Cross-sectional Shape Research Articles

Study of Corrsion System on Iron Artefacts through Neutronic Analysis

This study was conducted to confirm the possibility of using the corrosion products of iron artifacts and corrosion systems for non-destructive analysis using neutrons by applying the non-destructive analysis method and the destructive analysis method together to the analysis of the corrosion system of iron artifacts. As a result of transmission analysis, the shape of the artifact, the boundary between the metal layer and the corrosion layer, etc. could be confirmed, and through tomography, the shape, surface shape, and internal cross section of the artifact could be confirmed. It was confirmed that the corrosion thickness using the residual stress measurement method has a high reliability of less than 10% of an error compared to other analysis results, so it is highly likely to be used to measure the corrosion thickness. It was confirmed that the corrosion layer of the iron artifact analyzed this time was mainly Goethite among the types of DPL and was embedded with Magnetite/Maghemite. Since the neutron analysis can estimate the corrosion thickness non-destructive, it is highly likely to be used to study the corrosion rate of iron artifacts by burial environment through additional studies.

Characteristics of Straight Trapezoidal Cross-Sectional Fins under Unsteady Conditions

The aim of this research is to understand the characteristics of fins with a trapezoidal cross-section. The shape of the fin's cross-section is one of the influential factors affecting fin characteristics. In the design of fins, it is crucial to comprehend the characteristics of the fin as they relate to temperature distribution, heat transfer rate, and the efficiency of the fin. The research was conducted using numerical computation with an explicit finite difference method. Variations were made in the length of side 3 of the trapezium to 0 m, 0.02 m, and 0.04 m. The research results indicate that increasing the width of the fin enhances the temperature distribution, flow rate, and efficiency achievable by the fin. Significant improvement occurred when varying the side length from 0 m to 0.02 m, whereas subsequent variations did not considerably alter the efficiency. The highest efficiency achieved was 0.90 when the length of side 3 was 4 cm at the 300 seconds.

Collision Study on New Aluminum Alloy W-Beam Guardrail

Highway guardrails are safety installations set along the sides or center of roads to prevent vehicles from veering off the roadway, thereby protecting pedestrians and vehicles. However, traditional W-beam guardrails have issues such as poor energy absorption, susceptibility to rust, short lifespan, and a high risk of vehicles running off the road during severe collisions. Therefore, this study employs the partial differential equations of the vertical motion of beams to investigate the relationship between the deformation of wave beams and their moment of inertia. The cross-sectional shape of traditional W-beam guardrails was optimized accordingly. Combining this with the high ductility of aluminum alloy Al 6061-T6, a new aluminum alloy W-beam guardrail was proposed. Finite element simulation models of traditional steel guardrails, new steel guardrails, and the new aluminum alloy guardrail were established to evaluate the performance of the three types of guardrails. The results show that the deformation of the wave beam is inversely proportional to the square root of its moment of inertia. Compared to traditional W-beam guardrails, the moment of inertia of the new guardrail’s cross-section increased by 28.6%. In finite element collision simulations, the new guardrail reduced deformation by 12.8%, lowered the risk of vehicles running off the road, and improved safety performance.

Determination of longitudinal stability of strip in rolling cage – non-drive dividing device system

In modern industrial and civil construction, various rolled metal products are used in greater volumes. The largest share of them is occupied by rebar profiles produced at small-grade mills. The ever-growing demand for rebar rolling requires an increase in production volumes. The most promising technology in this regard is rolling – separation, which, with relatively low material costs, allows operating rolling mills to significantly increase the production volume of rebar profiles while reducing energy consumption. However, despite the obvious advantages of rolling – separation technology using non-drive dividing devices, it is very difficult to correctly determine the rational modes of conducting the process taking into account the peculiarities of production and equipment layout, which is due to insufficient theoretical knowledge. One of the main problems is determination of the permissible distance in the rolling cage – non-drive dividing device system. The conducted studies allowed us to propose a dependence for determining the maximum permissible distance in the rolling cage – non-drive dividing device system for reasons of longitudinal stability of the strip, taking into account the size and shape of cross-section of the split articulated profile, the nature of pinching, and the backstretch stress. It was experimentally established that when determining the permissible distance between rolling cage and non-drive dividing device, it is advisable to take the length reduction coefficient equal to 0.7.

