Structural element e.g. for incorporation in the surface of an aircraft wing

摘要

A structural element, with reversibly changeable surface shape, has a gastight elastomeric housing (2) contg. one or more pressure spaces (5) in which are embedded electrochemical cells (6) which, during charging, generate gas to enlarge the or each pressure space (5) and, during discharging, eliminates the gas to decrease the pressure space size. Pref. the pressure spaces (5) are contained in ordinary polyurethane foam (4) and the cells (6) are contained in open-pored polyurethane foam (5a) in the pressure spaces. Each cell (6) pref. comprises an outer cathodic casing of braided carbon fibre with a catalytic Pt coating, an inner potassium hydroxide gel electrolyte and an anodic braided silver wire core.