Beam System Research Articles

Analysis of Displacement Influence of Span of Prestressed Fish-Belly Beam on Foundation Pit Plane

As a new technology of antagonistic internal support, prestressed fish-bellied steel support system has been widely used in various foundation pit projects because of its advantages such as reutilization, effective displacement control and large mechanical operation space. But at present, the plane layout depends on experience, and has not yet formed a set of complete and reasonable plane layout methods. In the plane layout, the corner brace is arranged according to the condition of the plane stress balance of the corner brace, then the brace is arranged based on the corner brace balance theory, and finally the optimal span of the fish-belly beam is selected. The displacement diagram of supporting structure is obtained by using Midas/Gen with the span of fish-belly beam as the variable, the influence of the span of fish-belly beam on the horizontal displacement of foundation pit is analyzed, the relationship formula between the span of fish-belly beam and the size of foundation pit is obtained, and the plane layout method of prestressed fish-belly beam system is proposed.

Dynamic behavior of pin-free beam with torsional spring and hub at pinned end

This paper described the free vibration of a Euler-Bernoulli beam and discovered the first five dimensionless natural frequencies and mode shapes of motion for the pin-free beam model with a helical spring and rotating mass on the pinned side of the beam. The effect of changing the dimensionless torsional stiffness ratios was investigated, as was the effect of changing the dimensionless rotational inertia torque ratios Concerning the vibration properties of the beam. The mathematical equations that regulate the pin-free beam model were constructed using the exact analytical solution, establishing the Admissible Function and the natural frequency equation for the basic pin-free beam system. The approximate Rayleigh-Ritz approach was then used to determine the first five dimensionless natural frequencies, as well as the movement pattern for the pin-free beam model with a helical spring and a rotating mass on the side of the hinge. The results demonstrated that modifying the beam's natural frequencies is dependent on the ratios of the additional torsional spring parameters as well as the ratios rotational moment of inertia. The threshold system frequencies increase when the spring parameters are the major factor, and decrease when the inertia moment parameters are the main factor. Both play a role in influencing natural frequency to varied degrees. Unifying the final distribution of parameters might lead to optimizing the impact of parameters on the natural frequencies of the system.

Rare faction of flora of the designed landscape reserve “Balka Shchurovka”

The article is devoted to the study of the modern distribution of certain rare plant species within the "Balka Shchurovka" beam system (near the settlements of Dniprovske, Novomykolaivka of the Verkhnyodniprovska OTG of the Dnipropetrovsk region) and substantiation of the prospects for granting the object the status of a nature conservation area. The natural diversity of the vegetation cover of the designed reserve consists of zonal steppe vegetation, bairach forests, psamophilic and petrophilic communities, and meadow vegetation. According to indicators of biodiversity, the territory b. Shchurovka is one of the most valuable within the borders of Verkhnyodniprovska OTG of Dnipropetrovsk region. In the process of researching the flora of the planned reserve, a number of new locations of species rare for the region and the region were discovered. 26 regionally rare plant species grow here, 13 species listed in the Red Book of Ukraine, 3 species from Resolution 6 of the Berne Convention and Annexes of the Habitats Directive, presented in the flora of Ukraine, 1 species from the World Red List. The list of plants of the Dnipropetrovsk region included in the Red Book of Ukraine includes 56 species of vascular plants, of which 13 species grow within the b. Rat, which is 23% of the total number of red book species of Dnipropetrovsk region. An important and interesting feature of the layer of sand exposed on the right slope of the gully is the presence of blocks of red sandstone enriched with iron oxides. Near the sandstone outcrops, a characteristic complex of flora has formed on sandy soil with the participation of Sempervivum ruthenicum Schnittsp. & C.B. Lehm, Pulsatilla pratensis (L.) Mill. s.l., Thymus pallasianus Heinr.Braun, Peucedanum arenarium Waldst. & Kit. (Taeniopetalum arenarium (Waldst. & Kit.) V. N. Tichomirov), Achillea leptophylla M. Bieb. Jurinea cyanoides (L.) Rchb and Pulsatilla patens (L.) Mill grow here. s.l. - rare species from the Annexes of the Habitats Directive, Annex I of the Berne Convention, which prefer biotopes with an intact structure as part of rare coenoses. The study of the rare fraction of the flora of the beam system in the context of the conservation of biodiversity of the Right Bank Steppe of the Dnieper region can become the basis of the nature conservation concept of sustainable development of the region.

