Shape Fabrics Research Articles

Deep learning-based analysis of true triaxial DEM simulations: Role of fabric and particle aspect ratio

This study investigates the influence of micro-scale entities such as inherent and induced fabric anisotropy on the stress–strain behaviour of granular assemblies. In tandem with this exploration, our objective is to formulate a novel correlation that quantifies the evolution of fabric tensor across diverse loading paths. This correlation can be introduced to enhance the micro-mechanical insights in conventional constitutive models. Employing the Discrete Element Method (DEM), we simulate the drained and undrained responses of 680 transversely isotropic particulate assemblies with diverse initial fabrics and particle Aspect Ratio (AR) under true triaxial loading conditions. We consider a second-order fabric tensor based on inter-particle contact orientations to trace fabric evolution during loading. To account for fluid–solid interaction under undrained conditions, we adopted the DEM-Coupled Fluid Method (CFM). The simulation results highlight the significant influence of the Lode angle, particle shape and initial fabric on the stress–strain behaviour of granular materials, with fabric evolution primarily affected by the stress state, void ratio and particle AR. Lastly, we propose a new correlation for the quantification of the fabric tensor using a multi-layer feed-forward neural network. The satisfactory performance of the suggested correlation is demonstrated through a comparison between DEM data and predicted fabric tensor values.

X-ray tomography applied to tsunami deposits: Optimized image processing and quantitative analysis of particle size, particle shape, and sedimentary fabric in 3D

The analysis of particle size, shape, size, and their spatial arrangement (i.e. fabric) in a sedimentary deposit plays a significant role in their interpretation in terms of transport mechanism, flow conditions, and sediment source. The present work focuses on the use of X-ray computed tomography (X-CT) to analyze tsunami deposits (core samples), as examples of complex sedimentary assemblages. A workflow of image processing is proposed to measure 3D parameters of particle size, shape, and orientation using two different software packages (Fiji-ImageJ, and IPSDK) and two different methods of image segmentation. The semi-automated method provides better segmentation quality of the tsunami deposit, as compared with the poor performance of fully-automated image segmentation. We also provide some clues to reduce the computational time. This workflow is applied to two examples of tsunami deposits on the coasts of the Algarve (1755 Lisbon tsunami, southern Portugal). Optimized processing of X-CT images gives access to detailed vertical variations of grain size, grain shape, and componentry (clayey matrix, silicates, and carbonates, including marine bioclasts), as well as information on flow directions inferred from the sedimentary fabric in 3D. High-resolution analysis of the bedforms and vertical grain size grading allows determining the flow conditions during the inundation phase of the tsunami.

A three-dimensional constitutive equation for shape memory polymer composites considering energy dissipation under single loading–unloading condition

Shape memory polymer composites (SMPCs), composed of shape memory polymers (SMPs) and fabrics, can recover their deformed shapes to initial configurations by changing temperature. The shape recovery energy of the SMPs and the elastic energy of the fabrics are regarded as key points to predict the restored configuration of the SMPCs. In this research, a three-dimensional constitutive equation for SMPCs is newly developed, considering the energy dissipation of fabrics under a single loading–unloading condition. The constitutive equation is derived from Mooney–Rivlin, viscoelastic, and stored strain energy models for SMPs, as well as polynomial functions for fabrics. The Mooney–Rivlin and viscoelastic models describe the time- and temperature-dependent hyperelastic properties, and the stored strain energy model can explain the shape recovery. The polynomial functions are newly proposed to take into account the dissipated energy of fabrics, such as residual deformation and hysteresis effect. Because the elastic energy of fabrics considerably influences the shape recovery of SMPCs, the proposed constitutive equation can accurately predict the recovered configuration. Analyses of SMPCs are conducted using the finite element method and validated by comparing them with the results obtained from experiments. The constitutive equation is used to analyze the shape recovery behaviors of an SMPC skin. The skin can be largely stretched, and the deformed shape can be restored to its initial shape by applying electricity. The SMPC skin is applied to a morphing flap, and its shape-changing behaviors are demonstrated experimentally.

