Compressive characteristics of warp-knitted spacer fabrics with multi-layers

Abstract

Warp-knitted spacer fabrics (WKSFs) that have been recognized as one of the most promising materials are extensively applied in aerospace, military, construction, transportation and other fields owing to unique sandwich structure and excellent performance. In this paper, the compressive and low-velocity impact properties of three kinds of WKSFs with multi-layers have been evaluated. In flat plate compression test, compression process could be divided into three stages: linear compressive stage, yield stage and crushing stage. There is an obvious discrepancy among three kinds of WKSFs in the yield stage due to the varying layers. The fluctuation becomes more frequent with the increase of the number of layers, and the elastic modulus of WKSF with three layers is the largest. In fatigue-resistance compression test, the compressive trend of three kinds of WKSFs is coherent. The spacer monofilaments show a certain fatigue, resulting in a lodging phenomenon. In addition, WKSF with five layers has the best fatigue resistance. In low-velocity impact test, only the uppermost layer of three kinds of WKSFs is damaged due to their unique structure. WKSF with two layers absorbs more energy and has the best low-velocity impact resistance.