Orthogonal Wire Research Articles

Energy absorption performance of woven metallic lattices with orthogonal spiral wires under quasi-static compression

Woven metallic lattice (WML) structures are gaining attention for their beneficial mechanical properties, such as low weight and special energy absorption capability. They hold potential for diverse applications, including energy absorption components in aerospace. Drawing inspiration from the traditional double-arrow lattice, this study proposes a novel WML design featuring multi-plateau stresses. The deformation behavior of this structure under compression was investigated using finite element analysis and experimental methods. Three gradient structures defined by the different layer arrangements along load direction associated with specific structure variables, namely positive gradient (PG), negative gradient (NG), and hybrid gradient (HG), were introduced, along with an examination of their mechanical properties. The study explored the influence of key parameters of the cell structure on compression characteristics. Findings suggest that enhancing cell vertex angle and wire diameter can improve energy absorption, while the opposite holds true for cell base angle. Among the gradient structures analyzed, the PG WML structure demonstrates optimal energy absorption due to its dual-plateau stress characteristics. The NG WML structure is noteworthy for its uniform lattice deformation during initial compression stages, which is crucial for precision engineering with subtle deformation control strategies. Lastly, the deformation pattern of the HG WML structure during compression progresses from low to high strength.

Mechanical Behaviors of Hybrid Composites with Orthogonal Spiral Wire Mesh and Polyurethane Elastomer

This work aims to significantly improve the mechanical properties of conventional rigid lattice structures under repeatable large deformations. A novel hybrid material is proposed based on the concept of interpenetrating composite materials. The material utilizes a woven TC4 orthogonal spiral wire mesh as the skeleton and PU elastomer (OSWM‐PU) as the matrix. The uniaxial tensile tests demonstrate that OSWM‐PU possesses the excellent load‐bearing capacity, allowing for large deformations (≥60%) while maintaining partial integrity even after matrix fracture. Optical measurements and simulation analysis reveal that Poisson's ratio can be adjusted within a certain range by manipulating the microscopic parameters (p, d) of the longitudinal helical filaments. Cyclic tensile experiments further demonstrate that OSWM‐PU exhibits exceptional energy absorption performance, multiple energy dissipation modes, and a more pronounced Mullins effect. The stress relaxation experiment reveals the significant influence of the volume fraction of the skeleton on long‐term loading conditions. The orthogonal spiral wire skeleton exhibits a superior hooking effect without dividing the matrix, enabling OSWM‐PU to possess enhanced collaborative deformation capability and inherent designability in the orthogonal direction. These characteristics make it highly promising for applications in various robot joints and as flexible aircraft skin, offering excellent prospects for utilization.

Effects of lead and lean in multi-axis directed energy deposition

The present study examines the effect of varying laser incidence angles on textural, microstructural, and geometric characteristics of directed energy deposition (DED) processed materials, providing a more comprehensive outlook on participating laser-matter interaction phenomena and ultimately devising strategies to ameliorate print performance. In this study, single-layer, single-/multi-track specimens were processed to examine the effect of non-orthogonal angular configurations on bead morphology, microstructure, phase composition, and textural representation of DED-processed 316L stainless steel materials. It was observed that bead size decreased at increasing lead and lean angles. Asymmetry in the distribution of the bead morphology as a function of lead angle indicates better catchment for acute lead angle configurations over obtuse configurations. No significant differences in phase composition, texture, and microstructure were observed in moderate off-axis configurations. When the penetration depth for the deposits was below 20 μm, columnar structures dominated the microstructure of the deposited material. At deeper penetration depths, columnar and equiaxed structures were observed at the bead-substrate interface and center of the bead, respectively. Compared to powder-blown DED, wire-DED dilution profiles were found to be asymmetric in both orthogonal and non-orthogonal wire DED samples.

