Lamination Direction Research Articles

Influence of metallic properties on the fracture characteristics of Al2O3/Ti/Ni‐laminated composites

AbstractThe mutual confinement of ceramics and metals in laminated composites tends to change the original properties of ceramics and metals. In this study, two kinds of laminated composites, Al2O3/Ti and Al2O3/Ti/Ni, were prepared. Three‐point bending experiments revealed that Al2O3/Ti underwent brittle fracture after elastic deformation. The fracture morphology analysis revealed that the Ti in Al2O3/Ti became brittle due to the formation of columnar crystals. The temperature gradient perpendicular to the direction of laminations during preparation was responsible for the formation of columnar crystals. The force–displacement curves of the Al2O3/Ti/Ni combine the properties of elastic deformation of ceramics and plastic deformation of metals. The reason why the Al2O3/Ti/Ni did not fracture completely in the bending experiments is that Ni maintained the toughness, and there is a good interfacial bond among Al2O3, Ti, and Ni. The indentation crack analysis revealed that cracks have long transverse propagation and short longitudinal propagation in both laminated composites. Finite element analysis revealed that this was due to compressive stress in the Al2O3 layer and tensile stress in the metal layer. This compressive stress consumes the crack energy in the longitudinal direction and stops the crack in the metal layer. The brittle to ductile gradient transition among Al2O3, Ti, and Ni, combined with the guidance of crack propagation direction by the interfacial layer, enhances the ability of Al2O3/Ti/Ni to resist damage.

Electromagnetic shielding behaviors of planar frequency selective surface fabrics, with emphasis on decoupling analysis, lamination direction and tunable selective frequency

Planar frequency selective surface (FSS) fabrics with grids, strips or patches by simple methods of patching, embroidery, clipping and carving were fabricated. The periodic structures, laminated structures, processing method and materials pertaining to the electromagnetic shielding behaviors were investigated. Firstly, equivalent circuit and electromagnetic (EM) shielding behavior of basic frequency selective structure units and complex fretwork structure were provided, involving the decoupling of complex fretwork structure. In addition, various laminating structures of SPs and SGs were determined, one of superposition of SPs and SGs provides a SE peak of 40.2 dB (average SE of 25.1 dB in the whole frequency domain), the other presents a SE peak of 27.1 dB (average SE of 19.1 dB in the whole frequency regime). Furthermore, tunable selective electromagnetic shielding by a simple mechanical way was provided, which can realize a tunable SE peak varying from 730 MHz to 1580 MHz. This work might provide a perspective for the assemble and analytical approximation of FSS fabrics for scientists and engineers in this cross-disciplinary field.

Flexible Mechanoluminescent SrAl2O4:Eu Film with Tracking Performance of CFRP Fracture Phenomena.

Non-destructive testing of carbon-fiber-reinforced plastic (CFRP) laminates with bidirectional fiber bundles (twill-weave) using a mechanoluminescence (ML) technique was proposed. The dynamic strain distributions and fracture phenomena of the CFRP laminates in the tensile testing were evaluated by the fabricated ML sensor consisting of SrAl2O4:Eu (SAOE) powder and epoxy resin. The ML images for the ML sensor attached to the CFRP laminates with bidirectional fiber bundles gave a net-like ML intensity distribution similar to the original twill weave pattern. Specifically, it was found that the ML intensity on the longitudinal fiber bundle, which is the same as the tensile direction, is higher than that on the transverse fiber bundle. This indicates that the ML sensor can visualize the load share between fiber bundles in different directions of the CFRP laminate with high spatial resolution. Meanwhile, the ML sensor could also visualize the ultrafast discontinuous fracture process of the CFRP laminates and its stress distribution. The amount of SAOE powder in the ML sensor affects the tracking performance of the crack propagation. A higher SAOE amount leads to a fracture of the ML sensor itself, and a lower SAOE amount leads to poor ML characteristics.

