Experimental Study of the Influence of Strain-Rate on the Mechanical Properties of Cork and Its Agglomerates

This study investigates the potential of natural cork and white cork agglomerates as sustainable alternatives to expanded polystyrene (EPS) foams for energy-absorbing applications such as motorcycle helmets. EPS foams, although commonly used due to their low density, good weight-energy absorption ratio, and other appealing attributes, do not recover their shape after deformation, thus limiting their ability to absorb energy efficiently. Natural cork, a renewable and biodegradable material, exhibits the ability to regain its initial shape and mechanical properties after an impact, making it suitable for applications involving multiple impacts. This research focuses on characterizing the mechanical properties of natural cork, white cork agglomerates, and EPS foams under compression loads, and analysing the influence of strain rate on their behavior. This study refers to standards such as ISO 844 and ASTM D1621 for compression testing of cellular plastics, applying them to cork samples despite its non-plastic nature due to its similarities to cellular plastics. The results will contribute to the understanding of the cork resilience and its potential as a sustainable alternative for energy-absorbing applications.