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Khodadad, Iman, Nathan Nelson-Fitzpatrick, Kevin Burcham, Arsen Hajian i Simarjeet S. Saini. "Electron beam lithography using fixed beam moving stage". Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena 35, nr 5 (wrzesień 2017): 051601. http://dx.doi.org/10.1116/1.4997018.
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Mere, Viphretuo, i Shankar Kumar Selvaraja. "Method to fabricate taper waveguide using fixed-beam moving stage electron-beam lithography". Journal of Micro/Nanolithography, MEMS, and MOEMS 18, nr 04 (17.10.2019): 1. http://dx.doi.org/10.1117/1.jmm.18.4.043503.
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Demessie Yallew, Henock, Jana Jágerská i Martin M. Greve. "Long, stitch-free slot waveguide with s-bend tapered couplers for IR-sensing applications using electron beam lithography". Journal of Vacuum Science & Technology B 41, nr 1 (styczeń 2023): 012601. http://dx.doi.org/10.1116/6.0002187.
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We use the fixed beam moving stage (FBMS) electron beam lithography technique to pattern a 10 mm long slot waveguide with s-bend tapered double-tip couplers. The fabrication method solves two major limitations of the FBMS mode, namely, the requirement for fixed-width structures and the incidence of stage placement drift for patterns involving elements of different widths. This has been achieved by fracturing the outline of the structure into fixed-width elements of gradually increasing width and creating intermediate overlap areas between the elements to mitigate the stage placement drifts.
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Roselli, Luca, Valeria Palazzari, Federico Alimenti, Paolo Mezzanotte, Matteo Comez i Nicola Porzi. "Robust road-to-car communications by means of an active Ku-band RF Self-IDentification (RFSID) system". International Journal of Microwave and Wireless Technologies 2, nr 2 (kwiecień 2010): 145–52. http://dx.doi.org/10.1017/s1759078710000243.
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This paper deals with a robust RFSID (Radio Frequency Self IDentification) system for road-to-car communications. The RFSID-based system operates in Ku-band and consists of a fixed transmitter, located at the road side, and of a receiver unit placed on the moving target, i.e. a car in its first proposed application. A slotted waveguide antenna array is used to illuminate the moving object at the desired position, whereas a four-patch array antenna is adopted at the receiver side. Both the antennas have been designed using numerical simulations based on a Finite Difference Time Domain (FDTD) algorithm. When the moving object crosses the antenna beam a triggering pulse is generated by the receiver; such a pulse can be used to reset or update the electronics aboard the vehicle and to log specific information coming from location-based systems (LBSs), into the car equipments. A digital transmission of gold sequences and a post-processing unit have been exploited so far to increase the robustness and the accuracy of the system. At this stage of the development the system benefit of extensive field tests, being adopted for some years by many top Formula 1 racing teams as a lap trigger system, used to reset the on-board electronics when the car crosses either the finishing line and peculiar path reference points. The temporal accuracy exhibited is better than 1 ms with a coverage of about 90 m.
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Yang, Jing, Xuhui He, Haiquan Jing, Hanfeng Wang i Sévérin Tinmitonde. "Dynamics of Double-Beam System with Various Symmetric Boundary Conditions Traversed by a Moving Force: Analytical Analyses". Applied Sciences 9, nr 6 (22.03.2019): 1218. http://dx.doi.org/10.3390/app9061218.
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Dynamics of the double-beam system under moving loads have been paid much attention due to its wide applications in reality from the analytical point of view but the previous studies are limited to the simply supported boundary condition. In this study, to understand the vibration mechanism of the system with various boundary conditions, the double-beam system consisted of two general beams with a variety of symmetric boundary conditions (fixed-fixed, pinned-pinned, fixed-pinned, pinned-fixed and fixed-free) under the action of a moving force is studied analytically. The closed-form frequencies and mode shapes of the system with various symmetric boundary conditions are presented by the Bernoulli-Fourier method and validated with Finite Element results. The analytical explicit solutions are derived by the Modal Superposition method, which are verified with numerical results and previous results in the literature. As found, each wavenumber of the double-beam system is corresponding to two sub-modes of the system and the two sub-modes associated with the first wavenumber of the system both contribute significantly to the vibration of the system under a moving force. The analytical solutions indicate that the mass ratio, the bending stiffness ratio, the stiffness ratio of contact springs and the speed ratio of the moving force are the factors influencing the vibrations of the system under a moving force. The relationships between these dimensionless parameters and the displacement ratio of the system are investigated and presented in the form of plots, which could be referred in the design of the double-beam system.
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Kong, Lingyuan, i Robert G. Parker. "Vibration of an axially moving beam wrapping on fixed pulleys". Journal of Sound and Vibration 280, nr 3-5 (luty 2005): 1066–74. http://dx.doi.org/10.1016/j.jsv.2004.02.037.
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Chawda, Denil, i Senthil Murugan. "Dynamic Response of a Cantilevered Beam Under Combined Moving Moment, Torque and Force". International Journal of Structural Stability and Dynamics 20, nr 05 (maj 2020): 2050065. http://dx.doi.org/10.1142/s0219455420500650.
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This paper studies the dynamic response of a cantilevered beam subjected to a moving moment and torque, and combination of them with a moving force. The moving loads are considered to traverse along the length of the beam either from fixed-to-free end or free-to-fixed end. The beam is considered to have constant material and geometric properties. The beam is modeled using the Rayleigh beam theory considering the rotary inertia effects. The Dirac-delta function used to model the moving loads in the governing partial differential equations (PDEs) has complicated the solution of the problem. The Eigenfunction expansions coupled with the Laplace transformation method is used to find the semi-analytical solution for the resulting governing PDEs. The effects of moving loads on the dynamic response are studied. The dynamic effects are quantified based on the number of oscillations per unit travel time of the moving load and the Dynamic Amplification Factor (DAF) of the beam’s tip response. Numerical results are also analyzed for the two-speed regimes, namely high-speed and low-speed regimes, defined with respect to the critical speed of the moving loads. The accuracy of the analytical solutions are verified by the finite element analysis. The numerical results show that the loads moving with low speeds have significant impact on the dynamic response compared to high speeds. Also, the moving moment has significant impact on the amplitude of dynamic response compared with the moving force case.
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Berkani, Amirouche, i Nasser-eddine Tatar. "Stabilization of a viscoelastic Timoshenko beam fixed into a moving base". Mathematical Modelling of Natural Phenomena 14, nr 5 (2019): 501. http://dx.doi.org/10.1051/mmnp/2018057.
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In this paper, we are concerned with a cantilevered Timoshenko beam. The beam is viscoelastic and subject to a translational displacement. Consequently, the Timoshenko system is complemented by an ordinary differential equation describing the dynamic of the base to which the beam is attached to. We establish a control force capable of driving the system to the equilibrium state with a certain speed depending on the decay rate of the relaxation function.
