Orientation Of Layers Research Articles

The geometry, purity, and grain orientation database of the Cu stabilizer layer and the effect on the electrical and thermal properties of commercial REBCO tapes

Abstract Building upon our previous database of the thermal, electrical, and mechanical properties of commercial REBCO tape, we have constructed a subsequent database focusing on the Cu layer of such tapes from eight distinct manufacturers. This database encompasses information pertaining to the geometry, purity, and grain orientation of the Cu layer. The primary objective of this database is to not only elucidate the material science of the Cu layer across various commercial tapes but also to establish correlations between the thermal, electrical, and mechanical properties and the aforementioned geometry, purity, and grain orientation parameters. After analysis, three significant findings have been validated. Firstly, the non-uniformity of geometry plays a critical role in the electrical resistivity in the radial direction, primarily through altering the actual contact surface area. Secondly, it has been observed that the total grain boundary length per micrometer thickness exhibits a nearly linear correlation with the thermal conductivity in the circumferential direction. Thirdly, the purity of the Cu layer in all the commercial REBCO tapes is lower than anticipated. It is our aspiration that this database will facilitate enhanced comprehension of the Cu layer in REBCO tapes among a broader spectrum of researchers.

Rock fragmentation of simulated transversely isotropic rocks under static expansive loadings

Rock fragmentation is a critical process for mineral extraction and for mitigating overstressed rock in geotechnical applications. In this study, 3D-printed concrete was used to simulate the stratified rock mass, and experimental and numerical methods were employed to investigate crack propagation under static expansive loadings in transversely isotropic rocks. Two types of cracks were observed in the experiments: P-type (a crack propagates primarily along the weak layer) and T-type (a crack propagates across the weak layers) cracks. The findings revealed that the orientation of layers significantly influenced the initiation and propagation of cracks, with P-type cracks commonly observed in simpler P-P mode fragmentations and more complex P-P-T modes emerging under higher expansive loadings. P-T-T modes were characterized by the simultaneous presence of the T-type crack after an initial P-type crack. The AE energy levels in the P-P-T and P-T-T modes were much higher than those in the P-P mode. 2D-DDA models were further built to understand the effects of the loading scales, layer angles, and locations of weak layers on the cracking sequences. The results provided detailed insights into stress evolutions and the impact of expansive loadings on crack initiation and propagation.

Polymer Tools Produced by Fused Filament Fabrication for Steel-Bending Process: Effect of Layering Orientation

Rapid tooling with polymer tools produced via additive manufacturing offers significant benefits in sheet metal forming processes as it allows for the production of parts with high accuracy while reducing tool production costs. In this research, the authors evaluate the performance of polymer punches and dies in the sheet metal bending of 2 mm thick AISI 314 stainless steel. The tools were made using nylon filled with carbon fiber and produced through Fused Filament Fabrication. Two different print orientations—horizontal and vertical—were compared. This experimental study focused on the accuracy of the sheet’s bending angle and thickness while also measuring the deformation induced in the tools. A new methodology was proposed combining both tools and sheet measures to highlight not only the sheet’s accuracy but also the behavior of the polymer tools. The results demonstrate that despite the permanent deformation of the tools, they were able to produce sheets with a geometry accuracy of less than 0.5%

Inhibiting the current spikes within the channel layer of LiCoO2-based three-terminal synaptic transistors

Synaptic transistors, which emulate the behavior of biological synapses, play a vital role in information processing and storage in neuromorphic systems. However, the occurrence of excessive current spikes during the updating of synaptic weight poses challenges to the stability, accuracy, and power consumption of synaptic transistors. In this work, we experimentally investigate the main factors for the generation of current spikes in the three-terminal synaptic transistors that use LiCoO2 (LCO), a mixed ionic-electronic conductor, as the channel layer. Kelvin probe force microscopy and impedance testing results reveal that ion migration and adsorption at the drain–source-channel interface cause the current spikes that compromise the device's performance. By controlling the crystal orientation of the LCO channel layer to impede the in-plane migration of lithium ions, we show that the LCO channel layer with the (104) preferred orientation can effectively suppress both the peak current and power consumption in the synaptic transistors. Our study provides a unique insight into controlling the crystallographic orientation for the design of high-speed, high-robustness, and low-power consumption nano-memristor devices.

