Natural fiber-reinforced lightweight design and vibro-acoustic metamaterials

Lightweight design makes products competitive and sustainable. Safety and reliable functionality must be guaranteed. The exhibits from Fraunhofer LBF at the ELMIA Subcontractor in Jönköping/Sweden show promising new approaches for sustainable and efficient manufacturing processes with natural fiber-reinforced materials and the lightweight design potential of vibro-acoustic metamaterials.

Light and mobile with natural fiber reinforced plastics

For mechanical engineering and mobility to become even more economical, the components used there must be manufactured more efficiently and made lighter. The drivers are not only stricter emissions regulations but also society’s growing awareness of the environment and sustainability.

Current Fraunhofer research solutions for sustainable lightweight design include, for example, property-optimized, particularly lightweight structural solutions for function-integrated, intelligent lightweight design – always taking into account the reliability, sustainability and affordability of the technical product solution.

At the important trade fair for the technical supply industry in Scandinavia, Fraunhofer LBF is demonstrating the potential for series production with a sustainable battery housing for e-bikes. The car door is an example of how industrial applications benefit from vibro-acoustic metamaterials.

Vibration problems often occur with lightweight design, which have a significant impact on the quality of life and comfort in everyday life. Conventional approaches to reducing vibration and noise often reach their limits. Fraunhofer LBF is developing applications with vibroacoustic metamaterials for optimized structural dynamic behavior.

Vibroacoustic metamaterials reduce structure-borne noise

Vibroacoustic metamaterials (VAMM) represent a novel measure for vibration reduction and have advantages in influencing vibration behavior compared to conventional measures. They are used as a vibration reduction measure in a wide variety of industries, for example in mechanical and vehicle construction or in space travel.

VAMM reduce disruptive structure-borne or airborne noise and help to stabilize equipment and increase comfort. These are structures with specially, usually periodically, arranged structural dynamic and/or acoustic resonators. The high effectiveness of VAMM is based on the targeted design and arrangement of the unit cells in the network and the resulting interaction between the unit cells.

In order to be able to respond individually to customer requests and to meet social and political responsibility, the “BioBattery” research project was carried out at Fraunhofer LBF in collaboration with Ansmann AG to develop natural fiber-reinforced plastics for use in Li-ion battery housings.

The natural fiber-reinforced plastics are characterized by their low density, good mechanical properties, low tendency to splinter and comparatively low costs. In the project, different natural fiber fabrics were impregnated and modified according to requirements using a new process with plastic melt, while reducing the contact time.

Based on an adapted component design of the battery housing to meet numerous standards, local natural fiber reinforcements were introduced into the housing using an innovative injection molding process. The resulting housing impresses with a weight reduction of 30% compared to the original housing, while at the same time increasing rigidity by 15%.

More about the “Bio Battery”: www.lbf.fraunhofer.de/en/projects/lightweight-biobased-plastics.html

Technical details of “VAMM” project: www.lbf.fraunhofer.de/de/forschungsbereiche/adaptronik/vibroakustische-metamaterialien.html