Section Properties Research Articles

Machine learning-based prediction of ultimate load in pultruded glass fibre column under axial compression

ABSTRACT This experimental study investigates the axial compression effect of rectangular pultruded glass fiber-reinforced polymer (P-GFRP) tubular column sections, examining the impact of width-to-thickness ratio (B/t), aspect ratio (H/B), and column height on their structural performance. A total of 27 GFRP columns were subjected to axial compression tests to evaluate their ultimate load and initial stiffness. The columns exhibited a uniform failure pattern, characterized by crushing, mid-section fractures, and longitudinal splitting at the corners. The results revealed a negative correlation between the ultimate load and the aspect ratio, as well as the width-to-thickness ratio. This study utilized advanced machine learning algorithms, namely Response Surface Methodology (RSM) and Artificial Neural Network (ANN), to develop predictive models for the ultimate load of GFRP columns. The RSM model achieved an R2 value of 0.8347, demonstrating good accuracy in predicting ultimate load. The ANN model outperformed the RSM model, with an R criterion exceeding 0.68807 across training, testing, and validation phases, showing a stronger correlation between experimental and predicted outcomes. This research establishes a framework for forecasting the mechanical properties of column sections.

Study on Performance of Cable Stayed Bridge with Different Geometric Conditions

The construction of cable-stayed bridges has been on the rise in recent years, driven by their aesthetic appeal and unique structural design. This research focuses on the analysis of cable-stayed bridges, The study employed the MIDAS CIVIL software to model and analyse the cable-stayed bridges of two types H-shape and A-D shape, with all the bridges having the same material and section properties. For the seismic analysis time-history analysis has been performed by utilizing data from the 1940 El Centro earthquake, allowing for the investigation of the dynamic behaviour of the bridges. The cable-stayed bridge design is characterized by the transmission of the deck's reaction forces to the pylons, which in turn transfer the load to the foundation. The study reviewed a range of evaluations, including axial forces, displacements, and bending moments, to understand the structural behaviour of the cable-stayed bridges. The results reveal that as the complexity of the cable-stayed bridge design rises, the structural behaviour becomes more complex. The findings of this research contribute to the understanding of the dynamic response of cable-stayed bridges, which is vital for their structural health monitoring and design optimization.

Elevated temperature material properties of cold-formed advanced high strength steel channel sections

Fire safety remains a paramount concern in the design and application of cold-formed structures, making the understanding of mechanical properties of advanced high strength steel (AHSS) at elevated temperatures essential. This paper presents a comprehensive experimental investigation into the mechanical properties of cold-formed AHSS channel sections and their virgin material at elevated temperatures. A total of 60 coupon specimens were extracted from the middle of web element, the corner-flat adjunction of web element, as well as the middle of flange element of the cold-formed AHSS channel sections. Moreover, 20 additional coupon specimens were extracted from the cold-rolled AHSS sheets, which is the virgin material. Elevated-temperature tensile coupon tests were carried out by using steady-state test method under 10 different temperatures up to 800 °C. Full range of stress-strain curves were obtained for the virgin material and three locations of the cold-formed AHSS channel sections. Key mechanical properties including elastic modulus, yield stress and ultimate strength were obtained. Differences in the mechanical properties of coupons with different thicknesses and from various cutting positions were investigated. The obtained reduction factors of the studied AHSS were compared with existing design rules, including European, American, and Australian specifications, as well as predictive models from related research work. New design curves were proposed to provide an accurate and conservative estimation of the reduction in mechanical properties at elevated temperatures, and constitutive stress-strain models were also proposed.

Efficient Load-Bearing Capacity Assessment of a Degraded Concrete Manhole Using Sectional Homogenization.

