Substrate Plate Research Articles

Characteristics of band gaps of a metamaterial plate with membrane-type resonators based on the energy approach

Local resonance metamaterials have garnered substantial interest in recent years due to their potential to effectively control low-frequency noise and vibration. This study proposes a new metamaterial plate with double mass membrane-type resonators (DMMRs). Combining polynomial fitting and virtual spring method, the natural characteristics of the resonator and the dispersion surfaces of the metamaterial plate are obtained. Results show the proposed metamaterial plate exhibits multiple band gaps, resulting from the cancellation of shear forces in the plate by the reaction forces generated by the first two resonances of the resonators. Parametric analysis is performed to obtain the variation patterns of the band gaps, where approximate models of the resonator are adopted to explain the effects of the parameters. It is found that the occurrence and width of the two band gaps are closely related to the mass ratio between the masses on the resonator and the substrate plate. Furthermore, finite element analysis is conducted to verify the effectiveness of the theoretical derivation, as well as the suppression effect of the metamaterial plate. The findings demonstrate the advantages of the metamaterial plate in vibration control and band gap tuning. The study provides guidance for the design and analysis of elastic wave metamaterials.

Wettability and Surface Tension of Imidazolium, Ammonium, and Phosphonium Bis(fluorosulfonyl)amide Ionic Liquids: Comparison between Pentyl, Ethoxyethyl, and Ethylthioethyl Groups.

This study particularly compares the surface tensions and contact angles for molten bis(fluorosulfonyl)amide salts of imidazolium, ammonium, and phosphonium cations with the pentyl, ethoxyethyl, or ethylthioethyl group. The examined substrate plates for contact angle measurements include silicate glass, platinum, copper, graphene, and polytetrafluoroethylene (PTFE). In addition, quantum chemistry calculations were performed to obtain the optimized structures of the cations and anions of the ionic liquids (ILs) that were studied here along with some typical anions and their dipole moments, mean polarizabilities, and charge distributions. All ILs showed the same order of contact angles with respect to the substrates: PTFE > graphene ≈ copper ≈ platinum > silicate glass. By comparing the three functional groups, i.e., pentyl, ethoxyethyl, and ethylthioethyl, the ILs with the ethylthioethyl group featured a higher work of adhesion than the respective ILs with the pentyl or ethoxyethyl group. The values of the surface tensions of the ILs followed the same trend for the three functional groups. Based on the Fowkes theory, it was found that the larger surface tensions of the ILs with the ethylthioethyl group compared with pentyl and ethoxyethyl groups were because of the increase in both dispersive and nondispersive components. The quantum chemistry calculations of the ions showed a larger dipole moment and mean polarizability for the cations with the ethylthioethyl group as compared with the pentyl and ethoxyethyl groups. This is consistent with the analysis results of the surface tensions based on the Fowkes theory. By comparing other anions, the dispersive component of the surface tension of the ILs with bis(fluorosulfonyl)amide was large, which is attributed to the small dipole moment of the anion.

Distortion Analysis Method for Wire Arc Additive Manufacturing Component Using Thermomechanical Computation with Enhanced Separation and Deposition Algorithm.

This research is devoted to numerical and experimental analysis on deformation of completely removed component induced by wire arc additive manufacturing (WAAM). The component has the form of a hollow and rectangular thin wall made of deposition layer of stainless steel SS316L on top of substrate plate of mild steel S235. In this research, thermomechanical finite element analysis was applied with Goldak's double ellipsoid as heat-source model and isotropic hardening rule based on von-Mises yield criterion. A specialized numerical simulation software Simufact.Welding 2021 (SW) was utilized in developing the numerical model and the simulation of process enhanced with separation and deposition algorithm to predict the component deformation after removal of substrate. On determining the best possible mesh size, a sensitivity analysis was conducted before the advanced stage of model development. An advanced material modeling, the data of which were obtained based on the chemical composition of the evolved SS316L sample, was developed using an advanced material modeling software JMATPRO. For verification purpose, a series of WAAM experiments using robotic GMAW with synergic power source were conducted followed by the removal of substrate from component using machining process. Furthermore, component distortion was measured using industrial noncontact 3D scanner with structured blue light to fully capture the upper section deformation and compared with result of numerical computation. It can be concluded that this novel distortion analysis method using thermomechanical numerical computation with evolved material property and modified algorithms for substrate removal exhibits a surface deviation in vertical direction between 0.05 and 2.16 mm with acceptable pointwise and average error percentage of up to 3%.

