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This paper proposes a 7-way microstrip divider for hexagonal honeycomb structures. The honeycomb arrangement has advantages such as equidistant adjacent output ports and high space utilization. The structure comprises six output ports arranged hexagonally and one output port placed at the center of the hexagon in the same plane. To design such a divider considering the output ports' positions, this paper proposes the combination of a microstrip 6:1 unequal Wilkinson divider and a 6-way microstrip divider. To facilitate the implementation of the 6:1 unequal divider, including a transmission line with a high characteristic impedance, a microstrip coupler is used, and for the 6-way microstrip divider, a design scheme and analysis considering the impedance matching and isolation of the output ports are presented. Moreover, the ground layers of the two microstrip dividers are constructed in a back-to-back structure to minimize the size of the overall divider. For validation, a 5.8 GHz 7-way divider is designed, implemented, and measured. The measured S-parameters show that the proposed 7-way divider has appropriate return loss, insertion loss, isolation, and power distribution with a phase difference under 4.7°.

This article described a two-step structure layout grow method for a cellular reinforced hybrid sandwich structures design with CFRP face sheets. In the first step a ground structure method is applied to get the initial structure topology data and a homogenize operation is taken to distribute the material to the base mesh grid centroid. In the second step, a bionic graph-based topology method which like the cell division is present to make the layout automatically grow. And for the optimization process, an evolution method of genetic algorithm is used to get the optimize result from the varied feasible solutions. A comparison between the pure honeycomb core sandwich and ortho-grid core honeycomb sandwich are taken which reflect a high performance by our method in the gird stiffener topology design.

The design of matching media with different dielectric constants for the use in implant communications is presented in this paper. Each medium consists of a three-dimensional printed honeycomb structure filled with a high dielectric lossless semi-liquid. The dielectric constant of the media is determined by the infill percentage of the honeycomb structure as well as the dielectric constant of both the semi-liquid and the material of the structure. An algorithm is developed that can specify values for the infill percentage to reach a target dielectric constant value from a given material and semi-liquid. For the measurements, several honeycomb structures with different infill percentages are fabricated with polylactic acid using additive manufacturing. Water-based semi-liquids are developed to fill the structures. The dielectric constants of the fabricated media are measured with a half-filled rectangular resonant cavity. The practical results indicate that target dielectric constants ranging from 8 to 34 are reached by using semi-liquids with dielectric constants ranging from 20 to 65 between 2.2 GHz-3.2 GHz. The practical results are also shown to be in good agreement with the numerical ones with an error of less than 9% for all different cases.

Honeycomb materials, composite and aluminum, are widely used in aerospace, automotive and other fields due to their outstanding characteristics such as high strength, rigidity, low density and good thermal insulation properties. At the same time, the processing of honeycomb materials is associated with a number of difficulties, and one of the technologies that allows effectively solving the layout problems for honeycomb materials is ultrasonic cutting. In this work triangular blades for ultrasonic cutting of honeycomb materials with operating frequency 20 kHz with different geometric parameters for different variants of honeycomb structures are analyzed. Eigenfrequency properties are studied for ultrasonic triangular blade’s shape and length and experimental results for a number of deigns are presented.

In the paper the ozone generation in the process of barrier discharge directly inside the catalytic block of the honeycomb structure was considered.For given ozone-catalytic device mathematical model of the barrier discharge and ozone generation processes in gaseous environment was developed, that allows to calculate the heating of the device and to investigate of the dependence of the ozone generation efficiency on the temperature of the gases and on their concentrations.The results of the investigations are interesting in terms of solving the problem of exhaust gases purification at the cold start of an automobile engine.

UV Nanoimprint Lithography as a flexible and lowcost nonconventional lithographic method has been investigated with focus on resolution, shape and substrate size. Resolution in the range of 12.5 nm and up to several micrometers line width and space has been demonstrated. Flexibility in terms of pattern shape has been shown with gratings, pillars, wells, barrel lenses and honeycomb structures. The pattern fidelity using the same working stamp for up to 50 imprints has been investigated for pillar and grating structures, showing repeatable results and proving a durable polymer mold. Finally it has been shown the UV NIL technique described can be used for wafer sizes up to 300 mm diameter, which is the preferred wafer size. The application of this process to even larger substrates has been demonstrated with a successful imprint on panel size. The results shown here for UV NIL using polymer molds can be used for a for various photonic and bio-medical applications.

