Analytical Modelling of Textile Parameters and Draping Behaviour of 2D Biaxial Braided Sleevings

Abstract

Biaxial braided sleevings are commonly used for producing hollow complex-shaped composite parts through bladder inflation moulding. To enable feasibility analyses, part design and the prediction of mechanical properties of the resulting fibre-reinforced component, various geometrical and weight-related parameters of the braided fabric in its draped state must be known, such as fibre orientation, fibre volume fraction and areal weight. In the present work, a comprehensive analytical model describing fabric formation, preform architecture and weight as well as the change of relevant textile parameters of a biaxial braided sleeving during draping is established. The principal modelling approach is based on sporadic investigations found in literature and was substantially expanded to compile an extensive collection of relationships for the utilisation in a sleeving-on preforming process. Furthermore, a critical overview about the state of the art in the area of geometrical modelling of tubular 2D braided structures and a comparison of the identified procedures in regard to the desired application is given.

A methodology for determining preform compaction in bladder-assisted resin transfer molding with elastomeric bladders for tubular composite parts

“…for near-net shape preforms, for flat fabrics that are loosely wound around the bladder or for biaxial braided fabrics with rather low braid angles. However, some preforms such as braided fabrics with high braid angles can hinder bladder expansion due to high frictional forces or locking of the interlaced reinforcing yarns [23]. Thus, prior investigation of the fabric's drapability and jamming condition through experimental tests [24,25] or draping models [23,26] is recommended, but is out of scope of this paper.…”

“…However, some preforms such as braided fabrics with high braid angles can hinder bladder expansion due to high frictional forces or locking of the interlaced reinforcing yarns [23]. Thus, prior investigation of the fabric's drapability and jamming condition through experimental tests [24,25] or draping models [23,26] is recommended, but is out of scope of this paper. When the minimum pressure for full radial bladder expansion p b, min is reached, the preform is in full contact with both the bladder and the outer mold (Fig.…”

“…The tubular braid to be tested is draped and collapsed to a specific diameter and flattened width, respectively, considering the change of the interdependent braid parameters length, diameter or width and fiber angle [23,26]. The flattened fabric is then cut in longitudinal direction and unfolded as depicted in Fig.…”

An experimental investigation into the behavior of sand reinforced by tubular braided structures

“…The 3D shape of the braided structures has a potential for the confinement of the materials inside [20]. Depending on the fiber types, this kind of textile can expand both in the cross-section and length (before resin injection) [21]. Therefore, it can be filled easily by soil and/or other materials.…”