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Jun, Zhang, Ming Kang Gou i Chuan Liang. "Experimental Simulation of Bridges Subjected by Moving Loads". Applied Mechanics and Materials 873 (listopad 2017): 208–11. http://dx.doi.org/10.4028/www.scientific.net/amm.873.208.
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The effect of bridge vibrationinduced bylive loads such as vehicles and pedestrians is an important factor of bridge fatigue damage. It takes much labor and material resource to perform vibration experiments on bridges subjected by real moving loads in field. In order to carry out laboratory experiments on bridges subjected by moving loads, a fixed load with harmonic vibration simulates a moving load on bridge in the beam theory. A simply supported bridge is considered in the present study. The dynamic responses of bridge under different loads are established by the analytic method. Amplitude and frequency of the simulated load are generated on the principle of equal displacements due to both a moving load and a fixed harmonic load impacting on a simply supported beam. Comparisons of numerical results of two types of load on the same beam indicate that the harmonic load can simulate a moving load effectively. It is possible that the field test on bridge can be carried out indoors.
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Lu, Lei, Xiao-Dong Yang, Wei Zhang i Siu-Kai Lai. "On Travelling Wave Modes of Axially Moving String and Beam". Shock and Vibration 2019 (12.12.2019): 1–13. http://dx.doi.org/10.1155/2019/9496180.
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The traditional vibrational standing-wave modes of beams and strings show static overall contour with finite number of fixed nodes. The travelling wave modes are investigated in this study of axially moving string and beam although the solutions have been obtained in the literature. The travelling wave modes show time-varying contour instead of static contour. In the model of an axially moving string, only backward travelling wave modes are found and verified by experiments. Although there are n − 1 fixed nodes in the nth order mode, similar to the vibration of traditional static strings, the presence of travelling wave phenomenon is still spotted between any two adjacent nodes. In contrast to the stationary nodes of string modes, the occurrence of galloping nodes of axially moving beams is discovered: the nodes oscillate periodically during modal motions. Both forward and backward travelling wave phenomena are detected for the axially moving beam case. It is found that the ranges of forward travelling wave modes increase with the axially moving speed. It is also concluded that backward travelling wave modes can transform to the forward travelling wave modes as the transport speed surpasses the buckling critical speed.
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Afolabi, D. "STABILITY OF A TRANSLATING BEAM WITH FIXED AND MOVING VISCOUS DAMPING". Journal of Sound and Vibration 199, nr 4 (styczeń 1997): 701–3. http://dx.doi.org/10.1006/jsvi.1995.9989.
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Ye, Wei, Xiao Zhen Li, Hong Duan, Chun Sheng Shan i Xiao Han Liu. "Analytical Solution for Vertical Dynamic Response of Railway Simply Supported Beam Bridge under Bidirectional Moving Loads". Advanced Materials Research 594-597 (listopad 2012): 1552–56. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1552.
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In this thesis, the dynamic responses of simply supported beam bridge in a double-line railway under bidirectional moving loads are mainly studied. To study the characteristics of Euler- Bernoulli beam, a train is simplified as a series of concentrated forces with fixed wheelbase.Structural dynamics is used to deduce the analytical expressions of vertical vibration of simply supported beam under bidirectional moving loads. By simulation software MATLAB, the numerical result of the dynamic responses of simply supported beam bridge could be obtained. Then the 48 meters simply supported beam bridge in a high-speed railway is analyzed, the dynamic responses of simply supported beam of bidirectional moving loads with different interarrival times are discussed.Finally, some general laws for the design of double-line railway bridge are gained.
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Zhang, Zhi Xin, i Zhen Dong Hu. "An Analysis of the Lateral Dynamic Response of an Axially Moving Cantilever Beam under a Moving Mass". Applied Mechanics and Materials 215-216 (listopad 2012): 934–40. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.934.
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From the view of flexible multibody dynamics, this paper considers not only Euler-Bernoulli beam assumption but also the effects of rotary inertia and beam’s inner tension, the equation of motion and associated boundary conditions of the dynamic model are derived by using the extended Hamilton’s principle. Converting the varying-time equation into a varying-coefficient differential equation in fixed region by substituting argument. And truncating the equation to a set of varying-time ordinary equations expressed by modal coordinates based on Assumption Modal Method and Galerkin Discrete Method. Then the equations were solved by using Newmark time integration method. The results show that moving mass excites mainly the first order mode vibration of beam. Before the moving mass disengages the beam, the dynamic effect of mass is so small that cantilever beam is lacked of obvious vibration. Its transverse displacement was mainly driven by static load. After the moving mass disengages the beam, the shorten length and shrinking movement of beam make the instantaneous vibration frequency continuously reduce and the vibration displacement gradually decrease too. While, at the same time, its total mechanical energy is increasing, so the beam is in unsteady vibration state.
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Zhang, Xian Min, i Ya Dong Wang. "Research against the Effect of Inertia Loads on Dynamic Responses of a Simply Supported Beam". Advanced Materials Research 790 (wrzesień 2013): 283–86. http://dx.doi.org/10.4028/www.scientific.net/amr.790.283.
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In order to quantitative study the loads inertia on the effect of dynamic response on a simply supported beam, a simply supported beam with a fixed section forms and different span has been calculated under two different loading modes including moving load and moving mass by numerical method by MATLAB program. The calculated results shows the exact solution of beam vibration differential equation can be calculated and a quantitative description can be made about the load inertia effects on dynamic responses of the simply supported beam. These results provide guidance to the project practice.
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Mustafa, Aalim M., Muhammad A. Hawwa i David E. Hardt. "Vibration of an axially moving beam supported by a slightly curved elastic foundation". Journal of Vibration and Control 24, nr 17 (4.07.2017): 4000–4009. http://dx.doi.org/10.1177/1077546317717886.
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The vibration of an axially moving beam following a slightly curved path was studied. The simply supported beam was travelling axially on a curved frictionless foundation with nonlinear elastic characteristics. The main objective of this work was to investigate the effect of the moving beam path curvature on its vibration, and the effect of different parameters on the system’s dynamic response. These parameters include axial speed, applied tension, and stiffness of the supporting foundation. A Galerkin decomposition approach with four-term truncation accuracy was used to realize a mathematical model that describes the dynamic behavior of the axially moving beam on a slightly curved foundation. Numerical solutions showed that the natural frequency of the axially moving beam travelling on the curved elastic support was higher than that of an axially moving straight beam for all cases considered of different path curvatures and different degrees of support stiffness. Forced vibrations of an axially moving beam on a curved elastic support were also considered under harmonic excitation. Bifurcation diagrams were obtained for the primary resonance excitation using the excitation amplitude as a controlling parameter, while keeping the excitation frequency fixed. It was found that the amplitude–frequency diagram for the axially moving beam on the curved path exhibited many types of bifurcations, including period doubling bifurcation, period four bifurcation and many jumps, compared to that of an axially moving beam resting on a straight elastic support.
