Browsing by Keyword "Acoustics and Ultrasonics"
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Item LIFE+2010 QUADMAP Project: results obtained from the analysis of data collected during the application of the new methodology to the pilot quiet areas: Results obtained from the analysis of data collected during the application of the new methodology to the pilot quiet areas(2019-01-01) Bartalucci, Chiara; Borchi, Francesco; Carfagni, Monica; Governi, Lapo; Luzzi, Sergio; Aspuru, Itziar; Gaudibert, Piotr; Wolfert, Henk; CALIDAD Y CONFORT AMBIENTALSince the 90s, quiet areas have commonly been considered as places to be acoustically preserved or where acoustic interventions should be implemented to reduce noise levels. With the enforcement of the Environmental Noise Directive in 2002, a formal definition of a ‘quiet area in agglomeration’ and a ‘quiet area in open country’ was established. However, many Member States complained about the absence of guidelines regarding the identification and management of quiet areas. The LIFE QUiet Areas Definition and Management in Action Plans (QUADMAP) project started in 2011 to contribute to the Directive’s incomplete requirements for quiet areas. The project’s main result has been the introduction of a flexible methodology for the selection, analysis and management of quiet areas in agglomeration in which both acoustic and nonacoustic parameters are evaluated. The current paper illustrates the analyses carried out on the data collected during the application of the selection, analysis and management phases of the developed methodology in the different pilot cases selected during the Project. Mentioned analysis are aimed at verifying the benefits of the proposed complementary selection criteria (‘relative quiet urban areas’ identification criteria and ‘homogeneous urban areas’ subdivision criteria), at defining the measurement periods most representative of the areas and the acoustic and nonacoustic parameters to be considered as the most significant.Item Preventing chatter vibrations in heavy-duty turning operations in large horizontal lathes(2015-03-31) Urbikain, G.; Campa, F. J.; Zulaika, J. J.; López De Lacalle, L. N.; Alonso, M. A.; Collado, V.; MAQUINASProductivity and surface finish are typical user manufacturer requirements that are restrained by chatter vibrations sooner or later in every machining operation. Thus, manufacturers are interested in knowing, before building the machine, the dynamic behaviour of each machine structure with respect to another. Stability lobe graphs are the most reliable approach to analyse the dynamic performance. During heavy rough turning operations a model containing (a) several modes, or (b) modes with non-conventional (Cartesian) orientations is necessary. This work proposes two methods which are combined with multimode analysis to predict chatter in big horizontal lathes. First, a traditional single frequency model (SFM) is used. Secondly, the modern collocation method based on the Chebyshev polynomials (CCM) is alternatively studied. The models can be used to identify the machine design features limiting lathe productivity, as well as the threshold values for choosing good cutting parameters. The results have been compared with experimental tests in a horizontal turning centre. Besides the model and approach, this work offers real worthy values for big lathes, difficult to be got from literature.Item Vibration analysis of cable-driven parallel robots based on the dynamic stiffness matrix method(2017-04-28) Yuan, Han; Courteille, Eric; Gouttefarde, Marc; Hervé, Pierre-Elie; Tecnalia Research & InnovationThis paper focuses on the vibration analysis of Cable-Driven Parallel Robots (CDPRs). An oscillating model of CDPRs able to capture the dynamic behavior of the cables is derived using Lagrangian approach in conjunction with the Dynamic Stiffness Matrix method. Then, an original approach to analyze the modal interaction between the local cable modes and the global CDPR modes is presented. To illustrate this approach, numerical investigations and experimental analyses are carried out on a large-dimension 6-DOF suspended CDPR driven by 8 cables.