Transverse Direction Research Articles

Light-weighted quasi-zero stiffness device based on connected inclined beams on a flexible support

QZS isolators are particularly useful for low frequency excitations that are difficult to isolate for traditional isolation techniques. These isolators can be designed based on bistable structure which is very simple and of low weight. However, an external rigid restraint in transverse direction is often required for this kind of isolator which severely limits its application. This paper investigates a light-weighted QZS device that shows the QZS regardless of flexibility of the support. The device is based on inclined beams connected axially in series. Mechanism of the structure to generate the quasi-zero stiffness is discussed. A numerical model is developed for predicting its behavior. A series of tests were conducted to validate behavior of the structure and the numerical model, and a thorough numerical parametric study was performed. Based on the results, QZS isolators were designed and tested which is shown to have light weight and a good loading capacity.

Influence of Column–Base Connections on Seismic Behavior of Single-Story Steel Buildings

This study focuses on assessing the seismic performance of existing single-story steel buildings used as industrial buildings. This research aims to provide a systematic procedure for evaluating the seismic response of a single-story strategic building and properly accounting for the behavior of the column–base joints. Through meticulous data collection, advanced numerical modeling, and pushover analyses, this study highlights the significant impact of column–base joint behavior on the overall seismic performance of industrial buildings. The findings reveal that while single-story steel buildings show a satisfactory seismic performance in terms of lateral resistance and stiffness in the longitudinal direction, deficiencies in the joint design can strongly impact the performance in the transversal direction. This study emphasizes the necessity of incorporating joint flexibility into numerical analyses to accurately assess structural behavior. In conclusion, a precise assessment of the base joints provides insights for informing retrofitting strategies.

2B or not 2B, a study of bottom-quark-philic semi-visible jets

Semi-visible jets arise in strongly interacting dark sectors, resulting in jets overlapping with the missing transverse momentum direction. The implementation of semi-visible jets is done using the Pythia Hidden Valley module to mimic the QCD sector showering in so-called dark shower. In this work, only heavy flavour Standard Model quarks are considered in dark shower, resulting in a much less ambiguous collider signature of semi-visible jets compared to the democratic production of all five quark flavours in dark shower. The constraints from available searches on this signature are presented, and it is shown the signal reconstruction can be improved by using variable-radius jets. Finally a search strategy is suggested.

Allowable stress rating compared to load and resistance factor rating for timber bridges with and without steel-beam retrofit

This paper presents the relevancy of the Allowable Stress Rating (ASR) and the Load and Resistance Factor Rating (LRFR) methods for timber bridges. Benchmark bridges constructed in the 1930′s are upgraded with hollow structural steel (HSS) beams and three-dimensional finite element models provide technical information that is necessary for examining their behavior and rating evaluations. Complying with published manuals, a total of 17 rating vehicles are considered across three categories (Design, Legal, and Permit) so as to generate the maximum responses of the bridges. The position of the vehicles dominates the deflection profiles of the unrepaired bridges. After installing the HSS beams, the live loads are redistributed and stiffness enhancement is noticed in the transverse direction of the bridges. The rating factors calculated with ASR exceed those with LRFR for the unrepaired bridges, regardless of vehicle configurations, and the level of disparity between these rating approaches increases when the bridges are repaired owing to differences in load factors. In terms of sensitivity to average daily truck traffic, the LRFR factors of the bridges under the Legal vehicles are more responsive than the factors subjected to other vehicle types. From a probability perspective, the compatibility of these rating methodologies varies contingent upon vehicle categories and the presence of the HSS beams. Practice guidelines are proposed to facilitate the conversion of rating factors between ASR and LRFR as a function of the present condition of constructed timber bridges.

