Three-dimensional symmetry analysis of a direct-drive irradiation scheme for the laser megajoule facility

2014 ◽  
Vol 21 (8) ◽  
pp. 082710 ◽  
Author(s):  
R. Ramis ◽  
M. Temporal ◽  
B. Canaud ◽  
V. Brandon
Keyword(s):  
Three Dimensional ◽  
Symmetry Analysis ◽  
Direct Drive ◽  
Irradiation Scheme

scholarly journals Spatial Moduli of Non-Differentiability for Linearized Kuramoto–Sivashinsky SPDEs and Their Gradient

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1251
Author(s):  
Wensheng Wang
Keyword(s):  
Heat Equation ◽  
White Noise ◽  
Fourth Order ◽  
Gaussian Processes ◽  
Three Dimensional ◽  
Space Time ◽  
Symmetry Analysis ◽  
Stochastic Heat Equation ◽  
Moduli Of Continuity

We investigate spatial moduli of non-differentiability for the fourth-order linearized Kuramoto–Sivashinsky (L-KS) SPDEs and their gradient, driven by the space-time white noise in one-to-three dimensional spaces. We use the underlying explicit kernels and symmetry analysis, yielding spatial moduli of non-differentiability for L-KS SPDEs and their gradient. This work builds on the recent works on delicate analysis of regularities of general Gaussian processes and stochastic heat equation driven by space-time white noise. Moreover, it builds on and complements Allouba and Xiao’s earlier works on spatial uniform and local moduli of continuity of L-KS SPDEs and their gradient.

Additively Manufactured Continuous Fibre-Reinforced Thermoplastics for Mechanisms Subjected to Predominant Inertial Load: A Case Study

2020 ◽  
Author(s):  
Luca Luzi ◽  
Giacomo Quercioli ◽  
Riccardo Pucci ◽  
Guido Bocchieri ◽  
Rocco Vertechy ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Topology Optimization ◽  
High Performance ◽  
Permanent Magnet Synchronous Motor ◽  
Three Dimensional ◽  
Direct Drive ◽  
Continuous Fibre ◽  
Mechanical Components ◽  
Reinforced Thermoplastics

Abstract In the last decade, the adoption of additive manufacturing technologies (AMT) (3D printing) has increased significantly in many fields of engineering, initially only for rapid prototyping and more recently also for the production of finished parts. With respect to the long-established material subtractive technologies (MST), AMT is capable to overcome several limitations related to the shape realization of high-performance mechanical components such as those conceived via topology optimization and generative design approaches. In the field of structures and mechanisms, a major advantage of AMT over MST is that, for the same loading and constraining conditions (including kinematic and overall encumbrance), it enables the realization of mechanical components with similar stiffness but smaller volume (thus smaller weight, density being equal). Recently, the potentialities of AMT have also been increased by the introduction of the fuse filament deposition modeling (FDM) of continuous fibre-reinforced thermoplastics (CFRT), which combines the ease of processing of plastic AMT with the strength and specific modulus of the printed components that are comparable to those attainable via metallic AMT. In this context, the present paper investigates the potentialities of FDM-CFRT for the realization of mechanisms subjected to predominant inertial loads such as those found in automated packaging machinery. As a case study a Stephenson six-bar linkage powered in direct drive by a permanent magnet synchronous motor is considered. Starting from an existing mechanism realized in aluminum alloy with traditional MST, a newer version to be realized with FDM-CFRT has been conceived by keeping the kinematics fixed and by redesigning the links via three-dimensional topology optimization. To provide a fair comparison with the more traditional design/manufacturing approach, size optimization of the original mechanism made in aluminum alloy has also been performed. Comparison of the two versions of the mechanism highlights the superior performances of the one manufactured via FDM-CFRT in terms of weight, motor torque requirements and motion precision.

