Plane Of Section Research Articles

Theoretical calculation of bending capacity of a steel beam - ultra high performance concrete slab composite girder

The composite girder, which combines a steel beam with an ultra-high-performance concrete (UHPC) slab, has gained significant attention in recent years as a new type of bridge structure. However, accurately estimating the bending capacity of such girders remains a challenge, as practical methods are limited. In this article, the authors propose a theoretical approach based on the Euler-Bernoulli beam theory to determine the bending capacity of composite girders. This approach considers the assumptions of plane sections remaining plane and infinitesimal strains during bending. By applying this theoretical approach, the authors derive a formula that allows engineers to calculate the bending capacity of the composite girder. The formula takes into account the dimensions and properties of both the steel beam and the UHPC slab. The derived formula serves as a valuable tool for evaluating the structural behavior and performance of composite girders. To validate its accuracy, the authors compare the results obtained from their calculations with numerical simulations of composite girder failures caused by bending. The close agreement between the theoretical calculations and the numerical simulation results confirms the reliability and applicability of the proposed formula. This research significantly contributes to the field of composite girder design by providing a practical and reliable method for estimating the bending capacity of steel beam-UHPC slab composite girders. The proposed theoretical approach, validated through numerical simulations, offers valuable insights for the design and optimization of these composite girders in various engineering applications.

Fractal Dimension of Silhouette Magnetic Resonance Brain Images as a Measure of Age-Associated Changes in Cerebral Hemispheres

Aim: The aim of the present study was to characterize age-associated changes in the spatial configuration of cerebral hemispheres (including changes in spatial complexity and space-filling capacity) using fractal analysis of silhouette magnetic resonance brain images. Material and Methods: Magnetic resonance brain images of 100 (44 male, 56 female) participants aged between 18-86 years were studied. Five magnetic resonance images were selected from the magnetic resonance imaging dataset of each brain, including four tomographic sections in the coronal plane and one in the axial plane. Fractal dimension values of the cerebral hemispheres silhouettes were measured using the two-dimensional box-counting algorithm. Morphometric parameters based on Euclidean geometry (perimeter, area, and their derivative values) were determined as well. Results: The average fractal dimension value of the five studied tomographic sections was 1.878±0.0009, the average value of four coronal sections was 1.868±0.0010. It was shown that fractal dimension values of cerebral silhouettes for all studied tomographic sections and four coronal sections significantly decrease with age (r=-0.512, p<0.001 and r=-0.491, p<0.001, respectively). The difference in the character of age-related changes in males and females was not statistically significant. Based on the age and the fractal dimension values of the studied sample, the confidence intervals of the fractal dimension values of cerebral hemispheres silhouettes were determined, which can be used as norm criteria in clinical neuroimaging. Conclusion: The fractal analysis and obtained data can be used in neuroimaging for assessing the degree of age-related cerebral atrophy and for differentiating between normal aging and neurodegenerative diseases.

Alzheimer biomarkers esteem by sampling Kantorovich algorithm

In this paper, we take advantage of the reconstruction properties of the sampling Kantorovich (SK) algorithm to estimate the volume of the human brain for the quantification of Alzheimer's biomarkers. At first, the goodness of the reconstructions is evaluated, comparing it to different interpolation methods by means of the Peak Signal to Noise Ratio (PSNR) index; then the stereological Cavalieri/Point‐counting technique is used to infer volumetric data starting from the knowledge of the planar sections. The comparison of the achieved results with synthetic references confirms the good performances of the new methodology.

