Applications of auxetic designs in sports equipment: development of auxetic backpacks

Engineering of Sport 15 - Proceedings from the 15th International Conference on the Engineering of Sport (ISEA 2024)

Sport backpacks are essential for athletes, adventurers and outdoor enthusiasts, aiding gear transport during physical activities. Shoulder straps and back panels are pivotal for ergonomic and thermal comfort. Wider, adjustable straps for example, ensure load distribution, enhancing ergonomics and preventing strain. Conventional foamed back panels used in full-contact backpacks for outdoor activities such as mountain biking, guarantee mechanical comfort by enhancing load-bearing capacity and minimizing wobbling. Nevertheless, because of the close contact with the rider's back and shoulders, thermal comfort might be affected. Moreover, they do not provide impact protection to the user’s back in case of falls. The objective of the present work has been to develop innovative designs for sports backpacks shoulder straps and back panels with improved safety, comfort and performances by using hollow geometries, such as auxetic ones. These engineered structures are a class of mechanical metamaterial.