Broadband RCS Reduction Using Circular Sector Structure

In this paper, a new metasurface structure is designed to reduce radar cross section (RCS). In order to reduce the radar cross section (RCS), a new metasurface structure is designed. The unit adopts the polarization conversion metasurface structure, which is composed of asymmetric double arrow-shaped metal structure and etched on the dielectric substrate on the back of the metal plate. This polarization conversion metasurface (PCM) unit consists of asymmetric double arrow-shaped metal structure, and it is etched on a dielectric substrate backed with metallic plate. It can realize converting linear polarized waves to orthogonal ones in a broadband from 18.1 GHz to 32.7 GHz efficiently. According to the further development of the triangle chessboard layout, we also designed several new circular fan-shaped configurations, which realize RCS reduction in a wider -10 dB bandwidth compared with the triangle chessboard configuration. Finally, an optimized 8-lobed circular sector configuration composed of the designed PCM unit is selected for processing and testing. It can realize the RCS reduction greater than 10 dB in a wide bandwidth ranging from 13.7 GHz to 27.5 GHz, compared with the equal-sized metallic-backed dielectric substrate plate. The experimental results basically agree with the simulation ones. The proposed broadband circular sector structure has broad application prospects such as phased array antenna technology, electromagnetic stealth technology, and electromagnetic absorption technology.

Trajectory optimization for arbitrary layered geometries in wire-arc additive manufacturing

AbstractIn wire-arc additive manufacturing, a wire is molten by an electrical or laser arc and deposited droplet-by-droplet to construct the desired workpiece, given as a set of two-dimensional layers. The weld source can move freely over a substrate plate, processing each layer, but there is also the possibility of moving without welding. A primary reason for stress inside the material is the large thermal gradient caused by the weld source, resulting in lower product quality. Thus, it is desirable to control the temperature of the workpiece during the process. One way of its optimization is the trajectory of the weld source. We consider the problem of finding a trajectory of the moving weld source for a single layer of an arbitrary workpiece that maximizes the quality of the part and derive a novel mixed-integer PDE-constrained model, including the calculation of a detailed temperature distribution measuring the overall quality. The resulting optimization problem is linearized and solved using the state-of-the-art numerical solver IBM CPLEX. Its performance is examined by several computational studies.

Influence of durability of waterproofing solutions terraces protecting against water and moisture

The article analyses the changes in the durability of waterproofing of terraces, with particular emphasis on the properties of waterproofing materials as a result of utility factors. It was analysed the influence of tensile properties of the above-mentioned materials on their resistance against fatigue resulting from movements of the substrates caused by temperature changes on the surface of the terraces coverings. The adopted range of horizontal plate movements was from 0 to 2 mm at variable temperatures: – 15°C and +70°C. The durability of waterproofing sheets, such as reinforced bitumen sheets and PVC sheets and rubber sheets, as well as coating products was assessed. Thermal deformations of the substrate plates occurring within the terrace covering are most effectively transferred by flexibility sheets with a high relative elongation value, that is: bitumen sheets with polyester reinforcement, PVC sheets and EPDM sheets. The correlation between the mechanical properties of the coatings and their resistance to fatigue cannot be determined but the most favourable properties are shown by two-component (polymer-cement) liquid applied water impermeable products reinforced on the entire surface or reinforced with special tapes over the thermal expansion joints of the substrate plates.

Reversible bonding of microfluidics: Review and applications.

With the development of microfluidic technology, new materials and fabrication methods have been constantly invented in the field of microfluidics. Bonding is one of the key steps for the fabrication of enclosed-channel microfluidic chips, which have been extensively explored by researchers globally. The main purpose of bonding is to seal/enclose fabricated microchannels for subsequent fluid manipulations. Conventional bonding methods are usually irreversible, and the forced detachment of the substrate and cover plate may lead to structural damage to the chip. Some of the current microfluidic applications require reversible bonding to reuse the chip or retrieve the contents inside the chip. Therefore, it is essential to develop reversible bonding methods to meet the requirements of various applications. This review introduces the most recent developments in reversible bonding methods in microfluidics and their corresponding applications. Finally, the perspective and outlook of reversible bonding technology were discussed in this review.

