Safety, energy saving and environment are the three main objectives of the transport industry. This situation is generating a strong demand for lightweight high resistant metallic components capable to optimise the passengers/goods protection, fuel consumption and recycling ability. This explains the growing interest and developing market for cellular made components like the one using honeycomb and foam structures (3000 m3/year just for the AIRBUS). These materials, used as a core or filler in sandwich type and hollow structures, behave as mechanical energy absorbers and provide, with a minimum weight increase, additional shock resistance to the final component. The mechanical performances of the honeycomb and foam structures, although well adapted to areas where strength/weight ratio must be optimised, are not compatible with high resistance requirements like in crash situation in the automobile. Also, the anisotropy characterizing these products privileges optimum energy absorption in one or two dimensions only. Eventually, for the foams further development is necessary to be able to understand the influence of the manufacturing process parameters and constituent characteristics on the final properties of the products. This project will study a new light weight shock absorbent structure made of metallic hollow spheres assembled by adhesive bonding into pre determined configuration. The possibility to characterise and define the mechanical properties of one unitary cell (2 to 8 mm sphere) will allow to tailor the final performances of the structure for a given application. More, the spherical shape of the cells will confer perfect isotropy on the material. The versatality and high mechanical performances (expected 60 % deformation for over 40 Mpa compressive strength) of this new cellular structure are expected to merge on innovative applications and design methodologies for lightweight structural applications and highly stressed components in the transport industry. The core group of SMEs gathers all the competences necessary to the different steps of the new product manufacturing: the metallic hollow spheres, the bonding/joining techniques, the structure confinements and the assembly of the final component. The RTD performers will contribute to the selection and design of the new lightweight components for the aircraft and automobile industries, after characterizing and testing the new structure. At the end of the project, the performances of the hollow sphere structure will be analysed on real scale demonstration items under functional testing and compared to the current cellular structure (honeycombs and foams) technico economical specifications. At equal density, the hollow sphere material is expected to provide 50 % increase of the mechanical energy absorption capacity and 30% cost reduction on the final component in comparison to the current cellular material.
Funding SchemeCRS - Cooperative research contracts
95005 Saint-ouen L'aumone
10090 Ferriera Di Buttigliera Alta