This study addresses a practical and efficient approach to evaluating the load-bearing capacity of severely degraded concrete manholes. Concrete deterioration, often advanced and highly irregular, can be captured accurately through surface scanning to create a detailed model of the damaged structure and also to build a simplified modeling to enable rapid engineering-level assessment, filling a critical gap in infrastructure maintenance. The repair strategy involves applying an internal polyurea layer, a variable-thickness polyurethane foam layer depending on the degree of localized degradation, and an external polyurea layer to restore the original shape of the manhole. However, these repairs do not fully restore the manhole's original load-bearing capacity. A full 3D model, encompassing millions of finite elements, would provide a detailed analysis of strength reductions but is impractical for engineering applications due to computational demands. An alternative approach utilizing sectional homogenization is proposed, where sectional properties are sequentially averaged to calculate effective parameters. This approach enables the use of only a few hundred shell elements, each representing thousands of elements from the detailed 3D model, thus providing a rapid, engineering-level assessment of load-bearing reductions in degraded manholes. The study finds that while the repair method restores up to 76% of bending stiffness in heavily corroded sections, it does not fully recover the original load-bearing capacity.

Kinship and Descent System of Malbedey Community: A Case Study of Gopalpur Village in Munshiganj District.

The paper analyzes the kinship and descent system of Malbedey Community at Gopalpur village in Munshigonj District. An attempt has been made to explore the role of kin and descent in the traditional and changing life systems of the Malbedey community, in particular. Here Malbedey is a sub- branch of Bedey community. in Bangladesh who had lived on boats travelling along the rivers for their livelihood since past. They are also a marginal group who customarily catches and sells snakes. Additionally, they are a folk healer, selling beads, amulets and a few more items. At present, the Malbedey community has come out the boat life to live permanently settling on land, and many of them have abandoned their traditional occupations to make a living through various informal economic activities in rural areas. The Malbedey community has the same kinship and descent system having extended as part of larger population. Research shows that blood, marriage, fictitious kinship and descriptive kinship terminologies do exist among the Malbedey community. In their kinship system everyone is addressed specifically in descriptive kinship terminologies like, Mother, Father, Grandfather, Grandmother, Aunt, Uncle, Cousin, Nephew, Niece and so on. Apart from this, patrilineal descent is common among them. In this section inheritance, descent, property, titles and status are passed from father to son. It should be noted that in writing the article, data have been collected through intensive fieldwork in an anthropological method which is additionally supplemented by secondary data.

Inertial and elastic properties of general composite beams

Slender composite structures can be modeled using engineering beam models with properties computed using a cross-sectional analysis program, such as VABS. These properties are given in terms of the mass matrix, stiffness matrix, and compliance matrix in a general coordinate system. The invariance of strain energy and kinetic energy is employed to rigorously transform sectional properties into different coordinate systems with parallel shifts and rotations. Additionally, the computation of commonly used inertial properties (mass center, principal inertial axes, and mass moments of inertia) from the mass matrix, and commonly used elastic properties (extension stiffness, bending stiffness, torsion stiffness, tension center, shear center, principal bending axes, principal shear axes, etc.) from the compliance matrix, is elucidated. The elastic properties are given for both the Timoshenko model and the Euler–Bernoulli model. The definitions for shear center and twist center are clarified and consistently generalized for composite beams. Isotropic homogeneous beams are used to illustrate how to relate commonly used engineering beam properties with the compliance matrix and the stiffness matrix for composite beams. Finally, engineering beam properties necessary for general-purpose aeromechanical analysis programs such as CAMRAD II are derived from the properties computed by VABS.

Bending, torsion and flexural-torsional buckling of back-to-back cold-formed steel channels

The bending moment resistance of cold-formed steel channels can be improved by combining two channel sections with a pair of screw fasteners in the webs spaced intermediately along the member. By combining the two channels in this way, the moment capacity of the beam can be increased beyond the capacity of two single channels. Another advantage of this type of section is the coincidence of the centroid and shear centre which reduces the effects of stresses due to eccentric load and torsion. Most research on back-to-back channels in bending has focused on local and distortional buckling while data on flexural-torsional buckling is scarce. The flexural-torsional buckling resistance of a beam depends on various section properties which include the minor axis second moment of area, and the torsion and warping constants of the section. Although the flexural-torsional buckling moment can be easily determined for a single channel section because these section properties are relatively straightforward to calculate, the calculation of the flexural-torsional buckling moment for back-to-back channels with intermediately spaced screw fasteners is much more complicated due to the discontinuity of the cross-section along the length of the beam. In this paper, the shear stiffness of the screw fasteners connecting the channels is obtained from test results. The shear stiffness is then used to model the screw fasteners in a finite element analysis to analyse a beam composed of back-to-back channels under bending and torsion. The results are compared with two single channel sections and with back-to-back channels assuming full composite action. The effect of different screw fastener spacings is also investigated. Simple relationships between the bending and torsion section properties for single channels and back-to-back channels are presented. Suggestions for the design of back-to-back channels in bending are also proposed.

