DEVELOPMENT OF 3D-REINFORCED THICK-WALLED TUBES

摘要

The Army needs durable thick-section tubular structures made of glass fiber composites. Filament winding is the most obvious process for producing tubular structures. Another option is to layup and cure a thick flat plate followed by a machining step to achieve a tubular shape. The use of these architectures in applications that expose the materials to thermal shock and bending loads results in delamination after a relatively small number of cycles. In the present work, two fiber architectures with improved delamination resistance are compared. One case is a thick-walled 3D polar braided preform with a specific proportion of axial, circumferential, and radial reinforcements. This structure is macroscopically axisymmetric. The other case is a 3D Jacquard-woven (flat) preform with layer-to-layer construction, which is bent around a mandrel to achieve a hemi-annular shape prior to infusion. This structure is not macro scopically axisymmetric, but still maintains 3D reinforcement. Samples cut from cured specimens from each architecture type have been tested under 3-point bend conditions and deformations to failure are measured using digital image correlation.