Rare faction of flora of the designed landscape reserve “Balka Shchurovka”

The article is devoted to the study of the modern distribution of certain rare plant species within the "Balka Shchurovka" beam system (near the settlements of Dniprovske, Novomykolaivka of the Verkhnyodniprovska OTG of the Dnipropetrovsk region) and substantiation of the prospects for granting the object the status of a nature conservation area. The natural diversity of the vegetation cover of the designed reserve consists of zonal steppe vegetation, bairach forests, psamophilic and petrophilic communities, and meadow vegetation. According to indicators of biodiversity, the territory b. Shchurovka is one of the most valuable within the borders of Verkhnyodniprovska OTG of Dnipropetrovsk region. In the process of researching the flora of the planned reserve, a number of new locations of species rare for the region and the region were discovered. 26 regionally rare plant species grow here, 13 species listed in the Red Book of Ukraine, 3 species from Resolution 6 of the Berne Convention and Annexes of the Habitats Directive, presented in the flora of Ukraine, 1 species from the World Red List. The list of plants of the Dnipropetrovsk region included in the Red Book of Ukraine includes 56 species of vascular plants, of which 13 species grow within the b. Rat, which is 23% of the total number of red book species of Dnipropetrovsk region. An important and interesting feature of the layer of sand exposed on the right slope of the gully is the presence of blocks of red sandstone enriched with iron oxides. Near the sandstone outcrops, a characteristic complex of flora has formed on sandy soil with the participation of Sempervivum ruthenicum Schnittsp. & C.B. Lehm, Pulsatilla pratensis (L.) Mill. s.l., Thymus pallasianus Heinr.Braun, Peucedanum arenarium Waldst. & Kit. (Taeniopetalum arenarium (Waldst. & Kit.) V. N. Tichomirov), Achillea leptophylla M. Bieb. Jurinea cyanoides (L.) Rchb and Pulsatilla patens (L.) Mill grow here. s.l. - rare species from the Annexes of the Habitats Directive, Annex I of the Berne Convention, which prefer biotopes with an intact structure as part of rare coenoses. The study of the rare fraction of the flora of the beam system in the context of the conservation of biodiversity of the Right Bank Steppe of the Dnieper region can become the basis of the nature conservation concept of sustainable development of the region.

Analysis on Shear Resistance of Joint and Structural Mechanical Response of Assembled Composite Beam Joints

This article systematically studies the shear characteristics and structural mechanical response characteristics of composite beam joints. The results indicate that the shear stiffness of the connector is between 1000 N/mm and 2500 N/mm, with high stiffness performance. Meanwhile, as the stiffness increases, the frequency of the structure shows a significant increasing trend, indicating that high stiffness helps to improve the stability of the structure. In the trend chart of shear characteristics and performance of connectors over time, the shear characteristics of connectors significantly increased between 2018 and 2023, with an average shear strength increasing from 1500 N to 2100 N, an increase of 40%. By studying the static and dynamic response characteristics, as well as the bearing capacity, stability, and fatigue performance of composite beams. The results indicate that the response characteristics of the new connector are significantly better than those of traditional connectors. Based on the research results, this article proposes strategies and suggestions for optimizing connector design and improving overall structural performance, providing important theoretical support and practical guidance for practical engineering applications. This study not only enriches the theoretical system of composite beams, but also has important significance in promoting technological progress in related fields.

Weld-free mounting of lamellae for electrical biasing operando TEM

Recent advances in microelectromechanical systems (MEMS)-based substrates and sample holders for in situ transmission electron microscopy (TEM) are currently enabling exciting new opportunities for the nanoscale investigation of materials and devices. The ability to perform electrical testing while simultaneously capturing the wide spectrum of signals detectable in a TEM, including structural, chemical, and even electronic contrast, represents a significant milestone in the realm of nanoelectronics. In situ studies hold particular promise for the development of Metal-Insulator-Metal (MIM) devices for use in next-generation computing. However, achieving successful device operation in the TEM typically necessitates meticulous sample preparation involving focused ion beam (FIB) systems. Conducting contamination introduced during the FIB thinning process and subsequent attachment of the sample onto a MEMS-based chip remains a formidable challenge. This article delineates an improved FIB-based sample preparation methodology that results in good electrical connectivity and operational functionality across various MIM devices. To exemplify the efficacy of the sample preparation technique, we demonstrate preparation of a clean cross section extracted from a Au/Pt/BaSrTiO3/SrMoO3 tunable capacitor (varactor). The FIB-prepared TEM lamella mounted on a MEMS-based chip showed current levels in the tens of picoamperes range at 0.1 V. Furthermore, the electric response and current density of the TEM lamella device closely align with macro-scale devices. These samples exhibit comparable current densities to their macro-sized counterparts thus validating the sample preparation process and confirming device connectivity. The simultaneous operation and TEM characterization of electronic devices enabled by this process enables direct correlation between device structure and function, which could prove pivotal in the development of new MIM systems.