Experimental Method for the Controlled Cooling of Steel Sections with Varied Wall Thickness

The article presents the results of controlled cooling experiments after austenitising a V36 section made of structural steel S480W. The experiments involved variable cooling intensity affecting the cross-section of the test element. The tests aimed to investigate the possibility of modifying the microstructure and uniformly increasing the mechanical properties of steel sections with varied cross-sectional wall thickness in relation to free-air cooling. The research work involved the determination of section-related cooling characteristics identified using various parameters of compressed air blown from nozzles onto selected surfaces of the section. The accelerated cooling tests led to the formation of a fine ferritic-pearlitic microstructure having ferrite grain size Dα restricted within the range of 6.8 μm to 6.5 μm. In addition, the tests resulted in the obtainment of uniform hardness distribution in cross-section, an increase in yield point Re and tensile strength Rm (restricted within the range of approximately 40 MPa to 60 MPa) while maintaining similar elongation.

Educational Software for Stress Analysis of Open Thin-Walled Structures

Thin-walled structures are commonly employed in aerospace and automotive structures because of their high strength to weight ratio. Design and hence the stress analysis of thin-walled structures is tedious and time-consuming. An educational software which can aid students in stress analysis of thin-walled open sections will enhance the teaching-learning process. With the present available software, the number of sections that can be analysed is limited, hence in this work, a generalized section has been developed through which many new complex sections can be generated and analysed for stresses. The objective of the present work is to develop educational software that will provide a solution for the section properties like centroid, moment of inertia and shear centre, and the stresses on the section for a given loading. The software enables students to select different cross-sections which may be subjected to bending, shear or torsional loads and evaluate the stresses on it. Results obtained through this software have been validated against literature. The software has been developed using MATLAB with graphical user interface (GUI). The software is expected to be a useful tool for effective teaching learning process of courses on thin-walled structures, aircraft structures and advanced mechanics of materials.

Investigation and Improvement of Centrifugal Slurry Pump Wear Characteristics via CFD-DEM Coupling

Centrifugal slurry pumps are extensively applied in industrial industries such as power metallurgy, petrochemicals, deep-sea mining, and other industrial fields. The primary objective of this research is to assess how conveying settings and particle characteristics influence the 100SHL4147 slurry pump’s collision and erosion properties. Firstly, the computational fluid dynamics–discrete element method (CFD-DEM) coupling model fully coupled particle–fluid co-flow numerical simulation interface is built by utilizing the C++ language and the results are proven with tests. Subsequently, the simulation examines the wear properties of different sections through which the flow passes in the 100SHL4147 centrifugal slurry pump. In addition, following theoretical guidance, the slurry pump impeller’s wear resistance performance can be improved by adjusting design factors such as the intake edge location and the blade wrap angle. The results are as follows. It is recommended to replace the impeller promptly due to the findings that indicate that the entire blade’s pressure surface is vulnerable to different degrees of erosion under high-concentration situations. When the particle size increased from 0.4 to 0.8 mm, the wear rate decreased by up to 15%, as fewer particles were transported, lowering the collision frequency. Conversely, smaller particles intensify component wear. Adjusting the blade wrap angle from 66° to 96° reduced impeller and volute wear by an estimated 20%, enhancing the durability but slightly decreasing the delivery capacity. Extending the blade’s leading edge toward the intake improved the flow capacity, although it increased the wear frequency from one-third of the pressure surface to the trailing edge.