FEATURES OF THERMAL STABILISATION OF FLAX-CONTAINING “STRETCH” FABRICS

The analysis showed that achieving 15…30 % elasticity requires an input of textured yarns of about 40 %, while the same effect can be achieved by inputting 2…4 % elastane yarns. This makes it possible to produce stretch fabrics consisting of 96…98 % natural fibres. It is shown that the two-winding technology of joining elastane yarns with flax yarns allows the process to be carried out at a speed of at least 200 metres per minute. The article presents a laboratory technique for determining the process parameters for thermal stabilisation of flax-containing stretch fabrics to ensure a given elastic elongation of the fabric in the transverse direction. The possibility of producing stretch fabrics with a natural fibre content of at least 96 % is shown. The modes of fabric heat treatment to obtain elastic elongation from 12 to 36 % are given. The presented technique can be recommended for use in production conditions at the initial stage of industrial technology development.

One-dimensional Carrollian fluids. Part I. Carroll-Galilei duality

Galilean and Carrollian algebras acting on two-dimensional Newton-Cartan and Carrollian manifolds are isomorphic. A consequence of this property is a duality correspondence between one-dimensional Galilean and Carrollian fluids. We describe the dynamics of these systems as they emerge from the relevant limits of Lorentzian hydrodynamics, and explore the advertised duality relationship. This interchanges longitudinal and transverse directions with respect to the flow velocity, and permutes equilibrium and out-of-equilibrium observables, unveiling specific features of Carrollian physics. We investigate the action of local hydrodynamic-frame transformations in the Galilean and Carrollian configurations, i.e. dual Galilean and Carrollian local boosts, and comment on their potential breaking. Emphasis is laid on the additional geometric elements that are necessary to attain complete systems of hydrodynamic equations in Newton-Cartan and Carroll spacetimes. Our analysis is conducted in general Cartan frames as well as in more explicit coordinates, specifically suited to Galilean or Carrollian use.

Unveiling the mechanical anisotropy and related deformation mechanisms of heterostructured Mg alloy laminate with unique texture feature

In this study, a well-bonded AZ31/ZK60/AZ31 sandwich-structured laminate was prepared using extrusion. Microstructural heterogeneities in grain size, precipitate phases, and texture were evident between the constituent layers. Tensile testing revealed significant mechanical anisotropy in the laminates along the extrusion direction (ED), transverse direction (TD), and 45° directions, with the 45° direction samples exhibiting the highest tensile ductility, while ED and TD samples showed similar high strength. In-situ electron backscatter diffraction and slip trace analysis indicated that the heterogeneities in grain size and precipitates had minimal influence on the mechanical anisotropy of the laminates. Instead, texture emerged as the primary influencing factor, as it affected the initiation difficulty of basal slip and extension twinning mechanisms in various directions, thereby influencing the deformation coordination between the successive layers and resulting in varied mechanical responses in different directions.

Effects of transverse loading on the ultimate strength prediction of stiffened panels under biaxial loads: Potential improvements to the IACS rule formulation

The current International Association of Classification Societies (IACS) rule for designing stiffened panels was found in Wang et al. (2024) to conservatively predict the ultimate strength of panels when transverse loads predominate. This conservatism arises from the overestimation of bending moments acting on stiffeners by directly applying the beam analogy in both longitudinal and transverse directions in the rule formulation when evaluating stiffener yielding.To address this issue, this paper applies the orthotropic plate theory to calculate bending moments experienced by the stiffeners of panels under biaxial loads. Orthotropic properties are derived from equivalent sectional areas and moments of inertia. The predicted bending moments are validated through comparisons with numerical simulations. The effects of boundary conditions and deflection patterns with varying numbers of half-waves are discussed. Based on the analytical results, a modification of the IACS rule formulation is proposed by introducing a correction factor to account for transverse loading effects in the bending moment calculations. The factor is a function of the ratio between longitudinal and transverse loading.The modified IACS rule formulation is verified through numerical simulations of aluminium panels using ABAQUS and comparisons with results from existing literature on steel stiffened panels under various biaxial loading conditions. The modified rule formulation shows improved accuracy in predicting the ultimate strength of stiffened panels, particularly in cases with dominating transverse loads. The modified IACS rule formulation can be useful for more reliable and cost-effective design of ships and offshore structures.