Design of Millimeter-Wave Transmitting Liquid Crystal Cells with Orthogonal Wire Grid Electrodes

Design of Millimeter-Wave Transmitting Liquid Crystal Cells with Orthogonal Wire Grid Electrodes

Reinforcement learning to reduce failures in SOT-MRAM switching

A reinforcement learning strategy is applied to find a reliable switching scheme for deterministic switching of a perpendicularly magnetized spin-orbit torque magnetoresistive memory cell. Current pulses sent along orthogonal metal wires allow the field-free reversal of the magnetization. The current pulses are optimized such that reliable switching can be achieved over a wide range of material parameters. Micromagnetic simulations confirm the reliability of the presented approach.

Flexural performance evaluation of slab using welded bar mat

ABSTRACT This is an experimental study on flexural performance evaluation when welded bar mats (WBM), which improve the rib shape, strength, and diameter limits of the existing structural welded wire fabric (WWF), are applied to slabs. The purpose of this study was to verify the change in behavior and structural performance when a new material was applied to a structural member. Flexural tests were performed with a total of 10 slab specimens using various variables. The load-deflection relationship and crack patterns of the slab specimens were analyzed to evaluate the applicability of WBM as a structural reinforcement. The results of the structural test were compared with the proposed design formula of the current design standards to check the safety, and the serviceability were verified by comparing the performance with the case of using the conventional rebar. According to the material test results, the yield strength of the steel wires applied to the WBM did not appear clearly, the elastic modulus of the material increased by about 8% compared to that of normal rebar, so that the yield strain and elongation decreased compared to that of normal rebar. When WBM were used for slabs, the nominal strength of the member was found to sufficiently satisfy the design flexural strength. However, as the strength of the material increased, bond failure occurred due to stress concentration between orthogonal steel wires so that deflection and crack concentration phenomena increased.

Dual-band multifunctional coding metasurface with a mingled anisotropic aperture for polarized manipulation in full space

Integrated metasurfaces with diversified functionalities have demonstrated promising prospects for comprehensive implementations in compact 5G/6G communication systems by flexibly manipulating electromagnetic (EM) waves. Increasingly emerged multifunctional metasurfaces have successfully revealed integrated wavefront manipulations via phase gradient arrays, coding apertures, independent polarization control, asymmetric transmission/reflection, etc. However, multifunctional metasurfaces with more degrees of freedom in terms of multi-band/broadband operation frequencies, full-space coverage, and computable array factors are still in dire demand. As a step forward in extending manipulation dimensions, we propose and corroborate a dual-band multifunctional coding metasurface for anomalous reflection, radar cross-section reduction, and vortex beam generation through full-wave analysis and experiment. Our tri-layer meta-device comprises a shared coding aperture of split-ring and cross-shaped resonators sandwiched between two layers of orthogonal wire gratings. With an approach of independent control of a reflection–transmission wavefront under orthogonal polarization states and Fabry–Perot-like constructive interference, the low-cross-talk shared coding aperture features a smooth phase shift and high efficiency for 3-bit coding in the K-band and 1-bit coding in the Ka-band. Both numerical and measured results verify that the proposed coding metasurface can effectively realize full-space EM control and improve the capacity of the information channel, which could be developed for potential applications in multifunctional devices and integrated systems.

Improving failure rates in pulsed SOT-MRAM switching by reinforcement learning

Finding and optimizing robust schemes for field-free switching remains a challenging problem in spin-orbit torque magnetoresistive random access memories. In this work reinforcement learning is employed for the optimization of switching schemes for such memory cells. A cell is switched purely electrically by applying pulses to two orthogonal metal wires. It is shown that a neural network model trained on a fixed material parameter set is suitable to determine optimal pulse sequences for reliable switching in the presence of thermal fluctuations, material parameter variations and reduction of the current to a sub-critical value. Multiple realizations of switching by means of simulation prove the reliability of magnetization reversal based on the pulse sequences found via reinforcement learning and show that the failure rate due to material parameter variations in these memory devices can be significantly reduced.