Non-dimensional parameters governing the crashworthy performance of tubes with complex cross-sections

The crashworthiness of thin-walled tubes with various designs under axial compression has been extensively investigated. Despite this, the parameters that govern the performance of tubes and can be applied across different cross-sectional topologies have not hitherto been available. In this paper, twenty types of thin-walled tubes with different cross-sectional shapes (e.g., multi-celled, bi-tubular, and hierarchical square, hexagonal and circular tubes) have been numerically simulated and theoretically analysed. All the tubes are made from identical material and possess identical apparent cross-sectional area, height and mass. Six indicators are employed to characterise the crashworthiness performance of the tubes. Two novel non-dimensional indices, the geometric complexity index (RG) which is the ratio of the total length of solid segments in the cross-section of a tube to that of the square tube, and the topological index (RT) which is the non-dimensional coefficient in the expression of plastic energy dissipation closely related to the types and numbers of the wall junctions in cross-section, are identified for the first time. Both the indices RG and RT are used in a regression analysis of the indicators that characterise the crashworthiness of the tubes. The results reveal that the crashworthiness indicators of the tubes, the mean crushing force (MCF), the specific energy absorption (SEA) and the effectiveness of energy absorption (EEA) do not exclusively vary with RG. Instead, MCF, SEA and EEA are all properly fitted by linear relations with a single non-dimensional parameter ω, which is a simple function of RG and RT, i.e., ω=RT/RG. Increasing the magnitude of ω ultimately improves the crashworthiness of tubes, including enhanced specific energy absorption, effectiveness of energy absorption and crushing force efficiency, while reducing the force fluctuation during the crushing process. Of the tubes studied, the edge-based hierarchical circular tube (EH_C) has the highest SEA of 22.17 J/g, which is 133%, 60% and 41% larger than that of single-celled square, hexagonal and circular tubes, respectively.

Influence of the cross-sectional shape of a submerged body on its hydrodynamic characteristics in free water surface movement

Influence of the cross-sectional shape of a submerged body on its hydrodynamic characteristics in free water surface movement

Shape sensing of the thin-walled beam members by coupling an inverse finite element method with a refined quasi-3D zigzag beam theory

In structural safety field, the inverse finite element method (iFEM) is an effective methodology to reconstruct full-field displacement on beam, plate and shell structures, independently of the loading conditions and of the material properties. However, the current iFEM in principle requires uniform shear distribution over the thickness of beam, which is practically hardly possible due to these thin-walled beam with the general cross-section shape, such as I-section beam, hat-section beam and box-section beam, and there is no effective method to realize deformation online monitoring at home and abroad. To relieve this issue, a novel iFEM strategy is proposed to establish the shape sensing model of the thin-walled beam, where the thin-walled beam is replaced with an equivalent layered composite one based on a generalized layered global-local beam (GLGB) theory, and the improved quasi-3D zigzag shear deformation theory is presented to describe deformation field of the equivalent layered composite beam. The proposed iFEM method accounts for not only thickness stretching but also interlaminar continuity of shear stresses and displacements. Besides, the proposed iFEM formulation does not need any shear correction factors. Accuracy and effectiveness of the established shape sensing model are demonstrated through several case studies. The numerical results show that the proposed iFEM can accurately reconstruct the deformation of the thin-walled structure and the reconstruction accuracy can be improved by 5 %.

