Effect of eccentricity on sensing in spider web inspired cable nets

Abstract

Abstract Spider webs are multifunctional tools that, besides capturing prey, monitor vibration in the web to localize the prey. Spiders obtain an evolutionary benefit from improving monitoring because better information processing leads to more successful captures, leading to higher chances for survival. Based on this, combined with the costly energy requirements of signaling, biologists observe that the spider’s web operates as an extended cognition of the spider’s central nervous system. Here an extended cognition means that the web filters signals to make decoding information easier. Spider webs contain characteristic design patterns, such as an eccentric location of the central hub. This paper investigates how this eccentricity enables a spatially dependent dynamic response of web-like structures, potentially enabling extended cognition. Modeling consists of modal analyses in a Finite Elements Model on web-like structures where a mass is sequentially moved across all nodes. This yields the natural frequencies of the structure depending on the mass location. Analysis shows that the natural frequency forms patterns based on the mass location, and more importantly, it shows how these patterns become more intricate by including eccentricity. The resulting maximum change in natural frequency grows as the eccentricity in the design grows. This shows that eccentricity influences the dynamic response, hence indicating that eccentricity could enable the web’s extended cognition. The numerical model of spider web-inspired structures can investigate the effects of the geometry on any network-like structures besides spider webs. The authors believe the model can be utilized for impact/anomaly detection on network-like structures.