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Zakęś, Filip, i Paweł Śniady. "Application of Volterra Integral Equations in Dynamics of Multispan Uniform Continuous Beams Subjected to a Moving Load". Shock and Vibration 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/4070627.
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The dynamic behavior of multispan uniform continuous beam arbitrarily supported on its edges subjected to various types of moving noninertial loads is studied. Problem is solved by replacing a multispan structure with a single-span beam loaded with a given moving load and redundant forces situated in the positions of the intermediate supports. Redundant forces are obtained by solving Volterra integral equations of the first or the second order (depending on the stiffness of the intermediate supports) which are consistent deformation equations corresponding to each redundant. Solutions for the beam arbitrarily supported on its edges (pinned or fixed) due to a moving concentrated force and moving distributed load are given. The difficulty of solving Volterra integral equations analytically is bypassed by proposing a simple numerical procedure. Numerical examples of two- and three-span beam have been included in order to show the efficiency of the presented method.
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Wang, Yi-Ren, Chien-Chun Hung i Hsin Huang. "Vibration reduction of continuous moving loads on a nonlinear simple beam resting on an elastic foundation". Journal of Applied Engineering Science 20, nr 1 (2022): 53–62. http://dx.doi.org/10.5937/jaes0-30916.
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This technical note investigates a hinged-hinged nonlinear Euler-Bernoulli beam resting on an elastic foundation subjects to moving loads. The method of multiple scales (MOMS) is employed to analyze this nonlinear beam model. The fixed points plots are made to identify the system's internal resonance. The frequency ratio plot is proposed to predict the system internal resonance conditions. This study improved the author's earlier work for a wider range of prediction on internal resonance conditions. The continuous concentrated moving loads are applied to this nonlinear beam model. The dynamic vibration absorber (DVA) is attached on the beam to reduce vibration and prevent internal resonance. The mass, spring constant and location of the DVA are studied to obtain the best damping effect on the nonlinear beam with moving loads. The results are verified by numerical results and ANSYS simulations.
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Kasture, Sachin, Nikesh V. V., Gajendra Mulay i Achanta Venu Gopal. "Proximity error correction method for continuous moving stage electron beam writing". Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena 30, nr 5 (wrzesień 2012): 050602. http://dx.doi.org/10.1116/1.4746259.
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Sui, Wenwen, Zhencai Zhu, Guohua Cao i Guoan Chen. "Dynamic behaviors of 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle". Journal of Vibroengineering 18, nr 2 (31.03.2016): 1145–56. http://dx.doi.org/10.21595/jve.2016.16436.
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Dynamic behaviors of the 2-DOF axially telescopic mechanism for truss structure bridge inspection vehicle is investigated. The telescopic mechanism is a combination of one vertical beam that can move axially, one constant beam perpendicularly fixed at the end of the vertical beam and one telescopic beam that can move along the axial direction of the constant beam during work. The Euler-Bernoulli beam theory is utilized to simplify the beams. The Lagrangian description is adopted to account for the coordinate for the telescopic mechanism. The equations of motion are derived using the Hamilton’s principle and decomposed into a set of ordinary differential equations by employing the Galerkin’s method. The eigenfunctions are acquired based on the boundary conditions by adopting the dichotomy method. The solutions to the equations are acquired using the Newmark-β method. Experiments are carried out to prove the validity of the theoretical model. Numerical examples are simulated to explore whether the vertical beam and telescopic beam can extend or retract synchronously and obtain appropriate beam moving strategy. The results prove that synchronous motion of the vertical beam and telescopic beam will not always lead to pronounced stronger vibration than the separate ones. On the other hand, the beam moving strategies that the telescopic beam moving before the vertical beam when they all extend out or retract back and moving after the vertical beam when one extends out and the other retracts back will effectively reduce the vibration compared with otherwise.
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Gao, Hao, i Bingen Yang. "Dynamic Response of a Beam Structure Excited by Sequentially Moving Rigid Bodies". International Journal of Structural Stability and Dynamics 20, nr 08 (lipiec 2020): 2050093. http://dx.doi.org/10.1142/s0219455420500935.
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A coupled dynamic system consisting of a supporting beam structure and multiple passing rigid bodies is seen in various engineering applications. The dynamic response of such a coupled system is quite different from that of the beam structure subject to moving loads or moving oscillators. The dynamic interactions between the beam and moving rigid bodies are complicated, mainly because of the time-varying number and locations of contact points between the beam and bodies. Due to lack of an efficient modeling and solution technique, previous studies on these coupled systems have been limited to a beam carrying one or a few moving rigid bodies. As such, dynamic interactions between a supporting structure and arbitrarily many moving rigid bodies have not been well investigated, and parametric resonance induced by a sequence of moving rigid bodies, which has important engineering implications, is missed. In this paper, a new semi-analytical method for modeling and analysis of the above-mentioned coupled systems is developed. The method is based on an extended solution domain, by which the number of degrees of freedom of a coupled system is fixed regardless of the number of contact points between the beam and moving rigid bodies at any given time. This feature allows simple and concise description of flexible–rigid body interactions in modeling, and easy and effective implementation of numerical algorithms in solution. The proposed method provides a useful platform for thorough study of flexible–rigid body interactions and parametric resonance for coupled beam–moving rigid body systems. The accuracy and efficiency of the proposed method in computation is demonstrated in several examples.
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Jiang, Ji-Qing. "Transient responses of Timoshenko beams subject to a moving mass". Journal of Vibration and Control 17, nr 13 (17.01.2011): 1975–82. http://dx.doi.org/10.1177/1077546310382808.
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The dynamic behavior of beam structures subject to a moving mass is a topic of practical importance in many research fields. In this study, the method of reverberation-ray matrix is presented to investigate the dynamic responses of an undamped Timoshenko beam subject to a moving mass. Based on Inglis’s assumption, the moving mass is simplified into a moving force and a concentrated mass fixed at the mid-span of the beam. Two dual local coordinates are introduced. Based on the theory of elastodynamics, the general wave solutions with two sets of unknown amplitude coefficients are derived in the transformed domain by the dual integral transform. From continuity conditions of forces and displacements at each joint and the compatibility conditions with respect to the dual coordinates, the unknown amplitude coefficients can be determined exactly. The transient dynamic motions for a Timoshenko beam under a moving mass are then determined numerically by inverse integral transform in which the Neumann series expansion is employed to avoid the integral singularities. Two simple numerical examples are presented and the results so obtained are compared with both the experimental and theoretical ones. It is shown that the present method can be a simple alternative for determining dynamic responses of bridges subject to a moving vehicle.