Dual Data Streaming on Tropospheric Communication Links Based on the Determination of Beam Pointing Dynamics Using a Modified Ray-Based Channel Model

Tropospheric systems are widely used by military forces as they provide long-distance, real-time communication. Slow-fading propagation loss reduces link availability and limits its data-carrying capacity. Beam pointing dynamics provides knowledge of favorable heights at different times of the day in different seasons and a useful steering range. Beam steering, based on the beam pointing dynamics of the link, can overcome slow fading. The main contributions of this paper are the derivation of a realistic and accurate tropospheric channel model obtained by making important modifications to Dinc’s ray-based model. This paper also presents a method for determining beam pointing dynamics using the modified model. Beam pointing dynamics for two different links located in India have been determined in this paper using real-world data obtained from the Indian Meteorological Department. Another significant contribution of the paper is presenting the prospect of dual data streaming on tropospheric links using a fixed beam and a dynamically steered beam, based on the examination of beam pointing dynamics obtained for the two links. The main result presented in this paper is the comparison of powers received from the most favorable heights in a steerable beam system with the powers received in conventional fixed-beam systems for different days of the year. It has been shown that a higher received power can be achieved with beam steering. Another important result shown is the comparison of the achievable data rates for a single fixed-beam system and a dual-beam (one fixed beam and one dynamically steered beam) system. It has been shown that almost double the data rate is achievable in a dual-beam system. The method for the determination of beam pointing dynamics and the possibility of dual data streaming presented in this paper can significantly enhance the availability and capacity of tropospheric links.

Stabilization and tracking control of underactuated ball and beam system using metaheuristic optimization based TID-F and PIDD2-PI control schemes.

In this paper, we propose two different control strategies for the position control of the ball of the ball and beam system (BBS). The first control strategy uses the proportional integral derivative-second derivative with a proportional integrator PIDD2-PI. The second control strategy uses the tilt integral derivative with filter (TID-F). The designed controllers employ two distinct metaheuristic computation techniques: grey wolf optimization (GWO) and whale optimization algorithm (WOA) for the parameter tuning. We evaluated the dynamic and steady-state performance of the proposed control strategies using four performance indices. In addition, to analyze the robustness of proposed control strategies, a comprehensive comparison has been performed with a variety of controllers, including tilt integral-derivative (TID), fractional order proportional integral derivative (FOPID), integral-proportional derivative (I-PD), proportional integral-derivative (PI-D), and proportional integral proportional derivative (PI-PD). By comparing different test cases, including the variation in the parameters of the BBS with disturbance, we examine step response, set point tracking, disturbance rejection analysis, and robustness of proposed control strategies. The comprehensive comparison of results shows that WOA-PIDD2-PI-ISE and GWO-TID-F- ISE perform superior. Moreover, the proposed control strategies yield oscillation-free, stable, and quick response, which confirms the robustness of the proposed control strategies to the disturbance, parameter variation of BBS, and tracking performance. The practical implementation of the proposed controllers can be in the field of under actuated mechanical systems (UMS), robotics and industrial automation. The proposed control strategies are successfully tested in MATLAB simulation.

Stabilization of a Rao–Nakra Sandwich Beam System by Coleman–Gurtin’s Thermal Law and Nonlinear Damping of Variable-Exponent Type

In this paper, we explore the asymptotic behavior of solutions in a thermoplastic Rao–Nakra (sandwich beam) beam equation featuring nonlinear damping with a variable exponent. The heat conduction in this context adheres to Coleman–Gurtin’s thermal law, encompassing linear damping, Fourier, and Gurtin–Pipkin’s laws as specific instances. By employing the multiplier approach, we establish general energy decay results, with exponential decay as a particular manifestation. These findings extend and generalize previous decay results concerning the Rao–Nakra sandwich beam equations.