Force model based on heterogeneous components decoupling and machining behaviors of ultrasonic grinding continuous fiber-reinforced MMCs

Continuous fiber-reinforced metal matrix composites (CFMMCs), such as SiC fiber-reinforced TC17 matrix composites (SiCf/TC17), are renowned for their exceptional mechanical properties. However, their heterogeneous compositions present significant machining challenges, including fiber pullout, matrix cracking, and accelerated tool wear. Ultrasonic vibration-assisted grinding (UVAG) has proven to be an effective technique for overcoming these challenges. The material removal mechanisms in UVAG, especially in composites with both ductile and brittle phases, remain poorly understood. To explore these issues, UVAG and conventional grinding (CG) experiments were conducted on SiCf/TC17 along two grinding directions: fiber’s transverse direction (FT) and fiber’s longitudinal direction (FL). This paper aims to provide a new dynamic mechanical model and shed light on the complex removal mechanisms in CFMMCs, which are characterized by a near one-to-one alternation of ductile and brittle phases. The findings reveal that UVAG reduces fiber damage and surface roughness compared to CG, especially when grinding along FT. UVAG lowers normal (Fn) and tangential grinding forces (Ft) by 15.3% and 12.3%, respectively. This highlights UVAG’s potential for improving the machinability of complex materials like CFMMCs. The proposed grinding force model closely matches the experimental results. This paper hopes to support the precision abrasive machining of CFMMCs, a kind of complex and highly anisotropic composite material, and promote their application in the fields such as aerospace.

Bio-based epoxidized cardanol sorbate as an interface-localized compatibilizer for enhancing poly(lactic acid) (PLA) and poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) (P34HB) blend

PLA is a bio-based polyester with limited barrier and flexible properties. Adding poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P34HB), a biodegradable polyester known for its outstanding barrier properties, was the strategy employed to boost PLA performance. However, the blend’s immiscibility necessitates compatibilizers to bolster interfacial adhesion and dispersion. This study designed a novel bio-based compatibilizer, epoxidized cardanol sorbate (ECD-SA), to improve the compatibility of the blend. The molecular design of ECD-SA has been optimized to minimize steric hindrance, thereby enhancing interfacial reactions more effectively. Two commercial compatibilizers, specifically ADR 4468 and NC-514, were selected for comparison. Theoretical model was employed to calculate dispersion preferences of three different compatibilizers in the blend. A systematic investigation was carried out to analyze the effects of compatibilizers on the structure and properties of PLA/P34HB blends. The findings suggest that ECD-SA functions as an interface-localized compatibilizer in PLA/P34HB blends, enhancing their compatibility and performance significantly. Specifically, the incorporation of 2 phr (parts per hundred resin) ECD-SA into the PLA/P34HB film resulted in a marked increase in tensile strength from 35.6 MPa and 23.5 MPa to 48.6 MPa and 36 MPa in the longitudinal and transverse directions, respectively, and an increase in elongation at break from 31.9 % and 9.2 % to 104.8 % and 48.3 %, respectively. This underscores its significant potential as a compatibilizer for PLA/P34HB, pointing towards extensive application possibilities in present-day packaging industries.

Flow-induced vibrations of an equilateral triangular prism at subcritical Reynolds number

It has been well known that the shear layers behind a prism at subcritical Reynolds number (Re) remain persistently stable. However, potential response of an elastically mounted non-circular prism at subcritical Re is still open. In this study, we numerically investigate the flow-induced vibrations of an equilateral triangular prism at subcritical laminar flow using the immersed boundary method. The prism is allowed to vibrate only in the transverse direction. It is found that the prism vibration could be excited and sustained at subcritical Re due to the instability triggered by the prism's movability. Within angles of attack α = 0°–60°, the triangular prism experiences three responses: i.e., vortex-induced vibration (VIV) at α = 0°–30°, large-amplitude vibration at α = 37.5°–46.5°, and galloping at α = 47.5°–60°. The characteristics of vibration amplitude, frequency, and dependence of fluid forces on reduced velocity and α are investigated. Eight different wake modes exist behind the prism, i.e., one stable mode, two shear layer modes, and five vortex shedding modes. In the VIV regime, the 2S mode (2 single vortices per vibration cycle) is the only vortex shedding mode, while the vortex shedding mode with more than two vortices is unique in the other two regimes. In the end, we discuss (i) the influences of Re and mass ratio and (ii) prediction of the galloping instability using quasi-steady analysis. It is found that three different response regimes are noticed, although their characteristics are strongly affected by the two factors. Quasi-steady approach could provide a reasonable prediction of the emergence of galloping instability for non-circular prism.