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G. Wang, Greg, Yichi Zhang, David Lamond i Jie Ke. "Moving forward". Journal of Chinese Human Resource Management 5, nr 1 (6.05.2014): 2–13. http://dx.doi.org/10.1108/jchrm-02-2014-0011.
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Purpose – The purpose of this study is to review the current status of the Journal of Chinese Human Resource Management (JCHRM) in this initial stage and present a number of emerging unique Chinese phenomena for scholarly attention in relation to JCHRM entering its fifth year. Design/methodology/approach – Based on a review of JCHRM's status, we further reviewed literature and media reports to identify new research opportunities for indigenous Chinese human resource management (HRM) research. Findings – JCHRM has demonstrated its strength and uniqueness in contributing to management knowledge production and dissemination in the first four years, thanks to enthusiastic support from the worldwide research community. Moving forward, we identify a number of intriguing indigenous phenomena, including distinctive social political contexts in state-owned enterprises, emerging trends in embracing the Party Branches (dang zhi bu, Fixed graphic 1) by multinational corporations (MNCs) in China and the indigenous Chinese suzhi (Fixed graphic 2) phenomenon, for new opportunities in Chinese HRM research. Research limitations/implications – The three indigenous phenomena constitute only a few samples. Developing a theoretical understanding of Chinese HRM phenomena has a long way to go. Continued inquiries in this area will not only help build local knowledge on complex organizational dynamics but also enrich the overall management knowledge base. Originality/value – We review the status of JCHRM in its first four years and bring a sample of intriguing indigenous Chinese phenomena to the attention of the worldwide scholarly community for future research.
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Peng, Yu Xin, So Ito, Yuki Shimizu i Wei Gao. "A Micro-Stage for Linear-Rotary Positioning". Key Engineering Materials 523-524 (listopad 2012): 650–55. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.650.
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In this paper, a novel Z-θZ micro-stage is designed and constructed by utilizing an impact friction drive. The stage is configured by two driving units, a moving element and a stage base. Each driving unit consists of two PZTs and a friction element. One end of each PZT is fixed on the stage base, and the other end is attached on a permanent magnet as the friction element. The moving element, which is a steel cylinder, is supported and moved by the friction element. Magnetic force generated by permanent magnet is utilized to stabilize the driving condition between the moving element and the friction element for the friction drive. The size of the stage is less than 1 cm3. The stroke and the maximum speed of the stage in the Z-direction are 3.8 mm, 5.7 mm/s, respectively. The stroke in the θZ-direction is unlimited and the maximum rotational velocity is 26 rpm.
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Gao, Chong-yi, Guo-jun Du, Yan Feng i Jian-xiong Li. "Nonlinear Vibration Analysis of Moving Strip with Inertial Boundary Condition". Mathematical Problems in Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/216197.
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According to the movement mechanism of strip and rollers in tandem mill, the strip between two stands was simplified to axially moving Euler beam and the rollers were simplified to the inertial component on the fixed axis rotation, namely, inertial boundary. Nonlinear vibration mechanical model of Euler beam with inertial boundary conditions was established. The transverse and longitudinal motion equations were derived based on Hamilton’s principle. Kantorovich averaging method was employed to discretize the motion equations and the inertial boundary equations, and the solutions were obtained using the modified iteration method. Depending on numerical calculation, the amplitude-frequency responses of Euler beam were determined. The axial velocity, tension, and rotational inertia have strong influences on the vibration characteristics. The results would provide an important theoretical reference to control and analyze the vertical vibration of moving strip in continuous rolling process.
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Frahm, Ronald, Qianshun Diao, Vadim Murzin, Benjamin Bornmann, Dirk Lützenkirchen-Hecht, Zhen Hong i Tang Li. "Performance of nearly fixed offset asymmetric channel-cut crystals for X-ray monochromators". Journal of Synchrotron Radiation 26, nr 6 (16.10.2019): 1879–86. http://dx.doi.org/10.1107/s1600577519011123.
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X-ray double-crystal monochromators face a shift of the exit beam when the Bragg angle and thus the transmitted photon energy changes. This can be compensated for by moving one or both crystals accordingly. In the case of monolithic channel-cut crystals, which exhibit utmost stability, the shift of the monochromated beam is inevitable. Here we report performance tests of novel, asymmetrically cut, channel-cut crystals which reduce the beam movements by more than a factor of 20 relative to the symmetric case over the typical energy range of an EXAFS spectrum at the Cu K-edge. In addition, the presented formulas for the beam offset including the asymmetry angle directly indicate the importance of this value, which has been commonly neglected so far in the operation of double-crystal monochromators.
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Jimoh, Ahamed, i Emmanuel Omeiza Ajoge. "Exponentially Varying Load on Rayleigh Beam Resting on Pasternak Foundation." JOURNAL OF ADVANCES IN MATHEMATICS 16 (1.07.2019): 8449–58. http://dx.doi.org/10.24297/jam.v16i0.8219.
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This paper investigates the dynamic behavior of uniform Rayleigh beam resting on Pasternak foundation and subjected to exponentially varying magnitude moving the load. The solution techniques are based on finite Fourier sine transformed Laplace transformation and convolution theorem. The results show that for a fixed value of axial force, damping coefficient and rotatory inertia, increases in shear modulus and foundation modulus reduces the response amplitude of the dynamical system. It was also found that increases in axial force, rotary inertia, and damping coefficient for fixed values of shear modulus and foundation modulus lead to decreases in the deflection profile of the Rayleigh beam resting on Pasternak foundation. Finally, it was found that the effect of shear modulus is more noticeable that of the foundation modulus.
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Law, S. S., Tommy H. T. Chan i Q. H. Zeng. "Moving Force Identification—A Frequency and Time Domains Analysis". Journal of Dynamic Systems, Measurement, and Control 121, nr 3 (1.09.1999): 394–401. http://dx.doi.org/10.1115/1.2802487.
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This paper addresses the problem of identifying a system of forces from vehicle crossing a guideway using only the vibration responses caused by the forces as the input without knowledge of the vehicle characteristics. The vehicle is modeled as a single axle and two-axle loads with fixed axle spacing moving on a simply supported beam with viscous damping. The equations of motion of the beam are obtained through modal coordinate transformation, and the resulting set of equations relating the Fourier transforms of the responses and the moving forces are converted into time domain by a new method proposed by the authors. Correctness of the identified forces are checked by the correlation between the measured responses and the responses reconstructed with the identified forces moving on the beam. Experimental result shows that the method is effective to give good correlation when both measured bending moment and acceleration are used, and it is faster and it gives more accurate estimate of the total mass of the vehicle than an existing method.