Machine learning-based analytical approach for mechanical analysis of composite hydrogen storage tanks under internal pressure

This study is a practical exploration of the application of machine learning for the mechanical analysis of filament-wound thin-composite hydrogen storage tanks under internal pressure. Our innovative approach seamlessly integrates classical laminate theory, comprehensive parametric analysis, and machine learning to advance the state-of-the-art in composite tank design. This versatile framework holds promise for addressing challenges in other structurally complex systems. A comprehensive parametric study was then conducted to explore the influence of key design parameters, such as internal pressure, tank radius, order of layer, and layer orientation. Pearson's correlation analysis was used to determine the parameters that had the most significant impact on the mechanical behavior of the tank. In addition, five machine learning models, namely, Extreme Gradient Boosting, Adaptive Boosting, Artificial Neural Network, Support Vector Machine, and Random Forest, were examined to determine their predictive capability for the mechanical performance of these composite tanks. Key findings demonstrate XGBoost's superior predictive capabilities, achieving a remarkable 99% accuracy in predicting stress in the x-direction compared to Random Forest's 96%. XGBoost also outperformed Random Forest in terms of Mean Absolute Error (MAE) and Mean Absolute Percentage Error (MAPE) with values of 26 and 0.02, respectively, versus 207 and 0.16. These results underscore XGBoost's potential to revolutionize hydrogen storage tank design. The development of a user-friendly GUI application further enhances the practicality of this research, allowing engineers and composite designers to efficiently simulate the mechanical behavior of these tanks in real time by adjusting the cursors for variables such as the pressure, radius, layer order, and layer orientation. This tool, with its intuitive interface and elimination of manual calculations, promises significant enhancements in the design process, providing a platform for the rapid assessment and optimization of tank architectures, thereby improving the efficiency and reliability of the design process.

Contact damage response of alumina-based layered architectures under different loading configurations

Hertzian contact damage upon spherical indentation is investigated in alumina-based ceramics designed with embedded textured compressive layers. The effect of the location of the embedded layer and the testing configuration (parallel or normal to the layer orientation) on the sub-surface damage evolution is explored. An acoustic emission system for crack detection and post-mortem cross sectioning are employed to evaluate the onset and extension of damage in the different samples. Distinct acoustic signals detected at different contact loads are correlated with the onset of the ring crack, cone crack propagation and quasi-plastic deformation within the textured layer. The distinct damage mechanisms are influenced by the location of the embedded textured compressive layer and the loading orientation with respect to the layers. The design of layered ceramics for contact applications should consider the loading orientation as well as the contact stress field with respect to the “protective” layer to enhance damage tolerance.

Material removal and damage formation mechanisms induced by periodic indentation during ultrasonic vibration-assisted scratching of SiCf/SiC composites

Fiber-reinforced ceramic matrix composites (CMCs) exhibit high hardness, brittleness, heterogeneity, and anisotropy. This study explores the material removal and damage formation mechanisms during ultrasonic vibration-assisted scratching of SiCf/SiC composites through experimental and micro-finite element simulations. The research reveals that high-frequency periodic indentation-separation of abrasive grain influences stress transfer and crack propagation, which are affected by the interfacial layer and fiber orientation. Crack deflection plays a crucial role in material removal and determines the amplitude of normal scratching force. Stress transfer interference primarily governs damage formation, with more severe damage occurring along the longitudinal and transverse fiber directions due to secondary stress concentration and crack deflection. In contrast, scratching along the perpendicular fiber direction requires higher normal forces due to residual adjacent phase materials, but results in more controlled material removal and less damage. The study provides insights into optimizing the ultrasonic vibration-assisted machining of CMCs to minimize damage.

