Aircraft passenger and crew comfort is dependant from several issues, nevertheless most of the nuisances come from the level of cabin noise which is generally the consequence of a lack of vibration and noise source efficient attenuation. The Parvis proposal aims at offering a new passive damping system already validated in noise attenuation but not yet able to fully comply with the aeronautical requests on thermal environment and the no maintenance target. The Parvis proposal technical objectives are to acquire technology to be able to comply with aeronautical and societal demands for such a system. Parvis is a proposal coming from SMEs working in the aerospace supply chain, the goal of marketing the final product within one year after project completion is clearly indicated in the proposal.
WP1: This WP produced a detailed specification (report D1) of the damping material. The specifications displayed in this document correspond to the requirements of several aeronautic companies, when faced with vibro-acoustic problems. The most important properties of the material are: high damping performances, stability of the properties in a large temperature range, controllable implementation of the material on a maximum of supports.
WP2: Several materials have been developed by IQS, ISMANS and JEVSA. Rather interesting results have been obtained for the 3 main material designs studied (polyacrylates, butyl rubber formulations and IPN). These 3 materials have been produced in small quantities. The butyl rubber blend produced by JEVSA presents a high level of damping, but the broadening of the tan d peak is only of about 30°C. The IPN developed by IQS presents a high level of damping and the tan d peak is broad. The polyacrylate material developed by ISMANS presents a good level of damping on a widen temperature range.
WP3: The programme developed by MAKROSS permits to make the fitting of the DMTA curves thanks to a modelling of the viscoelastic materials based on Maxwell models using springs and dampers. The input of the programme is the DMTA results, e.g. the knowing of the evolution of the shear modulus G' and the loss factor tan d with strain rate, strain rate velocity, temperature and frequency.
WP4 : ARTEC has tested each material thanks to a DMTA test bench. The influence of the temperature in the range [-35(0)C ; +85(0)C], the strain rate in the range [0 ; 40%] and the frequency in the range [5 ; 500 Hz] has equally been evaluated. Thus, the knowing of the evolution of the viscoelastic parameters (shear modulus G' and loss factor tan d) permits to select the best material for damping a specified structure. From this test campaign, we can conclude that all the materials tested have high damping properties; unfortunately, the stability of the performances is not maintained on the entire temperature range specified by ARTEC in the WP1 report. However, the materials developed can be at least as interesting as those currently used by ARTEC, providing that there is no degradation of the performances between the laboratory and the industrial productions.
WP5: IACP JEVSA, has identified a manufacturing process for each optimised material. Concerning the butyl rubber, several ratios of the mixture of both polymers (butyl and acrylate) have been tested with IQS collaboration. The optimum proportion is 85% butyl + 15% acrylate. The kind of fillers has been defined (platelet fillers) as well as the cure system optimal parameters. The process of mixing and compounding is equally adapted to the material: temperatures, order of incorporation, time of mixing, ... Concerning the IPN, the manufacture is mainly included as a part of the synthetic process. Thus, the most suitable reagents and the order of synthesis have been identified. The latex film preparation has necessitated to identify the optimal characteristics of the vacuum chamber and the oven.
Funding SchemeCSC - Cost-sharing contracts
72000 Le Mans