Through a combination of direct measurement and inverse modelling, a route to characterising the main mechanical forming properties of engineering fabric is demonstrated. The process involves just two experimental tests, a cantilever bending test and a modified version of the uniaxial bias extension test. The mechanical forming properties of a twill weave carbon fabric have been determined, including estimates of the in-plane bending stiffness and the torsional stiffness of a sheared fabric. As a result of measuring and incorporating all the main mechanical properties of the fabric in forming simulations (tensile, shear, out-of-plane bending, in-plane bending & torsion), the specimen size-dependent shear kinematics and wrinkling response measured in experiments, is faithfully reproduced in simulations of the uniaxial bias extension (UBE) test.

TechnologyThe following points could make the Authors' method even more attractive.44. The calculation of the deteriorated critical load in $29 could be replaced by the simpler procedure of checking that ,l1 lies below this critical load, by using $510-12 of reference 29 with Kbi given by tangential stiffnesses, as in $29, instead of by equation ( 5 ) of reference 29. 45. The sway deflexions of $27 could then be found by the method of @3-6 of reference 29, with Kbi given by secant stiffnesses, as in 527, instead of by equation ( 5 ) of reference 29. This change and that in $44 are both ideally suited to programming, and coding economies result because both changes involve equations (3), (4) and (6)-(13) of reference 29.46. The methods of reference 29 optionally include the simple representation of cladding permitted in the Merchant-Rankine approach. Thus the changes proposed enable cladding to be included in all the Authors' sway deflexion and critical load steps. As their other steps are unaltered by this simple representation of cladding, the changes in $S44 and 45 enable the Authors' method to make an allowance for cladding. Dr Anderson and Dr IslamThe method Professor Williams proposes will enable a unified approach to be made to the calculation of both sway deflexion and the deteriorated critical load. Also, by including cladding stiffness, a less conservative approach, can be made to design. Reference 29. WILLIAMS F. W. Consistent, exact, wind and stability calculations for substitute sway frames with cladding.