Multi-domain functional metasurface with selectivity of polarization in operation frequency and time

In this paper, we propose the design of a multi-domain functional metasurface (MDFM) that can achieve selectivity of polarization in operation frequency and time. The MDFM consists of a wire grating as the front layer, a frequency selective surface as the middle layer and an active orthogonal wire grating loaded with positive-intrinsic-negative (PIN) diodes as the back layer. The front wire grating serves as a polarization selective surface that only passes electromagnetic (EM) waves polarized perpendicular to the wire, whereas the middle frequency selective surfaces exerts a pass-band in the frequency-domain. To further obtain selectivity in the time-domain, another orthogonal wire grating loaded with PIN diodes is adopted to switch on/off the pass-band. Three functional layers are combined to integrate the three selective functions. To verify this design idea, a MDFM operating at 3.19 GHz was designed, with a total thickness about λ/11. A prototype was fabricated and measured to validate the design. The experimental results are in satisfactory agreement with the simulated ones. Due to multi-fold selectivity, the MDFM can achieve high rejection for unwanted signals and may find wide applications in areas such as wireless communication, EM compatibility and stealthy radomes.

Ultra-wideband tri-layer transmissive linear polarization converter for terahertz waves

Polarization control is shown to enhance functionalities of terahertz waves in various applications. As a step toward introducing efficient practical devices operating in the terahertz band, we propose and experimentally validate a free-standing three-layer polarization converter operating in transmission. The device can efficiently convert a linearly polarized terahertz wave to its orthogonal counterpart. Our device comprises split-ring and H-shaped resonators inserted between two layers of orthogonal wire gratings. The sole dielectric material is a cyclic olefin copolymer (COC) that has exceptionally low-loss to terahertz waves. The measurement demonstrates a conversion efficiency of >80%, over 0.2–1.0 THz, giving an ultra-wide bandwidth of 133%. The wide bandwidth is attributed to multiple resonances of the two resonators in a unit cell. Importantly, an unconventional fabrication process yields a multi-layer low-loss COC that leads to high efficiency. The proposed design can also be tailored for practical applications across the electromagnetic spectrum.

Parametric study of metamaterial-inspired resonator for wireless power transfer

A metamaterial-inspired resonator for free-positioning wireless charging of several devices is proposed and numerically studied. The resonator is based on orthogonal metallic wires arrays deposited on a high permittivity low loss dielectric substrate. Given a fixed area of 50 × 50 cm, its resonant frequency can be tuned in a wide frequency band from 5 MHz to 45 MHz. A parametric study is performed to reveal the influence of resonant frequency, dielectric permittivity and number of wires on Q-factor.

Broadband high-efficiency cross-polarization conversion and multi-functional wavefront manipulation based on chiral structure metasurface for terahertz wave

In this paper, a broadband and high-efficient tri-layered chiral structure metasurface (CSM) for linear polarization conversion and multi-functional wavefront manipulation was proposed and investigated numerically in terahertz region. The unit-cell of the proposed CSM consist of two orthogonal metal wires sandwiched with square split-ring resonator (SRR) structure, which can manipulate the polarization and wavefront of the transmitted wave simultaneously. Based on the Fabry–Perot-like cavity-enhanced effect of proposed CSM, broadband and high-efficiency cross-polarization conversion can be achieved. Numerical simulation results indicate that the cross-polarization transmission coefficient is higher than 0.9 from 0.4 THz to 1.0 THz, with a fractional bandwidth of 85.7%. The proposed CSM can achieve complete 2π phase coverage by adjusting the geometric parameters of the unit-cell structure. Anomalous refraction with a wide angle, two kinds of focusing metalenses and vortex beam generation are investigated to verify the multi-functional wavefront manipulation performance of the proposed CSM. Our work provides an effective method of enhancing the performance of transmission-type metasurface and the proposed devices show endless potential in wavefront control and communication applications in terahertz region.