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Choura, S. "Reduction of residual vibrations in a rotating flexible beam with a moving payload mass". Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 211, nr 1 (1.02.1997): 25–34. http://dx.doi.org/10.1243/0959651971539669.
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The reduction of residual vibrations for the position control of a flexible rotating beam carrying a payload mass is investigated. The common practice used to find the position control of a flexible multi-link arm is to assign a torque actuator to each joint while the payload mass is kept fixed relative to the end-link during the time of manoeuvre. This paper examines the stability of the system if either the payload is freed accidentally to move along the beam during the time of manoeuvre or is allowed to span the beam in a desired path for control purposes. A candidate Lyapunov function is constructed and its time rate of change is examined. It is shown that the use of a PD (proportional plus derivative) torque control yields a convergence of residual vibration to zero, an attainment of the rigid-body rotation to a prespecified desired angle of manoeuvre and a constant velocity of the payload mass as it moves relative to the beam. For manipulation purposes, an additional control force is added to the moving actuator in order to regulate its axial motion. It is shown that allowing the axial motion of the payload mass in a prescribed manner leads to a considerable reduction of its residual vibrations as compared to the case where the payload mass is fixed to the beam tip during the time of manoeuvre. Stability is also verified through simulations of rigid-body rotation and payload axial motion track prespecified reference trajectories.
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Smyth, Noel F., i Bryan Tope. "Beam on beam control: Beyond the particle approximation". Journal of Nonlinear Optical Physics & Materials 25, nr 04 (grudzień 2016): 1650046. http://dx.doi.org/10.1142/s0218863516500466.
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The all-optical control of the trajectory of a nonlinear optical beam propagating in a nematic liquid crystal cell is studied using a combination of modulation theory and full numerical solutions of the governing nematic equations. In detail, the output position of a signal beam is controlled via its interaction with a second, co-propagating control beam. The input positions of both the signal and control beams are fixed, with the output position of the signal beam determined by the input angle of the control beam. A simple modulation theory based on treating the optical beams as mechanical particles in a potential well is found to give only adequate agreement with numerical solutions. However, extending this modulation theory to include the detailed profiles of the beams, so that the beams are treated as rigid bodies moving in a potential well, leads to simple, extended equations which determine the input angle of the control beam required for a given output position of the signal beam. The predictions of this extended particle theory, or rigid body theory, are compared with full numerical solutions of the nematic equations and excellent agreement is found.
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Du, Ai Hua, i He Qi Tang. "Research on Bearing Capacity of Column Underpinning Joint of Frame Structure Moving". Advanced Materials Research 243-249 (maj 2011): 426–30. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.426.
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An experiment of sixteen frame column underpinning joints of frame structure moving was introduced, the experiment sample failure phenomena and failure type was obtained. The type was like “deep beam” failure type-“tension bar arch”, and the last failure place occurred on the interface of column and beam. Then, the underpinning joint stress mechanism and failure mode was determined based on the experiment’s conclusion. In addition, the failure course of joint was divided two stages which were before and after interface punching slip by theoretical analysis, for the stage before interface punching slip a space “tension-bar-arch” mechanical model was presented for the underpinning joint, then theoretical bearing capacity equation for this underpinning joint were obtained. At the same time, for the stage of interface after punching slip, the theory of interface shear was put into the analysis of joint, then interface bearing capacity equation was obtained for this stage. At last the height equation was obtained by the analysis of the stage of after interface slip.
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Dyniewicz, Bartłomiej, i Czesław Bajer. "The Gao beam under a moving inertial load and harmonic compression". MATEC Web of Conferences 285 (2019): 00003. http://dx.doi.org/10.1051/matecconf/201928500003.
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In the present work the dynamics of the system of a mass moving on the beam is investigated in detail numerically in the case of vibrations about a buckled state. The differential equation that describes the motion is strongly nonlinear. Simulations are based on the space-time finite element method. It enabled us easily determine the influence of the moving inertial particle. At the computational stage it becomes a real problem when the mass particle traverses joints of neighbouring elements. The results of representative and interesting computer simulations are enclosed.
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HU, WEIPENG, ZICHEN DENG i HUAJIANG OUYANG. "GENERALIZED MULTI-SYMPLECTIC METHOD FOR DYNAMIC RESPONSES OF CONTINUOUS BEAM UNDER MOVING LOAD". International Journal of Applied Mechanics 05, nr 03 (wrzesień 2013): 1350033. http://dx.doi.org/10.1142/s1758825113500336.
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Based on the multi-symplectic idea, a generalized multi-symplectic integrator method is presented to analyze the dynamic response of multi-span continuous beams with small damping coefficient. Focusing on the local conservation properties, the generalized multi-symplectic formulations are introduced and a fifteen-point implicit structure-preserving scheme is constructed to solve the first-order partial differential equations derived from the dynamic equation governing the dynamic behavior of continuous beams under moving load. From the results of the numerical experiments, it can be concluded that, for the cases considered in this paper, the structure-preserving scheme is generalized multi-symplectic if the viscous damping c ≤ 0.3751 when the continuous beam is under a constant-speed moving load and the structure-preserving scheme is generalized multi-symplectic if the viscous damping c ≤ 0.3095 when the continuous beam is under a variable-speed moving load with fixed step lengths Δt = 0.05 and Δx = 0.025. Similar to a multi-symplectic scheme, the generalized multi-symplectic scheme also has two remarkable advantages: the excellent long-time numerical behavior and the good conservation property.
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Tran, Ngoc Thoai, i Thanh-Phong Dao. "Statics Analysis and Optimization Design for a Fixed-Guided Beam Flexure". Journal of Advanced Engineering and Computation 4, nr 2 (30.06.2020): 125. http://dx.doi.org/10.25073/jaec.202042.276.
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The ratchet mechanism has been used to ensure moving in one direction of rotation, i.e. either clockwise or counterclockwise. This mechanism is designed based on fixed-guided beam flexures to reduce friction and improves accuracy compared to the traditional mechanism. This paper presents a static analysis and parameter optimization for the fixed-guided beam flexures via using the pseudo-rigid-body model and a fmincon algorithm. The Finite Element Method (FEM) of the fixed-guided beam also has been used to verify the maximum stress and the x-direction displacement. Modified pseudorigid-body model (M-PRBM) is also applied to significantly enhance the accuracy of the maximum stress value. The results show that the averaged errors of maximum stress between MPRBM and FEM are 3.48% for aluminum, and less than 10.9% for titanium, carbon steel, and alloy steel. From the obtained results, the MPRBM is good for prototype design and fabrication of the ratchet mechanism in the future. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.
