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Leuven, Belgium

Mucchi E.,University of Ferrara | Vecchio A.,Lms International
Measurement: Journal of the International Measurement Confederation | Year: 2010

The noise situation inside modern helicopter cabins is still unsatisfying in comparison to modern jet. The requirement of a quieter helicopter needs a systematic study of its Noise Vibration and Harshness (NVH) behaviour. In this context, the authors have performed a wide experimental vibro-acoustic campaign in a helicopter cabin, which aims at evaluating the importance of the noise contribution produced by the jet engines with respect to the gearbox as well as finding possible noise sources and leakage points on the cabin surface. The results show that the main noise and vibration sources are the jet engines and the gearbox. Furthermore, the contribution of the jet engines is dominant with respect to the contribution of the gearbox, in terms of sound quality parameters. Finally, the paper suggests a fast and efficient experimental tool for leakage point detection and relative quantification on the cabin, very useful for noise control and quality check. © 2009 Elsevier Ltd. All rights reserved. Source


Pintelon R.,Vrije Universiteit Brussel | Peeters B.,Lms International | Guillaume P.,Vrije Universiteit Brussel
Mechanical Systems and Signal Processing | Year: 2010

Recently [R. Pintelon, B. Peeters, P. Guillaume, Continuous-time operational modal analysis in the presence of harmonic disturbances, Mechanical Systems and Signal Processing 22 (5) (2008) 1017-1035] a single-output algorithm for continuous-time operational modal analysis in the presence of harmonic disturbances with time-varying frequency has been developed. This paper extends the results of Pintelon, et al. [Continuous-time operational modal analysis in the presence of harmonic disturbances, Mechanical Systems and Signal Processing 22 (5) (2008) 1017-1035] to multi-output signals. The statistical performance of the proposed maximum likelihood estimator is illustrated on simulations and real helicopter data. © 2009 Elsevier Ltd. All rights reserved. Source


El-Kafafy M.,Vrije Universiteit Brussel | Guillaume P.,Vrije Universiteit Brussel | Peeters B.,Lms International
Mechanical Systems and Signal Processing | Year: 2013

The poly-reference Least squares Complex Frequency-domain (pLSCF) estimator - commercially known as the LMS PolyMAX estimator - is used intensively in modal analysis applications nowadays. pLSCF is non-iterative (deterministic) and relatively accurate modal parameter estimation algorithm. This algorithm has several advantages: it is polyreference, fast, numerically stable for large-bandwidth with high-model order analysis, and yields very clear stabilization diagrams even with highly noisy FRFs measurements. One drawback of the pLSCF-estimator is that it yields a poor damping estimates especially for highly damped and weakly excited modes when the FRFs are very noisy. In this contribution, an approach will be proposed to improve the accuracy of pLSCF estimator and in particular, the damping estimates in case of high noise level. The new proposed approach is a combined stochastic-deterministic frequency-domain algorithm. In this approach, a 2-step procedure is introduced to improve the damping estimates while maintaining the very clear stabilization diagrams. In the first step, a parametric Maximum Likelihood smoothing approach, which is the stochastic part, is used to remove the noise from the data and in the second step, the pLSCF estimator, which is the deterministic part, is applied to the smoothed data resulting in improved (damping) estimates. The presented algorithm is able to maintain the benefits of pLSCF and at the same time leads to an improvement of the damping estimates in highly damped and very noisy cases. In addition, the new procedure properly deals with uncertainty on the measurements where the data variance due to measurement noise is taken into account. The procedure is illustrated and tested by using simulated as well as experimental data. The presented procedure to process a highly damped noisy vibration data leads to very accurate estimates in comparison to the traditional pLSCF estimator. © 2012 Elsevier Ltd. All rights reserved. Source


Grant
Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2009.4.3 | Award Amount: 4.66M | Year: 2011

Data and knowledge management technologies are of strategic importance for industrial innovation, provided they are integrated in the company processes, in the organisational structure, and can be flexibly adapted to company evolution. In particular the Product Development Process (PDP) of manufacturing companies, requires the efficient management of huge amounts of data from different sources and their integration in the subprocesses that compose the product chain. The efficient use of information lifecycle, by the large adoption of virtual testing and by the inter-functional management of related data in the product management would become a strategic advantage for the innovation race. Present ICT solutions separately address parts of product development, but an integrated approach that includes data and services required for the whole Product Development Process does not yet exist.iProd will improve the efficiency and quality of the Product Development Process developing a flexible, service oriented, customer driven software framework that will be the backbone of computer systems associated with current and new development processes. To achieve these goals, iProd will rely on knowledge management (KM), knowledge based engineering (KBE) and process integration and automation technologies.iProd will assume the challenge of complexity, semantic diversity and richness of content establishing semantically rich, open and transparent methodologies that will enable knowledge workers from aerospace, automotive and home appliances industries to manage product and process complexity, managing higher value information like functional specifications, requirements, decision rationale and engineering and business knowledge in general. This knowledge base along with a reasoning engine will support information sharing, collaboration across companies, common understanding of PDP among different industries and will promote efficient decision taking.


Grant
Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2007.1.2 | Award Amount: 4.03M | Year: 2008

The existing licensing models for commercial applications are focusing on software used on compute resources within an administrative domain. A problem occurs when we want to use this software in a distributed service oriented infrastructure where the resources are often not in the same administrative domain that hosts the license server which is authorizing the application use. Today licenses usually are bound to hardware within the domain of the user and do not allow access from outside thus enforcing local use of the protected applications only. The Grid approach in contrary is about using distributed resources from different domains. The experience made in many recent projects trying to use commercial applications in Grid systems clearly indicates a technological barrier of current licensing mechanisms that must be overcome before the Grid becomes a fully commercial productive environment.\n\nSMARTLM solution is to implement licenses as Grid services thus providing platform-independent access just like other Grid resources. Service Level Agreements based on evolving standards will then govern licenses. Depending on the level of trust signed or encrypted, agreements will be used to transport licenses through the Grid to the resource to which a user has been granted access to execute his application tasks. The agreement on a license and the conditions of use for an application will be reached through negotiation between service providers and service customers.\n\nSMARTLM will provide new generic licensing virtualization technology based on standards as WS-Agreement and WS-Negotiation and integrate it in the major Grid middlewares. The project will also identify new service-oriented business models for this approach. A number of widely-used license-protected commercial applications will be adapted to be executed under control of the new licensing mechanisms and will become part of a highly quality show-case to convince more code-owners to adapt their applications.

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