This paper describes the physical and mathematical model of the force interaction of polarized charges in the liquid dielectric of binder with the charged surface of polymer paper in the process of honeycomb core manufacturing. The equation for the electric force of charge interaction is obtained, and the equation is analyzed for the electric force. It is shown that magnitude of the electrostatic force is comparable with the liquid - gas, solid - gas, liquid - solid forces of surface tension and has its effect on the surface of binder spreading on the charged surface of polymer paper.

In this article a sandwich beam structure with honeycomb core filled of MRE (magnetorheological elastomer) with different ratios of Elastomer and iron particles modeled in ANSYS is proposed. The simulation (resonance frequency, total deformation, equivalent stress and equivalent strain) results for structures with PLA (Polylactic acid) and ABS (Acrylonitrile butadiene styrene) honeycomb core were analyzed and compared for two different cases. The results showed that the resonance frequency of the structure decreased as the ratio of iron particles was increased for all the cases, this is due to the increase in stiffness of the structure due to higher ratio of iron particles. Secondly structure with ABS honeycomb core showed lower frequency and higher deformation than the structure with PLA honeycomb core.

Low observable antennas are integral part of stealth platforms. The major challenge in designing low observable antennas is reduction in antenna scattering without any degradation in its radiation performance. Inclusion of superstrate in the antenna structure is one of the possible methods to achieve the same. This paper presents the EM design and analysis of microstrip patch array with honeycomb structure- based superstrate. The main objective is to achieve a significant reduction in the antenna RCS without degrading the antenna gain, return loss and VSWR in the operating frequency range. The proposed model for the patch array with honeycomb structure-based superstrate has been designed in 2-layer (antenna and superstrate) and 3-layer (antenna, superstrate and MA layer) configurations. The 3-layered structure of antenna-superstrate shows significant RCS reduction in entire X-band, with optimum radiation characteristics.

The auxetic honeycomb core exhibits geometric nonlinearity under the in-plane load. As the load increases, the plastic deformation occurs. The elastoplastic model of the auxetic honeycombs with constant wall thickness is introduced based on nonlinear beam theory and elastoplastic theory. The solution algorithm is established. The elastoplastic properties of the auxetic honeycombs with different ratios of the thickness of honeycomb wall to the length of the inclined wall t/l, different ratios of the height of the vertical wall to the length of the inclined wall h/l, and different inclination angle θ are obtained. The results suggest that with the increase of strain, the geometric nonlinearity causes the overall stiffness of honeycombs to increase. Then it decreases gradually due to the plastic deformation.

Based on the actual working condition, the heat transfer model of honeycomb core in thickness direction was simplified. The out-of-plane equivalent thermal conductivity of aluminum honeycomb core was obtained by the methods of theoretical model and finite element numerical simulation. The present study indicates that the numerical simulation results are in good agreement with the calculation results of the simplified Swann-Pittman formula, which reveals that the numerical simulation method could accurately simulate the heat conduction of the honeycomb core.

In this paper, the feasibility and the opportunities of structural printing technologies for the integration of mechanical and mechatronic components in aircraft interior systems are shown. Hereby, the substrate material for cabin lining elements consists of composite materials with fiber reinforced face sheets and a honeycomb core. As structural printing technology the Fused Filament Fabrication (FFF) process was used. The described process enables a direct FFF-material injection in composite materials, the resulting pile-fixation as well as a subsequent structural printing process for the automated manufacturing of mechanical and mechatronic components on composite materials. Therefore, two decisive process steps need to be examined. Firstly, the injection process of a FFF-material into a honeycomb of a composite material will be investigated showing that a complete filling process is possible. Secondly, the tensile strength in dependence of the printing parameters will be presented. Thereby, an optimized parameter combination could be found to achieve a maximum tensile force of around 400 N for a base area of four square centimeters, which results in a tensile strength of 1 N/mm2.