Earthquake damage mitigation methods for buried pipelines under compressive loads: A case study of the Thames water pipeline

Promoting tensile failure by providing a proper orientation angle between the pipe axis and the fault line is the main seismic design philosophy for buried steel pipelines. However, most of the severe damage and failures experienced by pipelines are mainly due to negative crossing angle and thus compressive loads acting along the pipeline. This paper investigates different earthquake damage mitigation methods such as Carbon Fiber Reinforced Polymer (CFRP) wrapped pipes, Steel Pipes for Fault Crossing (SPF), and corrugated pipes for buried steel pipelines which are mainly subjected to compressive loads. Therefore, the Thames water transmission pipeline, which is a well-known case study, that suffered major and minor damage due to compressive forces in the 1999 Kocaeli earthquake, is considered to simulate and compare the earthquake damage mitigation capabilities of these countermeasures. The numerical studies are performed by using a three-dimensional nonlinear finite element model. The results show that the use of CFRP composites in buried pipelines, regardless of their thickness, wrapping length, or layer orientation, does not have the expected damage reduction effect, but does increase the effective length between major wrinkles or change the type of pipe failure. On the other hand, SPFs and corrugated pipes are more effective in earthquake damage reduction due to their high axial and rotational capabilities.

Behavior of CFRP-strengthened short spiral welded tubes under axial load

Spiral welded tubes (SWTs) are formed by rolling steel plates at a certain angle and welding the resulting abutting edges. They are extensively utilized because of their large diameter ranges, high production efficiency, and low production cost. Thin-walled spiral welded tubes with large diameter-to-thickness ratios are susceptible to local buckling under compressive load, and their performance can be affected by corrosive environments. Therefore, this paper proposed the use of carbon fiber-reinforced polymer (CFRP) to strengthen tubes by external bonding. There are limited studies on the axial compression behavior of CFRP strengthened spiral welded tubes, particularly studies that consider the initial imperfections and residual stresses in spiral welded tubes. To bridge this gap, this paper first investigated the distributions of initial imperfections and residual stresses in spiral welded tubes, finding that both are significantly influenced by distinct forming and welding manufacturing processes. Subsequently, axial compression tests were carried out on four unstrengthened specimens and twelve CFRP-reinforced specimens to investigate the compressive behavior by considering the diameter-to-thickness ratio, the length of the steel tubes, and CFRP layer orientation. The experimental results indicate that CFRP strengthening delays local buckling, and significantly enhances the yield load, ultimate load, and initial stiffness of spiral welded tubes, achieving a maximum increase of the yield load up to 69.11 % and the ultimate load up to 61.99 %, while its impact on the ductility index remains uncertain and is influenced by variables such as the diameter-to-thickness ratio of the tubes and the CFRP layer orientation. Finally, a comparison of the ultimate loads of the specimens by tests and design codes was conducted.

A structural mechanics analysis on a Type IV hydrogen storage tank during refueling and discharging

High-pressure hydrogen gas, as a power generation fuel widely used in transportation, has significantly contributed to the development of hydrogen fuel cell electric vehicles. However, obvious temperature rise and drop during fast refueling and discharging cause serious safety risk to the structural stability of on-board hydrogen storage tank. The American Society of Automotive Engineers SAE J2601 and the international standard ISO 15869 strictly stipulate that the operation temperature range of hydrogen storage tank varies from −40 °C to 85 °C. In this study, a finite element mechanics model was constructed using ACP and Static Mechanical software to better understand the deformation, stress, strain, and failure modes experienced by a Type IV tank during charging and discharging. Detailed parameters such as ply angle, ply thickness, mesh generation, and boundary conditions, were extensively elucidated. The results indicate that the high temperature and pressure generated during fast fueling of the storage tanks are less likely to cause yield failure of the inner, outer layers and plug, but the stress concentration caused by low temperature and high pressure may lead to the fracture rupture of internal polyethylene materials. Aluminum alloy plug, serving as sealing devices for the tank, are most susceptible to yielding failure under coupled conditions. The mechanical load reaching the yield stress of the plug is approximately 85 MPa with the nominal working temperature of 85 °C. Additionally, the maximum stress on the outer layer can be reduced by adjusting the circumferential layer direction from 90° to 70° or by optimizing the orientation of the maximum stress layer increasing it by 110°. The present study can offer new insights into the dynamic loading behavior of the Type IV tanks during fast charging and discharging, and may provide technical references for optimization design of the tank structures.