Utilization of functionalized paper-based microfluidic devices for the detection and characterization of starch in milk

We pronounce a quick cost-effective, and one-of-a-kind single-step approach for fabricating paper-based devices by using correction pens instead of expensive materials. The highlighted areas were filled with Deposits from the correction pen and the surroundings were coated with wax, showing that will have a wide range of aqueous resistances. In the transverse direction, favorable natural convection occurs during the process along the axial direction of the fabricated paper channel. Due to its cost-effectiveness, the platform is believed to be ideally suited for chemical sensing and point-of-care applications, as well as diagnostics in resource-limited settings. We show that a lab-on-a-chip method based on paper can be used for colorimetric analysis to identify both qualitative and quantitative changes in milk caused by the presence of starch impurities. The challenges of sample storage, handling, and transport to the laboratory are circumvented by combining detection technology with smartphone imagery that permits on-site data collection. Diagnostic and sensing applications in low-resource settings, such as those seen in developing nations, can now use this technology.

Mechanistic understanding of banded microstructure and its effect on anisotropy of toughness in low carbon-low alloy steel

In this study, the relationship between the anisotropy of toughness and microstructure in low carbon low alloy steel treated by quenching and tempering (QT) heat treatment was investigated with the aid of scanning electron microscope, electron back-scattered diffraction and transmission electron microscope combined with energy disperse spectroscopy techniques. Results show that the impact toughness of the quenched steel plate along the longitudinal and transverse directions are little different. However, after tempering, the longitudinal impact toughness of QT steel plate is improved by 88%, while the transverse impact toughness is slightly decreased, leading to a significant anisotropy of toughness. Microstructural characterizations reveal that banded microstructure with coarse grain size exists along longitudinal direction (i.e., rolling direction) of steel plate, which is attributed to co-segregation of Mn and C and the resulting uneven recrystallization during hot rolling. After tempering, fine and dispersed carbides are precipitated in matrix microstructure, but high-density coarse carbides are formed within banded microstructure. It is suggested that the coarse grains and high-density coarse carbides significantly deteriorate the resistance against crack propagation along banded microstructure, leading to the anisotropy of toughness of QT steel plate. The findings of this study will aid to design metallurgical processes including chemical composition design, hot rolling, and heat treatments to eliminate the anisotropy of toughness of low alloy steels with high strength and toughness.

3D-printed Bio-inspired porous electrode by bidirectional enhancement strategy with high mass loading and enhanced energy density for supercapacitors

The effective strategy for increasing areal capacity involves the use of 3D printed thick-electrode with high mass loading. However, thick-electrode still encounters challenges such as incomplete electrolyte penetration and slow ion transport. Here, we successfully prepared lignocellulosic nanofibrils (LCNFs) from abundant bamboo biomass and developed functional ink composed of LCNFs/ carbon nanotubes (CNTs) / polyaniline (PANI) / polyvinyl alcohol (PVA) for printing. An innovative 3D printing bidirectional enhancement strategy was proposed to increase the mass loading of active materials in the vertical direction and construct ion transport channels in the transverse direction. The biomimetic porous N-doped electrode obtained after annealing treatment exhibits a more continuous conductive network, larger surface area, higher utilization of active materials, and smoother ion transport pathways compared to thick-electrode. Therefore, the Triangles biomimetic electrode exhibits an enhanced areal/specific capacitance compared to thick-electrode, reaching 5.30F·cm−2 (184.03F·g−1) and 4.40F·cm−2 (122.22F·g−1) at 2 mA·cm−2, respectively. The symmetric device demonstrates an areal capacitance of 1.34F·cm−2 at 1 mA·cm−2 and achieves an energy density of 0.186 mWh·cm−2 at a power density of 0.49 mW·cm−2. The work provides valuable insights into the design of electrode structures for high-performance supercapacitors.

