Bio-Damping

Thanks to their numerous natural advantages, bio-sourced fibers are of increasing interest to industrialists. Indeed, bio-sourced fibers are closely linked to the fields of maritime-, air-, railway- and road-transportation, due to their intrinsic lightweight and damping capacities to improve the comfort of passengers and users. In an eco-design approach, manufacturers, especially those dealing in sailing with parts such as foils, masts, rudders and steering-gears are questioning the interest of incorporating bio-sourced fibers in all or part of a structure made of composite materials. Nowadays, incorporating bio-sourced fibers in composite materials still generates difficulty in dealing with production, mechanical characterization, modelling and simulation. The aim of the Bio-Damping project is to provide a solution to the last three locks. Based on an experimental test campaign, the project will enable to model the damping properties of the bio-sourced composite layer to be incorporated in a specific structure calculation code. For this purpose, two companies renowned for their ability and expertise to implement composite structures will produce test-specimens. The manufacturing process management will enable to keep control of the risks regarding the use of fibers of homogenous origin, resins of constant quality, reproducible manufacturing processes and controlled environments. The test-specimens produced thereby will make it possible to identify, define and characterize the supposed constitutive law (Maxwell, Zener, ...) of a fiber/matrix layer. This will take the fiber-orientation along with the specific parameters related to temperature, hygrometry, aging due to UV radiations, salty environment, into account. The influence of the manufacturing process will be studied by comparing the mechanical properties of the test-specimens from two different processes, i.e. the infusion process of prepregs and the method of placing fibers by a robot. The behavior model will be incorporated into a specific structure calculation code developed within the IRDL. This code is dedicated to solving non-linear problems. It provides efficient and robust resolution algorithms so as to determine the response of vibration (eigenmodes, structural damping) of a composite structure. Based on methods associating high order perturbation and continuation technique, the calculation code enables to carry out parametric studies. Thus, a sensitivity study of the response of vibration, related to the variability of the physical and mechanical characteristics of bio-sourced fibers and the environmental conditions will be carried out. At the end of the Bio-Damping project, a methodology dedicated to designing and sizing of composite structures based on bio-sourced fibers, will have been designed. Associated with an eco-design approach, the solutions gained during the project will enable an industrialist interested in these bio-sourced composites with uncertain properties, to substitute the current production for bio-sourced composite parts: they will be able to choose the relevant fiber-orientation in their multi-ply composite depending on the requested damping capacity. Specific parameters related to environmental and climatic conditions, such as temperature, hygrometry, aging due to UV radiations, salty environment – may also be taken into account.