Stretching behaviors of entangled materials with spiral wire structure

The entangled materials with spiral wire structure have been investigated in terms of the stretching behavior, mechanical properties, and stress–strain hysteresis effect. The results indicate that these materials are much more flexible than that with non-woven wire structure. They exhibit 1.05 MPa yielding strength and 5.7 MPa Young’s modulus in average at the porosity of 60%, and 2.47 MPa yielding strength and 12.3 MPa Young’s modulus in average at the porosity of 45%. Under tensile loading the materials exhibit a unique stress–strain behavior that goes through a long strain period after yielding and follows a quick stress increase on the stress–strain curve due to the ‘unclosing’ and ‘straightening’ mechanism of the spiral wire structure. In addition, these materials exhibit obvious stress–strain hysteresis effect. Their energy dissipation values determined according to the stress–strain hysteresis loops are 28.6 mJ/cm3 at the porosity of 60% and 102.3 mJ/cm3 at the porosity of 45%, which are much larger than that of the polymer foam, implying their promising applications for the energy absorption.