Mitigation of Erosion Wear Produced by Fly-Ash Slurry on 90<sup>0</sup> Elbow by Changing the Cross-Section Shape and Area Ratio

The predominant method of transporting fly ash involves conveying it in slurry form through pipelines within diverse industrial facilities. The key elements of slurry conveyance encompass bends, pumps, and valves. These components of the pipeline endure significant erosion and wear due to the impact of discrete particles. In this investigation, the study assessed the wear induced by slurry erosion in conventional 900 pipe bend and 900 square section elbows of different area ratios using ANSYS Fluent. The discrete phase model was used to estimate the slurry erosion wear for the fly ash-water suspension. From the investigation, the outcomes from the standard k-turbulence model were discovered to be in agreement with the experimental data. This study also looked at a number of other influencing factors, such as the solid concentration and velocity. The analysis reveals that the average erosion wear is lower in the square cross-section elbow compared to the standard elbow. Furthermore, the erosion wear is observed to decrease further with an increase in the cross-sectional area of the square section elbow.

Crashworthiness behavior of multi-cell structures reinforced with small tubes under axial and inclined loading

In this paper, a novel design for the cross-sectional shapes of square, hexagonal, octagonal, and decagonal structures has been proposed for the development of energy-absorbing devices. The deformation behavior of these structures, which contain multiple small tubes, was analyzed under axial and inclined loads (0°, 10°, 20°, and 30°) using a validated finite element model in LS-DYNA, supported by experimental and analytical data. Various crushing metrics such as specific energy absorption (SEA), peak crushing force (PCF), mean crushing force (MCF), crush force efficiency (CFE), and undulation of load-carrying capacity (ULC) were evaluated for the structures. The results indicated an optimal size for the small tubes that maximizes energy absorption capability. Through the TOPSIS method considering 12 criteria, the multi-cell octagonal structure O5, which includes the highest number of small tubes, was identified as the most effective energy absorber. It demonstrated significantly higher Specific Energy Absorption (SEA) values compared to simpler structures S1, H1, O1, and D1, with improvements of 89%, 65%, 53%, and 46%, respectively. Therefore, it could be utilized in automotive structures for crashworthiness applications.

Multiscale 3D printing via active nozzle size and shape control.

Three-dimensional (3D) printers extruding filaments through a fixed nozzle encounter a conflict between high resolution, requiring small diameters, and high speed, requiring large diameters. This limitation is especially pronounced in multiscale architectures featuring both bulk and intricate elements. Here, we introduce adaptive nozzle 3D printing (AN3DP), a technique enabling dynamic alteration of nozzle diameter and cross-sectional shape during printing. The AN3DP nozzle consists of eight independently controllable, tendon-driven pins arrayed around a flexible, pressure-resistant membrane. The design incorporates a tapered angle optimized for extruding shear-thinning inks and a pointed tip suitable for constrained-space printing, such as conformal and embedded printing. AN3DP's efficacy is demonstrated through the fabrication of components with continuous gradients, eliminating the need for discretization, and achieving enhanced density and contour precision compared to traditional 3D printing methods. This platform substantially expands the scope of extrusion-based 3D printers, thus facilitating diverse applications, including bioprinting cell-laden and hierarchical implants with bone-like microarchitecture.

Numerical simulation of all-vanadium redox flow battery performance optimization based on flow channel cross-sectional shape design

This paper numerically investigates optimizing trapezoidal flow channel cross-sectional shapes to improve all‑vanadium redox flow battery performance. A 3D steady-state multiphysics model coupling fluid dynamics, mass transfer, and electrochemistry was developed in COMSOL. Eight trapezoidal and one rectangular cross-section serpentine flow fields were simulated at varied flow rates. Results showed the TCS-T06 design reduced pressure drop by 12 % and pump power by 12 % versus the RCS. The concentration distribution of VO2+ was also improved, enhancing mass transfer. At 60 mA/cm2, TCS-T06 achieved 0.9 % higher pump power-based voltage efficiency. The optimized trapezoidal cross-section was proven to minimize losses, improve electrolyte distribution, and enhance VRFB performance. This work provides guidance for optimizing trapezoidal flow channel cross-sections to improve VRFB performance via enhanced mass transfer and reduced pressure drop.