Stability and Bifurcation Analysis of Two-Immiscible Liquids Film Down an Inclined Slippery Solid Substrate

In this work, the dynamic behavior of linear and nonlinear waves propagating at the separating surface between two thin layers of viscous Newtonian fluids is studied in the presence of the effect of insoluble surface surfactant. The two liquids are confined between two infinite rigid parallel plates and assumed to have different densities and viscosities. The equations of evolution for surface-wave elevation and concentration of surfactant are derived using the lubrication approximation. In the linear stage, by utilizing the normal mode approach, we have derived the dispersion relation that relates the wave angular frequency to the wave number and other parameters that is solved numerically to inspect the influences of some selected parameters on the stability criteria of the fluid flow. Also, analytical expressions for the growth rate as well as its maximum value with corresponding wave number are obtained in the special case of long-wave limiting. It is concluded that the Marangoni number text {Ma} has acquired a significant stabilizing influence on the fluid flow, whereas the inverse of the slippery length of substrate plate beta, resorts to the destabilize the motion of the interfacial waves. Consequently, both of the Marangoni number and the substrate slippy coefficient can be utilized to control the film flow regime, where they preserve the film laminar flow and tend to prevent the film breakdown. These can be useful in many industrial applications such as coating processes, heat exchangers, cooling microelectronic devices, chemical reactors, food processing, thermal protection design of combustion chambers in rocket engines and operation of Laser cutting and heavy casting production processes.

Bio-Inspired Circular-Polarized UHF RFID Tag Design Using Characteristic Mode Analysis

This paper presents a bio-inspired circularly polarized ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna for metallic and low-permittivity substances. This tag design is based on a leaf-shaped radiator, two shorting stubs and slots etched on F4B substrate. Initially, the tag antenna is designed using characteristics mode analysis (CMA) by analyzing the first six CM modes and characteristic angles. The width of orthogonal slots is varied to get the resonance of CM modes in the required US RFID band. Moreover, the edges are blended to get orthogonal current distribution, which is necessary for circular polarization. Additionally, the proposed tag design is optimized further using CST Microwave studio and an RFID chip is exploited as a capacitive coupling element (CCE) to run CM modes with the orthogonal current pattern. This tag can also be tunable to European RFID (EU) band (866 – 868 MHz) by changing the length of shorter diagonal slot. The tag design offers a read range of 7 m and 4.5 m on 100 × 100 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> metals plate and low-permittivity substrates, respectively (for 902 – 928 MHz band). In EU band, the corresponding read ranges are 5.7 m and 3.5 m above metal and low-permittivity objects, respectively. This circularly polarized tag antenna is advantageous in terms of cost, circular polarization feature, and ease of fabrication due to the absence of vias, shorting pins, and matching circuits. Therefore, this tag design is suitable for labeling various low-permittivity objects, industrial conveyer belt applications, baggage handling systems, and IoT applications.

An Investigation into Heat Transfer Enhancement by Using Oscillating Fins

The present work describes numerical and experimental investigation of the heat transfer characteristics in a plate-fin, having built-in piezoelectric actuator mounted on the base plate (substrate). The geometrical configuration considered in the present work is representative of a single element of the plate-fin and triple fins. Air is taken as the working fluid. A performance data for a single rectangular fin and triple fins are provided for different frequency levels (5, 30 and50HZ) , different input power (5,10,20,30,40 and 50W) and different inlet velocity (0.5, 1, 2, 3, 4, 5 and 6m/s) for the single rectangular fin and triple fins with and without oscillation. The investigation was also performed with different geometrical fin heights ( 50mm and 35mm) and distance between the fins (3mm and 6mm). It is observed that the heat transfer increases with the increase in the frequency and Reynolds number. It is further observed that triple fins with (height=50mm and distance between the fins=3mm) gives better enhancement as compared to othercases, The study shows that the piezoelectric actuator when mounted on the rectangular fins gives great promise for enhancing the heat transfer rate

