This work examines the history of industrial fabrics and investigates how certain of these fabrics have developed to meet the changing demands of their end-uses. It also examines how woven textile fabrics are increasingly competing with the traditional engineering materials as new fibres and filaments allow an ever increasing range of properties; improved fabric engineering techniques are also ensuring that industrial fabrics are more suited to their end-uses. To aid fabric engineering a greater knowledge is required of fabric structure and mechanics, so developments in this field are examined. To help improve fabric research of this type, realistic physical testing methods are required both to test the usefulness of mathematical models, and to simulate conditions experienced in use. Due to certain restrictions of this type of testing, a suitable selective fabric extension measuring device is required so that problem areas such as clamping effects can be avoided. The. lack ofa suitable device to help overcome problems such as this has been a long standing difficulty, so the development of a new fabric extension gauge was one of the main objects of this work. Before such a device could be developed research first involved a survey of many of the previous extension measuring devices, however, as expected nothing suitable emerged. After considering many ideas for possible new devices, it was decided to try and develop a gauge using the relatively new material PVDF piezo polymer film. This is a thin, low modulus film which develops an electrical charge proportional to a CHANGE in mechanical stress, and which can be easily cut to any desired dimensions. Initial attempts to develop a suitable extension measuring device were not completely successful, but when suitable following circuitry was found, and a proper mounting procedure determined, the new gauge appeared very promising. When it was considered that a suitable extension measuring device was available, the next task involved the design of a biaxial tensile and shear testing machine for the new Clothworkers' Textile Hechanics and Structures Laboratory. It was considered that the availability of a suitable selective extension measuring device was of paramount importance before the design of the new tester could be considered. This apparatus was based essentially on, the proven principles of Yendell's and Bassett's testers, but a number of unique features were to be added, such as independently controlled clamps, and the ability to cycle in shear. The principles involved in the design of the mechanical hardware are described, as also are certain original recommendations which have been suggested for the second stage of the project in which the sophisticated control, measurement and analysis techniques will be developed.