Fully integrated monitoring systems have shown promise in improving confidence in composite materials while reducing lifecycle costs. A distributed optical fibre sensor is embedded in a fibre reinforced composite laminate, to give three sensing regions at different levels through-the-thickness of the plate. This study follows the resin infusion process during fabrication of the composite, monitoring the development of strain in-situ and in real time, and to gain better understanding of the resin rheology during curing. Piezoelectric wafer active sensors and electrical strain gauges are bonded to the plate after fabrication. This is followed by progressive loading/unloading cycles of mechanical four point bending. The strain values obtained from the optical fibre are in good agreement with strain data collected by surface mounted strain gauges, while the sensing regions clearly indicate the development of compressive, neutral, and tensile strain. Acoustic emission event detection suggests the formation of matrix (resin) cracks, with measured damage event amplitudes in agreement with values reported in published literature on the subject. The Felicity ratio for each subsequent loading cycle is calculated to track the progression of damage in the material. The methodology developed here can be used to follow the full life cycle of a composite structure, from manufacture to end-of-life.
In this paper, a passive structural health monitoring (SHM) method capable of detecting the presence of damage in carbon fibre/epoxy composite plates is developed. The method requires the measurement of strains from the considered structure, which are used to set up, train, and test artificial neural networks (ANNs). At the end of the training phase, the networks find correlations between the given strains, which represent the ‘fingerprint’ of the structure under investigation. Changes in the distribution of these strains is captured by assessing differences in the previously identified strain correlations. If any cause generates damage that alters the strain distribution, this is considered as a reason for further detailed structural inspection. The novelty of the strain algorithm comes from its independence from both the choice of material and the loading condition. It does not require the prior knowledge of material properties based on stress-strain relationships and, as the strain correlations represent the structure and its mechanical behaviour, they are valid for the full range of operating loads. An implementation of such approach is herein presented based on the usage of a distributed optical fibre sensor that allows to obtain strain measurement with an incredibly high resolution.
The socio‐economic struggles in Africa are partly attributed to the low productivity of the agricultural sector. The Sustainable Development Goals Centre for Africa (SDGC/A) and the African Development Bank Group (AfDBG) both agree that the continent needs sustainable interventions to boost agricultural productivity, employment, and income. In this regard, mycelium composite production can present one potential solution. The added value to agricultural waste used to produce mycelium composites can generate additional revenue for farmers, serving as an incentive to increase agricultural productivity. Furthermore, the establishment of mycelium composite start‐ups can increase employment and income, especially for women and the youth. Mycelium composites can also aid in mitigating environmental and health challenges caused by some of the current waste management practices in Africa. This review offers valuable insights into the potential use of mycelium composites as a sustainable alternative for Africa. It explores the potential use of locally accessible resources, the potential applications for the composites in Africa, and the potential challenges that may arise with this technology. It further assesses the potential contribution of this technology to sustainable development in Africa in line with the Sustainable Development Goals (SDGs) set by the United Nations (UN).