Opposite Shear Sense from Quartz Shape and Crystallographic Preferred Orientation – a Dichotomy and Its Implications for Kinematic Analysis

ABSTRACT The present paper is written to bring to light a dichotomy that is noted in a naturally deformed rock, where the sense of shear inferred from quartz shape preferred orientation (SPO) is opposite to that deciphered from the crystallographic preferred orientation (CPO). Microstructural and quartz CPO data (obtained through SEM-EBSD analysis) from a quartz vein hosted in sinistrally sheared mylonitized granite of Gadwal region (Dharwar Craton) are presented. The vein thin section is prepared parallel to the kinematic reference frame (XZ section of the strain ellipsoid) using field-based information, which allows determination of sense of shear using microstructures. Three domains viz. Domain-I, II and III are identified in the rock thin section with grain size being 300-180 µm, 70-35 µm, and <20 µm, respectively. Of these, quartz grains of Domain-II show a well-defined quartz oblique grain shape fabric, which is indicative of dextral sense of shear. However, quartz CPO from the same Domain-II, as well as Domains-I and III, consistently shows a sinistral sense of shear; the latter complements the kinematics noted from the host rock mylonite. The dichotomy noted from Domain-II indicates that there maybe pitfalls in direct interpretation of kinematics based exclusively on quartz SPO analysis. Hence, caution must be exercised while extrapolating microscale kinematics based on quartz SPO to the regional scale.

The structural analysis of Kunya‐Urgench chondrite: The nondestructive neutron studies

AbstractWe present the results of neutron methods, specifically neutron diffraction and neutron tomography, in studying the structural organization of a Kunya‐Urgench chondrite fragment. The major phases of the meteorite fragment and variation of the phase content across the studied volume were revealed using neutron diffraction. The 3‐D model of the spatial distribution of metal and silicate phases inside the meteorite volume was obtained using neutron tomography. The distributions of volumes, average sizes, and shape‐related parameters of kamacite and silicate phases were analyzed. Shape preferred orientations of the kamacite particles were observed and the origins of shape fabric of these particles were discussed.

Coupling of a water permeability function with a bounding surface hydromechanical model for unsaturated soils

This paper presents a water permeability function that predicts the hydraulic conductivity of deformable and unsaturated soils as the product of two interacting terms. The former term accounts for the effect of the degree of saturation, suction, particle size distribution, particle shape and soil fabric on the water permeability at a given void ratio. The latter term describes instead the influence of the void ratio on the saturated permeability. Overall, the resulting water permeability function is dependent on five model parameters: two parameters can be estimated from permeability tests on saturated soils, another parameter is dependent on the particle size distribution of the soil while the remaining two require unsaturated testing. The proposed water permeability function has then been coupled with the bounding surface hydromechanical model proposed by Bruno and Gallipoli (2019). The coupled model was then validated against three sets of experimental data published in literature. Results show the good capability of the coupled constitutive framework to capture the variation of water permeability of soils with different granularities ranging from clay to sand. Finally, the proposed coupled model can be implemented into a Finite Element code to study coupled flow-deformation problems in geotechnical and geo-environmental engineering.

Grain Fabric Heterogeneity in Strained Shales: Insights From XCT Measurements

AbstractUnderstanding the fabric of rigid grains in strained shales is essential for predicting transport or mechanical properties. Fabric analysis of rigid grains is also key to infer deformation mechanisms in fine‐grained materials. In this study, we investigate the quartz shape fabric of two millimeter‐sized drill cores of tectonically deformed shales by means of X‐ray microtomography. The samples originate from the Jaca basin (Spain) and present a slaty cleavage perpendicular to the bedding. The representativeness of fabric data and heterogeneities are characterized at the microscale and compared with published magnetic fabric data. We extract both the individual grain data and the bulk data in sub‐volumes of increasing dimensions, and focus on identifiers, such as feature size, anisotropy, and shape. In the second step, the spatial heterogeneity of the matrix is assessed. We show that the bulk quartz fabric of a single millimeter‐sized sample is consistent with the magnetic fabric obtained based on a large number of centimeter‐sized samples. Yet, the individual grain analysis demonstrates that this bulk fabric hides a competition between two planar fabrics (bedding and cleavage), where both act differently depending on the grain size and morphology. Inter‐sample comparison reveals the existence of a petrofabric with a characteristic length that exceeds the sample size. These insights are directly applicable to the study of the bulk fabric at a larger scale. In this way, X‐ray microtomography complements petrophysical measurements in shales and helps to avoid misinterpretation of the rock fabric based on bulk measurements.