Well-posedness and general energy decay for a nonlinear piezoelectric beams system with magnetic and thermal effects in the presence of distributed delay

In this paper, we consider one-dimensional nonlinear piezoelectric beams with thermal and magnetic effects in the presence of a distributed delay term acting on the heat equation. First, we show that the system is well-posed in the sense of a semigroup. Through the construction of an appropriate Lyapunov functional, we establish a general decay result for the solutions of the system, for which the exponential and polynomial decays are only special cases, under a suitable assumption on the weight of the delay that the damping effect through heat conduction is strong enough to stabilize the system even in the presence of a time delay. Furthermore, our result does not depend on any relationship between system parameters.

Vehicle Load Identification Using Machine Vision and Displacement Influence Lines

In recent years, bridge collapses resulting from vehicle overloading have underscored the crucial necessity for real-time monitoring of traffic conditions on bridges, making pavement-based weigh-in-motion systems indispensable for large bridges. However, these systems usually have poor durability and will cause traffic interruptions during their installation and maintenance processes. This paper addresses the challenge of recognizing vehicle loads by proposing a vehicle load identification method based on machine vision and displacement influence lines. The technology consists of three essential steps. Firstly, machine vision technology is utilized to identify vehicle trajectories. Following this, the displacement response, monitored by millimeter-wave radar, is integrated to calculate the influence lines of the structure’s displacement. Lastly, an overall least squares method incorporating a regularization term is applied to calculate axle weights. The efficacy of the proposed method is validated within the monitoring system of a specific continuous beam. Importantly, the calibration of vehicles and the validation dataset rely on information monitored by the pavement-based weigh-in-motion system of adjacent arch bridges, serving as ground truth. Results indicate that the identification errors for gross vehicle weight do not exceed 25%. This technology holds significant importance for identifying vehicle weights on small to medium-span bridges. Due to its cost-effectiveness, easy installation, and maintenance, it possesses a high potential for widespread adoption.

Efficient Dynamic Analysis of Complex Beam Systems for Artillery Firing Using Time-Varying Mechanics

Efficient Dynamic Analysis of Complex Beam Systems for Artillery Firing Using Time-Varying Mechanics

Dynamic modeling and parameter sensitivity analysis of AUV by using the POD method and the HB-AFT method

Autonomous Underwater Vehicle (AUV) parameterization is a geometric modification method, and can quickly obtain excellent structure with low vibration and noise performance. Blindness and inefficiency are common outcomes of the lack of an efficient parameter selection approach. But not enough research has been done in this area. In this paper, the finite element (FE) method is used to establish the propeller–shaft–shell double beam system with ball bearings, which is more similar to the real model. The basic theory of the proper orthogonal decomposition (POD) method is introduced in detail, and the original full order model (FOM) is reduced to 4 DOFs. It is found that the accuracy of the reduced order model (ROM) is high enough and the calculation time is greatly reduced. The semi-numerical semi-analytical expression of the ROM system is solved by the harmonic balance and alternating frequency/time domain (HB-AFT) method, whose results are in good agreement with those by the Runge–Kutta method. The sensitivities of the shell responses to the spring stiffness are discussed. The AUV setup is designed to analysis of numerical and experimental results. These results in this paper can provide an advanced theoretical basis for the structural parameter design of the AUV.

A hybrid beam system of aramid-fibre-reinforced concrete and high-strength concrete

ABSTRACT This paper investigates the flexural behaviour of hybrid reinforced concrete (RC) beams having aramid fibre reinforced concrete (AFRC) in the tension zone and high-strength concrete (HSC) in the compression zone. In two series of experimental investigations, the depth of AFRC layer and the concrete strength in the compression zone were varied. The hybrid beams were tested in series 1 to explore the effects of the depth of AFRC layer on load-carrying capacity and flexural toughness. The effects of compressive strength of the concrete in the top half of the hybrid beams on load-deflection behaviour, failure mode and cracking pattern were studied in series 2. The experimental results reveal that the use of AFRC only in the bottom half of the beam enhanced load-carrying capacity and flexural toughness by 62.44% and 87.66%, respectively, compared to the control specimen with no AFRC. The hybrid beam with AFRC-HSC exhibited 5% higher load-carrying capacities, 45% higher ductility and better cracking behaviour than the conventional RC beam. These enhanced structural performances are beneficial for specific purposes such as structures in marine environment where rebar corrosion is the main concern, or structures under extreme loadings where high ductility is required.

