesives and different honeycomb cell sizes. CFRC sandwich structures were fabricated with multi-walled carbon nanotube (MWCNT) added and neat PU adhesives, 6.78 and 10.39 mm honeycomb cell sizes, and carbon fiber prepregs. Neat and nanotube added PU adhesives with MWCNT at reinforcement of 0.1% and 0.2% by weight percent were prepared. Sandwich composite panels were manufactured using the hot pressing method. Specimens of 100 × 100 mm were cut from the sandwich panels, and low-velocity impact tests were conducted at 100 J initial impact energy according to ASTM D7136 standard. After experiments, load-deflection curves, load-time, and energy-time histories were acquired. The absorbed energy values at maximum load were evaluated as a function of MWCNT content and honeycomb cell size. Specimens were sectioned from the impacted region and scanned using scanning electron and optical microscopes to analyze the damaged area. Specimens with MWCNT reinforced adhesives carried higher maximum loads compared to neat ones. CFRC sandwich structures with MWCNT added PU adhesives exhibited a 6% higher impact resistance at 100 J energy levels. Experimental results demonstrated that an increase in MWCNT loading and a decrease in PU adhesive cell size increased the maximum load values in CFRC sandwich panels. Among the nanotube added adhesives, 0.1 wt percent showed the best impact performance.

Fabrication of aluminum honeycomb cored carbon fabric/epoxy composite sandwich structures via vacuum assisted resin infusion technique

AbstractA detailed step‐by‐step fabrication procedural document of thin‐walled aluminum honeycomb sandwich composite structures, panels, and specimens using vacuum assisted resin infusion process was delivered in this paper. By and large, honeycomb sandwich structures are made by keeping the honeycomb core in between two face sheets, which are glued with the help of adhesives. In the present fabrication process, aluminum honeycomb core was glued in between the carbon fabric reinforced epoxy composite face sheets through vacuum assisted resin infusion technique. The present paper is aimed at fabricating two configurations of honeycomb sandwich composite panels namely, without considering any filler material inside the honeycomb cell, with considering the filler material inside the honeycomb cell. Plastic pellets made up of poly carbonate were considered as filler material for stiffening the aluminum honeycomb sandwich composite panels.

State‐of‐the‐art review on honeycomb sandwich composite structures with an emphasis on filler materials

AbstractHoneycomb sandwich composites are suitable for making structural materials that are mainly characterized by their lightweight and high stiffness strength. The honeycomb structures filled with foam materials or granular materials concerning to the applications enhance the strength and the damping properties. In this paper, an emphasis has been provided for the comprehensive review of response of honeycomb sandwich structures in different conditions, namely, static, dynamic, and damping behaviors with and without filler material from an experimental and finite element simulation perspective. Various applications of honeycomb sandwich composites in different fields are also reviewed in this paper. Potential new directions in honeycomb sandwich composites are also identified in this paper in addition to the current practices. Conclusions and recommendations from different technical papers are reviewed by considering the honeycomb sandwich composites with filler materials. The given area of research seeks more scientific analysis, modeling, and experiments in future structural applications.

Finite Element Analysis of Honeycomb Sandwich Composite Structures With Various Joints

This work focuses on the numerical investigation of mechanical properties of aluminium honeycomb sandwich composite structures with lap and butt joints. The joints are bonded using adhesive, welded and bolted which were designed using CATIA software. The static and dynamic structural analyses were performed to compute the mechanical properties of aluminium honeycomb composite structures with various joints using ANSYS software. Finally, the models were developed for estimating the failure strength of joints in honeycomb sandwich composite structures.

Electromechanical impedance-based damage localization with novel signatures extraction methodology and modified probability-weighted algorithm

Damage localization with electromechanical impedance is a significant technique in structural health monitoring and engineering community. In this paper, a newly-developed damage localization method is presented by integrating the novel signatures extraction methodology, direct-coupled mechanical impedance (DCMI), with a modified probability-weighted function. The DCMI methodology can be utilized to extract more damage-sensitive characteristic signatures from experimentally acquired raw signatures. Then a damage indicator, root mean square deviation (RMSD), is calculated in terms of real part and imaginary part of raw and DCMI signatures. The investigation on damage location imaging with a modified probability-weighted algorithm is subsequently performed and analyzed using the aforementioned indicators. To demonstrate the effectiveness of the proposed damage localization method, a series of verification experiments are conducted on a honeycomb sandwich composite structure with the surface-mounted piezoelectric sensor array. By comparing experimental results of damage localization, it is demonstrated that combining DCMI methodology with modified probability-weighted algorithm is capable of dramatically increasing the accuracy of damage location imaging.

Modelling and analysis of honeycomb sandwich structure using finite element method

The present study attempts to investigate the natural frequency of honey comb sandwich composite structure made up of carbon/glass fibre unidirectional as face sheets while Aluminium 5052 as hexagonal honeycomb core material using FE based software ANSYS. Natural frequencies were calculated for specimen with face sheet thickness varying from 0.5 mm to 2.5 mm under static loading. The natural frequencies were found to increase and converge with increase in the face sheet thickness. Deformation as well as equivalent Von Mises stresses were predicted and were found to decrease with increase in the face sheet thickness.