Thermoplastic-based microfluidic chip bonding with PES hot melt adhesive film

ABSTRACT In this study, a low-cost and rapid bonding method for thermoplastic-based microfluidic devices is introduced. The thermoplastic substrate and cover plate were directly bonded with PES copolyester hot melt adhesive film. Compared with conventional bonding methods for thermoplastic chips, e.g. thermal fusion and chemical-assisted bonding, the proposed bonding process can be finished within minutes without sophisticated instruments or volatile chemical solvents. Several microfluidic devices were also fabricated and tested, the measured bonding strength is comparable to the conventional thermal fusion bonding method. The biocompatibility of the proposed bonding method was also evaluated by culturing bacteria in the PES adhesive covered culture dish. The proposed bonding method for thermoplastic-based microfluidic is especially suitable for the massive fabrication of POCT devices with advantages in processing speed, instrument requirement, cost, and bonding strength.

Smart hybrid composite sensor technology to enhance the detection of low energy impact damage in composite structures

This paper introduces novel structural health monitoring (SHM) sensors to improve the detection of low energy impact damage in laminated composites. The sensor is a purposely designed thin-ply hybrid composite, composed of a layer of unidirectional S-glass/epoxy and another layer of unidirectional ultra-high modulus (UHM) carbon/epoxy. The sensor was incorporated onto both the impacted face and back of a substrate plate made from unidirectional T800 carbon/MTM49-3 epoxy prepregs with the stacking sequence of [45/0/90/-45]4S. A series of drop tower tests were conducted on the composite plates with and without the attached hybrid sensing layer, with two different in-plane dimensions and varying energy levels ranging from 3 J to 124 J. The results indicate that the sensors functioned satisfactorily and provided direct correlations between visible and internal hidden damage detected by C-scan. The sensor can be optimized by selecting appropriate material properties and adjusting it to the in-plane dimensions of the substrate.

A potential-responsive ion-pump system based on nickel hexacyanoferrate film for selective extraction of cesium ions

A nickel hexacyanoferrate (NiHCF) film electrode was prepared with NiHCF, conductive carbon black, and polyvinylidene difluoride, which was coated on graphite plate substrate for selective extraction of Cs+ ions by using electrochemically switched ion exchange (ESIX) technology. A potential-responsive ion-pump system for efficient extraction of Cs+ ions was designed, and the effect of wet film thicknesses, charging modes, flow rates, and chamber widths on Cs+ ions extraction performance was investigated. In the system, the adsorption capacity and removal percentage of Cs+ ions on the NiHCF film electrode reached as high as 147.69 mg·g−1 and 92.47%, respectively. Furthermore, the NiHCF film electrode showed high selectivity for Cs+ ions and stability. After seven cycles of adsorption/desorption, the desorption percentage could reach about 100%. The excellent Cs+ extraction performance should be attributed to the strong driving force produced by the potential-responsive ion-pumping effect in the ESIX process, as well as the low ion transfer resistance of the film electrode which is caused by the special crystal structure of NiHCF. In addition, the NiHCF film electrode was implemented to work together with the bismuth oxybromide (BiOBr) film electrode to accomplish the simultaneous extraction of Cs+ and Br–. And the adsorption capacity and removal percentage of Br– ions on the BiOBr film electrode reached 69.53 mg·g−1 and 77.32%, correspondingly. It is expected that such a potential-responsive ion-pump system based on NiHCF and BiOBr film electrodes could be used for the selective extraction and concentration of Cs+ and Br– ions from salt lake brine..

Influences of a Variety of Reinforcements on the Durability of Reinforced Bitumen Sheets Operating at Variable Temperatures

This manuscript provides an overview of the most commonly-produced bitumen roofing sheets, focusing on the types of reinforcements used for their production and the reinforcements’ effects on the durability of tensile mechanical properties of roofing sheets under thermal loads. The paper includes the analysis of working conditions of roof coverings in the mid-European transitional climate, i.e., exposed to temperatures passing through 0 °C for three seasons in a year, periodic exposure to negative temperatures reaching −15 °C and positive temperatures up to +70 °C, justifying the above-mentioned emphasis on thermal load. It draws attention to technical problems related to the cooperation of roofing sheets with roofing substrates, with particular emphasis on concrete substrates. For the purposes of the work, the analyses were carried out with regard to the assessment of the service life of roof coverings made of various reinforcements working in conditions of variable temperatures and thus exposed to the transfer of thermal movements of substrate plates. The analyses also included the impact of different coefficients of thermal expansion of the materials in contact with other materials within roof coverings on the incidence of damage to cover layers. Particular attention was paid to the conditions resulting from the production process of roofing sheets effect on the durability of roof coverings made of these materials. Additionally, there were set directions for further work to calculate the impact of stresses, arising in layers of roof coverings during their operation in changeable negative and positive temperatures, on the incidence of mechanical damage to these coverings.

