Poisson's ratios (Microcellular) are mechanical property values that indicate strain in a specific direction, caused by stress from another direction. These results are used in a subsequent Stress analysis.
Mesh type:
Midplane 
Dual Domain 
3D
Analysis sequences that include:
- Fill (3D mesh)
- Fill+Pack (Midplane and Dual Domain mesh)
You do not need a fiber-filled material to produce this microcellular result, because the bubbles themselves will affect the mechanical properties of the material.
Using this result
These results are recorded for each element in the model at the end of the analysis and are used in the thermal loading calculation of subsequent Stress analyses.