Monitoring Auxetic Structure with FBG Sensor

Auxetic materials are a particular class of materials which present a negative Poisson ratio (NPR). This means that once they are stretched, they expand in the directions orthogonal to the applied load. The dual behaviour occurs during compression tests. Due to this characteristic, they present many interesting properties like increased resistance to fracture indentation and shear stress, lower crack propagation rate, synclastic behaviour, and the ability to tune their porosity by applying stress. Because of these properties, auxetic materials are gaining the attention of researchers. Their applications are diverse, ranging from automotive and aerospace to medicine and seismic applications. Because of their application potential, it is important to find an effective way to monitor their condition during use. Fibre Bragg grating (FBG) sensors are widely used in structural health monitoring (SHM) applications. They are particularly attractive due to their unique properties, such as multiplexing capability, resistance to electromagnetic interference, high measurement accuracy, chemical inertness that enables operation in harsh environments, and their very small size. However, due to the novelty and unique geometry of auxetic materials, monitoring them with FBG sensors presents challenges. In this work, we investigate the possibility of monitoring auxetic materials using FBG sensors.