Feasibility and Structural Transformation of Electrodeposited Copper Foils for Graphene Synthesis by Plasma‐Enhanced Chemical Vapor Deposition: Implications for High‐Frequency Applications

AbstractLarge‐area graphene is typically synthesized on rolled‐annealed copper foils, which require transferring to other substrates for applications. This study examines large‐area graphene growth on electrodeposited (ED) copper foils—used in lithium‐ion batteries and printed circuit boards—via plasma‐enhanced chemical vapor deposition (PECVD). It reveals that, for a set plasma power, a minimum growth time ensures full graphene coverage, leading to monolayer and then multilayer graphene, showing PECVD growth on ED copper is not self‐limited. The process also beneficially modifies the ED copper substrate, like removing the surface zinc layer and changing copper grain size and orientation, thus improving graphene growth. Additionally, the study includes high‐frequency scattering parameter (S‐parameter) measurements in a coplanar waveguide (CPW) system. This involves graphene on a sapphire substrate with a silver electrode. The S‐parameter data indicate that the CPW with graphene shows reduced insertion losses in high‐frequency circuits compared to those without graphene. This underscores graphene's role in reducing insertion losses between metallic and dielectric layers in high‐frequency settings, offering valuable insights for industrial and technological applications.

Anisotropic mechanical and sensing properties of carbon black-polylactic acid nanocomposites produced by fused filament fabrication

3D-printable conductive polymers are gaining remarkable attention for diverse applications, including wearables, pressure sensors, interference shielding, flexible electronics, and damage identification. However, the relationship between the anisotropy of their mechanical and electrical properties remains rather unexplored. This study focuses on characterizing Polylactic Acid/Carbon Black nanocomposites manufactured through fused filament fabrication. It aims to investigate the effect of the orientation of 3D printing layers on the mechanical properties, failure mechanisms, and self-sensing capabilities of the 3D printed material. To this end, we use a coupled health monitoring system in which electrical resistance measurements are applied to diagnose the damage state of 3D-printed samples during tensile testing. The results provide novel insights into the strong dependence of the material behavior on 3D printing pattern orientation, suggesting avenues for optimizing mechanical and electrical anisotropy through a multi-objective approach. Additionally, they offer guidelines for designing self-sensing components for structural health monitoring applications and strain gauge sensors with superior performance.

Measuring thermomechanical response of large-format printed polymer composite structures via digital image correlation

Large-format additive manufacturing (LFAM) is a branch of additive manufacturing (AM) research with the ability to create large structures typically measuring several meters in scale. LFAM is advantageous for tooling applications, not only because it offers the ability to create complex geometries not easily made using subtractive manufacturing processes, but the cost savings of pelletized feedstock used by these systems result in larger parts printed at faster speeds than traditional AM systems. Fiber reinforced polymer (FRP) is a commonly used feedstock material in LFAM structures because it reduces the distortion experienced during printing. However, FRP introduces highly anisotropic thermomechanical properties and contributes to a nonhomogeneous microstructure that can result in critical distortion of dimensions during tooling. Measuring the global thermomechanical response of LFAM structures requires a more representative method that accounts for not only anisotropic properties but also the nonhomogeneous nature of the final part. This is where traditional techniques to measure thermomechanical response, such as thermomechanical analysis (TMA), fall short as they assume homogeneity. This study evaluated the coefficient of thermal expansion (CTE) of LFAM structures as measured by TMA as compared to a novel digital image correlation oven (DIC Oven) system. The LFAM structures were made from 20 % by weight carbon fiber reinforced acrylonitrile butadiene styrene (CF-ABS). TMA measurements showed significant variations in CTE across a single LFAM bead, confirming the need for a global technique that captures overall thermomechanical response. The CTE values measured using the DIC Oven compared well to average TMA values obtained from localized measurements across the sample. The DIC Oven was also used to quantify the effects of different layer orientations on thermomechanical properties, which cannot be easily captured using TMA. A predictive model was also developed by using localized TMA values across an LFAM bead to predict the overall thermomechanical response of an LFAM structure.