The transverse dynamic behavior study of a beam system coupled through a local nonlinear coupling layer

In engineering, some complex systems can be reduced to the beam system connected by serval coupling elements. To explore the potential application of local coupling nonlinearity on the transverse dynamic behavior of beams, this work establishes the physical model of a beam system coupled by a local nonlinear coupling layer. On the basis of ensuring the validity of the results, studies the effect of the nonlinear coupling layer on the transverse forced vibration of the beam system. Exploring the characters and reason for complex responses of the beam system coupled through a local nonlinear coupling layer. After discussing the numerical results, it can be found that the beam system presents complex responses within some parameters of the local nonlinear coupling layer, including amplitude jumping, quasi-periodic state, and targeted energy transfer, in which the change of the nonlinear restoring force is the reason for the appearance or disappearance of complex responses. For single-frequency responses, complex responses of the beam system can be motivated by changing the parameters of the local nonlinear coupling layer. With the simultaneous variation of the nonlinear stiffness and viscous damping, responses of the beam system contain both amplitude-sensitive regions and amplitude-jumping regions, in which the amplitude-sensitive region provides an effective parameter range for controlling the vibration by adjusting the local nonlinear coupling layer. On the whole, a suitable combination of nonlinear stiffness and viscous damping of the local nonlinear coupling layer can effectively reduce the vibration at the boundaries of the beam system.

Exponential stability and numerical computation for a nonlinear shear beam system

Exponential stability and numerical computation for a nonlinear shear beam system

Resistive hose modes in tokamak runaway electron beams

Beams of energetic runaway electrons are generated during disruptions in tokamaks, and fluid models are used to study their effects on macroscale dynamics. Linear computations of a massless, runaway electron beam coupled to MHD plasma show that resistive hose instabilities grow faster than tearing modes at large resistivity. Eigenvalue results with reduced models of the resistive hose instability are compared with results from the full MHD and beam system, showing that the resistive hose decouples from any plasma response. An estimate of plasma temperature at which growth of the resistive hose dominates tearing for post-disruption DIII-D plasma parameters is in a physically relevant regime.

The ABMS - Automatic Balancing Mechatronic System

This work focuses on the design, construction, functionality of an educational device called the ABMS (Automatic Balancing Mechatronic System) and its communication with simulation environments. The ABMS device is an implementation of the Ball on Beam system, commonly used in system control education. From virtual design to construction, we intend to implement the new device in a way that respects the principles of open-source and free software. The dimensions of the virtual model and, subsequently, the real device are adapted to respect the compactness of the whole system as well as the possibility of its 3D printing.

Coulomb and symmetry-energy effects on proton and neutron density-distributions in central heavy-ion collisions, across beam energies and system masses

In this contribution, we review our current and previous investigations of total, proton, and neutron particle number densities and the asymmetry of proton and neutron density distributions achievable in central heavy-ion collisions at beam energy below 800 MeV/nucleon. Furthermore, the effects of the Coulomb interaction and the dependence on a system size in three representative symmetric and asymmetric Ca, Sn and Pb systems are studied. The Boltzmann-Uhlenbeck-Uehling (pBUU) transport and Time-Dependent Hartree-Fock (TDHF) models, employing the SVbas, SkT3 and SVsym Skyrme interactions, are used in these simulations. We find that (i) the highest total densities predicted at Ebeam = 800 MeV/nucleon are on the order of ∼ 2.5ρ0 (ρ0 = 0.16 fm−3), (ii) the proton-neutron asymmetry for maximal densities, δ = (ρnmax−ρpmax)/(ρnmax+ρpmax) do not generally exceed the asymmetry in the initial state of the collision at all beam energies and tend to decrease during the reaction, and (iii) a significant portion of this asymmetry has its microscopic origin in Coulomb forces, masking the pure nuclear contribution. In addition, the evolution of normalized maximal proton, neutron, and total nucleon number density with increasing beam energy, the impact of correlations in the reaction, and the time evolution of the proton and neutron density distributions in the plane transverse to the beam direction are illustrated and discussed.

Beam energy and system size dependence of heavy flavor production at STAR

We report the measurements of quarkonia (J/ψ and ψ(2S)) in heavyion collisions via the e+e− decay channel at midrapidity (|y| < 1) by the STAR experiment. The centrality and transverse momentum dependence of the yield ratio of ψ(2S) to J/ψ is measured for the first time in heavy-ion collisions at RHIC. These results, together with the new measurement of collision energy dependence of inclusive J/ψ suppression in Au+Au collisions, allow for a systematic study of the quarkonium production in the medium. In addition, we present the first measurement of J/ψ polarization in heavy-ion collisions at RHIC in both the Helicity and the Collins-Soper frames, which provides a new insight for studying the properties of the Quark-Gluon Plasma created in heavy-ion collisions.