Caractérisation expérimentale de la transmission acoustique de structures aéronautiques

Le confort des passagers à l'intérieur des avions pendant le vol est un axe en voie d'amélioration constante. L'augmentation de la proportion des matériaux composites dans la fabrication des structures aéronautiques amène de nouvelles problématiques à résoudre.Le faible amortissement de ces structures, en contre partie de leur poids/raideur faible, est non favorable sur le plan acoustique, ce qui oblige les concepteurs à devoir trouver des moyens d'amélioration. De plus, les mécanismes de transmission du son au travers d'un système double paroi de type aéronautique ne sont pas complètement compris, c'est la raison qui motive cette étude. L'objectif principal de ce projet est de constituer une base de données pour le partenaire industriel de ce projet : Bombardier Aéronautique. En effet, les données expérimentales de performance d'isolation acoustique, de systèmes complets représentatifs d'un fuselage d'avion sont très rares dans la littérature scientifique. C'est pourquoi une méthodologie expérimentale est utilisée dans ce projet. Deux conceptions différentes de fuselage sont comparées. La première possède une peau (partie extérieure du fuselage) métallique raidie, alors que la deuxième est constituée d'un panneau sandwich composite. Dans les deux cas, un panneau de finition de fabrication sandwich est utilisé. Un traitement acoustique en laine de verre est placé à l'intérieur de chacun des fuselages. Des isolateurs vibratoires sont utilisés pour connecter les deux panneaux du fuselage. La simulation en laboratoire de la couche limite turbulente, qui est la source d'excitation prépondérante pendant la phase de vol, n'est pas encore possible hormis en soufflerie. C'est pourquoi deux cas d'excitation sont considérés pour essayer d'approcher cette sollicitation : une excitation mécanique (pot vibrant) et une acoustique (champ diffus). La validation et l'analyse des résultats sont effectuées par le biais des logiciels NOVA et VAONE, utilisés par le partenaire industriel de ce projet. Un des objectifs secondaires est de valider le modèle double paroi implémenté dans NOVA. L'investigation de l'effet de compression local du traitement acoustique, sur la perte par transmission d'une simple paroi, montre que cette action n'a aucun effet bénéfique notable. D'autre part, il apparaît que la raideur des isolateurs vibratoires a un lien direct avec les performances d'isolation du système double paroi.Le système double paroi avec peau composite semble moins sensible à ce paramètre.Le modèle double paroi de NOVA donne de bons résultats concernant le système double paroi avec une peau métallique. Des écarts plus importants sont observés en moyennes et hautes fréquences dans le cas du système avec une peau composite. Cependant, la bonne tendance de la prédiction au vu de la complexité de la structure est plutôt prometteuse

Updating the case studies of the political economy of science granting councils in sub-saharan Africa : national case study report of Rwanda

This report identifies the different political, economic and social aspects affecting science, technology and innovation (STI) in Rwanda. The National Council for Science and Technology (NCST) is mandated to coordinate and monitor national science, technology, research and innovation activities but will shift to the newly formed Ministry of ICT and Innovation. Having NCST housed within a ministry of education may mean more focus on universities (University of Rwanda) and their role in STI production rather than industrial partnerships. The decision to consolidate research into a single university needs to be reviewed

Updating the case studies of the political economy of science granting councils in sub-saharan Africa : national case study report of Tanzania

The Tanzania Commission for Science and Technology (COSTECH) was established as a successor to the Tanzania National Scientific Research Council (NSRC) and is the main regulatory body for all science, technology and innovation (STI) related activities in Tanzania. Although impacts in innovation have been made and recognized in the past 5 years, coordination of COSTECH with other government bodies is often frustrated by insufficient resources. R&D funding is primarily dependent on government and foreign donor organisations, along with implicit agendas. Preparation of a new STI policy is in progress for 2018/2019

Updating the case studies of the political economy of science granting councils in sub-saharan Africa : national case study report of Ethiopia

The most recent reforms (2018) to the science technology and innovation (STI) system in Ethiopia are the formation of the Ministry of Innovation and Technology (MInT) and the Ministry of Science and Higher Education (MoSHE). The limited involvement of the government, private sector and academia in STI has resulted in insufficient funding and poorly qualified human resources. A national technological infrastructure is lacking along with limited access to finances. However, the current MInT mandate is focussed on supporting local innovations and technology development through a product and services engineering directorate, incubation centre development directorate, and a start-up strategy

Updating the case studies of the political economy of science granting councils in Sub-Saharan Africa

This study, Updating the Case studies of the Political Economy of Science Granting Councils in sub-Saharan Africa, is a follow-up (Phase 2) to the case studies of the Political Economy of Science Granting Councils (SGCs) in sub-Saharan Africa research completed in 2017 (Phase 1, or baseline study). The study supports the Science Granting Councils Initiative (SGCI) in sub-Saharan Africa (SSA), funded by Canada’s International Development Research Centre (IDRC), the UK Department for International Development (DFID) and South Africa’s National Research Foundation (NRF). In the interest of generating evidence that can be deployed for economic and social development, the SGCI supports SGCs in 15 SSA countries. This research has been commissioned in response to an increasing recognition of the importance of improving understanding of the political economy (PE) of science and research in Africa and the roles that science, technology and innovation (STI)1play in the processes involved.The aims of the SGCI are to strengthen the capacity of SGCs to: manage research; design and monitor research programmes based on the use of robust STI indicators; support exchange of knowledge with the private sector; and establish partnerships among SGCs, and with other science system actors

Updating the case studies of the political economy of science granting councils in sub-saharan Africa : national case study report of Kenya

Government funds are currently directed towards supporting priority sectors: health, food security, housing and manufacturing, with insufficient grants for research. Science, technology and innovation (STI) funding is provided in a patchy manner such that everyone competes for available resources. The absence of strong linkages between learning institutions, research institutions and the industry/private sector has been a recurrent problem in Kenya. This country study finds that private sector funding remains low; a new model for STI funding is called for. Specifically, there is a need to de-link education funding from funding for STI at the Ministry level

Updating the case studies of the political economy of science granting councils in sub-saharan Africa : national case study report of Senegal

This report highlights issues in Senegal with regard to science granting councils. Policy makers and politicians need to complete the formulation and adoption of the anticipated national science, technology and innovation (STI) policy, and to further emphasise the role of STI for socioeconomic development and transformation. Efforts are needed in articulating specific goals and allocation of funding. As it stands, the majority of funding for research (STI and R&D) is from the government. The number of researchers has increased in 2020 to 22,185 compared to 14,335 in 2017. However, the number of full-time researchers remains small

La réglementation économique dans les pays scandinaves de l'Union européenne

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