The Effect of the Rare Earth Element Cerium on the Electrocrystallization and Microstructure of Nickel Electrodeposits in Industrial Electrolytes

To meet the industrial production needs for high-quality and precisely controllable structured high-end nickel foils, rare Earth compounds are added as additives in complex industrial electrolytes to improve the quality of the nickel deposition layer. This study investigates the effects of adding rare Earth compounds to the existing industrial production electrolytes (which already contain various organic and inorganic additives in a mixed acid solution) on the surface microstructure, cerium content, grain size, and crystal orientation of the nickel deposition layer. Using direct current electrodeposition, different concentrations of rare Earth compounds were added to the industrial electrolyte, and the cerium content, grain size, and crystal orientation were characterized. The results show that adding 0.8 g·l−1 CeCl3 accelerates the nucleation rate and shortens the nucleation relaxation time. The addition of rare Earth elements promotes multi-directional preferential growth, resulting in uniform and fine grain size, improved grain structure of the deposition layer, and reduced surface roughness of the nickel plating layer. Therefore, rare Earth elements can be used to regulate the structure, microstructure, and grain refinement of the nickel deposition layer without affecting its composition.

Mechanical properties of layered composites based on AA1050 and AA5056 aluminum alloys produced by WAAM technology

Abstract The possibility of producing layered aluminum materials using wire-arc additive manufacturing (WAAM) technology has been investigated. Deformation characteristics of composites based on AA1050 and AA5056 aluminum alloys are considered. Mechanical tests of specimens with different orientations of AA1050 layers in AA5056 alloy matrix are presented. The results are analysed in the light of the structural characteristics of the composites.

Effect of Process Parameters on the Appearance of Defects of Flake-Pigmented Metallic Polymer.

This study investigates the influence of the main process parameters of injection molding(mold temperature, melt temperature, and injection rate) on the appearance of defects of flake-pigmented metallic polymer parts. To understand the influence of process parameters, an appearance defects index (ADI) is proposed to quantify the appearance defects. In this process, we propose a criterion for judging the appearance of defects based on the results of fiber orientation and tensor distribution analyses of the skin layer, which is then verified analytically by simulating experiments from the literature. Using the Taguchi experimental method, we designed an L25 orthogonal array to systematically evaluate the influence of process parameters. For each experimental condition, the signal-to-noise ratio (S/N ratio) was calculated to determine the optimal level of each factor and its influence on the appearance of defects. According to the results, mold temperature has the greatest influence on the appearance of defects, with an influence of 48.7%, followed by injection rate with an influence of 40.8%, and melt temperature with an influence of 10.5%. The optimal process parameters were found to be a mold temperature of 40 °C, a melt temperature of 250 °C, and an injection rate of 10 cm3/s, which resulted in a 12.6% improvement in the Appearance defects index (ADI) compared to the standard injection molding condition of ABS materials. This study confirmed that it is possible to improve the appearance of defects by adjusting the process parameters of injection molding.

Experimental analysis of the piezomagnetic behavior of double-shear bolted connections of wire and arc additively manufactured steel

ABSTRACT In this paper, the piezomagnetic behaviour of WAAM double-shear connection specimens were investigated. It aims to develop a damage monitoring method based on piezomagnetic effect for WAAM steel bolted connections. Eight WAAM steel coupons with two different print layer orientations were fabricated to measure the mechanical properties of WAAM materials. A total of 32 WAAM double-shear bolted connection specimens with two print layer orientations were designed to analyse the structural properties of WAAM members. A magnetic probe was used to monitor the variations of the piezomagnetic field. The evolutions of piezomagnetic field of transversal and longitudinal WAAM coupons were compared and analysed. Notably, it is found that piezomagnetic field manifests anisotropy consistent with the mechanical properties. The characteristics of five failure modes including net section tension, end-splitting, shear-out, bearing, block shear were discussed. The correlation between the magnetic field–displacement curve and the load-displacement curve was systematically examined. The characteristics of magnetic field of specimens failing by bearing were emphatically explored. The results show that bearing failure can be distinguished from other failure modes by monitoring the magnetic field. In addition, the evolution of magnetic field serves as a predictor of the ultimate capacity and failure of double-shear bolted connections.