Numerical investigation of liquid dispersion by hydrophobic/hydrophilic mesh packing using particle method

Liquid dispersion in chemical processes is significant for increasing mass or heat transfer. A particle-based method, the moving particle semi-implicit (MPS) method, was employed in this study to simulate the process of liquid dispersion by mesh packing. The computational framework includes a designed inlet flow model, hydrophilic/hydrophobic surface boundary conditions, and a surface tension model. This study mainly focuses on the effect of hydrophobic/hydrophilic mesh packing on liquid dispersion performance. The mechanism of liquid dispersion is systematically investigated in basic situations as a liquid passing through a single wire, an orthogonal wire and a single aperture. The results indicate that hydrophobic and hydrophilic mesh packing have different effects on the formation of the free surface, which is the key to the mechanism of the liquid dispersion process. Hydrophobic mesh packing can disperse a liquid into several fine columns with detected droplets, which further develop into fine droplets, whereas hydrophilic mesh packing will guide a liquid to converge into a column at the bottom of the mesh packing. In addition, the surface area density and dispersion range of a liquid are quantitatively analyzed to illustrate liquid dispersion performance.

Intra- and Inter-Chip Transmission of Millimeter-Wave Interconnects in NoC-Based Multi-Chip Systems

The primary objective of this paper is to investigate the communication capabilities of short-range millimeter-wave (mmWave) communication among network-on-chip (NoC)-based multi-core processors integrated on a substrate board. This paper presents the characterization of transmission between on-chip antennas for both intra- and inter-chip communication in multi-chip computing systems, such as server blades or embedded systems. Through simulation at 30 GHz, we have characterized the inter-chip transmission and studied the electric field distribution to explain the transmission characteristics. It is shown that the antenna radiation efficiency reduces with a decrease in the resistivity of silicon. The simulation results have been validated with fabricated antennas in different orientations on silicon dies that can communicate with inter-chip transmission coefficients ranging from −45 to −60 dB while sustaining bandwidths up to 7 GHz. Using measurements, a large-scale log-normal channel model is derived, which can be used for system-level architecture design. Using the same simulation environment, we perform design and analysis at 60 GHz to provide another non-interfering frequency channel for inter-chip communication in order to increase the physical bandwidth of the interconnection architecture. Furthermore, densely packed multilayer copper wires in NoCs have been modeled in this paper to study their impact on the wireless transmission for both intra- and inter-chip links. The dense orthogonal multilayer wires are shown to be equivalent to copper sheets. In addition, we have shown that the antenna radiation efficiency reduces in the presence of these densely packed wires placed in the close proximity of the antenna elements. Using this model, the reduction of inter-chip transmission is quantified to be about 20 dB compared with a system with no wires. Furthermore, the transmission characteristics of the antennas resonating at 60 GHz in a flip-chip packaging environment are also presented.

A bio-inspired model for bidirectional polarisation detection

This study investigated a novel polarisation detection model based on the microstructure of rhabdom in mantis shrimp eyes, in which a single unit can detect two directions of orthogonal polarisation. The bionic model incorporated multi-layered orthogonal Si wire grids, and the finite-difference time-domain method was used to simulate light absorption. A single-layer Si wire grid was simulated to study the effects of thickness and duty cycle on extinction ratios. A multi-layer orthogonal wire grid was simulated to study the effects of distance between adjacent layers. The simulations revealed that the bionic model can achieve orthogonal polarisation detection. Additionally, for 600 coupled layers, the extinction ratios in both directions were greater than 60, and light absorption in the absorptive directions exceeded 96%.