Composite sandwich structures are renowned for their ability to provide high flexural stiffness to weight ratios. This ability made them appealing to aerospace, wind turbines, and marine industries. The functionality of sandwich structures primarily depends on the stiffness and strength of the two composite sheets bounding their inner cores. However, when sandwich structures are subjected to transverse impacts or transverse concentrated loads, their cores can fail due to local buckling. This can subsequently trigger the failure of the entire sandwich structure. To prevent such failure, inner cores with increased buckling strengths are sought. However, currently, increasing the buckling strength of sandwich structures' cores mostly comes at the cost of increasing their weights. Conversely, this work aims to increase the buckling strength of one of the most common sandwich structure cores, namely the hexagonal honeycomb core, without increasing its weight. This is accomplished through superposing periodic imperfections to its cell walls. The introduced imperfections follow a sinusoidal form and are applied to each cell wall as a perturbation. Finite element simulations are used to determine the effect of applying the imperfections to the cell walls and to determine the imperfection level that leads to significant improvement in the core's buckling strength. Results demonstrate that the buckling strength of honeycomb cores can be enhanced by more than 30% with the introduction of a minimal amount of sinusoidal periodic imperfections.

In this paper, we propose a fast method for optimizing multiple size parameters of honeycomb absorbing material including honeycomb height and dip coating thickness, based on deep convolutional neural networks (CNN). The reflection coefficients (S 11 ) of honeycomb absorbing material are simulated to generate CNN training data as inputs to the CNN in this paper. The network consists of six concatenated convolution-maximum pooling layers and three fully-connected layers. The convolutional layers and the fully-connected layers perform feature extraction and data regression, respectively. When the correlation coefficient between the predicted value and the true value of the cellular absorbing material using CNN inversion is close to 1.0, it means CNN performs well in inversion. The trained CNN model is used to optimize the honeycomb absorbing material in a given size range. Numerical results show that the optimized S 11 of honeycomb absorbing material is even about 10 dB lower than that of the honeycomb without optimizing at some frequencies. This CNN based method provides a faster and more efficient approach for electromagnetic analysis.

Honeycomb sandwich structure combines high flexural rigidity and bending strength with low weight. Sandwich structures with honeycomb as core have number of applications for aerospace, automobile and civil engineering structures. Finite element analysis of detailed honeycomb core model is too complex and it takes a lot of computation time. Therefore, the solution is to replace the honeycomb core by an equivalent orthotropic material. The main objective of this research paper is to first define an appropriate equivalent model which provides results as that of the detailed 3D model in order to minimize computation time and to investigate the geometric parameters of honeycomb structure such as the core height, face plate thickness and changing cell angle on the Equivalent model through numerical study. The geometry of cells for the core and core height variation can alter the sandwich panel behavior in a significant manner. A good agreement is found between detailed and equivalent model and in-depth analysis of cell height and face plate thickness and in the honeycomb structures has been carried out and the results show that by both face-sheet and core height has inverse relation with deformation, Moreover the value of orthotropic properties varies exponentially as cell angle changes.

Detection of water inclusions in honeycomb composites is an urgent task during construction and operation of various aircrafts. This includes diagnostics of helicopter composite rotor blades, since the presence of moisture condensed in the internal air cavities leads to gradual development of cracks and results in blade deterioration, icing and imbalance. The imbalance of helicopter rotor blades may influence the comfort and safety of a flight, result in thrust loss and increased load in dynamic components caused by the helicopter vibration. Currently, restoring balance is a complex and time-consuming procedure under the operating conditions of a helicopter. This paper presents the results of detecting moisture inside the honeycomb structure of the blades using microwave holography, which can be used to simplify and speed up the procedure for their diagnosis and prevent imbalance.

In order to solve the mechanical properties of lightweight unloading flange model, this paper presents a design method of lightweight honeycomb 3D printing structure unloading flange. The results of quantitative inspection and evaluation are given by scanning and testing the 3D printing unloading flange sample.

The thermal properties of the new negative Poisson's ratio honeycomb structure is investigated. The Poisson's ratio is calculated subject to pure bending. On this basis, the influence of auxetic effect caused by negative Poisson's ratio on thermal conductivity is further investigated. The thermal anisotropic characteristics are also reported in accordance with the anisotropic physical mechanism. Applying this structure to the satellite antenna reflection surface, the thermal deformation value of the antenna reflection surface under a uniform temperature field can be calculated by finite element analysis. Using particle swarm optimization, the optimization target is the accuracy of the antenna reflection surface profile and the total mass of the antenna. The optimization parameter is the design parameters of the negative Poisson's ratio honeycomb structure. The results show that the satellite's overall profile accuracy is reduced by 22.6%. Effectively improving the accuracy of the reflective surface of the antenna.