Experimental Validation of Topology Design Optimization Considering Lamination Direction of Three-dimensional Printing

본 연구에서는 3D 프린팅 FDM 방식의 적층 방향에 따라 기계적 물성이 달라지는 이방성 특성을 확인하고 이를 이용하여 위상 최적설계를 수행하였다. 벤치마크 문제인 자동차 현가장치 부품 중 하나인 로어 컨트롤 암에 대하여 밀도법 기반 위상 최적설계를 수행하였으며, 외부 하중과 이방성 특성에 따라 위상 최적결과가 다르게 나타나는 것을 확인하였다. 이를 이용하여 최적화된 모델에 대하여 3D 프린터로 적층 방향을 달리하여 2가지 시험품을 제작하였으며 인장시험을 수행하였다. 시험시 3D 비접촉 변형률 측정기를 이용하여 변형률을 구하였으며 이를 CAE 응답해석으로 얻은 변형률과 비교한 결과가 정량 및 정성적으로 일치하는 것을 확인하였다. 3D 프린팅 적층 방향을 고려한 위상 최적모델의 인장 실험 결과를 통해 해당 최적설계 방법론의 유효성을 검증하였다.

Performance Prediction of Composite Marine Propeller in Non-Cavitating and Cavitating Flow

The purpose of this study is to compare the performance of specific composite propellers with different ply angles from a cavitation inception speed (CIS) perspective. Composite propellers have a relatively large deformation compared to existing propellers manufactured using nickel aluminum bronze alloys. Therefore, it is necessary to understand the correlation between the stacking method of the composite materials and the propeller performance in order to design composite propellers that provide sufficient strength and generate the desired deformation. In addition, in the case of composite propellers, the deformation is closely related to the CIS because it can delay or accelerate the occurrence of tip vortex cavitation (TVC). Fluid-structure interaction (FSI) analysis of the model-scale composite propellers is performed using a coupled computational fluid dynamics (CFD)-finite element method (FEM) to examine the influence of the lamination direction on the deformation of the composite propeller. Finally, a hydroacoustic analysis of the noise generated and propagated by a composite propeller in non-cavitating and cavitating flows is conducted. The study found that some deformed parameters of the propeller affect the performance, the deformation of the composite propeller itself has no significant effect on the sound pressure level, and the volume change of cavitation has a decisive effect on the variation of the sound pressure level radiated from the composite propeller. These results can improve the feasibility, conceptual design, performance, and manufacturing methods for composite propellers.

Bloch spectral analysis in the class of non-periodic laminates

In this work, we introduce Bloch waves to study the homogenization process in a class of simple laminates which are obtained as a particular Hashin-Shtrikman microstructure involving translations and dilations in only one direction. This makes this class of microstructures non necessarily periodic in the direction of lamination. We derive explicit formulae for the Bloch wave spectral representation of the homogenized coefficients.

Deformation activated negative group velocity state in soft laminates

We report the observation of deformation-induced negative group velocity (NGV) state in the non-periodic media. The phenomenon is illustrated by examples of the shear waves traveling along the non-periodic direction of pre-strained soft laminates. We show that the NGV state can be induced in absolutely stable laminates without invoking buckling. These stable composites with activated NGV states are achieved through tailored stiffening behavior of their non-Gaussian soft phases. The deformation range – for which the NGV state is activated – is multiple times higher in the proposed absolutely-stable composites than those prone to buckling. Finally, we analyze how this unusual NGV state can be induced and further tuned by variations in the material and geometric parameter spaces.

Thermal dynamic damage of aircraft composite material suffered from lightning channel attachment based on moving mesh method

There is a complex nonlinear dynamic coupling and multi-physical damage between lightning channel and composite material. This paper aims to study the coupling mechanism between lightning channel and composite material. Magneto Hydro Dynamics (MHD) model is established to describe physical characteristics of lightning channel. Moving mesh approach and interface tracking method are applied to deal with the dynamic damage of composites material exposed to lightning channel. This coupling numerical method is validated by a case of aluminum (Al) alloy plate under lightning channel. It is also investigated the current flow, dynamic damage, interaction mechanism of composite laminate during lightning channel attachment. The results reveal that lightning current mainly flows along carbon fiber direction in plane. Current density decreases along the depth direction of composite laminate. Magnetic field contours exhibit a whirlpool shape around the discharge channel. Electromagnetic force is perpendicular to composite laminate surface. Lightning damage morphology of composite laminate exhibits an inverted cone shape. Ablation depth is about 1.57 mm and damage area is about 2080 mm2, which are consistent with experimental results. There exits mutual relationship between lightning damage morphology and lightning channel evolution.