A NUMERICAL MODEL FOR ANALYZING CROSS LAMINATED TIMBER UNDER OUT OF PLANE LOADING

This paper targets the validity of a novel numerical model for analyzing CLT under out of plane loading. This numerical model was initially developed for determining the shear lag effect that appears in laminated thin walled composite beams. A parametric study was conducted in order to determine the influence of orientation of layers in CLT panels on bending strength and deflection. For confirming the accuracy of the proposed model, the results from the numerical model are compared with the external results of the computer software Ansys. The differences in bending stress vary from 0.27% to 1.69% depending on the orientation of layers and for deflection the differences are ranged from 2.25% to 7.42%. A numerical study was conducted and obtained data corresponds to results obtained from experimental study. It was concluded that the proposed numerical method can enough precisely predict the behavior of CLT under out of plane loading.

Strength Weakening and Phase Transition Mechanisms in Nanoindentation of Al/Mg-Layered Nanocomposites: A Molecular Dynamic Study

Molecular dynamics (MD) simulations were performed to investigate the nanoindentation behavior of Al/Mg-layered nanocomposites with varying layer thicknesses and Mg layer orientations in this study. The aim is to understand the weakening mechanisms at low layer thicknesses and the phase transition mechanisms associated with the dislocation slip angle in the Mg layer. Results indicate that the nanoindentation strength of nanocomposites increases with the layer thickness in the range of 1–10 nm, with the strength of 9.5 × 10−7 N at 10 nm being approximately 73% higher than that at 1 nm. This strength increase is mainly attributed to high interfacial stress, the higher percentage of amorphous atoms, weakened interatomic interactions, and the transition of adjacent interfaces to fully coherent interfaces that significantly reduce their ability to hinder dislocations at the low-layer thickness range. Additionally, in the initial deformation process, the hexagonal close-packed (HCP) phase of the Mg layer firstly transforms into the body-centered cubic (BCC) phase due to its lower energy barrier, followed by the emergence of a faced-centered cubic (FCC) phase driven by 1/3<1−100> dislocations. In the late stage of deformation, new dislocations are generated in the FCC phase and move along its slip planes, altering the dislocation direction. The FCC/HCP interfacial configuration also affects the HCP phase transition mechanism in the Mg layer. When the dislocation slip angle is 0°, the primary phase transition is the BCC phase, whereas a 45° slip angle results in the FCC phase. These findings will provide a guide for the preparation and manufacturing of new high-quality layered nanocomposites.

Design for disassembly: Using a multi-material approach in 3D printing for easier recycling strategies

Due to the rapid expansion of the electronics sector, e-waste is becoming a growing issue that requires immediate attention. In particular, the complex assemblies and miniaturisation of these devices makes it difficult to recycle them properly. Additive manufacturing (AM), also known as 3D printing, offers a potential solution to this problem. The ability to print structures in μm- range makes it possible to print and manufacture electronic components in such a way that predetermined breaking points can be incorporated. Parts printed in this way are subject to the concept of Design for Disassembly, which describes the production of multi-material compounds or composites that can be easily separated or recycled. Using a multi-material approach in combination with Thermally Expandable Microspheres (TEMs) and processed by 3D printing, we produced easily separable compounds on demand. The compounds were characterized regarding their (thermo)mechanical behaviour. The study investigated the influence of the printed separation layer on the mechanical properties of the overall compound for various layer orientations. The printed parts were separated using heat as an external impulse, without requiring extensive force. This was achieved by subjecting the parts to a temperature of 200 °C for 10 minutes in a conventional oven.