Effective field theory descriptions of Higgs boson pair production

Higgs boson pair production is traditionally considered to be of particular interest for a measurement of the trilinear Higgs self-coupling. Yet it can offer insights into other couplings as well, since – in an effective field theory (EFT) parameterisation of potential new physics – both the production cross section and kinematical properties of the Higgs boson pair depend on various other Wilson coefficients of EFT operators. This note summarises the ongoing efforts related to the development of EFT tools for Higgs boson pair production in gluon fusion, and provides recommendations for the use of distinct EFT parameterisations in the Higgs boson pair production process. This document also outlines where further efforts are needed and provides a detailed analysis of theoretical uncertainties. Additionally, benchmark scenarios are updated. We also re-derive a parameterisation of the next-to-leading order (NLO) QCD corrections in terms of the EFT Wilson coefficients both for the total cross section and the distribution in the invariant mass of the Higgs boson pair, providing for the first time also the covariance matrix. A reweighting procedure making use of the newly derived coefficients is validated, which can be used to significantly speed up experimental analyses.

Wide-angle low-scattering transmitarray antenna based on transmit-reflect selective metasurface

Abstract A high-gain transmitarray antenna with low radar cross section (RCS) properties is presented in this paper. Compared with conventional high-profile multilayer designs, we introduce a transmit-reflect selective metasurface integrated with high-gain transmission and random scattering functions, achieving a reduced thickness of 0.13 λ 0 (where λ 0 is the wavelength at the center frequency). For the meta-atom design, we combine geometric rotation and dimension optimization to realize 1-bit independent transmit and reflection phase modulation, respectively. Moreover, in metasurface coding strategy, we employ an initial phase optimization method and a simulated annealing algorithm to determine the optimal coding matrices. The experimental results demonstrate high-performance radiation characterized by the peak gain of 23.6 dB, maximum aperture efficiency of 28.5%, and 3 dB gain bandwidth of 18.4%. For x-polarization, measured 10 dB RCS reduction bandwidth under transverse magnetic (TM) 0°-45° and transverse electric (TE) 0°-20° incidence are 9.02–11.36 GHz. For y-polarization, 10 dB RCS reduction bandwidth under TM 0–60° and TE 0–30° incidence is 8.82–10.96 GHz.

Exploring Soliton Solutions and Chaotic Dynamics in the (3+1)-Dimensional Wazwaz–Benjamin–Bona–Mahony Equation: A Generalized Rational Exponential Function Approach

This paper investigates the explicit, accurate soliton and dynamic strategies in the resolution of the Wazwaz–Benjamin–Bona–Mahony (WBBM) equations. By exploiting the ensuing wave events, these equations find applications in fluid dynamics, ocean engineering, water wave mechanics, and scientific inquiry. The two main goals of the study are as follows: Firstly, using the dynamic perspective, examine the chaos, bifurcation, Lyapunov spectrum, Poincaré section, return map, power spectrum, sensitivity, fractal dimension, and other properties of the governing equation. Secondly, we use a generalized rational exponential function (GREF) technique to provide a large number of analytical solutions to nonlinear partial differential equations (NLPDEs) that have periodic, trigonometric, and hyperbolic properties. We examining the wave phenomena using 2D and 3D diagrams along with a projection of contour plots. Through the use of the computational program Mathematica, the research confirms the computed solutions to the WBBM equations.

Low and elevated temperature mechanical properties of cold-formed Q1200 ultra-high strength steel sections: Experiment and constitutive model