Microstructure evolution along build direction for thin-wall components fabricated with wire-direct energy deposition

PurposeThe use of a gas metal arc welding-based weld-deposition, referred to as wire-direct energy deposition or wire-arc additive manufacturing, is one of the notable additive manufacturing methods for producing metallic components at high deposition rates. In this method, the near-net shape is manufactured through layer-by-layer weld-deposition on a substrate. However, as a result of this sequential weld-deposition, different layers are subjected to different types of thermal cycles and partial re-melting. The resulting microstructural evolution of the material may not be uniform. Hence, the purpose of this study is to assess microstructure variation along with the lamination direction (or build direction).Design/methodology/approachThe study was carried out for two different boundary conditions, namely, isolated condition and cooled condition. The microstructural evolution across the layers is hypothesized based on experimental assessment; this included microhardness, scanning electron microscopy imaging and electron backscatter diffraction analysis. These conditions subsequently collaborated with the help of thermal modeling of the process.FindingsDuring a new layer deposition, the previous layer also is subject to re-melt. While the newly added layer undergoes rapid cooling through a combination of convection, conduction and radiation losses, the penultimate layer, sees a slower cooling curve due to its smaller exposure area. This behavior of rapid-solidification and subsequent re-melting and re-solidification is a progressing phenomenon across the layers and the bulk of the layers have uniform grains due to this remelt-re-solidification phenomenon.Research limitations/implicationsThis paper studies the microstructure variation along with the build direction for thin-walled components fabricated through weld-deposition. This study would be helpful in addressing the issue of anisotropy resulting from the distinctive thermal history of each layer in the overall theme of metal additive manufacturing.Originality/valueThe unique aspect of this paper is the postulation of a generic hypothesis, based on experimental findings and supported by thermal modeling of the process, for remelt-re-solidification phenomenon followed by temperature raising/lowering repetitively in every layer deposition across the layers. This is implemented for different types of base plate conditions, revealing the role of boundary conditions on the microstructure evolution.

Genetic model for Jurassic shale-hosted Zn-Pb deposits of the Arak Mining District, Malayer-Esfahan metallogenic belt: Insight from sedimentological, textural, and stable isotope characteristics