Simulation Analysis of Planetary Gears Train of Semi-Direct Drive Wind Turbine Based on ADAMS

2015 ◽  
Vol 789-790 ◽  
pp. 311-315 ◽  
Author(s):  
Yan Li Cheng ◽  
Zheng Ming Xiao ◽  
Li Rong Huan ◽  
Fu Chen
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Planetary Gear ◽  
Gear System ◽  
Direct Drive ◽  
Three Dimensional Model ◽  
Velocity Change ◽  
Planetary Gears

The speed increasing gearbox is the key part of the wind turbine and its role is to transmit power which is generated by wind turbines to the generator through the gear system. The single-stage planetary gears train system is commonly used in the semi-direct drive wind turbines. In this paper Pro/E is used to establish the three-dimensional model of the speed increasing planetary gear system of the semi-direct drive wind turbine. Motion pairs, drive and load of the model are added by ADAMS. Angular velocity change rule of the parts is obtained. The change rules of the mesh force of the planetary gears, ring and sun gear can be obtained through the dynamic simulation and analysis using the contact algorithm. These are useful to study the vibration and noise of the system.

scholarly journals Irradiation uniformity at the Laser MegaJoule facility in the context of the shock ignition scheme

2014 ◽  
Vol 2 ◽  
Author(s):  
Mauro Temporal ◽  
Benoit Canaud ◽  
Warren J. Garbett ◽  
Rafael Ramis ◽  
Stefan Weber
Keyword(s):  
Inertial Confinement Fusion ◽  
Three Dimensional ◽  
Inertial Confinement ◽  
Direct Drive ◽  
Azimuthal Component ◽  
Hydrodynamic Simulations ◽  
Available Energy ◽  
Confinement Fusion ◽  
Hydrodynamic Calculations ◽  
Shock Ignition

AbstractThe use of the Laser MegaJoule facility within the shock ignition scheme has been considered. In the first part of the study, one-dimensional hydrodynamic calculations were performed for an inertial confinement fusion capsule in the context of the shock ignition scheme providing the energy gain and an estimation of the increase of the peak power due to the reduction of the photon penetration expected during the high-intensity spike pulse. In the second part, we considered a Laser MegaJoule configuration consisting of 176 laser beams that have been grouped providing two different irradiation schemes. In this configuration the maximum available energy and power are 1.3 MJ and 440 TW. Optimization of the laser–capsule parameters that minimize the irradiation non-uniformity during the first few ns of the foot pulse has been performed. The calculations take into account the specific elliptical laser intensity profile provided at the Laser MegaJoule and the expected beam uncertainties. A significant improvement of the illumination uniformity provided by the polar direct drive technique has been demonstrated. Three-dimensional hydrodynamic calculations have been performed in order to analyse the magnitude of the azimuthal component of the irradiation that is neglected in two-dimensional hydrodynamic simulations.

scholarly journals Three-dimensional modeling of direct-drive cryogenic implosions on OMEGA

2016 ◽  
Vol 23 (5) ◽  
pp. 052702 ◽  
Author(s):  
I. V. Igumenshchev ◽  
V. N. Goncharov ◽  
F. J. Marshall ◽  
J. P. Knauer ◽  
E. M. Campbell ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Direct Drive ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling

Three-Dimensional Oscillation Dynamics of the In Situ Piston Rod Transmission Between Buoy Line and the Double Hinge-Connected Translator in an Offshore Linear Wave Energy Converter

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Erland Strömstedt ◽  
Mats Leijon
Keyword(s):  
Tilt Angle ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Elastic Displacement ◽  
Direct Drive ◽  
Energy Converter ◽  
Oscillation Dynamics ◽  
Guiding System ◽  
Displacement Measurements