Analytical model for near-crack debonding in fiber-reinforced polymer composite-overlaid metallic plates with a central crack

Extensive research has been undertaken on the use of fiber-reinforced polymer (FRP) in the strengthening of fatigue-damaged and fatigue-prone civil engineering metallic structures. Evaluation of the static load-bearing capacity and fatigue life of the so-strengthened structures necessitates the accurate prediction of the stress intensity factor (SIF) for an FRP-overlaid crack in a metallic structure. This paper first presents a new analytical model for predicting the near-crack interfacial debonding process and its effect on the SIF of a centrally cracked metallic plate that is bonded on both sides with an FRP overlay. The stress distributions in both the overlays and the metallic plate, the interfacial shear stress distribution, the crack opening displacement profile, and the SIF can all be found without the need for any a priori assumption of the near-crack interfacial debonding process/pattern. The accuracy of the analytical model is evaluated with both finite element predictions and experimental data. The analytical model is then used to advance our understanding of the mechanisms of near-crack interfacial debonding, including both the initiation and propagation of debonding, as well as the effect of near-crack debonding on the SIF. It should be noted that while the study was conducted with explicit reference to metallic plates bonded with FRP overlays, the analytical model is applicable to combinations of other materials as long as the substrate plate material is isotropic, and both components remain linear-elastic during the loading process.

Electro-structural modeling of smart laminated composite plate under hygrothermal environment for optimum vibration energy harvesting

Smart laminated composite structures with piezoelectric patches are widely used in vibration control applications in several engineering fields. Precise mathematical models are required for the coupling of base structural and piezoelectric field variables. This paper presents the electro-structural analysis and optimization studies of piezoelectric energy harvester with laminated composite substrate plate subjected to base excitations. The coupled electro-mechanical equations are derived from recently proposed first-order shear deformation theory via the Hamilton’s principle by considering hygrothermal effects. The coupled-field solution is obtained from Ritz-approximation and validated with three-dimensional finite element analysis. Effects of multiple piezoelectric patch topologies over the plate surface on the open-circuit voltage and displacement response are illustrated. Furthermore, the influences of piezoelectric-patch sizes, ply-orientation, size, and location of the tip mass are initially studied on the magnitude of output power and efficiency. An optimization study is conducted to identify the geometric and material variables for improvement of the harvester power output and efficiency.

Nonlinear Modeling of Contact Stress Distribution in Thin Plate Substrates Subjected to Aspect Ratio.

The foundation substrate's basal contact stresses are typically thought to have a linear distribution, although the actual form is nonlinear. Basal contact stress in thin plates is experimentally measured using a thin film pressure distribution system. This study examines the nonlinear distribution law of basal contact stresses in thin plates with various aspect ratios under concentrated loading, and it establishes a model for the distribution of contact stresses in thin plates using an exponential function that accounts for aspect ratio coefficients. The outcomes demonstrate that the thin plate's aspect ratio significantly affects how the substrate contact stress is distributed during concentrated loading. The contact stresses in the thin plate's base exhibit significant nonlinearity when the aspect ratio of the test thin plate is greater than 6~8. The aspect ratio coefficient-added exponential function model can better optimize the strength and stiffness calculations of the base substrate and more accurately describe the actual distribution of contact stresses in the base of the thin plate compared to linear and parabolic functions. The correctness of the exponential function model is confirmed by the film pressure distribution measurement system that directly measures the contact stress at the base of the thin plate, providing a more accurate nonlinear load input for the calculation of the internal force of the base thin plate.