Dynamic model decomposition study on the influence of cutback surface length on the wake characteristics of turbine blades

Abstract The flow within a cascade of pressure-side cutback cooling blades with different cutback surface lengths is predicted using the unsteady numerical method. Dynamic Mode Decomposition (DMD) is used for flow field order reduction analysis. The relationship between varying cutback surface lengths and the wake dynamics is analyzed. The analysis shows that the shear layer behind the trailing edge and lip dominates the unsteady flow in the wake region. As the cutback surface length diminishes, an increase in the modal frequencies of both the lip shear layer and the wake shear layer is observed. As the cutback surface length is shortened, the shear layer behind the lip causes stronger oscillations in the shear layer behind the trailing edge, subsequently leading to an augmentation in the amplitude width of the wake mode across the transverse direction.

Non-destructive ultrasonic measurement of residual stress in metallic materials

<p>The relationship between the applied stress σ, and the measured shear wave birefringence <b>B</b> was measured in the laboratory for several low alloy steel. The birefringence response was measured with a dual polarization electromagnetic transducer comparing the time of flight for the two polarizations, in the rolling direction and the transverse direction. This stress-birefringence relationship showed a linear dependence and can be described with the relation σ = <b>K</b> * <b>B</b> + σ<sub>0</sub>. The slope of this relationship when applying a tensile stress in the transverse direction of the sample, <b>K</b>, was measured to − 1280 MPa/<b>B</b>(%) and was independent of material chemistry, whereas the position/offset of the curves, i.e., σ<sub>0</sub> , varied in between steel grades, assumed to be due to microstructural texture. A non-contact EMAT probe has been installed in a levelling mill at SSAB Special Steel in Oxelösund, Sweden, to measure the residual stress dependence on the levelling process, in daily production of steel plates. The EMAT probe has been provided by Nordinkraft AG, Remchingen, Germany. This single EMAT probe has been applied along the centerline of plates. Measurements have been made on more than 2000 plates. The responsive or reactive residual stress was successfully measured and calculated for all plates using the above stress-birefringence relationship, showing typical residual stress difference values on the production plates after levelling in the range of less than ± 100 MPa.

DIAGNOSIS IN CHILDREN WITH AN OPEN BITE

Recently, the city of Samarkand has implemented a set of measures aimed at improving, diagnosing and treating vertical anomalies, namely open bite, and at the moment many scientists and practitioners have begun to study more deeply the factors leading to the development of this anomaly. In clinical practice, etiological factors, endogenous and exogenous factors, as well as the living conditions of this patient, taking into account the age of the patient, are of particular importance. We carried out preventive measures for children aged 6 to 15 in 37 patients with an open bite.[1,2] Taking into account all aspects of this anomaly, we set ourselves the task of diagnosing patients with open occlusion using modern methods, taking into account their age and type of anomaly. open bite is considered as an independent form of dental anomalies, and can be combined with other disorders in the transversal or sagittal direction.[3] According to the literature, an open bite occurs in 62% of cases together with the mesial ratio of dentition An open bite is a serious anomaly of the maxillary system. According to the results of a survey and observation by Nigmatova R.N., Shaamukhamedov F.A., Nigmatova I.M. (2017), open bite was 1.4% among children aged 3-6 years. According to L.P. Grigoriev (1995), 1.12% in children aged 7-16 years. 2.7% in the distribution of anomalies of the maxillary system.[5,6]. However, a number of researchers claim that by the age of 9-10, the frequency of open bite decreases, which is associated with the elimination of bad habits that contribute to the development of the anomaly, as well as with the normalization of respiratory and swallowing functions. In later adolescence, there may be a repeated increase in the prevalence of open bite due to late bone growth in the facial region of the skull [4].