Metamaterials-inspired resonator for wireless power transfer systems

Metamaterial-inspired resonator for a wireless power transfer system is proposed and studied numerically. The resonator consists of two orthogonal wire layers separated by a short distance. To reduce the resonant frequency from several hundreds of MHz it is placed in a background dielectric material with high permittivity. By tuning the permittivity of the background material, the radiation losses can be significantly reduced resulting in a high Q-factor of 900. The wireless power transfer efficiency greater than 80% from the wire resonator to a small loop receiver has been numerically demonstrated at the frequency of 19 MHz. The large area of the proposed resonator (50 cm × 50 cm) offers a possibility to charge multiple receivers simultaneously.

Layer-by-Layer Assemblies of Coordinative Surface-Confined Electroactive Multilayers: Zigzag vs Orthogonal Molecular Wires with Linear vs Molecular Sponge Type of Growth

Surface-anchored coordination-based molecular assemblies (CBMA) are very powerful tools for the design of modern materials. The CBMAs were created using bis-terpyridine–iron coordination chemistry by the alternation of linear or bent bis-terpyridine ligands and Fe(II) metal centers. The coordination of the bent ligand results in the formation of zigzag structures that experience linear growth with each successive deposition step. Interestingly, the deposition of the linear ligand has two distinct steps. During the first four deposition cycles, the thickness and iron uptake (surface coverage) of the multilayer change similarly to ones of the bent ligand based multilayer. However, during the following deposition cycles, the linear ligand based multilayer demonstrates significantly higher growth rate. This unusual behavior might be attributed with the reorganizational transformations leading to a higher organizational level of the assembly. As a result, a part of templating layer molecules, which due to ster...

Using domain walls to perform non-local measurements with high spin signal amplitudes

Standard non-local measurements require lateral spin-valves with two different ferromagnetic electrodes, to create and to detect the spin accumulation. Here we show that non-local measurements can also be performed in a cross-shaped nanostructure, made of a single ferromagnetic wire connected to an orthogonal non-magnetic wire. A magnetic domain wall located underneath the ferromagnetic/non-magnetic interface is used to control the magnetizations of the injection and detection zones. As these zones can be very close, our results display spin signals possessing amplitudes larger than those obtained in conventional non-local measurements. We also show that this method can be used as a domain wall detection technique.

Design and Characterization of a High-Precision Digital Electromagnetic Actuator with Four Discrete Positions

A high-precision planar digital electromagnetic actuator with two displacement directions and four discrete positions is presented in this paper. The four discrete positions are located at each corner of a square cavity where a mobile permanent magnet moves thanks to Lorentz forces generated when a driving current passes through two orthogonal wires placed below the cavity. Four fixed permanent magnets are placed around the cavity in order to ensure high-precision magnetic holding of the mobile magnet at each discrete position. An analytical model of the actuator is presented and used to characterize its properties (switching time, energy consumption, and displaceable mass). Based on this model, an experimental prototype has been developed and then characterized. Comparisons between experimental and simulated results are carried out and show good agreement. The positioning repeatability errors have also been characterized according to the input signal in order to qualify the digital behavior of this high-precision actuator. Finally, an application of this digital actuator as a linear conveyor is presented and experimentally tested.

Fabrication of embedded electrodes by reverse offset printing

We developed a novel offset-printing process that permits the fabrication of silver-nanoparticle electrodes embedded in a dielectric layer. We succeeded in embedding approximately 1 µm thick silver electrodes to a dielectric layer with thickness ratio of 1:1.4. The surface-height difference between the embedded electrode and the surrounded dielectric layer was less than 80 nm. By virtue of the surface uniformity of this embedding process, the interconnect breakage of orthogonal wires printed on top of the underlying wire was drastically reduced to 4%, compared to 41% for non-embedded wires. The electric conductivity of embedded electrodes with thickness ≈110 nm was about 10 µΩ cm−1, which was comparable to that of a silver pattern formed on a glass substrate alone. We also examined the characteristics of fully printed thin-film transistors composed of the embedded electrodes, and measured an average mobility of 0.07 cm2 V−1s−1. These results demonstrate the applicability of the proposed technique to the fabrication of printed circuits and devices including active elements.