Force and displacement measurements have been performed in situ on the piston rod mechanical lead-through transmission in the direct drive of the second experimental wave energy converter (WEC) 3 km offshore at the Lysekil research site (LRS) during a 130-day continuous full-scale experiment in 2009. The direct drive consists of a buoy line and a piston rod transmission with a double-hinged link (DHL) at the lower end connecting the point absorbing surface-floating buoy to the translator of an encapsulated permanent magnet linear generator on the seabed. The buoy line is guided by a funnel in the buoy line guiding system 3.2 m above the generator capsule. The 3 m long piston rod reciprocates through a mechanical lead-through in the capsule wall, sealing off seawater from entering the generator capsule. A setup of laser triangulation sensors measures the relative lateral displacement of the piston rod. This paper introduces a method and a system of equations for calculating piston rod relative tilt angle and piston rod azimuth direction of tilting from the relative lateral displacement measurements. Correlation with piston rod axial displacement and forces enables evaluation of the three-dimensional (3D) oscillation dynamics. Results are presented from 2 weeks after launch and from 3 months after launch in altogether four cases representing two different stages of wear in two different sea states. Piston rod tilting from accumulated wear in the buoy line guiding system is separated from tilting due to elastic displacement. Structural mechanical finite element method (FEM) simulations verify the magnitude of elastic displacement and indicate negligible stress and strain at the mounting point of the laser sensor setup. The proposed theory for piston rod 3D motion is validated by the experiment. As the experiment progressed, wear in the buoy line guiding system accelerated due to splitting of the buoy line jacketing compound, thereby increasing the piston rod tilt angles. Over 94 days into the experiment, 21.8 mm of accumulated wear in the buoy line guiding system had altered the characteristics of the piston rod oscillations and increased the maximum piston rod relative tilt angle by 0.39 deg in the predominant azimuth direction of wave propagation. Further accumulated wear in the buoy line guiding system led to buoy line rupture 130 days after launch. The results presented in this paper have been used in assessments for improving the mechanical subsystems in subsequent experimental WECs based on the Uppsala concept.

scholarly journals Design and Analysis of a Permanent Magnet Vernier Machine with Non-Uniform Tooth Distribution

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7816
Author(s):  
Fei Zhao ◽  
Mengzhu Cao ◽  
Encheng Tao ◽  
Liyi Li
Keyword(s):  
Permanent Magnet ◽  
Uniform Design ◽  
Three Dimensional ◽  
Torque Ripple ◽  
Uniform Structure ◽  
Direct Drive ◽  
Cogging Torque ◽  
Dimensional Finite Element ◽  
Aerial Vehicle ◽  
Three Dimensional Finite Element

To improve the torque performance of the permanent magnet vernier machine in the direct-drive system for Unmanned Aerial Vehicle (UAV), this paper proposes the topology of non-uniform tooth distribution. This distribution, considering the additional flux harmonics, aims to contribute to torque improvement, whereas the cogging torque also increases at the same time. A phasors method is proposed to solve the issue caused by the non-uniform structure, adjusting the mechanic angle of each tooth reasonably to restrict the cogging torque. In addition, the non-uniform design is illustrated in detail, which includes the method of grouping the teeth, considering the factors of series pole ratio and winding layout. By using the three-dimensional finite element method, torque is significantly increased without additional torque ripple, which satisfies the desired design target.

Time Fractional Third-Order Evolution Equation: Symmetry Analysis, Explicit Solutions, and Conservation Laws

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
Dumitru Baleanu ◽  
Mustafa Inc ◽  
Abdullahi Yusuf ◽  
Aliyu Isa Aliyu
Keyword(s):  
Power Series ◽  
Conservation Laws ◽  
Series Solution ◽  
Three Dimensional ◽  
Nonlinear Ordinary Differential Equation ◽  
Symmetry Analysis ◽  
Power Series Solution ◽  
Lie Symmetry Analysis ◽  
Third Order ◽  
Contour Plots

In this work, Lie symmetry analysis for the time fractional third-order evolution (TOE) equation with Riemann–Liouville (RL) derivative is analyzed. We transform the time fractional TOE equation to nonlinear ordinary differential equation (ODE) of fractional order using its Lie point symmetries with a new dependent variable. In the reduced equation, the derivative is in Erdelyi–Kober (EK) sense. We obtain a kind of an explicit power series solution for the governing equation based on the power series theory. Using Ibragimov's nonlocal conservation method to time fractional partial differential equations (FPDEs), we compute conservation laws (CLs) for the TOE equation. Two dimensional (2D), three-dimensional (3D), and contour plots for the explicit power series solution are presented.

Three-dimensional active microcatheter combining shape memory alloy actuators and direct-drive tubular electrostatic micromotors

1998 ◽  
Author(s):  
Gilles Bourbon ◽  
Patrice Minotti ◽  
Philippe Langlet ◽  
Takahisa Masuzawa ◽  
Hiroyuki Fujita
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Three Dimensional ◽  
Direct Drive
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