Controlling False-Positives in Automatic Lung Nodule Detection by Adding 3D Cuboid Attention to a Convolutional Neural Network

Background and ObjectiveFalse-positive diagnoses often occur during pulmonary nodule detection, which directly affects the prognosis of patients. The development of intelligent computing and the wide application of deep learning technology have brought about the intelligent detection of lung nodules, which has greatly improved the detection efficiency and detection accuracy. MethodsThis paper explores a convolutional neural network filled with a 3D cuboid attention module for lung nodule detection comprehensively encompassing nodules in the cross, coronal, and sagittal planes of CT sections. First, 3D cuboid attention module extracts image features in order from the plane, space, and volume directions of CT slices (PSV-AM). Second, the model adopts a structure named UPSV-Net of 9 modules to expose the lesion area as much as possible. The PSV-AM is embedded into the network to guide it in extracting the structural features of nodules. At the same time, the features extracted from the shallow and deep layers are associatively concatenated. Thirdly, on the basis of the convolution module shared from the detection branch, deepening the convolution path to form the true and false nodule classification network, which is committed to reducing the false positive rate. ResultsThe model study was validated on the 2016 Lung Nodule Analysis challenge dataset. On the test bench, the detection accuracy is 96.15%, and the sensitivity is 97.6%. Subsequently, the sensitivity to the true and false nodules reached 97.61% and the average false-positive detection rate (FPDR) was 0.893, which was comparable to the diagnosis results of clinicians.

Lateral Force Evaluation in Vehicle’s Wheel Interaction with a Rut

The operation of roads under modern conditions associated with high speeds and traffic density results in wear of pavement and formation of a rut. When crossing the ruts, instability can occur when relatively small steering inputs lead to large changes in the trajectory. The lateral force acting on a wheel of a car is of particular importance in the study of stability and controllability. The magnitude of this force is determined by various factors: tire stiffness, speed, change in the angle of rotation of the wheel, the geometry of the transverse profile of the rut.The objective of the study refers to the problem of determining the angles of inclination of side walls of the rut that are safe for movement at different speeds. The paper considers the interaction of a car wheel with the road surface, proposes a mathematical model for interaction of a tire with ruts, considers the angle of the wheel running on the rut wall. To describe the elastic response of a tire in contact with a rut, an elastic foundation model and a plane section method are used. The lateral force was estimated based on equations of motion of the wheel when crossing the rut. The dependences of the ratio of the lateral force to the normal load for various rut depths and angles of inclination of its walls on the angle of rotation of the wheel and the speed of the vehicle were obtained. It is shown that at a rut inclination angle exceeding five degrees, the lateral force begins to increase significantly with an increase in the angle of rotation of the wheel, as well as the speed of the vehicle, and may exceed the applied normal load. According to the condition of vehicle stability against skidding on a wet surface, limiting average angles of inclination of the side walls of the rut are estimated for various values of the vehicle speed and wheel rotation angles.

Analysis and calculation method for concrete-encased CFST columns under eccentric compression

This paper presents a computational method for concrete-encased concrete-filled steel tube (CFST) columns under eccentric compression, which adopts the form of equivalent rectangular stress integrated by material constitutive curve. When establishing finite element model via ABAQUS, confinement provided by stirrup was considered to modify the constitutive law of encased concrete, so that the numerical modeling was in good agreement with tests. By analyzing the simulation results, the applicability of basic assumptions, such as plane section assumption, was discussed, and a database of 207 models with various parameters was created. The developed method took into account the influences of geometric nonlinearities of section shape, and its accuracy was verified against various collected tests and the database. It turned out that the formula presented was applicable to a wide range and had sufficient precision, while the predictions of N-M interaction curves of concrete-encased CFST columns in EC4, AISC and CECS were conservative due to the ignorance of the exact integration about irregular section-shape.

Polaron induced local spin texture and anomalous Hall effect in the quadrilateral prism-shaped nanotube with Rashba and Dresselhaus spin–orbit coupling

We theoretically study the spin-texture dynamics and the transverse asymmetric charge deflection induced by the polaron in a quadrilateral prism-shaped nanotube with the Rashba and Dresselhaus spin–orbit coupling (SOC). We reveal the polaron gives rise to the nontrivial local spin textures in the nanotube within the cross section plane. The spins demonstrate oscillations and the oscillating patterns are dependent on the SOC type. For the nanotube containing a segment of the ferromagnetic domain, the sizable asymmetric charge deflections could additionally take place, namely, the anomalous Hall effect. The amount of the deflected charges is determined by the strength and orientations of the ferromagnetic magnetization as well as the SOC type. The work provides a valuable insight of the coherent transport of polaron through a quasi-one-dimensional nanotube with Rashba and Dresselhaus SOC and open avenues for the potential device applications.

