INFLUENCE OF ACCURATE STRETCH DATA FOR REINFORCEMENTS ON THE PRODUCTION OF COMPLEX STRUCTURAL MOLDINGS .1. DEFORMATION OF ALIGNED SHEETS AND FABRICS

The useful flow properties of mats and fabrics are seldom exploited to the full because of inadequate information on the extent to which they may be deformed prior to moulding. In the composites industry complex shapes are usually produced by empirical techniques. Only when the load-bearing properties of the final structure are found to be obviously deficient are the incidental changes in orientation, variability, and mass/unit area taken into account. Once the effect of deformation on these factors is understood, design and fabrication can usually be made simpler and more reliable. Data are presented describing the deformability of three classes of material: cloths and similar angle ply materials; prepregs of aligned but discontinuous fibre; and two-dimensionally random materials. The effects of prior deformation on the strength of finished mouldings is also discussed. Some examples are given which demonstrate the simplified fabrication of components of complex shape. © 1979.