Wavy network structures dispersed in a hard phase
The present invention is directed at materials and methods for their formation having wavy network structures dispersed in a second and relatively harder phase. The materials can be designed to exhibit auxetic properties (e.g. a negative Poisson's ratio) in response to an application of force.
1. A network structure comprising:
three wavy segments that extend in three directions from a first connection location wherein said wavy segments have a Young's modulus value Ei and said wavy segments are dispersed in a second phase of material having a Young's modulus E h where Eh>Ei;
wherein said wavy structure is positioned between said first and a second connection location and at about a midpoint between said connection locations said wavy structure changes direction and defines an angle 2θ m wherein the value of θ m is greater than or equal to 5° and the value of E h /Ei is greater than or equal to 1×10 3 .
2. The network structure of claim 1 wherein the value of θ m is greater than or equal to 5° up to 40° and the value of E h /Ei is greater than or equal to 1×10 3 up to 10 5 .
3. The network structure of claim 2 wherein said network structure indicates a negative Poisson's ratio.
4. The network structure of claim 1 wherein one or a plurality of polygonal geometric shapes can be superimposed on said wavy segments.
5. The network structure of claim 1 wherein said network structure indicates a negative Poisson's ratio.