1,721,025 research outputs found
Integration of active vibration control methods with finite element models of smart laminated composite structures
No full textVibration control problems can be directly and systematically solved in a single analysis stage using commercial finite element programs. Integration of control methods into the finite element solutions (ICFES) can be achieved in ANSYS. In this work, first, the direct velocity feedback (DVF) control is tested on a 3-DOF mechanical system under a step input. The simulation results obtained by the ICFES are compared with the analytical results obtained by the Laplace transform method. Then, active control of free and forced vibrations in a smart laminated composite structure (SLCS) with two different lay-ups is studied numerically and experimentally. The SLCS consists of a symmetric laminated glass-epoxy composite beam with [0/90](s) and [451-45](s) lay-ups and a piezoelectric actuator. For the vibration suppression, the DVF control tested on a mechanical system is applied to the SLCS. In addition, displacement feedback (DF) control is studied. Experiments are conducted to verify the natural frequencies and the closed loop time responses. Analytical results for the mechanical system and experimental results for the SLCS match well to the corresponding results obtained using the ICFES technique. (C) 2009 Elsevier Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The effect of ride frequency to the dynamic characteristics of a military truck
No full textRide frequency is one of the major factors that affect vehicle dynamics characteristics. While it is an attribute for comfort feeling, it is also the basic phenomenon for vehicle handling. To determine dynamic characteristics, dynamic responses of a 44 tonnes gross vehicle weight, 8 x 8 configuration military truck which is subjected to a succession of different ride frequency cases, is investigated. Ride frequency cases are created for different primary and secondary suspension spring-damper rates. A full vehicle model is generated in ANSYS, and road irregularities are created via Matlab and Visual Basic. The dynamic behaviours are studied by applying road irregularities to the full vehicle model. The natural frequencies are found for roll, pitch and bounce modes via modal analysis. The comparison of dynamic responses is performed by analysing nodal solutions obtained from three different road excitations that trigger roll, pitch and bounce modes
Automotive Active Suspension System Design for a Quarter Bus An Acceleration Feedback Approach
No full text
Simulation and experimental analysis of active vibration control of smart beams under harmonic excitation
No full textIn the present study, active control of a smart beam under forced vibration is analyzed. The aluminum smart beam is composed of two piezoelectric patches and strain gauge. One of the piezoelectric patches is used as controlling actuator while the other piezoelectric patch is used as vibration generating shaker. The smart beam is harmonically excited by the piezoelectric shaker at its fundamental frequency. The strain gauge is utilized to sense the vibration level. Active vibration reduction under harmonic excitation is achieved using both strain and displacement feedback control. Control actions, the finite element (FE) modeling and analyses are directly carried Out by using ANSYS parametric design language (APDL). Experimental applications are performed with LabVIEW. Dynamic behavior at the tip of the beam is evaluated for the uncontrolled and controlled responses. The simulation and experimental results are compared. Good agreement is observed between simulation and experimental results under harmonic excitation
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Analysis of end point vibrations of a two-link manipulator by integrated CAD/CAE procedures
No full textin this work, the effect of flexibility on the trajectory of a planar two-link manipulator is studied using integrated computer-aided design/analysis (CAD/CAE) procedures. The solid models and finite element models of the parts of the manipulator are created by using the CAD/CAE software I-DEAS. The assembly is defined, and knowing the payload and the end point trajectory, the velocities and accelerations of the parts, joint forces and driving torques are calculated using the rigid body dynamics. All the time dependent nodal forces acting on the parts including distributed gravity and inertia forces are created in files with the I-DEAS program file format. The finite element vibration analysis of the parts is performed by I-DEAS. The end point vibrations and the deviations from the rigid-body trajectory are analyzed for different types of end point acceleration curves. A circular trajectory is considered as an example. It is observed that the precision of the manipulator can be increased by testing different end point acceleration curves without changing the trajectory and the duration of the end point work. The procedure explained in this work can be used for this purpose successfully. (C) 2004 Elsevier B.V. All rights reserved
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
