Spacer fabric/flexible polyurethane foam composite sandwiches: Structural design and quasi-static compressive, bursting and dynamic impact performances

Abstract

Nylon fabrics are used as the reinforcing upper layer. A warp-knitted spacer fabric that is saturated with flexible polyurethane foam is used as the lower layer. They are combined in order to form innovative impact energy absorbent composite sandwiches employing a two-step foam process. The quasi-static compressive strength, bursting strength, and dynamic shock cushioning characteristic of the composite sandwiches are evaluated, the latter of which is tested using a drop weight impact tester in order to simulate the impact resistance corresponding to complex environments. The experimental results suggest that a combination of warp-knitted spacer fabric increases the compressive strength and bursting strength of composite sandwiches by 107% and 60%, respectively. The shapes of impactors determine the contact force and dynamic impact time. The greater contact area results in the smaller contact force, indicating that the composite sandwiches have greater cushioning efficacy. Designed with a gradient combination, the flexible polyurethane foam strongly bonds the upper polyamide nonwoven fabric and the lower warp-knitted spacer fabric. The optimal compression resistance, a bursting strength of 1677 N, and a maximum energy absorption of 90% at a 15 J impact energy are presented. The innovative composite sandwiches have a promising perspective in packaging and individual impact protection in the future.

Review on the performances and applications of mesh-fabrics

“…For 3D mesh-fabrics, such as warp knitted mesh spacer fabric, its excellent compression resistance (Figure 2(e)) has also been concerned and studied by many scholars. 37–39 When it is used as reinforcement to prepare foam 40,41 or concrete composites, 42 the geometric structure of yarn and the mechanical behavior of fabric play a crucial role in the infiltration and reinforcement of composite matrix, which involves the study of its flexural and shear resistance. 43–47…”

Topological design of the hybrid structure with high damping and strength efficiency for additive manufacturing

“…The latter mainly selects different materials in the hybrid lattice structure. Aluminum foam (Yan, 2014; Yan, 2013), glass fiber (Tian et al , 2019; Shahdin et al , 2009; Sargianis and Suhr, 2012; Yang, 2016), polyurethane foam (Gama et al , 2017; Wang et al , 2019), carbon/epoxy (Baba et al , 2010) and ceramics (Ni et al , 2014) have been studied as the filling material for hybrid structures.…”

Study of matrix modifications by nano-clay on the mechanical properties of AA3003 honeycomb sandwich panels

“…Composite face sheets are preferred due to their flexible design, cost advantages, and resistance to environmental attacks. 1 Such composite structures can have high energy-absorption ability and desirable damping properties apart from their high specific strength and stiffness. Core helps to increase the thickness without adding weight, as well as strength and bending stiffness.…”