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Hanke, U., E. C. Lovasz, M. Zichner, N. Modler, A. Comsa i K. H. Modler. "Synthesis of PR-/RP-chain-based compliant mechanisms – design of applications exploiting fibre reinforced material characteristics". Mechanical Sciences 6, nr 2 (25.08.2015): 155–61. http://dx.doi.org/10.5194/ms-6-155-2015.
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Abstract. Compliant mechanisms have several advantages, especially their smaller number of elements and therefore less movable joints. The flexural members furthermore allow an integration of special functions like balancing or locking. Synthesis methods based on the rigid body model (Howell, 2001; Sönmezv, 2008) or topology optimisation (Zhou and Mandala, 2012) provide practical applications from the advantages of compliant elements. Beside these methods, a much simpler approach is the geometric-based synthesis (Ehlig et al., 2013) which is focused on solving guidance tasks by using RR-chain1-based compliant linkages. More compact compliant linkages can be build up by using only PR2 or RP3 chains. Therefore a tool is needed to extend the RR-chain-based approach. The necessary analysis of the compliant beam element can be done by numerical analysis and through experiments. Due to the validity of the Bernoulli beam model the elastic similitude can be specialised and a more general synthesis of compliant beam elements can be created. Altogether a generalised synthesis method can be created for handling different linkage structures as well integrating beam elements derived numerically or by measurement. The advances in this method are applied in the synthesis for a cupholder mechanism made of fiber reinforced material. 1 one link with two rotational joints (R) 2 one link with one frame fixed prismatic joint (P) and one moving rotational joint (R) 3 one link with one frame fixed rotational joint (R) and one moving prismatic joint (P)
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Wolszczak, Piotr, Grzegorz Litak i Krystian Lygas. "Analysis of dynamics of a vertical cantilever in rotary coupling to the moving frame with movement limiters". MATEC Web of Conferences 241 (2018): 01021. http://dx.doi.org/10.1051/matecconf/201824101021.
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The efficiency of the mechanical energy harvesting with the use of vibrating elements can be improved by synchronizing stimulation vibrations and own linear frequencies of systems as well as super or sub harmonics induced by non-linear phenomena. The article presents numerical cross-sectional study of the mechanical system. The system consists of an elastic beam set vertically, which the lower end is fixed in the rotary support, and is stimulated to move in the horizontal axis. The upper end of the beam is free but below its level there are bumpers limiting the free rotation of the beam. Numerical studies took into account the variability of the frequency and amplitude of the excitation beam movement, and horizontal distance between bumpers. Beam deflection was observed, on the basis of which the amount of energy generated by the piezo element was estimated. Nonlinear phenomena and analysis of frequency synchronization of vibrations improving the energy effect of an energy generator are presented.
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Nguyen, Quoc Chi, Nguyen Tri Giang Vu i Phuong Tung Pham. "Input shaping control of a flexible cantilever beam excited by a moving hub". Science & Technology Development Journal - Engineering and Technology 3, nr 2 (16.08.2020): First. http://dx.doi.org/10.32508/stdjet.v3i2.605.
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Introduction: A cantilever beam is a well-known structural element in engineering, which is only fixed at one end. This structure can be used to describe a manipulator, whose stiffness is large to ensure rigidity and stability of the system. A flexible cantilever beam provides a light-weight structure and high cost efficiency but generates vibration under high-speed positioning. In this paper, we aim to control the vibratory behavior of a flexible cantilever beam attached to a moving hub. Method: The mathematical model of the flexible beam is described by partial differential equations (PDEs) using Euler-Bernoulli beam theory. Then, The PDE model is approximated by using the Galerkin method, which is resulted in a set of ordinary differential equations (ODEs). Experiment is used to determine unknown parameters of the system to complete the model. The ODE model enables the control design of three input shapers: (i) Zero-Vibration (ZV), (ii) Zero-Vibration-Derivative (ZVD), and (iii) Zero-Vibration-Derivative-Derivative (ZVDD), which are employed to drive the flexible beam to the desired position and to reduce vibrations of the beam. Results and conclusion: The dynamic model is obtained in term of ordinary differential equations. Unknown parameters of the system are determined by experimental process. Various controllers are designed to eliminate the vibration of the beam. The simulation is applied to predict the dynamic response of the beam to verify the designed controllers numerically. Experiment shows the validity of the mathematical model through the consistency between the simulation and experimental data and the effectiveness of the controllers for the real system. These controllers show several advantages such as no need of extra equipment; the positioning controller is intact, which means it may be applied to many existing systems.
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Wang, Yuanbin, Zhimei Lou, Kai Huang i Xiaowu Zhu. "Size-Dependent Free Vibration of Axially Moving Nanobeams Using Eringen’s Two-Phase Integral Model". Applied Sciences 8, nr 12 (10.12.2018): 2552. http://dx.doi.org/10.3390/app8122552.
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In this paper, vibration of axially moving nanobeams is studied using Eringen’s two-phase nonlocal integral model. Geometric nonlinearity is taken into account for the integral model for the first time. Equations of motion for the beam with simply supported and fixed–fixed boundary conditions are obtained by Hamilton’s Principle, which turns out to be nonlinear integro-differential equations. For the free vibration of the nanobeam, the critical velocity and the natural frequencies are obtained numerically. Furthermore, the effects of parameters on critical velocity and natural frequency are analyzed. We have found that, for the two-phase nonlocal integral model, regardless of the boundary conditions considered, both the critical velocity and the natural frequency increase with the nonlocal parameter and the geometric parameter.
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Wang, Junqi, Guoyan Zhou i Shantung Tu. "Study on the Transient Creep Stage by Small Beam Specimen with Fixed Constraints". IOP Conference Series: Materials Science and Engineering 562 (8.08.2019): 012138. http://dx.doi.org/10.1088/1757-899x/562/1/012138.
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Mamandi, Ahmad, i Mohammad H. Kargarnovin. "Nonlinear Dynamic Analysis of a Timoshenko Beam Resting on a Viscoelastic Foundation and Traveled by a Moving Mass". Shock and Vibration 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/242090.
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The dynamic response of a Timoshenko beam with immovable ends resting on a nonlinear viscoelastic foundation and subjected to motion of a traveling mass moving with a constant velocity is studied. Primarily, the beam’s nonlinear governing coupled PDEs of motion for the lateral and longitudinal displacements as well as the beam’s cross-sectional rotation are derived using Hamilton’s principle. On deriving these nonlinear coupled PDEs the stretching effect of the beam’s neutral axis due to the beam’s fixed end conditions in conjunction with the von-Karman strain-displacement relations is considered. To obtain the dynamic responses of the beam under the act of a moving mass, derived nonlinear coupled PDEs of motion are solved by applying Galerkin’s method. Then the beam’s dynamic responses are obtained using mode summation technique. Furthermore, after verification of our results with other sources in the literature a parametric study on the dynamic response of the beam is conducted by changing the velocity of the moving mass, damping coefficient, and stiffnesses of the foundation including linear and cubic nonlinear parts, respectively. It is observed that the inclusion of geometrical and foundation stiffness nonlinearities into the system in presence of the foundation damping will produce significant effect in the beam’s dynamic response.
