Strain Dependent Densification during Indentation in Auxetic Foams
Source abstract
Abstract
Negative Poisson's ratio foams have improved indentation resistance over conventional materials. The mechanism for this is thought to be strain dependent densification but experimental verification of this has been lacking. Novel Surface Displacement Analysis (SDA) software, which uses a speckle analysis technique, allows visualisation of displacements and strains over a surface. Cross sections of foam specimens with various Poisson's ratios, bulk densities and moduli undergoing indentation were examined using the SDA software. We define a Poisson's function analogous to a tangential Poisson's ratio. The specimens with negative Poisson's function demonstrated enhanced indentation resistance independent of bulk density and modulus. The results of the tests with the SDA software showed that auxetic foams do densify under indentation, and the strain field under the indenter is much larger, probably due to enhanced shear stiffness.
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Research context
OpenAlex topics: Cellular and Composite Structures · Pickering emulsions and particle stabilization · Polymer Foaming and Composites
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Engineering, University of Exeter, Exeter, EX4 4QF, UK.
Instron Corporation, Canton, MA, USA.
School of Biological Sciences, Hatherly Laboratories, University of Exeter, Exeter, EX4 4PS, UK.
References (17)
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