Pressing Strength of Plastic Bottle Couch as a Form of Waste Management Innovation in UMKM Sobotik

Abstract In general, people burn plastic waste openly because they do not know the impact it can cause. Couch from plastic bottles one of the effective alternative innovations. The objective of this study was to determine the strength of the plastic bottle couch from the UMKM Sobotik couch product as the effort to develop creativity in utilizing plastic waste. Plastic bottles that have been glued according to the size and shape designed are given a load (load cell) at the center point of the test object. The shortening of the specimen during compression was observed by two linear variable differential transformers (LVDT) which were placed on the top of the flat surface on different sides of the specimen. The difference in the compressive strength of the plastic bottle couch specimen was based on the variable height of the plastic bottles making up the couch, the cross-sectional shape of the couch, and the position of the fastener (duct tape). There are three types of plastic bottles that make up the couch for this test, namely 1500 ml, 600 ml and 330 ml with the height of each bottle being 290 mm, 226 mm and 170 mm respectively. The results of the compressive load test on the plastic bottles that make up the couch ranged from 241 kgf-621 kgf. The strength of the couch is influenced by the number of adhesives, the location of the adhesive and the shape of the couch. The specimen with the smallest rigidity is a rectangular cross section. Round cross sections tend to have advantages over other cross sections. Due to the pressure received by the test object can be spread evenly throughout the radius of the test object. For a square cross section, there is a cross section that is shorter than the other parts, resulting in non-uniformity of the load received by the parts of the cross section, so that the round shape has great strength.

Phenotypic Diversity of Pomegranate Cultivars: Discriminating Power of Some Morphological and Fruit Chemical Characteristics

In modern agricultural production, where a small number of commercial cultivars dominate, the collection, evaluation, and preservation of germplasm are important tasks to reduce the erosion of genes and preserve biodiversity. The aim of this study is to characterize the morphological and fruit chemical properties of the pomegranate germplasm grown on the East Adriatic coast, including the commercial cultivars ‘Hicaznar’, ‘Granada’, and ‘Wonderful’, and to highlight the characteristics with the greatest discriminating power. The characterization of the tree, leaf, flower, arils, seed, and juice was carried out using the UPOV descriptor. The colors of the peel, arils, and juice were analyzed according to the CIEL*a*b* method, total soluble solids were measured using refractometers, and total acidity was determined by titration with 0.1 M NaOH. The research results showed significant diversity between the cultivars, which were grouped into several clusters using an unsupervised analysis technique. Factors such as plant vigor, plant growth habit, predominant number of leaves per node on young shoots, crown type, fruit shape, fruit shape in cross-section, peel weight, total aril weight, aril weight, number of arils per fruit, seed length and width, seed yield, total acidity, TSS/TA ratio, and color parameters of the peel, arils, and juice showed high variability, indicating their strong discriminating power in determining the phenotypic diversity of pomegranate.

A one-dimensional augmented Shallow Water Equations system for channels of arbitrary cross-section

This work provides a new formulation of the one-dimensional augmented Shallow Water Equations system for open channels and rivers with arbitrarily shaped cross sections, suitable for numerical integration when discontinuous geometry is encountered. The additional variable considered can be the bottom elevation, a reference width, a shape coefficient, or a vector containing these or other geometric parameters. The appropriate numerical method, which is well suited to coupling with the mathematical one, is a path-conservative method, capable of reconstructing the behaviour of physical and geometrical variables at the cell boundaries, where the discrete solution of hyperbolic systems of equations is discontinuous. A nonlinear path suitable for the shallow water context is adopted. The resulting model is shown to be well-balanced and accurate to the second order and is further validated against analytical solutions related to channels with power-law cross-sections, specifically for dam break patterns over a variable-width channel and the run-up dynamics of long water waves over sloping bays.