MP05-20 KIDNEY STONE GROWTH ‘RINGS’ VISUALIZED USING MICRO CT AND FLUORESCENCE MICROSCOPY: SIMILARITIES IN GROWTH OF RANDALL’S PLAQUE CALCIUM OXALATE STONES FROM THE SAME KIDNEYS

You have accessJournal of UrologyCME1 Apr 2023MP05-20 KIDNEY STONE GROWTH ‘RINGS’ VISUALIZED USING MICRO CT AND FLUORESCENCE MICROSCOPY: SIMILARITIES IN GROWTH OF RANDALL’S PLAQUE CALCIUM OXALATE STONES FROM THE SAME KIDNEYS Emily Wachter, Angela Sabo, Tarek El-Achkar, Elaine Worcester, James Lingeman, and James Williams Emily WachterEmily Wachter More articles by this author , Angela SaboAngela Sabo More articles by this author , Tarek El-AchkarTarek El-Achkar More articles by this author , Elaine WorcesterElaine Worcester More articles by this author , James LingemanJames Lingeman More articles by this author , and James WilliamsJames Williams More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003216.20AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Recent work has shown that mechanisms of stone growth can be demonstrated at the microscopic level using fluorescence microscopy. The objective here was to study multiple stones to observe patterns of mineral and organic deposition within and between patients. METHODS: Stones were removed by basket during endoscopic procedure, and a total of 12 stones were studied from 3 patients. All stones were verified by micro CT as having grown on Randall’s plaque by residue visible on the stone. Each stone was mounted on polystyrene and ground down to reveal a planar surface inside the stone. The stone was then imaged using confocal microscopy (Leica SP8) with a water immersion lens (20x, 0.75 NA). Each stone was ground repeatedly to collect as many interior planes as possible, with micro CT verification of each plane of section and mineral regions exposed. RESULTS: Within a patient, similarities of layering (both thickness and color) were apparent in stones from the same kidney, but stones from different patients had different fluorescent features. Several stones showed evidence of episodic growth by deposition of aggregates of calcium oxalate dihydrate crystals, and these stones with evidence of dihydrate aggregates tended to be larger stones within a given patient. Regions of apatite adjacent to Randall’s plaque showed yellow fluorescence distinctly different from apatite in later stone overgrowth. CONCLUSIONS: The unique fluorescence of apatite laid down as the first overgrowth on Randall’s plaque is suggestive of special urine molecules deposited at the initiation of stone growth. Outside of this consistent finding, fluorescent molecules laid down with mineral in calcium oxalate stones are not universal among patients, but stones from the same kidney showed similar fluorescence patterns. Source of Funding: NIH R01 DK124776, NIH P01 DK056788 © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e52 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Emily Wachter More articles by this author Angela Sabo More articles by this author Tarek El-Achkar More articles by this author Elaine Worcester More articles by this author James Lingeman More articles by this author James Williams More articles by this author Expand All Advertisement PDF downloadLoading ...

Probing measurements of the Meyer hardness index of radial, tangential and cross section of various types of wood

The Meyer index is a power exponent appearing in Meyer hardness power law, which describes the dependence of the indenting force on the diameter of the indentation caused by the ball (or alternatively a cylinder). A perfectly plastic material should have a Meyer hardness index of 2 and a perfectly elastic material of 3. Previous research by the author and co-workers indicated that the Meyer index of beech wood is 2.5 and for metals aluminum 2.25, copper 2.0. This gave rise to the hypothesis that the hardness index of each wood is about 2.5. It was decided to verify this hypothesis for different types of wood, different anatomical cross-sectional directions. Research on such diversity must therefore be of a probing nature. Nevertheless, these probing measurements indicate that different types of wood in given sectional planes have similar Meyer indexes, but in each section it is a different value. The measured mean value in the radial section was 2.41, in the tangential section 2.28 and in the cross section 1.98. Thus, the initial hypothesis of the value 2.5 was confirmed only for the radial section, and for the tangential and cross sections, new values of 2.25 and 2.0 were hypothesized. Only the extreme values of the Meyer indexes (on the radial and cross section) turned out to be statistically significantly different.

