C. Frankrone , L. Fromme ,
 Department of Engineering Sciences and Mathematics, Bielefeld University of Applied Sciences, Bielefeld, Germany
Machines with rotating components are prone to vibrations because an imbalance of the rotor would always act as a harmonic excitation force to the machine. Thus oscillations close to the natural frequencies are tried to pass through fast in the run-up and cast-down or even completely avoided for higher structural frequencies. Nevertheless vibrations still occur and affect the design of the ...
L. Martinelli, A. Lamberti, and P. Ruol
DISTART Idraulica, Università di Bologna, Bologna, Italy
IMAGE, Università di Padova, Padova, Italy
Objective of this contribution is to present a procedure for evaluating second order drift forces on floating bodies, often the most important loading component for mooring design, in case of high waves propagating in relatively shallow water depths. The non linearity associated to this condition, which is typical of installations involving wave energy converters, makes this problem particularly ...
A.W.M. van Schijndel
Eindhoven University of Technology, Eindhoven, The Netherlands
Chaotic systems may lead to instability, extreme sensitivity and performance reduction. Therefore it is unwanted in many cases. Due to these undesirable characteristics of chaos in practical systems, it is important to recognize such a chaotic behavior. The existence of chaos has been discovered in several areas during the last 30 years. However, there is a lack of studies in relation with ...
Y. Li, T.C. Lieuwen, J. Zhou, H. Cao
Zhengzhou University, Zhengzhou City, Henan Province, China
Georgia Institute of Technology, Atlanta, GA
One can hardly get the exact analytic solution of a full time-dependent convection-diffusion equation, for describing the dynamics of a non-premixed flamelet. The analytic solution of the linearized form with such a model was studied by MATLAB®. And also, a numerical computation was made with the linearization model in COMSOL Multiphysics® software, to provide a perfect accordance with the ...
AGH University of Science and Technology
This elaboration presents a pre-study on automatic rotor construction for the flywheel energy storage system dedicated to operate in the levitation mode. The optimization profile model is used as a basic profile source. The 3D flywheel shape is generated on the base of obtained profiles. Eigenfrequencies are calculated to validate the operation on rigid mode. A steel and aluminum based ...
Equation-Based Modelling: True Large Strain, Large Displacement and Anand's Plasticity Model with COMSOL's Moving Mesh Application Mode
O. Toscanelli, V. Colla, and M. Vannucci
Scuola Superiore S. Anna, Pontedera, PI, Italy
In this work the solution of the structural problem obtained by mean of the velocity approach is presented. More in detail the balance and constitutive equations are expressed in Eulerian form, the mesh is not material. The approach is general, is suitable both for material boundary or no-material boundary and for a generic material model. The Hooke's elastic model and the Anand's plasticity ...
R. S. Wadhwa, T. Lien, and G. Monkman
NTNU Valgrinda, Inst. for produksjons- og kvalitetstek., Trondheim, Norway
FH Regensburg, Regensburg, Germany
The magnetic field gradient produced by an electromagnet gripper head depends on its design. Stochastic Methods offer certain robustness to the design optimization process. In this paper, Improved Discrete Particle Swarm Optimization (IDPSO) searching technique is applied to the shape and magnetic field gradient optimization of an electromagnet head. The magnetic field and forces are ...
徐肖飞 , 徐光楠 , 刘志远 , 吴鹏 , 彭金霖 , 许保磊 ,
引言：铁电薄膜材料是一类具有优异性能的功能材料而被广泛应用于电子元器件中。理想状态下铁电薄膜材料为绝缘体或宽禁带半导体，但实际中铁电薄膜材料会因为制备或者在元器件中因为界面引入带电粒子或缺陷，引起较大的电流，影响电子元器件的性能。我们建立了考虑挠曲电效应及带电粒子漂移扩散的相场模型用以研究挠曲电效应对 Pt/PZT/Pt 多层结构的 I-V 特性的影响。 COMSOL Multiphysics® 的使用：我们使用 COMSOL 建立了一个二维平面模型(如图1)，使用的是 PDE 接口，未使用案例库模型。 结果：我们通过模拟得到了不同挠曲电耦合系数下铁电薄膜的应变梯度云图(如图2)、极化云图(如图3)和电势云图(如图4)，做出了不同挠曲电耦合系数下铁电薄膜的 I-V 曲线。 结论：极化与纵向应变梯度之间的耦合会导致铁电薄膜内电势的降低，增加载流子空穴在铁电薄膜内的浓度 ...
H. Karakuzu, M. Dubov, S. Boscolo
 Aston University, Birmingham, UK
We present an optimization procedure to improve the propagation properties of the depressed-cladding, buried micro-structured waveguides formed in a z-cut lithium niobate (LN) crystal by high repetition rate femtosecond (fs) laser writing. It is shown that the propagation wavelength for which the confinement losses of ordinary (O) and extraordinary ordinary (E) polarizations are below 1 dB/cm ...
P. Kladisios , A. Stegou , Z. Sagia ,
 National Technical University of Athens, Athens, Greece.
Humanity is faced with an imminent energy crisis. The exponential growth of the human population and the consequential increase of the required energy on a global scale, the dramatic climate change and the exhaustibility of natural resources combined, force us to strive towards a sustainable future. The majority of energy is being produced by fossil fuels, carriers of high density of primary ...