Mechanical responses of a composite sandwich structure with Nomex honeycomb core

Weights of honeycomb sandwich composite structures are strictly controlled in scenarios such as in contexts of aerospace engineering. However, such structures extensively studied in past investigations were partly or completely made of aluminum or other metallic materials. Sufficient research has not been reported for honeycomb sandwich composites made of lightweight non-metallic materials. This paper presents an investigation into the mechanical responses of the Nomex honeycomb sandwich structure in a three-point bending test. The mathematical relationship between the shear stress distribution in the skin and that in the Nomex honeycomb core under the bending load was deduced. By applying the commercial software ABAQUS/Explicit, numerical simulations were performed with a highly detailed finite element model (micromechanical level) and equivalent elastic parameters. By comparing the experimental and numerical results, the validity of the theoretical derivation was verified. The effects of the thickness of the skin and the direction of the core on the mechanical responses of the honeycomb sandwich structure were studied. The results showed two different failure patterns of the honeycomb sandwich structure in the three-point bending test, which has rarely been reported previously. The improving effect of the increase in the skin thickness on the ultimate bearing capacity was more remarkable when the honeycomb core had a higher shear rigidity. For the same core direction, the honeycomb sandwich structure with the thicker skin had a better crashworthiness. The skin shear force distribution coefficient decreased exponentially with the ratio of core height-to-skin thickness.

Modified electromechanical impedance-based disbond monitoring for honeycomb sandwich composite structure

The increasing use of honeycomb sandwich composites in industries has attracted much interest in its structural health monitoring (SHM) for the localization and quantification of disbond on skin-core interface. The disbond monitoring in sandwich composites is more complicated than that in laminates. In this paper, a comprehensive active monitoring scheme (CAMS) and direct coupling mechanical impedance (DCMI) signatures extraction approach are proposed. It is developed from a modified electromechanical impedance (EMI) analytical model to extract more useful signatures from measured raw signatures (RS). A damage index (DI), root mean square deviation (RMSD), is adopted to locate and quantify the disbond extent inside structures. Experiments are conducted on a honeycomb sandwich composite with a 4 × 4 sensors array mounted on top skin to validate the effectiveness of proposed monitoring scheme. The experimental results show that both disbond location and severity on skin-core interface can be monitored efficaciously.

Ultrasonic Lamb wave‐based debonding monitoring of advanced honeycomb sandwich composite structures

AbstractHoneycomb sandwich composites are extensively used in military shelters, aerospace structures, ground transportation structures, auto‐racing bodies, ship panels, and other special purpose structures requiring lightweight construction materials. But debondings at the face‐sheet‐to‐core junctions frequently occur due to the variable operating and loading conditions, which may menace the safety and overall integrity of the structural assembly. This paper aims to effectively identify such hidden debonding regions in these advanced structures, using Lamb wave‐based monitoring technique. A semianalytical analysis of Lamb wave dispersion in a healthy sandwich structure is carried out to identify various Lamb modes and to study their propagation phenomenon. A combined finite element‐based simulation and experimental analysis of Lamb wave propagation in sandwich panels (healthy and with debonding) are then carried out using piezoelectric transducer networks. It is observed that the presence of debonding significantly reduces the propagating Lamb wave mode amplitudes. A debonding detection algorithm, which uses the differential changes in Lamb mode amplitudes, is applied to efficiently identify single and multiple debonding regions in the structure.

Damage-induced acoustic emission source monitoring in a honeycomb sandwich composite structure

A coordinated semi-analytical, finite element, and experimental analysis of damage induced acoustic emission (AE) wave propagation and source monitoring in a honeycomb sandwich composite structure (HSCS) have been carried out. Towards this, a global matrix method based two-dimensional (2D) semi-analytical formulation is first applied to obtain the AE response and dispersion characteristics in the HSCS. The finite element simulation of AE-wave propagation in the HSCS is then carried out using different AE-sensor network configurations. Eventually, the damage source locations are efficiently identified by applying a source localization algorithm, which uses the registered AE signals from the sensor networks. In order to verify the robustness of the proposed damage source monitoring technique, the localization is further broadened for randomly selected multiple damage source locations for each sensor network configuration. The obtained results distinctly represent the efficiency of the proposed online monitoring strategy for localizing the damage-source in such complex and advanced structures. Moreover, it is shown that the proposed damage source monitoring technique is reliable and independent of sensor positions.

Investigation of Honeycomb Sandwich Composite Structure with Pre-Damage under Uniaxial Compression

In this paper, the failure modes of the honeycomb sandwich structure under uniaxial compressions after impact (CAI) are analyzed through experiments and Finite Element Method (FEM). Three cases of impact damage location, two cases of impact damage depth and adhesive properties are investigated by the comparisons of corresponding non-destructive structure. Several conclusions are drawn: the failure modes and the initial damage positions obtained from experiments and FEM simulations are almost the same; the location of impact damage may affect the overall loading capabilities of the sandwich structure, whose decreasing rate peaks when the damage is at the top surface and drops when the damage is at the marginal area; different adhesive layer property of interface may lead to the failure mode change, that is, instead of honeycomb core failure, interlaminar failure will occur when the fracture energy of the adhesive layer is low; the damage level and risky location of the structure will vary relevant to the impact energy.

Instrumentation for Determining the Local Damping Capacity in Honeycomb Sandwich Composites

Abstract A mechanical percussion probe originally designed for determining the damping capacity of dental implants has been adapted to assess the damping capacity in a localized area of honeycomb sandwich composites without inflicting damage on the structure. The new instrumentation is light, portable, and inexpensive compared with other testing techniques. Furthermore, it allows quick access to areas not easily accessible by ultrasonic methods. The damping capacity of honeycomb sandwich composite structures is of interest to engineers as it reflects the ability of a material to absorb and isolate vibration. Honeycomb sandwich structures with various damping treatments were constructed and accurately evaluated with the instrumentation. Detection capabilities and limitations were also evaluated.