Time-dependent behaviour of circular steel tube confined reinforced concrete (STCRC) slender columns

Steel tube confined reinforced concrete (STCRC) columns are usually used as key structural elements in long-span and high-rise structures with high load resistance and outstanding seismic behaviour. To date, no investigation has been conducted on the long-term behaviour of slender STCRC columns. In this context, the long-term tests on axially loaded slender STCRC columns were firstly presented with various slenderness ratios and grades of concrete. The distributions of the tube’s circumferential and vertical stresses along the length of the column were carefully monitored throughout the tests to investigate the time-dependent tube stiffness contribution and their coupling effects with the confining pressure. By considering these two factors, a reliable analysis method was proposed and validated by the available test results. It was shown that, within the test parameters in this paper, the steel tube can contribute up to 12.6 % of axial stiffness of the composite columns, which is different from that predicted based on plane section assumption. The tube stiffness contribution increased with time and was more pronounced in columns with higher slenderness ratio or lower concrete strength. The coupling effects between the vertical stress and the confining pressure were not negligible for slender STCRC columns. The proposed method showed good accuracy in predicting long-term responses with errors less than +6.4 % and −2.9 %.

Experimental study and performance analysis of the flexural strength of reinforced ice slabs

In recent years, interest in the prefabricated ice rink for international competition has increased. The ice sheet, whose support is extruded polystyrene foam board, is prone to bending failure. To maintain the advantage of recycling prefabricated ice rinks, the method of reinforcing ice slabs with welded steel mesh (SRI) was proposed. However, the flexural properties of SRI remain unclear. Therefore, three-point bending tests, theoretical derivation, and finite element analysis were conducted in this study to better understand SRI. First, the three-point bending tests with 17 specimens were performed considering the effects of reinforcement ratio (0%∼0.812%). The results showed that the SRI's cracking load capacity and ultimate load capacity improved significantly with 1.84 and 4.49 times higher than the plain ice slab at most. Additionally, reinforcement can reduce the stiffness drop caused by cracking, which can be increased to 0.913 at most. Then, the calculation formula of the cracking load, which is a segmentation function, is derived based plane section assumption and gets good agreement with experimental results. At the same time, the calculation formula of the ultimate load is derived, although the calculation result is conservative, it can reflect the trend of the ultimate load with the variation of reinforcement ratio. Finally, finite element simulation analysis of three-point bending tests of SRI were conducted, using the brittle cracking model and the Coulomb-Moore plasticity model, respectively. Simulation results show that using both models alone have the limitation of use range. As a result, a B + C combined numerical model (the brittle cracking model is used for the tension zone and the Coulomb-Mohr plasticity model is used for the compressive zone) was proposed, and the simulation results agree well with the cracking load of both experiment and formula. Taken together, the welded steel mesh effectively improves the flexural performance of ice slabs and the findings of this study are beneficial for the design and finite element analysis of SRI in the future.

Safety and precision of frontal trajectory of lateral habenula deep brain stimulation surgery in treatment-resistant depression.