Unravelling the evolution of regional-scale shear zones with the aid of microstructures and textural analysis: an example from the central Himalaya

Microstructure and texture data on the Main Central Thrust zone (MCTz) in central Himalaya, on two nearly N-S oriented valleys in the Manaslu range (Western Nepal), are provided. Kinematic indicators at the meso and microscale support a south-directed flow. From south to north, greenschist facies paragneiss in the garnet-zone pass to amphibolite facies rocks in the kyanite-zone, suggesting an up-section metamorphic temperature increase. Combining microstructures and data from two different texture analysers (X-ray Texture goniometry and crystal-fabric microanalyzer) allowed to link the temperature path (from 460°C to 600°C up-section) and kinematic vorticity estimates. The “orientation of oblique grain shape fabrics” method was applied, pointing out a general shear flow (40-56% of pure shear) at the MCTz top. Results are in line with a “decelerating strain-path” model, as relatively high simple shear components are recorded at deeper structural levels. This work highlights that the combination of X-ray texture goniometry and crystal-fabric microanalyzer techniques is a good strategy to ensure quartz full-fabric.

Decrypting Magnetic Fabrics (AMS, AARM, AIRM) Through the Analysis of Mineral Shape Fabrics and Distribution Anisotropy

AbstractAnisotropy of magnetic susceptibility (AMS) and anisotropy of magnetic remanence (AARM and AIRM) are efficient and versatile techniques to indirectly determine rock fabrics. Yet, deciphering the source of a magnetic fabric remains a crucial and challenging step, notably in the presence of ferrimagnetic phases. Here we use X‐ray micro‐computed tomography to directly compare mineral shape‐preferred orientation and spatial distribution fabrics to AMS, AARM and AIRM fabrics from five hypabyssal trachyandesite samples. Magnetite grains in the trachyandesite are euhedral with a mean aspect ratio of 1.44 (0.24 s.d., long/short axis), and >50% of the magnetite grains occur in clusters, and they are therefore prone to interact magnetically. Amphibole grains are prolate with magnetite in breakdown rims. We identified three components of the petrofabric that influence the AMS of the analyzed samples: The magnetite and the amphibole shape fabrics and the magnetite distribution anisotropy. Depending on their relative strength, orientation and shape, these three components interfere either constructively or destructively to produce the AMS fabric. If the three components are coaxial, the result is a relatively strongly anisotropic AMS fabric (P' = 1.079). If shape fabrics and/or magnetite distribution anisotropy are non‐coaxial, the resulting AMS is weakly anisotropic (P' = 1.012). This study thus reports quantitative petrofabric data that show the effect of magnetite distribution anisotropy on magnetic fabrics in igneous rocks, which has so far only been predicted by experimental and theoretical models. Our results have first‐order implications for the interpretation of petrofabrics using magnetic methods.

Crystallographic preferred orientation, seismic velocity and anisotropy in roofing slates

Mica-rich rocks (shales, slates, schists) are a major and significant component of the continental crust. They are often characterized by a strong seismic anisotropy, a key factor in the seismic interpretation of the architecture of the continental crust. Roofing slates are a group of natural rocks used in construction that must possess a continuous and undeformed slaty cleavage. This makes roofing slates an exceptional benchmark to study the relation between the rock microstructure and the development of seismic anisotropy in single-foliated low-grade slates. Direct measurements of seismic velocities using an ultrasonic wavemeter at room conditions were done on eight cubic samples from active quarries in the NW Iberian Peninsula. Seismic velocities were also calculated using the Hill averaging method from crystallographic preferred orientation (CPO) maps of slate-forming minerals on the same sample blocks using electron backscatter diffraction (EBSD), achieving unprecedented coverages of up to 87%. The seismic velocities estimated by both methods are similar parallel to the slaty cleavage but much slower using direct measures in the axial direction, producing anisotropies for Vp and Vs1 up to 7 and 5 times higher than the calculated velocities. The results are indicative of the highly anisotropic contribution that cracks, pores and fractures have in single-foliated slates, given the strong shape fabric that the rocks present. The samples selected also show that not all slates exhibit near-transverse isotropy, as it has been commonly assumed.