In the paper we propose an original design of the ozone-catalytic device, in which the process of ozone formation occurs directly inside the catalytic block of the honeycomb structure, that allows to solve the problem of exhaust gases purification at the cold start of an automobile engine. For the ozonator design under consideration, mathematical modeling of the barrier discharge process in a gaseous environment with a multicomponent composition, close to the composition of automobile exhaust gases, was performed, that allows investigating the dependence of the barrier discharge efficiency on the temperature of the environment and on the concentration of certain chemical substances.

We propose an all-dielectric broad terahertz planar Luneburg lens with radial gradient honeycomb structure. Exquisite microstructure in the form of radial symmetric honeycomb column within subwavelength dimension was put forward to satisfy the requirement of refractive index of Luneburg lens. The results of full-wave simulation demonstrate excellent performance of our designed lens. Far field radiation pattern of the present lens is highly directive, incident waves could be concentrated on the opposite side of the lens with high convergence, and its operating frequency spans from 0.06THz to 0.24THz. Our design has great potential to be applied in terahertz communication and imaging via the growing 3D printing technology

International audience; In this study, we propose to apply a 3D printing technology to the realization of honeycomb microwave absorbers. At first, printability of simple honeycomb structures was demonstrated and validated by microwave measurements between 2 and 18 GHz. Then, we designed and manufactured multi-scale honeycomb absorbers. These complex absorbers that cannot be manufactured by a standard process, make it possible to increase absorption level at high frequencies, and thus bandwidth. This new shaping technique of microwave absorbers paves the way for the design and fabrication of complex high-performance topologies that cannot be reached by conventional materials and processes.

This paper presents an architecture of a discrete coordinate system that features uniformity and isotropy aiming to describe regular hexagon tilings. The hexagon tilings, or honeycomb structures, are widely applied for formulizations of robotic system control: navigation mapping, multi-robot motion planning, and area segmentation of sensing images, for example. With implementing an ordinary Cartesian coordinate system or an oblique coordinate system over the honeycomb structure, extra treatments are unavoidable for the computation scheme, such as re-scaling in certain directions or case-division with respect to belonging quadrants. The proposing coordinate system, named “H'Cl? (HoneyComb by Projection),” can be constructed with a simple mapping of a three dimensional cube tessellation on a projecting plane. The framework of H Cl? shows the preferable characteristics of uniformity and isotropy over the whole coordinate surface. The theoretical background of H'Cl? and its construction process are presented in this paper with considering handedness and other possible variations. The consistent computation environment developed over H‘Cl’ is also described, including a distance function and a conversion method with the Cartesian system.

Sandwich structures with honeycomb as core have number of applications for aerospace, automobile and civil engineering structures. Finite element method is an efficient and reliable tool for the extensive evaluations and analysis of engineering structures. In analyzing honeycomb sandwich structures, the problem is the huge involved personal effort and computational cost which is associated with the detailed multi-cell honeycomb core finite element modeling and its analysis. A common and more practical approach is the equivalent or homogenized, two or three dimensional finite element model for the honeycomb core. The equivalent models have some limitations in predicting the local behaviors of the structures while the global responses such as deflection can be well predicted. The homogenization process under static and dynamic regime also respond differently. This article reviews the existing homogenization methods for honeycomb core for static and dynamic analyses and tries to figure out the optimum methodology for different finite element analyses.

A mathematical model of the aircraft avionics thermal state describing the heat exchange of the on-board equipment housing with a honeycomb structure made of a carbon fiber composite, the process of heat transfer of the onboard equipment elements and the air is developed. The considered heat transfer process in a heterogeneous medium is described by the boundary value problem for the heat equation with boundary conditions of the third kind. To solve the direct problem of the on-board equipment housing honeycomb structure thermal state, the Monte Carlo method on the basis of the probabilistic representation of the solution in the form of a diffusion process functional expectation is used. The inverse problem of the honeycomb structure heat exchange is solved by minimizing the function of the squared residuals weighted sum using an iterative stochastic quasigradient algorithm. The developed mathematical model of the on-board equipment in the unpressurized compartment thermal state was used for optimizing the temperature and airflow of the thermocontrol system of the blown on-board equipment in the unpressurized compartment of the aircraft.