The lateral habenula (LHb) is a promising deep brain stimulation (DBS) target for treatment-resistant depression (TRD). However, the optimal surgical trajectory and its safety of LHb DBS are lacking. We reported surgical trajectories for the LHb in six TRD patients treated with DBS at the General Hospital of the Chinese People's Liberation Army between April 2021 and May 2022. Pre-operative fusions of magnetic resonance imaging (MRI) and computed tomography (CT) were conducted to design the implantation trajectory of DBS electrodes. Fusions of MRI and CT were conducted to assess the safety or precision of LHb DBS surgery or implantable electrodes locations. Results showed that the optimal entry point was the posterior middle frontal gyrus. The target coordinates (electrode tips) were 3.25 ± 0.82 mm and 3.25 ± 0.82 mm laterally, 12.75 ± 0.42 mm and 13.00 ± 0.71 mm posterior to the midpoint of the anterior commissure-posterior commissure (AC-PC) line, and 1.83 ± 0.68 mm and 1.17 ± 0.75 mm inferior to the AC-PC line in the left and right LHb, respectively. The "Ring" angles (relative to the AC-PC level on the sagittal section plane) of the trajectories to the left and right LHb were 51.87° ± 6.67° and 52.00° ± 7.18°, respectively. The "Arc" angles (relative to the midline of the sagittal plane) were 33.82° ± 3.39° and 33.55° ± 3.72°, respectively. Moreover, there was small deviation of actual from planned target coordinates. No patient had surgery-, disease- or device-related adverse events during the perioperative period. Our results suggested that LHb-DBS surgery via frontal trajectory is safe, accurate, and feasible. This is an applicable work to report in detail the target coordinates and surgical path of human LHb-DBS. It has of great clinical reference value to treat more cases of LHb-DBS for TRD.

Modular lightweight robot system for aircraft production using a generic OPC UA skill concept

There is a continuing trend in the aircraft industry to automate production. In order to be able to react to shortages of skilled workers, high order fluctuations and machine breakdowns, cost-effective, mobile and flexible systems are required to support the workers. This paper focuses on the integration of existing skill-based engineering concepts into production using standard OPC Unified Architecture interface, where production systems can be built quickly by simply interconnecting modules. The interconnected modules together form higher level subsystems enabling reusability of the individual modules as well as the assembled subsystems across several use cases. The approach is evaluated on a production related mobile robot system, whose task is to drive to the workstation, reference the component and drill holes in a vertical tail plane section of an aircraft. All devices from different suppliers contain skill-based modules based on standards defined by OPC Foundation and communicate via OPC UA-based Client/Server communication.

Restoring force model of hollow prefabricated square pier with grouted sleeves connection and high-strength steel bars

Seismic-performance investigation of piers under cyclic loading is based on the restoring force model (RFM). In this paper, the seismic performance of a hollow prefabricated square pier with grouted sleeve connections and high-strength steel bars was investigated; and a calculation method for its RFM was established. Based on the plane section assumption and the ideal elastic-plastic material assumption, the stress distribution of the pier's weak sections and the curvature of the pier body at different stress periods were analysed. The coordinates of the characteristic points of the pier's load–displacement curve were obtained. Next, the trilinear model of the pier's skeleton curve was obtained. The residual displacement of the pier under different loading displacements was calculated using a fitting equation for the unloading stiffness of the pier. Based on the principle of maximum point pointing, the loading and unloading paths of the pier under reciprocating loads were determined; and the RFM curve of the pier was finally established. This laid a foundation for the investigation of the pier's performance under reciprocating loads.

Mechanical influence of periacetabular osteotomy on late total hip arthroplasty.