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Takamasu, Kiyoshi. "Measurement System for Multiple Degrees of Freedom Moving Robot". Journal of Robotics and Mechatronics 5, nr 5 (20.10.1993): 453–56. http://dx.doi.org/10.20965/jrm.1993.p0453.
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The multiple degrees of freedom (multi-DOF) moving robot and its measurement system have been developed realize a positioning system with high flexibility. The multi-DOF robot is driven by six piezo-electric devices; and it moves in two modes, an absolute motion mode and a relative motion mode. In the absolute motion mode, it walks on a surface plate by a two-dimensional inchworm method having 3-DOF, in X and Y directions and a rotation. After a frame body is fixed, a center table can be positioned on 6-DOF. For measuring its position, the novel position measurement system has been developed. It has two measurement modes; an absolute measurement mode and a relative measurement mode. In the absolute mode, the two-dimensional position of the robot can be calculated from the length of a laser interferometer and the angle of a tracking mirror. After the tracking mirror is fixed, the relative displacement of the center table is measured by the laser interferometer, and the position of a reflecting laser beam is measured on a Position Sensitive Detector (PSD). We conclude that the high flexibility positioning system can be realized using the multi-DOF robot and the measurement system.
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Wang, Yan, Xiu Li Liu i You Sheng Yu. "The Mechanical Behavior Study on Reduced Beam Section and Widened Beam Section Connections of Steel Frames". Advanced Materials Research 163-167 (grudzień 2010): 717–25. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.717.
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In the paper, finite element models are established by using numerical methods to study the mechanical behavior of these kinds of connections. By discussing the range of design parameter of reduced beam section connection and widened beam section connection, stress distribution of connections and the influence of design parameter on bearing capacity at elastic stage and plastic stage are studied. The FEM models of these two kinds of connections behaved good ductility behavior. The purpose of moving plastic hinge outward from the beam and column interface is realized. Stress concentration near welds at the end of beam is reduced significantly. The bearing capacity of widened beam section connection increase obviously due to expanding the local area of beam flanges at the end of beam, but that of reduced beam section connection decrease due to trimming beam flanges. After studies, the range of design parameter of reduced beam section connection and widened beam section connection are given in the paper, and comparing with FEMA-350 [14] of American. The suggestion parameters would be useful for seismic design of steel frames.
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Lou, P., G.-L. Dai i Q.-Y. Zeng. "Modal Coordinate Formulation for a Simply Supported Bridge Subjected to a Moving Train Modelled as Two-Stage Suspension Vehicles". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 219, nr 10 (1.10.2005): 1027–40. http://dx.doi.org/10.1243/095440605x31940.
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Modal coordinate formulation for analysing the dynamic interaction between a moving train and a simply supported bridge is presented in this article. The train is composed of a series of identical vehicles, and each vehicle is modelled as a four-wheelset mass-spring-damper multi-rigid body system with two-stage suspension having ten degrees of freedom (DOFs). A simply supported bridge, together with the track, is modelled as a Bernoulli-Euler beam. The deflection of the beam is described by superimposing modes. The train and the beam are regarded as an entire dynamic system, and then the modal coordinate formulation with time-dependent coefficients for this system is directly derived from the principle of virtual work. The formulation is solved by direct time integration method, to obtain the dynamic responses of this system. The correctness of the proposed formulations is illustrated by a comparison with the existing literature. The formulation helps save computer time using a few beam modes for analysing the dynamic responses of an entire train-bridge interaction system. The proposed formulation can also be applied to analyse the dynamic responses of a simply supported bridge subjected to a moving train modelled as two-wheelset four DOFs vehicles. Two numerical examples are given for illustrating the applications of the proposed formulation.
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Kordestani, Hadi, Chunwei Zhang i Mahdi Shadabfar. "Beam Damage Detection Under a Moving Load Using Random Decrement Technique and Savitzky–Golay Filter". Sensors 20, nr 1 (31.12.2019): 243. http://dx.doi.org/10.3390/s20010243.
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In this paper, a two-stage time-domain output-only damage detection method is proposed with a new energy-based damage index. In the first stage, the random decrement technique (RDT) is employed to calculate the random decrement signatures (RDSs) from the acceleration responses of a simply supported beam subjected to a moving load. The RDSs are then filtered using the Savitzky–Golay filter (SGF) in the second stage. Next, the filtered RDSs are processed by the proposed energy-based damage index to locate and quantify the intensity of the possible damage. Finally, by fitting a Gaussian curve to the damage index resulted from the non-damage conditions, the whole process is systematically implemented as a baseline-free method. The proposed method is numerically verified using a simply supported beam under moving sprung mass with different velocities and damage scenarios. The results show that the proposed method can accurately estimate the damage location/quantification from the acceleration data without any prior knowledge of either input load or damage characteristics. Additionally, the proposed method is neither sensitive to noise nor velocity variation, which makes it ideal when obtaining a constant velocity is difficult.
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Li, Yi-Tsung, i Kuang-Chao Fan. "A novel method of angular positioning error analysis of rotary stages based on the Abbe principle". Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 232, nr 11 (30.01.2017): 1885–92. http://dx.doi.org/10.1177/0954405416688936.
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Abbe error is the inherent systematic error in linear displacement measurement due to the measuring axis being out of line with the moving axis. The resulting gap is called the Abbe offset, which will multiply the angular pitch error of the moving stage to become the positioning error of the linear stage along the moving axis. Analogous to the Abbe principle, in the rotary stage, the rotary encoder is used to detect the worktable’s rotational angle. The encoder is normally mounted at a distance from the bearing. This distance can be also regarded as Abbe offset. Due to the inherent tilt and radial motions of the axis of rotation, the encoder’s rotating component, that is, the circular grating, would result in a lateral displacement relative to its sensing head that is fixed inside the stage housing. The actual measured angle is, therefore, different from the commanded angle, causing the angular positioning error of the rotary stage in machine tools and open-loop controlled system. In this article, the angular positioning error of the rotary stage caused by the tilt motion error and radial motion error of the spindle, the offset and the size of encoder is analyzed and experimentally verified.
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Li, Yue Feng, Xu Dong Pan i Guang Lin Wang. "Moving Load Simulation Method of the Evolute Cylinder Gears". Key Engineering Materials 522 (sierpień 2012): 297–301. http://dx.doi.org/10.4028/www.scientific.net/kem.522.297.