Country of manufacture in garment marketability by Japanese and Chinese experts

Purpose The authors compared garments made in Poland, Japan and China to investigate the effect of country of manufacture (COM) on garment marketability by Japanese and Chinese experts. The purpose of this paper is to investigate the differences between the Japanese and Chinese experts. Design/methodology/approach The authors compared ten jackets and ten skirts manufactured by four factories in Poland, Japan and China and one Japanese sample maker using five different textiles. The authors provided the same specifications and sample pattern to each of the garment makers. The garment’s marketability was evaluated by 16 Japanese and 18 Chinese experts using a questionnaire survey, considering garment shape, silhouette, face fabric, sub-materials, anticipated appeal to consumers, sewing and ironing skills, and estimated selling price. Findings There were high correlations between the Japanese experts’ estimated selling price and evaluation scores in relation to shape, silhouette and face fabric. There were high correlations between the Chinese experts’ estimated selling price and evaluation scores in relation to all items except for face fabric and buttons. However, there were no significant differences between manufacturing countries. Therefore, the garment quality was not dependent on COM because the manufacturing skills of all selected factories were adequate. Originality/value This study experimentally investigated the effect of COM on garment marketability by evaluating garments manufactured in Japan, China and Poland using the same pattern and specification sheet. Moreover, these results show differences between the Japanese and Chinese experts for the COM effect.

Crystal clustering in magmas: Insights from HP–HT experiments

We have studied by high-resolution X-ray Computed Tomography the effect of crystal clustering on the Shape-Preferred Orientation (SPO) development in synthetic magmas experimentally deformed at 300 MPa and 475–550°C. A fully connected solid network that could potentially induce the onset of yield strength is not achieved in these suspensions containing 16 vol% of crystals. The alumina grain population exhibits a glomeroporphyritic texture made of isolated grains (59.6%) and clusters of touching grains (40.4%). The SPO of the sub-population of isolated grains exhibits foliation and lineation, which are closely parallel to the plane and direction of shear, respectively. The SPO of clustered grains has little influence overall shape fabric. The angular relationships between the average foliation and cluster elongation provide a good indicator of the shear sense. Finally, we highlight the strain partitioning between nearly non-deformed large clusters acting as rigid glomerocrysts and highly sheared zones in low concentrated suspensions.

First investigation of quartz and calcite shape fabrics in strained shales by means of X-ray tomography

We document the evolution of the 3D fabric of shale along a km-long strain gradient in the Jaca basin (Southern Pyrenees, Spain). With respect to the distance from a thrust, samples were collected in the cleavage-free domain, at the onset of the pencil-cleavage domain, within the pencil-cleavage domain and within the slaty-cleavage domain. By combining high resolution X-ray computed tomography (XCT) and energy dispersive X-ray spectroscopy (EDS), the morphology and the Shape Preferred Orientation (SPO) of thousands of quartz grains, calcite grains and pores was studied. In the least deformed samples, quartz and calcite display mean foliation parallel to bedding with comparable dispersion. In the pencil-cleavage domain, quartz foliation still follows the bedding while calcite foliation is mostly governed by cleavage. In the slaty-cleavage domain, calcite shows a much better organization, with foliation parallel to cleavage, mimicking closely the pore fabric. By contrast, the quartz shape fabric is much less defined, scattered between bedding and cleavage planes. This suggests that quartz grain act as rigid marker in the ductile matrix, while calcite grain orientation is governed by dissolution-precipitation processes.

Establishment of Correlation between Anisotropy of Magnetic Susceptibility and Magma Flow Fabric:An Insight from Nandurbar–Dhule Dyke Swarm of Deccan Volcanic Province

There are rising concerns about the robustness of interpretation from Anisotropy of Magnetic Susceptibility (AMS) studies, because often correlation between AMS and geological fabric is not properly established before a wide regional- scale interpretation is made. Here, we document case studies on two dykes from the Nandurbar–Dhule dyke swarm (western India) of Deccan Volcanic Province (Figure 1 a), where we have tested if shape-preferred orientation of the elongated mineral grains (flow fabric) is actually represented by AMS fabric. In one of the dykes, we observed that AMS fabric is coplanar with the fabric of major constituent silicate minerals; hence it represents magma flow fabric. In the other dyke, AMS fabric largely represents the shape fabric of the opaque minerals which were deposited in the interstitial spaces of the mineral grains after the dyke was emplaced; hence it does not correspond to the primary magma flow fabric. These findings reinforce the need for detailed understanding of rock fabric in order to make robust interpretation of AMS data.