In an industrial environment, data driven smart diagnosis of the milling is a difficult task. In this work, the diagnosis using machine learning techniques has been developed and implemented for composite sandwich structures based on honeycomb core. The objective is to predict online the resulting surface flatness. The time domain and frequency domain features are calculated from the measured milling forces and different algorithms have been implemented and compared. The experimental results have shown that a good milling diagnosis can be obtained with a Linear Support Vector Machine (SVM) algorithm resulting to good accuracy and short training time.

Dielectric honeycomb structures are a suitable substrate for microwave applications since their dielectric constant and losses are low and when laminated they offer excellent mechanical properties and light weight. This paper studies the electrical properties of dielectric honeycomb structures composed of various materials for large antenna distribution networks. Glass fiber honeycomb with polyimide resin is shown to have very low losses although they are higher than that of a closed cell polyethylene foam material. Additionally, the honeycomb material is shown to be anisotropic in the two axes containing the honeycomb cells, which can complicate the distribution network design and manufacturing. Finally, the adhesive placed near the Cu track needed to build the laminated structure is shown to increase the losses, while the adhesive near the ground is not critical in this regard.

The application of equivalent medium theory to inhomogeneous materials with periodic structure is studied. Based on the principle of free space method, analyze the basic method of equivalent dielectric constant, using the electromagnetic simulation software HFSS on infinite honeycomb structure to perform the electromagnetic analysis, and then obtain the equivalent complex permittivity using mathematical formula. In order to verify the correctness of the method, the amplitude and phase of the transmission reflection coefficient of the plate with equivalent dielectric constant and the corresponding honeycomb are compared, and the results are in good agreement.

In this paper, we analyze the refraction of magneto-inductive waves by surrounding metallic loops in underwater sensor networks. Previous work proposed positive and negative refraction of magneto-inductive waves. Here, we discuss properties of different structures of the placement of coils with the aid of the dispersion equation and compare the performance of lattice and honeycomb structures with planar and planar-axial configurations.

A honeycomb photodetector architecture is proposed for low-cost CMOS-compatible blue-enhanced sensing applications. In this paper, a physical model is developed to characterize the responsivity of honeycomb photodetectors. The model is then used to determine the optimum honeycomb physical dimensions for maximum responsivity and quantum efficiency. To implement the model in a real application, a test chip with honeycomb structures is designed, fabricated, and characterized using a commercial 0.35 pm standard CMOS process through Austria Micro Systems (AMS). Based on measured data, the optimal honeycomb structure in this fabrication process improves the quantum efficiency by 63% at 375 nm wavelength.

We present a computational analysis and comparison of nanowire arrays for efficient transmission of electromagnetic power at optical frequencies. A reliable simulation environment involving the multilevel fast multipole algorithm for fast iterative solutions of surface integral equations is used to accurately compute field intensity and power density values in the vicinity of nanowires in diverse configurations. The results demonstrate favorable properties of honeycomb structures that can provide efficient power transmission in comparison to other arrangements.

Honeycomb periodic structures have been known for thousand years. The study of such structures has been renewed in the last years in relation to the unique physical properties of graphene. Here we report experimental and theoretical studies of optical diffraction from planar photonic structures with honeycomb symmetry known as “photonic graphene”. We employ the two-photon polymerization method to fabricate honeycomb structures, and then study their optical diffraction properties.