Improving the local and distortional resistance of CFS trapezoidal self-supporting roof members

This paper reports the development, numerical implementation and application of a methodology to perform the multi-objective optimisation, with respect to local and distortional failures, of cold-formed steel (CFS) trapezoidal cross-section shapes used in members belonging to self-supporting roof systems and manufactured by bending the steel sheets with roll-forming machines. Initially, a brute-force approach is adopted to search for optimal unstiffened cross-section shapes of members subjected to positive (sagging) and negative (hogging) bending moments. Next, an optimisation procedure based on a Genetic Algorithm (GA) is employed to find stiffened cross-sections that (i) outperform the original (plain/unstiffened) ones, as far as the resistance against local and distortional failures is concerned, and (ii) can be fabricated with minimal additional cost, through the sole addition of small intermediate stiffeners, whose possible locations are pre-defined in accordance with a map of executable fold-line positions – the original cross-section typology, overall dimensions and wall angles are retained. The design approach adopted to estimate the member ultimate strengths is based on the Direct Strength Method (DSM), and Generalised Beam Theory (GBT) is used to calculate the elastic buckling stresses due to bending. The application and capabilities of the proposed methodology are illustrated, by means of numerical results presented in terms of cross-section families belonging to optimal Pareto Fronts – an excellent performance of the procedure was found in all cases.

Damped kink motions in a system of two solar coronal tubes with elliptic cross sections

Aims. This study is motivated by observations of coordinated transverse displacements in neighboring solar active region loops, addressing specifically how the behavior of kink motions in straight two-tube equilibria is impacted by tube interactions and tube cross-sectional shapes. Methods. We worked with linear, ideal, pressureless magnetohydrodynamics. Axially standing kink motions were examined as an initial value problem for transversely structured equilibria involving two identical, field-aligned, density-enhanced tubes with elliptic cross sections (elliptic tubes). Continuously nonuniform layers were implemented around both tube boundaries. We numerically followed the system response to external velocity drivers, largely focusing on the quasi-mode stage of internal flows to derive the pertinent periods and damping times. Results. The periods and damping times that we derive for two-circular-tube setups justify the available modal results found with the T-matrix approach. Regardless of cross-sectional shapes, our nonuniform layers feature the development of small-scale shears and energy accumulation around Alfvén resonances, indicative of resonant absorption and phase mixing. As with two-circular-tube systems, our configurational symmetries still make it possible to classify lower-order kink motions by the polarization and symmetric properties of the internal flows; hence, such motions are labeled as S​x and Ax. However, the periods and damping times for two-elliptic-tube setups further depend on cross-sectional aspect ratios, with Ax motions occasionally damped less rapidly than S​x motions. We find uncertainties up to ∼20% (∼50%) for the axial Alfvén time (the inhomogeneity lengthscale) if the periods (damping times) computed for two-elliptic-tube setups are seismologically inverted with canonical theories for isolated circular tubes. Conclusions. The effects of loop interactions and cross-sectional shapes need to be considered when the periods, and in particular the damping times, are seismologically exploited for coordinated transverse displacements in adjacent coronal loops.

A data-driven procedure for one-dimensional dynamic analysis of thin-walled beams with arbitrary cross-sections

This paper develops a one-dimensional dynamic model for thin-walled beams with arbitrary complex cross-sections in a data-driven way. In order to consider complicated deformations in the framework of a beam theory, a universal node system is first created to fit the deformed shape of a thin-walled cross-section, whether prismatic or curved, with or without symmetry. This helps to reduce the three-dimensional displacement field of the thin-walled beam to one dimension, and results in a preliminary higher-order beam model with limited precision loss. For the purpose of largely condense DOFs of the new model, a data-driven approach is proposed to identify cross-section deformation modes through the principal component analysis of free vibration deformation data of an unconstrained thin-walled beam. As a result, a compact set of core deformation modes are obtained and selected to update the preliminary model, leading to the refined higher-order beam model of high accuracy and efficiency. Examples are presented to illustrate the concrete implementation and check the effects of data-related controlling parameters of the proposed procedure. We also verify through numerical examples that the proposed model agrees well with plate/shell and other beam theories, and has remarkable advantages in physical interpretation, modeling simplicity and computation efficiency.