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The curve intensity of deddendum plays a significant role in gear strength design. Due to the complicated shape of gears, traditional method utilizes the cantilever beam model adds the concentrated load at a fixed point and then revises it by coordinating with different factors so as to calculate the gears the curve intensity of deddendum. In this paper, based on evolute formulas, a methodology about finite element analysis was used for establishing the accurate tooth profile model of the evolute cylinder gear. The moving load was added by programming and the regularity that the amplitude of load changes with the position of the point of application in a tooth meshing cycle was determined. Based on proposed model, this paper provides the variation regularity of the magnitude of the stress of deddendum by simulation.
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Abbas, Ammar N., i Muhammad Asad Irshad. "Parallel P-PD controller to achieve vibration and position control of a flexible beam". IAES International Journal of Robotics and Automation (IJRA) 10, nr 2 (1.06.2021): 149. http://dx.doi.org/10.11591/ijra.v10i2.pp149-160.
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Robotic arms are considered as a cantilever beam fixed at one end and due to the length-to-weight ratio, it has a significant vibration-induced that needs to be controlled to achieve accurate position, speed control and to increase its efficiency. In this project, a discretized Timoshenko beam model is used to discuss the dynamics of the system. Further, to implement the control on the hardware an experimental setup is fabricated to observe the open-loop and closed-loop responses of the beam made of low-density polyethylene. An accelerometer as a feedback sensor is attached at one end of the flexible beam while another end is fixed at the moving cart having DC motor as an actuator. Simulink is used as the programming tool to perform all of the experimentation. Proportional-integral-derivative (PID) tuning is performed. Following that open-loop responses of the deflection of the beam parallel to the motion are observed with different input waveforms. By applying a proportional control scheme, another experiment is performed to demonstrate the disturbance rejection with an accelerometer as a feedback sensor, while ignoring position control. Finally, a PD and P based parallel control scheme is proposed to obtain simultaneously both position control and vibration reduction.
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Abbas, W., Omar K. bakr, M. M. Nassar, Mostafa A. M. Abdeen i M. Shabrawy. "Analysis of Tapered Timoshenko and Euler–Bernoulli Beams on an Elastic Foundation with Moving Loads". Journal of Mathematics 2021 (19.04.2021): 1–13. http://dx.doi.org/10.1155/2021/6616707.
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This research studies the vibration analysis of Euler–Bernoulli and Timoshenko beams utilizing the differential quadrature method (DQM) which has wide applications in the field of basic vibration of different components, for example, pillars, plates, round and hollow shells, and tanks. The free vibration of uniform and nonuniform beams laying on elastic Pasternak foundation will be studied under three sets of boundary conditions, that is, mixing between being simply upheld and fixed while utilizing the DQM. The natural frequencies and deflection values were produced through the examination of both beam types. Results show great concurrence with solutions from previous research studies. The impact of the nonuniform cross-section area on the vibration was contemplated. A comparison between the results from both beams is obtained. The focus of this work is on studying the deflection difference between both beam theories at different beam dimensions as well as showing the shape of rotation of the cross section while applying a nodal point load equation to simulate the moving load. The results were discussed and a general contemplation about the theories was developed.
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Kaneko, Toshiaki. "MeV Cluster Ion Beam–Material Interaction". Quantum Beam Science 6, nr 1 (24.01.2022): 6. http://dx.doi.org/10.3390/qubs6010006.
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This paper treats the characteristic topics of MeV/atom cluster ion beams produced using tandem accelerators both in the production stage and in the penetration stage from the viewpoint of fundamental processes. The former is related to atomic collisions in that production and decay of a cluster ion Cn+ (n=1−4) colliding with a charge-changing rare gas underlined through the electron-loss process. Regarding the latter, relatively small carbon clusters Cn+ (n=2−10) are treated. The reduction effect of the average charge of cluster ions in a material is first presented. Next, the electronic stopping power and the energy loss, the polarization force, and the coulomb explosion under cluster-ion impact are described in the dielectric function form. Alignment and structure effects are stressed. As a large and highly symmetric cluster, the electronic stopping power and the average charge are shown for a C60 cluster ion moving inside a solid. Throughout the paper, it is emphasized that the vicinage effect originating from correlation on spatial structure and orientation of constituent ions plays the key role. Moreover, results obtained in cluster production and penetration phenomena are mostly different from multiplication of those under single-ion impact.
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Noda, Koji. "Development of heavy-ion radiotherapy technology with HIMAC". International Journal of Modern Physics: Conference Series 44 (styczeń 2016): 1660219. http://dx.doi.org/10.1142/s2010194516602192.
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Since 1994, HIMAC has carried out clinical studies and treatments for more than 9000 cancer patients with carbon-ion beams. During the first decade of the HIMAC study, a single beam-wobbling method, adopted as the HIMAC beam-delivery technique, was improved for treatments of moving tumors and for obtaining more conformal dose distribution. During the second decade, a pencil-beam 3D scanning method has been developed toward an “adaptive cancer treatment” for treatments of both static and moving tumors. A new treatment research facility was constructed with HIMAC in order to verify the developed 3D scanning technology through a clinical study that has been successfully conducted since 2011. As the next stage, a compact heavy-ion rotating gantry with a superconducting technology has been developed for the more accurate and shorter-course treatments. The twenty-year development of the heavy-ion radiotherapy technologies including accelerator technologies with HIMAC is reviewed.
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Wang, Xuezhen, Vincent Chau, Hau Chan, Ken C. K. Fong i Minming Li. "Multi-Stage Facility Location Problems with Transient Agents". Proceedings of the AAAI Conference on Artificial Intelligence 37, nr 5 (26.06.2023): 5850–57. http://dx.doi.org/10.1609/aaai.v37i5.25725.
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We study various models for the one-dimensional multi-stage facility location problems with transient agents, where a transient agent arrives in some stage and stays for a number of consecutive stages. In the problems, we need to serve each agent in one of their stages by determining the location of the facility at each stage. In the first model, we assume there is no cost for moving the facility across the stages. We focus on optimal algorithms to minimize both the social cost objective, defined as the total distance of all agents to the facility over all stages, and the maximum cost objective, defined as the max distance of any agent to the facility over all stages. For each objective, we give a slice-wise polynomial (XP) algorithm (i.e., solvable in m^f(k) for some fixed parameter k and computable function f, where m is the input size) and show that there is a polynomial-time algorithm when a natural first-come-first-serve (FCFS) order of agent serving is enforced. We then consider the mechanism design problem, where the agents' locations and arrival stages are private, and design a group strategy-proof mechanism that achieves good approximation ratios for both objectives and settings with and without FCFS ordering. In the second model, we consider the facility's moving cost between adjacent stages under the social cost objective, which accounts for the total moving distance of the facility. Correspondingly, we design XP (and polynomial time) algorithms and a group strategy-proof mechanism for settings with or without the FCFS ordering.