摘要 |
This invention is concerned with means for detecting potential fracturing, such as stress fractures, or damage to, a fibre based structure, by incorporating either hollow fibres containing coloured fluids, or solid fibres, or hollow fibres containing coloured fluids or fluids, which are capable of changing their visual appearance when exposed to external forces, and/or by incorporating fibres within the structure which can change a property such as electrical resistance, capacitance or inductance so that there is an indication whenever and wherever and the extent when a fracture occurs. Where coloured fluids are used, detection is by leakage of the fluid around the fracture. Where colour changing fluids are employed, detection is by observation of change of colour of the fluid. Different fluids can be used for different levels in the strata of tubes in the structure and where these are embedded within the structure, they can be observed where the fibres emanate from the body of the structure. Where fibres are incorporated into the structure that rely on electrical properties to sense a fracture, these fibres may be solid and formed from electrically conductive material and may be coated with such material. Alternatively, though used together with solid fibres, hollow fibres may be used where those hollow fibres contain and/or are coated with electrically conductive material. Appropriate detector means are associated with these fibres to detect the occurrence of a fracture.
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