Substrate effect and structure optimization of fabric-based circularly polarized dipole antenna for radio frequency energy harvesting

Radio frequency energy harvesting on textiles is seen as a method of enabling sustainable battery-free operation for wearable devices, while few works have clarified the influence of fabric properties on antenna performance. To prepare successfully a fabric-based circularly polarized antenna for radio frequency energy harvesting, this paper will clarify the effect of key fabric characteristics (such as dielectric properties and fabric thickness) on antenna performance by a finite element simulation. The simulated results showed the antenna resonant frequency is inversely proportional to the half square of the fabric’s dielectric constant, and the antenna radiation efficiency and gain are inversely proportional to the square of its dielectric loss tangent and thickness. Then, for the typical fabric substrates, the structure parameters of the existing circularly polarized antenna are optimized to work in the expected working frequency band, and the dominating structure parameter of the antenna in performance was identified. The optimized antenna prototype has excellent performance. The antenna has a bandwidth of 350 MHz and a maximum transmission distance of 190 cm. The received signal strength indication per unit area is 2.35 mW/cm2 and the output voltage is 1.19 mV/cm2 at a distance of 100 cm. It is concluded that the flexible size-minimized wide bandwidth circularly polarized radio frequency energy harvesting antenna screen-printed on fabric was derived from a commercial circularly polarized antenna with fiber-reinforced epoxy plate (FR4) substrate, and the critical geometrical and material parameters of the fabric substrate for this antenna performance as well as the affecting mechanism were identified.

Ratiometric Luminescent Thermometer Based on the Lanthanide Metal–Organic Frameworks by Thermal Curing

The high-performance optical thermometer probes are of great significance in diverse areas; lanthanide metal-organic frameworks (Ln-MOFs) are a promising candidate for luminescence temperature sensing owing to their unique luminescence properties. However, Ln-MOFs have poor maneuverability and stability in complex environments due to the crystallization properties, which then hinder their application scope. In this work, the Tb-MOFs@TGIC composite was successfully prepared using simple covalent crosslinking through uncoordinated -NH2 or COOH on Tb-MOFs reacting with the epoxy groups on TGIC {Tb-MOFs = [Tb2(atpt)3(phen)2(H2O)]n; H2atpt = 2-aminoterephthalic acid; phen = 1,10-phenanthroline monohydrate}. After curing, the fluorescence properties, quantum yield, lifetime, and thermal stability of Tb-MOFs@TGIC were remarkably enhanced. Meanwhile, the obtained Tb-MOFs@TGIC composites exhibit excellent temperature sensing properties in the low-temperature (Sr = 6.17% K-1 at 237 K), physiological temperature (Sr = 4.86% K-1 at 323 K), or high-temperature range (Sr = 3.88% K-1 at 393 K) with high sensitivity. In the temperature sensing process, the sensing mode of single emission changed into double emission for ratiometric thermometry owing to the back energy transfer (BenT) from Tb-MOFs to TGIC linkers, and the BenT process enhanced with the increase of temperature, which further improved the accuracy and sensitivity of temperature sensing. Most notably, the temperature-sensing Tb-MOFs@TGIC can be easily coated on the surface of polyimide (PI), glass plate, silicon pellet (SI), and poly(tetrafluoroethylene) plate (PTFE) substrates by a simple spraying method, which also exhibited an excellent sensing property, making it applicable for a wider T range measurement. This is the first example of a postsynthetic Ln-MOF hybrid thermometer operative over a wide temperature range including the physiological and high temperature based on back energy transfer.

Experimental and simulative investigation of welding sequences on thermally induced distortions in wire arc additive manufacturing

PurposeThe purpose of this paper is to demonstrate the impact of the welding sequence on the substrate plate distortion during the wire and arc additive manufacturing (WAAM) process. This paper also aims to show the capability of finite element simulations in the prediction of those thermally induced distortions.Design/methodology/approachAn experiment was conducted in which solid aluminum blocks were manufactured using two different welding sequences. The distortion of the substrates was measured at predefined positions and converted into bending and torsion values. Subsequently, a weakly coupled thermo-mechanical finite element model was created using the Abaqus simulation software. The model was calibrated and validated with data gathered from the experiments.FindingsThe results of this paper showed that the welding sequence of a part significantly affects the formation of thermally induced distortions of the final part. The calibrated simulation model was able to capture the different distortion behavior attributed to the welding sequences.Originality/valueWithin this work, a simulation model was developed capable of predicting the distortion of WAAM parts in advance. The findings of this paper can be used to improve the design of WAAM welding sequences while avoiding high experimental efforts.