Ultra-high strength steel (UHSS) has extensive application prospects in building structures due to its excellent mechanical properties. Because of the cold-forming process, the mechanical properties of the corner portion differed from those of the flat portion. However, research on the mechanical properties of the corner and flat portions of cold-formed UHSS sections at low and elevated temperatures was very limited. Therefore, the steady-state test was employed to investigate the mechanical properties and constitutive models of the Q1200 UHSS corner and flat couple specimens at low and elevated temperatures. The target temperatures set in this study were −80 °C, −60 °C, −40 °C, −20 °C, 20 °C, 200 °C, 300 °C, 400 °C, and 500 °C. After the steady-state test, the failure modes, fracture surfaces, stress-strain curves, and key mechanical parameters of the Q1200 UHSS corner and flat couple specimens at different temperatures were obtained. In addition to increasing the elastic modulus of the corner specimen by more than 10 %, the effect of low temperature on the mechanical properties of the flat and corner specimens was within 10 %. The strength properties of Q1200 UHSS decreased with increasing elevated temperature, but the ductility properties increased with increasing elevated temperature. Remarkably, the ultimate strength of the flat and corner specimens at 200 °C increased by 5 % and 2 %, respectively. At 500 °C, the strength properties decreased by more than 60 %. The low- and elevated-temperature reduction factors of yield strength, ultimate strength, and elastic modulus of different structural steels obtained from recent studies and current codes were compared with those of the Q1200 UHSS. Based on the experimental results, predictive formulae for the key mechanical parameters of Q1200 UHSS corner and flat specimens at low and elevated temperatures were proposed. Furthermore, constitutive models of Q1200 UHSS corner and flat specimens at different temperatures with strains less than the ultimate strain were developed. The proposed predictive formulae and constitutive models provided an important basis for the structural analysis and design of cold-formed Q1200 UHSS structures in low- and elevated-temperature environments.

Framework of Physically Consistent Homogenization and Multiscale Modeling of Beam Structures

In this work, a framework of physically consistent homogenization and multiscale modeling (PCHMM) is developed to analyze complex slender structures with homogenized one-dimensional beam models. Firstly, it is highlighted that periodic boundary conditions are not valid for the representative volume element (RVE)-based homogenizations if a shear-deformable beam model is to be obtained. Addressing this issue, physically consistent boundary conditions (PCBCs) are discussed in detail, which accounts for the influence of shear forces on the behavior of the slender structure and the corresponding RVE. A procedure of enforcing such boundary conditions is also given, applying sectional stresses to the RVE with fictitious DoFs. Additionally, we introduce a newly developed correct formula to calculate effective sectional properties which guarantee the cross-scale energy conservation though a modified Hill’s condition. The PCHMM framework, with homogenization/dehomogenization procedures using PCBC and the modified Hill’s condition, is also conveniently integrated into a commercial finite element software. The correctness and effectiveness of the developed framework of homogenization and multiscale analysis are demonstrated through several numerical examples, including lattice beams, twist-morphing metamaterial spars, and a realistic wing. The extension of this theory to plate/shell structures will be presented in our future work.

Psychometric evaluation of the Clinical Interview for Externalizing Disorders (ILF-EXTERNAL) in an online setting - Results from the consortium project INTEGRATE-ADHD.

The study examines the psychometric properties of the ADHD section of the semi-structured diagnostic interview ILF-EXTERNAL, which was conducted online via video chat. As part of the INTEGRATE-ADHD research project, 202 children and adolescents (age M = 12.87 years, SD = 3.04, 28.2 % female) with an administrative diagnosis of ADHD registered with their health insurance company were clinically assessed for the presence of ADHD according to the German ADHD S3 guideline. Using the ILF-EXTERNAL, one parent and, from the age of eight, also the children themselves were interviewed. A proxy rating by a parent was made using the German FBB-ADHS rating scale. In a subsample (n = 65), an independent blind interviewer rated the videorecordings of the ILF-EXTERNAL parent interview to determine the interrater reliability of the ILF-EXTERNAL. All ADHD symptom scales of the ILF-EXTERNAL showed good to excellent internal consistency (α = 0.89 to 0.93). Interrater reliability was high for both categorical and dimensional analyses (κ = 0.78 and κ = 0.81; ICC(1,1) = 0.97 and 0.98). High correlations of the ILF-EXTERNAL parent interview with the FBB-ADHS (r = 0.79 to r = 0.85) and with the ILF-EXTERNAL child interview (r = 0.60 to r = 0.71) demonstrated convergent validity. Sound psychometric properties of the ILF-EXTERNAL were also confirmed for its use in an online setting. High interrater reliabilities demonstrate the quality of the ADHD diagnostics carried out in the consortium project INTEGRATE-ADHD.