The genetic model, including conditions under which mineralization formed, and relative timing of mineralization are critical questions for SEDEX (or shale-hosted massive sulfide, SHMS) deposits. There is increasing awareness that sub-seafloor replacement is an important process in the formation of some SEDEX deposits. We have studied the Hossein-Abad and Western Haft-Savaran Zn-Pb SEDEX deposits located in the Arak basin of the Malayer-Esfahan Metallogenic Belt, Iran, to address these questions of genesis. This metallotect formed in a back-arc paleotectonic setting as a result of the subduction of the Neo-Tethys oceanic plate beneath the Sanandaj-Sirjan Zone. The rocks that host the mineralization are Jurassic organic matter-bearing, fine-grained sandstones, siltstones, and shales. Asymmetric lenticular bedding, unidirectional flow (based on oblique silt lamination direction relative to horizontal bedding), graded bedding, and clay-rich interbeds indicate sediments were deposited from turbidity currents in a low-energy basin environment.There are three ore facies in the Hossein-Abad and Western Haft-Savaran Zn-Pb deposits: 1) bedded ore; 2) massive ore; 3) feeder zone. Bedded ore contains pyrite framboids and polyframboidal clusters. The size range of the pyrite framboids (3 to 6 µm in diameter) indicates they formed in the water column and not in the subsurface. Characteristic structures in bedded ore are: 1) sulfide-bearing silt injections into clay-filled burrows, 2) injection of sulfide-bearing silt into flame structures of claystone laminae, and 3) organic matter in claystone oriented obliquely relative to bedding. These structures are the result of seismic deformation induced by synsedimentary earthquakes, whereby sulfides that formed in permeable unconsolidated sediment were injected into the organic matter-bearing claystone unit.The δ18O and δ13C values of siderite, calcite and dolomite in veins from the feeder zone and massive ore range from 12.2 to 23.8‰ and −16.7 to 1.7‰, respectively. These values indicate that formational water, seawater and organic matter oxidation-decomposition all played a role in hydrothermal carbonate formation. Melting and homogenization temperatures for CO2 for CO2-bearing fluid inclusions range from −57.5 to −60 °C and 6.6 to 29.5 °C, respectively, and indicate the presence of < 15 mol percent CH4. The CO2 homogenization temperature range suggests the CO2-rich phase is a CO2-CH4 mixture. The CH4 and CO2 in the H2S-bearing fluid were likely generated by biodegradation and oxidation of organic matter via BSR and methanogenesis.The sulfur isotope compositions of pyrite, galena, sphalerite and chalcopyrite from the feeder zone and the massive ores range from δ34S −4.3 to + 7.2‰ and display equilibrium fractionations, indicating that the sulfur originated from two processes: (a) bacterial reduction of seawater sulfate (BSR) (distal from mineralization site), and (b) thermochemical reduction of seawater sulfate (TSR) (in both massive ore and feeder zone). Sulfur isotope geothermometric calculations (Δgalena-sphalerite) for two samples give temperatures in the range 209–224 °C for the massive ore facies. Such high temperatures negate a contribution of sulfur from BSR. However, BSR likely occurred in sediments distal to the feeder zone, where seawater sulfate was bacterially reduced to H2S, and this H2S migrated to the mineralization site during diagenesis. Collectively, the stable isotope data indicate mineralization formed in response to mixing occurred between ascending hot metalliferous hydrothermal fluid that rose up the fault and fracture network, with H2S-bearing fluid and sulfate-bearing percolating seawater, triggering sulfide deposition.

Electromagnetic Analysis and Efficiency Improvement of Axial-Flux Permanent Magnet Motor With Yokeless Stator by Using Grain-Oriented Silicon Steel

This article employs grain-oriented (GO) silicon steel in an axial-flux permanent magnet (AFPM) machine to improve its torque and efficiency. Rolling direction of the GO material have been studied to ensure the machine&#x2019;s main magnetic flux passes through the easy magnetization direction. Based on the study of the electromagnetic characteristics of AFPM machine, GO silicon steel is laminated to form a stator according to a certain lamination direction. The torque and efficiency of the proposed machine with GO material shows an increase in comparison with that of the conventional non-oriented (NO) silicon steel machine under identical conditions. In addition, an equivalent magnetic circuit model is established to illustrate little difference of electromagnetic property under no-load condition for the yokeless stator AFPM using two kinds of silicon steel sheet. Furthermore, a AFPM machine with stator yoke is also established to highlight the superiority of GO in the application of the AFPM machine with yokeless stator.

Superficial Effects of Ball Burnishing on TRIP Steel AISI 301LN Sheets

This paper explores the consequences of applying an ultrasonic vibration-assisted ball burnishing process and its non-vibration assisted version on the topology and subsurface microstructure of a transformation-induced plasticity AISI 301LN alloy. More specifically, four different metallographic conditions provided as 1.5-mm thickness sheets and characterized by different starting martensite content (3, 10, 20 and 40 wt.%) are included in the study. Ball burnishing was performed along the lamination direction and perpendicular to it. Results show that the effect of ball burnishing is strongly correlated with the pre-existing microstructure. The steel containing the lowest quantity of initial martensite is the most affected by the process, achieving a higher residual hardening effect, similar to the untreated steel with an original martensitic content of around 40 wt.%. Moreover, the process succeeds in generating a 100-nm thick nanograin layer under the plate subsurface. Finally, no conspicuous effect of the application of vibration assistance was observed, which encourages the application of alternative measurement techniques in future works to define its effect on the properties after being ball burnished.