Deciphering morphology patterns of environmental microfibers: Insights into source apportionment

Microfibers, a prevalent form of microplastics, undergo diverse environmental interactions resulting in varied morphological changes. These changes can offer insights into their environmental trajectories. Despite its importance, comprehensive studies on microfiber morphology are scarce. This study collected 233 microfibers from the East China Sea and South China Sea. Based on morphological features observed in microscopic images of microfibers, such as curvature, cross-sectional shapes, diameter variations, and crack shapes, we identified a general morphological pattern, classifying the environmental microfibers into three distinct morphological types. Our findings highlight noticeable differences in morphological metrics (e.g., length, diameter, and surface roughness) across three types, especially the diameter. Microfibers of Type I had an average diameter of 19.45 ± 4.93 μm, significantly smaller than Type II (263.00 ± 75.15 μm) and Type III (299.68 ± 85.62 μm). Within the three-dimensional (3D) space fully defined by these quantitative parameters, the clustering results of microfibers are also consistent with the proposed morphology pattern, with each category showing a potential correlation with specific chemical compositions. Type I microfibers correspond to synthetic cellulose, while 94.79 % of Types II and III are composed of polymers. Notably, we also validated the great applicability of the morphology categories to microfibers in diverse environmental compartments, including water and sediments in nearshore and offshore areas. This classification aids in the efficient determination of microfiber sources and the assessment of their ecological risks, marking a significant advancement in microfiber environmental studies.

Effect of Plate Thickness of Stainless Steel Core Plate Wall on Load Carrying Capacity under Pure Shear and Compression Shear Conditions

The shear walls have been employed as a lateral force opposing systems in numerous multistory buildings. The Stainless- Steel Core Plate Wall (SSCPW) is a recent and innovative addition to structural elements. The adoption of stainless steel over traditional steel has been driven by its advantageous properties, such as its lightweight nature, durability, and resistance to corrosion. The SSCPW comprises stainless-steel plates interconnected with orthogonally positioned stainless steel core tubes through welding. Depending on the specific orientations chosen, SSCPW can function as beams, columns, walls, floors and other essential structural components. Different cross-sectional shapes of SSCPWs are available, and this study focused on L- and T-shaped SSCPWs subjected to pure shear and compression shear conditions. The analysis and investigation of the impact of plate thickness on load-carrying capacities was conducted using ANSYS Workbench software. It was observed load-carrying capacity of SSCPW increases as the plate thickness increases. Plate thicknesses of 8, 12, 16 and 20 mm were chosen for modelling. Results show that SSCPW of plate thickness 20 mm has the maximum load-carrying capacity.

Estimation of pipe wall thickness variation during bending rolling

Abstract. The presented work examines the process of bending pipes using the cold rolling method. The main pa-rameters of bending that affect the change in wall thickness during the deformation process are analyzed. The influence of changing the shape of the cross-sectional shape, the increase in the pipe diameter, and the displacement of the neutral layer of bending, is identified. Theoretical values of thickening and thinning of the pipe wall are presented depending on the bending parameters. The authors provide theoretical and experimental data to assess the wall thickness variation. Data on the wall thickness of a bent pipe fitting with a diameter of 57 mm were obtained using two methods. The first method involves indirect measurements using an ultrasonic thickness gauge, while the second method involves direct measurements using a micrometer. A comparative analysis showed that the actual measurements of the wall thickness of the bent pipe fitting align with the theoretical values. Due to methodological discrepancies in the thickness measurements, it is recommended to use direct physical measurements to obtain more accurate results