Study on an innovative knitting technology of spacer fabrics and the low-velocity impact properties of its composites

Spacer fabric has a variety of spacer structures which can exhibit different physical properties. Traditional double-layer U-shape (rectangular structure) spacer fabrics have been used in a variety of applications. Among the geometric structures, triangles are more stable than others. This paper introduces a knitting technique for an innovative double-layer V-shape (triangular structure) weft-knitted spacer fabric. The innovative V-shape and traditional U-shape weft-knitted spacer fabrics are knitted on a computerized flat knitting machine. Tensile tests are carried out in course and wale direction for these weft-knitted spacer fabrics, and their force-displacement curves are compared. The results show that V-shape weft-knitted spacer fabric has a tensile force of 2605.63 N in course, which is higher than U-shape. This paper also presents an experimental study on the compressive behavior of these weft-knitted spacer fabrics impregnated with shear thickening fluid when subjected to low-velocity impact loadings. The experiments prove that the composites of innovative structures show higher energy absorption and lower peak load than traditional structures. Weft-knitted spacer fabrics impregnated with shear thickening fluid also show better performance than pure weft-knitted spacer fabric.