Effect of Z-pin inclined angle on the impact damage suppression effectiveness for cross-ply composite laminates

Z-pins can enhance through-thickness direction of composite laminates effectively by reducing the delamination damage area. In this paper, the low velocity impact behaviors of [02/902]4S cross-ply composite laminates by inserting Z-pins with two different angle 0° and ±45° along the thickness direction were compared. T300 carbon fiber Z-pins were used as the reinforcements for Z-pinned laminates impacted by 5 J, 10 J, 20 J and 30 J impact energies. The mechanical responses including the impact force-time/central displacement curves were recorded during the tests. Afterwards, ultrasonic C-scanner, scanning electron microscope (SEM) and X-ray micro-computed tomography (μCT) techniques were used to characterize the impact damage. Experimental results demonstrated that the Z-pins were unable to delay the delamination initiation, which led to basically consistent delamination initiation threshold regardless of Z-pin inclined angle. Based on the mechanical characteristics, 0° Z-pinning could improve the resistance to the onset of penetration by comparing to the ±45° Z-pinning. In addition, the effectiveness of 0° Z-pinning on suppression of delamination damage and internal defects was better than the ±45° Z-pinning at high impact energy.

Anisotropy in ultrasonic pulse velocity and dynamic elastic constants of laminated sandstone

Some rocks of the crust, such as sandstones, contain fabric elements including lamination. In general, these rocks show anisotropic behaviour. In this study, anisotropic behaviour of ultrasonic pulse velocities ( V p and V s ) and dynamic elastic constants (elastic modulus ( E ) and Poisson's ratio ( ν )) were investigated for a laminated sandstone. For this purpose, some cylindrical specimens of the sandstone were prepared at angles ( β ) of 0°, 30°, 45°, 60° and 90° to lamination direction. The V p , V s , E and ν were measured for the specimens for the different β values. The study confirms that anisotropy is one of the most important factors affecting V ­, V s , E and ν . The obtained results reveal that V p , V s and E show a decreasing trend with an increase in β from 0° to 90°; whereas ν shows an increasing trend. According to the values of maximum and minimum V p , V s , E and ν for different β values, anisotropy ratios for sandstone samples are 1.16, 1.26, 1.52 and 1.15, respectively. Finally, it can be concluded that calculated V p , V s , E and ν corresponding to different β values are useful for the analysis and design of geotechnical projects in the absence of borehole explorations.

Anisotropic Conductivity Measurements by Two Kinds of Multimode Rectangular Plate-Laminated Cavities

In this article, we present anisotropic conductivity measurements by using two kinds of multimode rectangular cavities. Plate-laminated waveguides are fabricated by diffusion bonding of etched thin metal plates and their sidewalls have anisotropic conductivity characteristics. The anisotropic conductivity is measured by two multimode rectangular cavities when polarization is vertical or horizontal to the lamination direction. Transmission characteristics of the cavities are measured and the conductivity is calculated by the measured resonant frequencies and unloaded quality factors. The anisotropic conductivities are derived by solving a linear equation. As an example, aluminum alloy (A6063) E-band (60.5–91.9 GHz) rectangular cavities are fabricated and the conductivity is characterized.

Singularity aware de-homogenization for high-resolution topology optimized structures

Homogenization-based topology optimization has been shown to be effective but does not directly create mechanical structures. Instead, the method gives a multi-scale description of the optimized design, e.g., lamination thicknesses and directions. To obtain a realizable single-scale design, one can perform a subsequent de-homogenization step. This is done by converting the lamination directions to integrable vector fields from which it is possible to compute a parameterization of the domain. Unfortunately, however, singularities often make it impossible to find integrable vector fields that align with lamination directions. We present a short introduction to homogenization-based topology optimization followed by an overview of different types of singularities and how they impinge on the problem. Based on this, we propose a singularity aware de-homogenization pipeline, where we use a method for vector field combing which produces consistent labeling of the lamination directions but also introduces necessary seams in the domain. We demonstrate how methods from computer graphics can subsequently be used to compute the final parameterization from which the mechanical structure can easily be extracted. We demonstrate the method on several test cases.

