Poisson’s ratio (v12) result

The Poisson’s ratio (v12) result indicates the strain in the second principal direction caused by the stress in the first principal direction.

In general, vij = Poisson’s ratio for transverse strain in the j-direction when stressed in the i-direction.

This result is generated from a Fiber orientation Pack analysis.

Tip: Click New PlotResults tab > Plots panel > New Plot and create this result as an XY or Path plot also so that you can view the Poisson’s ratio distribution at a particular element, or with respect to the model geometry.

Using this result

For a Midplane and Dual Domain analysis, the Poisson’s ratio (v12) result is recorded for each laminate in the model over the duration of the analysis. Therefore, each laminate in the model will have different results. You can check the Poisson’s ratio in each laminate by animating the default contour plot, which will animate the result over the Normalized thickness.

Tip: You can view the contour plot at a single laminate on the model. To do so, click Plot PropertiesResults tab > Properties panel > Plot Properties. The Plot properties dialog opens. Select the Animation tab, and from the Animate result over drop-down list, select Single dataset.

This result is very important when proceeding to perform a Stress analysis because the results will be used in the thermal loading calculation.

For a 3D Fiber orientation analysis, the Poisson’s ratio (v12) result is recorded for each tetrahedral element in the model at the end of the analysis.

Orthotropic assumption

The thermo-mechanical property calculation for fiber-filled composites are based on the orthotropic assumption, that fiber-filled material properties are different in three orthogonal principal directions. Under this assumption, there are 9 independent mechanical constants and three independent thermal expansion coefficients. In models analysed using Midplane or Dual Domain analysis technologies, because of the plain stress assumption in the shell structure analysis in Warp, only 4 mechanical constants (tensile modulus in first/second principal directions, Poisson ratio v12, shear modulus G12) are necessary.

The Orthotropic set option selects the 9 mechanical constants (E1, E2, E3, v12, v23, v13, G12, G23, G13) and 3 CTE’s (thermal expansion coefficient in first/second/third directions) all at once. In a Fiber analysis, the complete set of thermo-mechanical properties with orthotropic assumption is necessary for a Warp analysis using 3D analysis technology. These properties are element-based, so each tetrahedral or beam element has its own orthotropic set of properties.
Note: To access the Orthotropic set option ensure you have selected an analysis sequence that includes Fill+Pack.
  1. Click Process SettingsHome tab > Molding Process Setup panel > Process Settings. The Process Settings Wizard dialog opens.
  2. If necessary, click Next until you reach the Fill+Pack Settings page of the Wizard.
  3. Select the option Fiber orientation analysis if fiber material, and then click Fiber parameters. The Fiber Orientation Solver Parameters dialog opens
  4. Click Composite property calculation options, and then from the Fiber-filled property output drop-down list, select Orthotropic set.
Parent topic: Fiber Orientation analysis results