| 摘要 |
A pressure transducer using as a component for changing shape in response to a change in the pressure being measured a composite elongated body, with specially arranged reinforcing fibers. Such a pressure transducer can use various means for sensing the change in shape of the elongated body, including an optical fiber affixed to the elongated body so as to itself change in length in response to a change in pressure, and having a Bragg grating as part of the optical fiber, with the Bragg grating positioned and arranged so as to convey, in response to an optical signal, information about the change in shape of the elongated body. The elongated body is provided with at least one pair of contra-helically wound reinforcing fibers, which may even be bi-axially braided, and are wound either to amplify the effect of pressure acting on the elongated body or to insulate the elongated body from the effects of pressure and other sources of stress. The reinforcing fibers are embedded in a resin, and in some applications more than one pair of contra-helically wound reinforcing fibers are used, so that the composite body consists of more than one layer of reinforcing fibers. The resulting elongated body is a non-isotropic material and can be designed to have a Poisson's ratio significantly greater than ½, the maximum possible Poisson's ratio for an isotropic material, providing an enhanced axial strain accompanying any radial or circumferential strain. The elongated body can also be designed to have a small Poisson's ratio by using an inner layer and outer layer of contra-helical windings where the reinforcing fibers of the two layers intersect at different angles. |