Periacetabular osteotomy (PAO) is an effective technique to treat symptomatic hip dysplasia. However, following PAO, some patients still experience persistent pain or development of hip arthritis, requiring total hip arthroplasty (THA). Issues such as whether patients with PAO are necessarily at increased risk of post-THA complications and revision of the prosthesis remain debatable. The purpose of this study was to evaluate the biomechanical influence of PAO on the acetabulum after THA by finite element analysis. Eight patients with developmental dysplasia of the hip (DDH) diagnosed in the Fourth Medical Center of the PLA General Hospital were enrolled in this research. Patient-specific hip joint models were reconstructed from computed tomography scans, and the hip prosthesises, were established via computer-aided design (CAD) modeling technology. The finite element analysis was conducted to compare the surface and internal stress through the process mapping of the model due to the THA. Compared with the THA after PAO, the position of the high-stress area of the acetabular fossa of patients without PAO decreased, and the high-stress area developed toward the lower edge of the acetabulum. Although the high-stress area of the suprapubic branch did not change significantly, the peak stress was higher (t=.00237). The analysis of the section plane showed that the high-stress area of cancellous bone had a large distribution. The acetabular size and vertical distance of rotation center (VDRC) were significantly correlated with the maximum postoperative acetabular equivalent stress (p=.011, p=.001). In the Post group, both the horizontal distance of rotation center (HDRC) and A-ASA were significantly correlated with postoperative maximal acetabular equivalent stress, with a significance of 0.014 and 0.035, respectively. The risk of postoperative prosthetic revision following THA is not increased by PAO, although the risk of postoperative suprapubic branch fracture is increased.

Visualization and quantification of coconut using advanced computed tomography postprocessing technology.

Computed tomography (CT) is a non-invasive examination tool that is widely used in medicine. In this study, we explored its value in visualizing and quantifying coconut. Twelve coconuts were scanned using CT for three months. Axial CT images of the coconuts were obtained using a dual-source CT scanner. In postprocessing process, various three-dimensional models were created by volume rendering (VR), and the plane sections of different angles were obtained through multiplanar reformation (MPR). The morphological parameters and the CT values of the exocarp, mesocarp, endocarp, embryo, bud, solid endosperm, liquid endosperm, and coconut apple were measured. The analysis of variances was used for temporal repeated measures and linear and non-linear regressions were used to analyze the relationship between the data. The MPR images and VR models provide excellent visualization of the different structures of the coconut. The statistical results showed that the weight of coconut and liquid endosperm volume decreased significantly during the three months, while the CT value of coconut apple decreased slightly. We observed a complete germination of a coconut, its data showed a significant negative correlation between the CT value of the bud and the liquid endosperm volume (y = -2.6955x + 244.91; R2 = 0.9859), and a strong positive correlation between the height and CT value of the bud (y = 1.9576 ln(x) -2.1655; R2 = 0.9691). CT technology can be used for visualization and quantitative analysis of the internal structure of the coconut, and some morphological changes and composition changes of the coconut during the germination process were observed during the three-month experiment. Therefore, CT is a potential tool for analyzing coconuts.

New constraints on macroscopic dark matter using radar meteor detectors

We show that dark-matter candidates with large masses and large nuclear interaction cross sections are detectable with terrestrial radar systems. We develop our results in close comparison to successful radar searches for tiny meteoroids, aggregates of ordinary matter. The path of a meteoroid (or suitable dark-matter particle) through the atmosphere produces ionization deposits that reflect incident radio waves. We calculate the equivalent radar echoing area or `radar cross section' for dark matter. By comparing the expected number of dark-matter-induced echoes with observations, we set new limits in the plane of dark-matter mass and cross section, complementary to pre-existing cosmological limits. Our results are valuable because (A) they open a new detection technique for which the reach can be greatly improved and (B) in case of a detection, the radar technique provides differential sensitivity to the mass and cross section, unlike cosmological probes.