Effect of Cross-Section Stiffness on Strength of Rectangular Steel

Concrete-filled steel tubes (CFSTs) have better application in the application of beams and columns. This application form has obvious advantages, mainly because they are not restricted by the forming process, and the filled concrete does not need long-term maintenance. However, the design and analysis of steel-concrete beam-columns is a complex task involving many factors. In the design of CFSTs, it is essential to understand the influence of these factors on the behavior of steel-concrete members. In particular, the cross-sectional shape of the member has a significant impact on its bearing capacity, stiffness, and buckling behavior. However, there is relatively little research on the influence of member slenderness on the strength of CFSTs. Therefore, this study conducted an in-depth analysis of the stability of the member, and explored in detail the influence of the member slenderness ratio on the section properties and the overall bending strength of the beam. This study provides a basis for the application of CFSTs in beam-column design and analysis. In the bending strength analysis, the member slenderness ratio has an important influence. Smaller slenderness ratios have better strength performance, but the attenuation is also relatively significant. The larger the slenderness ratio, the slower and more stable the strength change becomes. In terms of section properties, when the slender section is reached, the influence of effective section reduction will be greater, and the strength reduction may exceed the engineering allowable error range. Therefore, special attention should be paid when using slender sections.

Inverse Element for Surreal Number

Summary Conway’s surreal numbers have a fascinating algebraic structure, which we try to formalise in the Mizar system. In this article, building on our previous work establishing that the surreal numbers fulfil the ring properties, we construct the inverse element for any non-zero number. For that purpose, we formalise the definition of the inverse element formulated in Section Properties of Division of Conway’s book. In this way we show formally in the Mizar system that surreal numbers satisfy all nine properties of a field.

Close Look into the Spatial-Temporal Distribution of Speed, Lane Changes, and Heavy Vehicles in a Congested Freeway Weaving Section

Traffic behavior around major freeway weaving sections exhibits complex dynamics associated with multi-directional maneuvers such as lane changes (LCs) accompanied by shockwave-generating braking. Data to study both microscopic and macroscopic properties of congested weaving sections have been generally lacking, leaving an important lacuna in the underlying traffic science. The Third Generation Simulation (TGSIM) trajectory data set collected on multiple freeway locations in the USA provides a rich opportunity to examine the phenomena associated with high-density weaving operations on freeways. The focus of this paper is to examine the spatial-temporal distribution of average speed, LCs, and heavy vehicles (HVs). In addition, we examine the time-shifted association of speed with LCs and HVs. Our analysis reveals considerable variation of speed across lanes and longitudinal locations. LCs are generally associated with higher speeds of the surrounding traffic and correlate with the speed changes on the original and target lanes differently. In addition, differences of speed change have been found for vehicles that execute mandatory LCs (MLCs) and discretionary LCs (DLCs). Finally, while a lower average speed is associated with the existence of HVs, it tends to recover gradually when the HVs move downstream.

Environmental Bond Degradation of Different Laminated Glass Panels.

Since buildings are designed to endure over time, it is crucial to comprehend how laminated glass (LG) windows, and consequently, the polymer interlayer materials, respond to weathering. This paper explores the impact of accelerated humidity on the mechanical properties of several polymer interlayer materials and LG sections. The study specifically focuses on three polymer interlayer materials of industrial interest: polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), and ionomer (SG). To examine the environmental effects, testing setups were devised to subject the polymeric materials and LG panels to specific conditions. Uniaxial tension coupons and LG disks were submerged in a water bath to simulate the environmental effect. A dedicated testing fixture was designed and manufactured for the LG disks. The results showed that the properties of EVA, including strength, maximum strain, and toughness, were not significantly affected by the environmental conditions. However, the properties of SG5000 were notably impacted, with a significant reduction in its bond strength due to water immersion.