Novel Weaving Technology for the Manufacture of 2D Net Shape Fabrics for Cost Effective Textile Reinforced Composites

Abstract Despite significant weight and performance advantages over metal parts, today’s demand for fiber-reinforced polymer composites (FRPC) has been limited mainly by their huge manufacturing cost. The combination of dry textile preforms and low-cost consolidation processes such as resin transfer molding (RTM) has been appointed as a promising approach to low-cost FRPC manufacture. This paper presents an advanced weaving technique developed with the aim to establish a more cost-effective system for the manufacture of dry textile preforms for FRPC. 2D woven fabrics with integrated net shape selvedge can be obtained using the open reed weave (ORW) technology, enabling the manufacture of 2D cut patterns with firm edge, so that oversize cutting and hand trimming after molding are no longer required. The introduction of 2D woven fabrics with net shape selvedge helps to reduce material waste, cycle time and preform manufacturing cost significantly. Furthermore, higher grade of automation in preform fabrication can be achieved.

Pluton construction and deformation in the Sveconorwegian crust of SW Norway: Magnetic fabric and U-Pb geochronology of the Kleivan and Sjelset granitic complexes

The Kleivan and Sjelset granitic complexes are two composite plutons, containing both orthopyroxene and biotite (± hornblende) facies, emplaced in the Sveconorwegian (Grenvillian) high-grade basement of SW Norway. A structural study of these two plutons, based on the anisotropy of magnetic susceptibility (AMS) technique and combined with high-precision U-Th-Pb zircon dating, is presented here. Geochronological data demonstrate a rapid emplacement of successive magmatic pulses in the Kleivan complex (from 936.94 ± 0.42 Ma to 935.62 ± 0.67 Ma) and, on the contrary, a non-negligible rest period (∼3.2 Ma) in the construction of the Sjelset complex that was formed by two pulses emplaced, respectively, at 935.67 ± 0.37 Ma and 932.43 ± 0.75 Ma. Locally discordant magnetic fabrics in the latter pluton confirm this rather protracted construction time. Thermomagnetic and hysteresis measurements supporting the AMS data indicate a magnetic mineralogy dominated by a multidomain, Ti-poor titanomagnetite, except in samples having a very low magnetic susceptibility. The susceptibility magnitudes, paramagnetic to ferromagnetic in agreement with the rock magnetic data, rely on the petrographic rock-types and on the alteration degree. Image analysis confirms that the magnetic fabric is usually coaxial with the shape fabric in both complexes, supporting the use of AMS as a proxy for the petrofabric orientation. Combined with micro- and macrostructural data, the magnetic fabric demonstrates that the Kleivan and Sjelset granitic complexes have their internal fabrics largely dominated by tectonic strain. Models of synfolding emplacement coeval with the last stage of Sveconorwegian contraction recorded in the area are proposed for the two plutons.

Kinematic analysis of rock flow and deformation temperature of the Sirjan thrust sheet, Zagros Orogen, Iran

AbstractMicrostructural, finite strain and vorticity analyses of quartz-rich mylonites were used in order to investigate kinematics of rock flow and deformation temperature in the Sirjan thrust sheet exposed in a structural window within the Sanandaj–Sirjan High Pressure – Low Temperature (HP–LT) metamorphic belt that forms part of the hinterland of the Zagros orogenic belt of Iran. A dominant top-to-the-SW sense of shear in the study area is indicated by several shear sense indicators such as asymmetric boudins, rotated porphyroclasts, mica fish and S/C fabrics. Quantitative analyses reveal approximately plane strain deformation conditions with Rxz values ranging from 2.5 to 4.3 and increasing towards the Sirjan thrust. Opening angles of quartz c-axis fabrics and recrystallization regimes suggest deformation temperatures vary from 430 to 625 ± 50°C in the hanging wall rocks. Oblique grain shape and quartz c-axis fabrics were used to estimate the degree of non-coaxiality during deformation. The obtained vorticity profile indicates a down-section increase in kinematic vorticity number (Wm) from 0.6 to 0.89. This range of vorticity numbers confirms contributions of both simple (41–68 %) and pure shear (32–59 %) deformation components. The structural characteristics of the study area ultimately were controlled by oblique motion of the Afro-Arabian plate relative to the Iranian plate.