Seismic response of shallow circular openings to Rayleigh waves

Closed-form solutions are presented for an unsupported shallow circular opening subjected to Rayleigh waves. It is assumed that the ground is homogeneous and elastic, that the wave motion is perpendicular to the tunnel axis, with motions on the plane of the cross section of the tunnel. Thus, plane strain conditions apply. A quasi-static analysis is taken because Rayleigh waves have a large wavelength, arguably of the order of kilometers and velocities about 10% smaller than that of shear waves. Complex variable theory and conformal mapping are used to reach the solution, which is given as a system of equations that provides the parameters of the complex analytic functions needed to compute stresses and displacements. Solutions are found for drained and undrained loading conditions. For the latter, the principle of effective stresses is assumed, which requires no volume change of the ground during the passage of the Rayleigh wave. Because the vertical and horizontal free-field motions of the Rayleigh waves are out of phase, the stresses and displacements induced are also out of phase and cannot be superimposed. Thus, stresses and displacements obtained from the free-field motions are also out of phase, uncoupled and treated separately. The results show that the normal stress terms induced by the free-field motions dominate the response of shallow tunnels and that stresses and tunnel distortions decrease with tunnel depth. An additional solution for a deep circular tunnel subjected to Rayleigh waves is also proposed. A comparison between stresses and displacements obtained with the assumption of shallow or deep tunnel suggests that the largest demand on the tunnel can be approximated with the solution for a deep tunnel, for tunnels at depths larger than about five to six times their radius.

Analysis of the stability behavior of cross bracings in transmission towers based on experiments and numerical simulations

Angle steel towers are widely used in various transmission lines owing to their convenient connections, easy availability, simple production processes, and high efficiencies. Cross bracings play an important role in resisting wire tension, wind, and snow loads as the main support components ensuring the stability of an angled steel tower. Thus, an analysis of the buckling resistance of cross bracings is significant in improving the bearing capacity of transmission towers. In this study, full-scale tests of equal-leg and unequal-leg angles in planar tower sections were conducted. The influence of the axial force ratio on the stability of a cross bracing was studied based on numerical simulations and compared with the current codes. The results revealed that the failure mode of an equal-leg angle cross bracing was always out-of-plane buckling, whereas the final failure mode of an unequal-leg angle steel cross bracing could be out-of-plane buckling or both out-of-plane and in-plane co-buckling. With an increase in the axial force ratio, the buckling resistance of the cross bracing decreased rapidly, with over 40% decline in the amplitude. The buckling resistance of the unequal-leg angle was approximately 20% higher than that of the equal-leg angle at all axial force ratios. Compared with the current codes for tower structures, we discovered that the code values and finite-element results were considerably different. Notably, the calculation methods of ASCE 10-15 and EN1993-3-1 neglect the variation in the effective length with the axial force ratio. Although DL/T 5154-2012 considers the effect of the axial force ratio, the values are all greater than the finite-element results. The findings of this study can help elucidate the cross bracing stability in angle steel lattice towers.

Flexural Behavior of Graphite Tailings RC Beams in Chloride Environment

This paper investigates the mechanical properties of graphite tailings concrete beams under various curing environments. The results show that the concentration of graphite tailings has an important influence on the mechanical properties of concrete. Finally, the bending characteristics of the beam and the modified bearing capacity calculation formula are obtained, which provides a theoretical basis and the reference value for the construction of green building materials. Through research, the main innovations and main findings of this paper are as follows: (1) In the three kinds of concrete experimental environment, the fracture load and ultimate load of concrete beams with graphite tailings replacement rate of 20% are the largest. (2) In the three kinds of concrete test environment, when the concrete test beams under the same load, with the increase of graphite tailings replacement rate, the mid-span deflection of concrete beams showed a trend of decreasing first and then increasing. When the replacement rate of graphite tailings sand is 20%, the mid-span deflection of the test beam is the smallest. (3) Through experiments, it is found that the normal section bearing capacity of graphite tailings concrete beams after chloride salt erosion conforms to the plane section assumption. After chlorine salt erosion, the strain of the longitudinal tensile steel bar of concrete beams with different graphite tailings sand replacement rates is the same as that of ordinary concrete beams, and the slope of the strain curve is the same, showing a linear trend. The experimental results show that the replacement rate of graphite tailings sand has an insignificant effect on the strain of steel bars. (4) The Gauss function is used to fit the experimental value of normal section bearing capacity of concrete beam, and the calculation formula of normal section ultimate bearing capacity of graphite tailings sand concrete beam under chloride environment is established. The research results of this paper have significant reference value for the study of mechanical properties of graphite tailings sand concrete components.