Effect of Lamination Direction on the AE Behavior of 3D Printed Specimen during Tensile Testing

Additive manufacturing (AM) methods have become popular but the fracture mechanism of products made by AM is not well understood. In particular, the fracture of parts made by 3D printing needs more investigation. We have already investigated the effect of the lamination direction on the fractures in bearing specimens. In this study, we made some specimens by using a 3D printing method and performed some tensile tests. We investigated the effect of the lamination direction on the Young’s modulus of the specimens and tried to detect inner defect initiation using an acoustic emission (AE) sensor.

Influência da corrosão no aço inoxidável duplex S31803 submetido a íons de cloreto em diferentes temperaturas

Neste trabalho foi avaliada a influência do meio corrosivo e da temperatura nas propriedades de resistência à corrosão do aço inoxidável duplex S31803. O processo corrosivo foi realizado utilizando solução ácido clorídrico 1,5%, à 25, 50 e 80 °C, que é uma solução típica quando se deseja avaliar a corrosão puntiforme, por envolver íons de cloreto. A microestrutura da amostra conforme recebida foi analisada antes e após processo corrosivo utilizando as técnicas de microscopia ótica e confocal. Em seguida, foram realizados os ensaios mecânicos e de resistência à corrosão. A microestrutura do aço inoxidável duplex S31803 é composta de duas fases, ferrita e austenita, orientadas no sentido de laminação, com um balanço aproximado de 50% em volume das frações de fases presentes. O meio corrosivo de ácido clorídrico, nas temperaturas de 25 e 50 °C, proporcionaram o desenvolvimento da corrosão uniforme e da corrosão por pites no material, o que é típico de soluções contendo íons de cloretos. Com o aumento da temperatura até 80 °C, foi observado a deterioração do filme passivo, aumentando expressivamente a corrosão uniforme, onde está se desenvolveu de forma seletiva, tendo a ferrita como anodo e a austenita como catodo. As amostras quando submetidas ao meio corrosivo e as diferentes temperaturas, tendem a diminuir seus valores de propriedades mecânicas quando sofrem a corrosão puntiforme. Em contrapartida quando a corrosão uniforme foi verificada nas amostras, a tendência foi ter um aumento nos valores das propriedades mecânicas quando comparado com o estado inicial; fato que está relacionado à corrosão seletiva do material.

Microtentacle Actuators Based on Shape Memory Alloy Smart Soft Composite

AbstractRecent advances in miniature robotics have brought promising improvements in performance by leveraging the latest developments in soft materials, new fabrication schemes, and continuum actuation. Such devices can be used for applications that need delicate manipulation such as microsurgery or investigation of small‐scale biological samples. The shape memory effect of certain alloys is one of the promising actuation mechanisms at small scales because of its high work density and simple actuation mechanism. However, for sub‐millimeter devices, it is difficult to achieve complex and large displacement with shape memory alloy actuators because of the limitation in the fabrication process. Herein, a fabrication scheme for miniaturized smart soft composite actuator is proposed by utilizing two‐photon polymerization. The morphing modes are varied by changing the direction of the scaffold lamination. In addition, the actuation is controlled via local resistive heating of a carbon nanotube layer deposited inside of the actuators. The proposed design can generate a 390 µN force and achieve a bending angle up to 80°. Applications of the actuators are demonstrated by grasping small and delicate objects with single and two finger devices.

Finite Element Failure Analysis of GFRP Laminates in Plate-Cone Reticulated Shell

Plate-cone reticulated shell is a new type of spatial structures with good mechanical behavior, technical economy, and architectural appearance. In this paper, using ANSYS software, the strength failure analysis model of composite laminates is established in cooperation with the Strength Criterion of Hoffman. The effects of layer number, laying direction, and thickness of laminates on the ultimate strength of laminates are studied by detailed parametric analysis, which provides a theoretical basis for the design of composite plate-cone reticulated shell and GFRP laminated plates. Some important conclusions are obtained and can be applied to engineering practice.