Fangfang Sun

Experimental investigations on the failures of woven textile sandwich panels

To reveal the deformation, strength, and failure modes of woven textile sandwich composites (WTSCs), test methods suggested by national standards were referenced and discussed to carry out flatwise and edgewise compression experiments, uniaxial stretching experiments, and three-point bending experiments according to the structural characteristics of WTSC. Strength and failure modes of WTSCs in flatwise compression and uniaxial tension were acquired. Anisotropy and size dependency of strength and failure modes of WTSC panels in edgewise compression were revealed. Strength of weft-compressed panels has few variations when the length is smaller than 60 mm and then decreases obviously when the length is over 60 mm, accompanying with the failure modes turning from crushing, fracture to buckling. Progressive crushing and bending fracture are two observed post-failure modes. Two competing shear failure modes and facesheet failure were observed in three-point bending experiments. Shear strength of the woven core of WTSC was deduced by beam flexure. To acquire facesheet failure mode by long beam flexure, the span should be above 36 times the thickness of the panel.

Light-Weight Design of CRH Wind Deflector Panels based on Woven Textile Sandwich Composites

The woven textile sandwich composite (WTSC) is a promising lightweight composite. In bending, two competing core shearing failure modes reduce the strength; deflection induced by the core shearing deformation reduces the flexural rigidity. To replace a solid composite laminate, the span of WTSC panel must be greater than a critical value, which was deduced on the condition that the load capacity and flexural rigidity of the WTSC panel are equal to those of the composite laminate. Three WTSC panels were tested in bending, so that the failure modes were observed, and the critical spans were determined. Using the alternative design method, the WTSC based wind deflector with reduced weight has been fabricated and mounted on the CRH (China Railway High-speed).