A Comparative Analysis of Orientation on the Shape Memory Effect of Fabric Reinforced Shape Memory Polymer Composites

Shape memory polymer composites (SMPC) are a new kind of smart materials where many researches have been carried out. In SMPC, shape memory polymers serves as a matrix material and particles or fibers act as reinforcements. As structural applications demand structures to withstand load and stiffness, particles reinforced SMPC does not serve for it. Therefore fiber/fabric reinforced SMPC used widely for such applications. SMPC’S changes its shape during a typical thermo-mechanical cycle and retracts to its original shape upon external stimulus (temperature). Molecular mechanism is the driving force of these SMP’s. SMP consists of 1.molecular switches and 2. netpoints. This project deals with Epoxy shape memory resin (Matrix material) and fabrics such as Glass, Kevlar and Carbon (Reinforcements).A Comparative analysis was carried out to find which combination gives the best results by bend test. Different orientations were tried for bidirectional fabrics such as (0/90)3, (0/45)3, ((0/90)/(±45)/(0/90)) specimens. Finally it was concluded that Carbon fabric which has the orientation of (0/90/±45/0/90) gives better shape memory performance.

Exploring the geological features and processes that control the shape and internal fabrics of late diagenetic dolomite bodies (Lower Khuff equivalent – Central Oman Mountains)

The Lower Permian carbonate rock succession of the Oman Mountains represents a stratigraphical surface analogue for Middle Eastern Lower Khuff hydrocarbon reservoirs. The characteristics of the carbonate rocks are highly variable both laterally and vertically due to the superposition of several episodes of dolomitization. A stratabound early dolomitization event affected the well-bedded limestones during Triassic times. Subsequently, a later burial dolomitization led to the emplacement of several hundreds of meter wide and tens of meter thick dolomite bodies. The goal of our study is to understand the distribution and genetic controls on the formation of late diagenetic dolomite bodies.Field mapping in Wordian to Capitanian beds was conducted in the Jebal Akhdar tectonic window in the Central Oman Mountains to determine the shape, internal fabrics and associated structures of late diagenetic dolomite bodies. The longest extension of late diagenetic dolomite bodies was found to follow predominantly the strike direction of fracture planes, bed-to-bed contacts, the Precambrian–Permian unconformity and the bottom rim of early diagenetic dolomite. Two groups of diagenetic fabrics were observed in association to fractures and bedding planes. First, vug related fabrics comprise vuggy pores and zebra dolomite. Second, breccia related fabrics consist of either small-scale crackle/mosaic breccia fabrics and centimeter sized vugs followed by bedding-parallel vugs lined up. Petrographic analysis revealed three types of diagenetic phases referred to as D1, D2 and D3. The matrix replacive phase D1 represents the main diagenetic phase formed during burial. Coarse crystalline dolomite rhombs (phase D2) and saddle dolomite (phase D3) were found along stylolites, in vugs and in fractures. Based on the presence of saddle dolomite and zebra dolomite textures, late diagenetic dolomite bodies are interpreted to have formed by the circulation of warm dolomitizing fluids of at least 60 °C.

Shape fabric development in rigid clast populations under pure shear: The influence of no-slip versus slip boundary conditions

Shape fabrics of elliptical objects in rocks are usually assumed to develop by passive behavior of inclusions with respect to the surrounding material leading to shape-based strain analysis methods belonging to the Rf/ϕ family. A probability density function is derived for the orientational characteristics of populations of rigid ellipses deforming in a pure shear 2D deformation with both no-slip and slip boundary conditions. Using maximum likelihood a numerical method is developed for estimating finite strain in natural populations deforming for both mechanisms. Application to a natural example indicates the importance of the slip mechanism in explaining clast shape fabrics in deformed sediments.