To assure mission success of the Solar Probe Plus (SPP) spacecraft, defined by achieving its final mission orbit with a perihelion distance of less than 10 solar radii, it is necessary to define the dust hypervelocity impact (HVI) protection levels provided by its Multi-Layer Insulation (MLI)/thermal blankets with a reliability that is on par with that available for metallic Whipple shields. Recently, we presented an experimentally validated approach being developed at the Johns Hopkins University Applied Physics Laboratory (JHU/APL) for designing and analyzing MLI to meet this challenge. This paper extends the results to Whipple shield configurations consisting of an MLI bumper, 0–1″ standoff, and an Aluminum honeycomb rear wall. With 0″ MLI-honeycomb standoff, 0.05 g/cm2 MLI layered in a manner similar to that found in actual blankets and an Aluminum honeycomb consisting of 8 mil-thk. facesheets, 0.125″-dia. cells and 1%″-thk. core is adopted for 2D and 3D analyses. Bonding of the core to the facesheets was included in the modeling to account for channeling of the debris cloud within the core. The passage of the dust through the center of the core's symmetry axis is considered to be the most conservative dust-H/C interaction as the other scenarios — normal dust entry closer to a core wall or oblique dust entry — are expected to be less damaging overall owing to interactions with the core material and disruption of channeling. For this reason, dust impact along a core symmetry axis is evaluated. The failure criterion chosen is complete perforation of the rear facesheet and extending to the entire cell area. The average critical particle diameter is indicated to be in the 300–900 μm range. It is noteworthy that the pass-fail transition is not sharp and is indicated to occur over a ±100 μm particle size range for the 0” standoff configuration considered. For comparison purposes, the average critical particle diameter is indicated to be in the 140–750 μm range for the bare honeycomb (no MLI). With 1″ MLI-honeycomb standoff, direct modeling of the passage of the vapor/debris cloud through the honeycomb was found to be computationally prohibitive. Test data shows that a honeycomb offers better HVI shielding than an equivalent monolithic wall with the same areal density. So for this set of analyses, the honeycomb was (conservatively) represented as a monolithic 16 mil-thk. wall, obtained by combining the two facesheets and neglecting the core. The average critical particle diameter is indicated to be in the 425–1300 μm range for this configuration. The size range over which the pass-fail transition occur is ±200 μm at 7 km/s but only ±25 μm at 150 km/s. In addition to presenting these new ballistic limit equations (BLEs) for honeycomb structure shielded by MLI in the 7–150 km/s range, an empirical method for predicting the critical particle size at 7 km/s is provided, developed from data obtained for honeycomb configurations used in the New Horizons, Rosetta, METOP and ATV spacecraft. Insights gained from sensitivity analyses using a 12 mil-thk. facesheet and elimination of the core are also discussed.

As one kind with the best comprehensive performance of various honeycombs, triangular honeycomb is an important structure to achieve lightweight. Focusing on the deficiency of the non-optimized macro-material distribution in uniform triangular honeycomb, a design and modeling method of variable-density triangular honeycomb structures was proposed. With a three-point bending beam as the design object, type and sizes of honeycomb cells were specified beforehand. The beam was topology-optimized and the density results were mapped to the relative density matrix of cells. The rapid and automatic modeling of variable-density triangular honeycomb was realized with the cyclic definitions of the User-Defined Features (UDF). The simulation results show that the mechanical performance of variable-density triangular honeycomb is better than uniform honeycomb and the efficiency of the proposed method is validated.

A new kind of non-pneumatic tire with spring for attenuating vibration is introduced. The constituent material of tire is selected by polyurethane and the structure of tire is chosen as honeycomb. This article is mainly focusing on parameters affecting natural frequency of non-pneumatic tire with spring, which plays an important role in attenuating vibration. The structural parameters of honeycomb structure are investigated on natural frequency in theory and commercial finite element code has been used to verify the accuracy of theory. The effect of stiffness of spring equipped within tires on natural frequency is also investigated and the theory is verified by finite element analysis, as well as experiment. The natural frequency in the vertical direction of tires can be decided by honeycomb structure and the stiffness of spring in series: honeycomb structure may be decided firstly to set upper limit for natural frequency; the stiffness of spring can be selected later to determine the natural frequency of tire according to different occasions for attenuating vibration. This new structure of tire with spring provides advantage that natural frequency of tire in vertical direction can be changeable with the spring, by selecting different stiffness of spring to adapt different occasions. With sample of tire and experiment, theory obtaining stiffness of NPT is verified.

As a method of increasing electric power generation in a size-limited installation area, photovoltaic (PV) modules assembled with a three-dimensional (3D) structure that is based on the Fibonacci sequence (hereafter referred to as FPMs) have proven effective. Since the power generation of a 1/3 phyllotaxis, two-stage FPM exceeds that of a planar module, it may be possible to construct mega-solar sized power generation forests using multiple FPMs. In this study, the shadowing effect of adjacent FPMs on power generation in a power generation forest was investigated and comparisons were made in the amount of power generation per installation area for various FPM arrangement patterns, and a particular honeycomb structure was identified as having the highest value.