Ultrafast laser-enabled optoacoustic characterization of Three-dimensional, nanoscopic interior features of microchips

The recent advances in micromanufacturing have been pushing boundaries of the new generation of semiconductor devices, which, in the meantime, brings new challenges in the material and structural characterization – a key step to ensure the device quality through the micromanufacturing process. An ultrafast laser-enable optoacoustic characterization methodology is developed, targeting in situ calibration and delineation of the three-dimensional (3-D), nanoscopic interior features of opaque semiconductor chips. With the guidance of ultrafast electron–phonon coupling effect and velocity-perturbated optical interference, a femtosecond-laser pump–probe set-up based on Sagnac interferometer is configured to generate and acquire picosecond ultrasonic bulk waves (P-UBWs) traversing the microchips. The interior features of the microchips shift the phase of acquired P-UBW signals, reflected in the perturbed probe laser beam. The phase shifts are calibrated to compute signal correlation of P-UBW signals between different acquiring positions, whereby to delineate the interior features in an intuitive manner. The approach is experimentally validated by characterizing nanoscopic, invisible interior aurum(Au)-gratings with periodically varied depths in typical microchips. Results highlight that the 3-D nanoscopic features of the microchips can be revealed with a microscopic and a nanoscopic spatial resolution, respectively along the transverse and depth directions of the chip, where the Au-gratings become “visible” with a depth variance of a few tens of nanometers only. This proposed approach has provided a fast, nondestructive approach to “see” through an opaque microchip with a nanoscopic resolution.

Analytical assessment of suspension bridge's 3D curved cable configuration and cable clamp pre-installation angle considering the main cable torsional and flexural stiffnesses

For a suspension bridge with a spatial cable system, the 3D curved main cable undergoes large lateral and torsional deformations during construction, which increases the difficulty of construction control. If using the traditional ideal flexible cable assumption, the torsional deformation cannot be analyzed. Therefore, incorporating the main cable's torsional and flexural stiffnesses in shape-finding analysis remains highly challenging. This study develops an analytical method for determining the target configuration of the main cable by applying the multi-segment catenary method and the Cosserat rod model. The closed-form solution of the geometrically exact force-displacement-strain relationships is derived, comprehensively considering the tension, shear, bending, and torsion of the main cable, as well as the initial curvatures and axial strains in the reference configuration. Then a two-layer shape-finding framework is established, with the first layer being recursive calculations of the cable shape and the second layer being numerical calculations of the nonlinear governing equations using the Levenberg-Marquardt method. Furthermore, a novel method for calculating the pre-deflection angle of the cable clamp in the free cable state is presented for the first time. A classic cantilever model and a suspension bridge with the spatial main cable are studied to investigate the accuracy of the proposed algorithms. Numerical results indicate that when the spatial main cable is twisted, the bottom edge of the cable cross-section moves outward along the transverse direction of the bridge. The torsion of the main cable includes both elastic deformation and rigid body displacement caused by the bidirectional bending effect. At the mid-span, the torsional angle of the main cable cross-section is 10.088°, and the pre-deflection angle of the cable clamp at the mid-span should be set to 10.851°. Moreover, the target configuration is highly sensitive to the flexural and torsional stiffnesses of the main cable while the effect of shear deformations on cable configurations can be ignored.

Semiclassical transport in two-dimensional Dirac materials with spatially variable tilt

We use Boltzmann theory to study the semi-classical dynamics of electrons in a two-dimensional (2D) tilted Dirac material in which the tilt varies in space. The spatial variation of the tilt parameter induces a non-trivial spacetime geometry on the background of which the electrons roam about. As the first manifestation of graivto-electric phenomena, we find a geometric planar Hall effect according to which a current flows in a direction transverse to the chemical potential gradient and is proportional to gxy component of the emergent spacetime structure. The longitudinal conductivity contains information about the gravitational red-shift factors. Furthermore, in the absence of externally applied electric field there can be “free-fall” or zero-bias currents that can be used as detectors of terahertz radiation.