It is an increasing number of the applications of new materials in modern aircraft manufacture, especially composites are largely used in some key parts, such as the rudder and wing. However, more non-destructive problems appear because of the restriction of the traditional non-destructive testing methods for the new materials. In this paper, the principle of infrared thermography about two kinds of heat stimulation methods is introduced, several composite and metal materials used in the aircraft is manufactured as the specimen for the inspection experiments, the temperature decreasing data after heat stimulation is processed and the defects are shown in the thermal images, furthermore, the results of CFRP impact damages inspected by using different kinds of heat stimulations are shown as a comparison, and the advantages and disadvantages of the two methods for this kind of material is analyzed, In addition, the characteristic and develop trend of this technology in aircraft is summarized.

This paper introduces the efficient three-dimensional (3D) simulation of thick SU-8 structures realized by single-step projection lithography. Profiles of 3D structures obtained by this lithography method depends on two process parameters: (i) The exposure dose and (ii) the focus depth. For fabricating complex 3D structures used in microfluidics or bio-engineering tools, the resulting geometries depending of these two process parameters should be predicted before processing. Although several lithography simulation methods have been developed for SU-8 processing, the existing models are unsuited for single-step projection lithography technique. This paper described how the simulation process have been developed and successfully tested on a specific design of honeycomb structures. Through the various experiments, simulation results revealed similar dependence on two process parameters, and the validity of simulation algorithm was therefore confirmed.

This paper reports on the fabrication of PDMS micropillars as force sensor for C. elegans locomotion measurement. Three different designs have been fabricated; starting from a channel like design with two parallel rows, to increasing the number of micropillar rows in Design 2, and finally a 9 × 9 mm square chamber with multiple arrays of PDMS pillars arranged in a lattice and honeycomb structure. Results of worm locomotion forces show that different parts of the worm's body exert forces on five individual pillars that were in contact with the worm throughout its movement. The fabrication process of the PDMS device is also explained in detail, along with the device casting procedures. The final section discusses the challenges and limitations tackled in this research, in particular during the fabrication process.

Heat storage in wall building via phase change materials (PCMs) can be an alternative solution to problems related to high energy consumption for air conditioning. Paraffins are usually used as thermal storage materials thanks to their quality of high storage capacity and nearly constant thermal energy. The objective of this study was to compare the thermal behavior and the heat storage capacity of two aluminum panels: a simple panel and a honeycomb panel both filled with paraffin RT27. For this aim, a 3D numerical model based on the effective heat capacity method using Fluent® software was adopted to study the process of phase change.

A high gain tunable annular ring antenna structure for WiFi bands are reported by stacking passive elements over an active element realized on magneto-dielectric composite substrate. The composite substrate of active antenna is realized by utilizing the FeCo soft magnetic nanoparticles on commercial available FR4 dielectric and the superstrates are processed using Honeycomb structure. The key features of low coercivity FeCo cubic nanoparticles of 40nm are a relatively high permeability, low loss, and high saturation magnetic moment that effectively results in over 100MHz tuning per 100mT of applied magnetic field. The purpose of this paper is addressing the solution for increasing the low gain and bandwidth that has been accomplished for the single substrate printed circuit antennas. The Finite Element Method (FEM) computational method is used for design and performance optimization to achieve gain.

Novel stretchable microsupercapacitor (MSC) arrays with single-wall carbon nanotube (SWCNT) electrodes and a honeycomb polydimethylsiloxane (PDMS) substrate were fabricated and tested. The stretchability of the MSC array system is controlled by the deformation of the honeycomb PDMS structure. Unique features of the present stretchable MSC array include: (i) the strain in the MSCs is almost five orders of magnitude lower than the nominal strain applied to the entire device, (ii) the fabricated devices demonstrate a stretchability up to 150% without undergoing discernible capacity degradation, and (iii) the MSC arrays exhibit excellent rate capability, as demonstrated by the rectangular characteristics of cyclic voltammetry (CV) responses obtained for a scan rate up to 100 V/s. The excellent stretchability characteristics and high charge/discharge rate make the present stretchable MSC arrays good candidates for a wide range of applications in wearable electronic systems.