Poisson's ratio (3D fiber) (overmolding)

Poisson's ratios (3D fiber) 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:

• 

Analysis sequences that include:

• Overmolding Pack

To create these results, the Fiber orientation analysis if fiber material option must be selected, and a material with filler or fiber data must be chosen. This option can be found on the Fill+Pack Settings page of the Process Settings Wizard.

Tip: These results are not shown by default. To view these results, click (Result tab > Plots panel > New Plot) and select them from the list of Available results.

Important: If these results do not appear in the list of available results, check that you have a shrinkage model selected. Click (Home tab > Molding Process Setup panel > Process Settings) and click Advanced options. Click Edit associated with Molding material and select the Shrinkage Properties tab. Select a shrinkage model.

Poisson's ratio (v12) (3D fiber) (overmolding) result

The Poisson's ratio (v12) (3D fiber) (overmolding) result indicates the strain in the second principal direction for the overmolded component, caused by stress in the first principal direction. This result is recorded for each tetrahedral element in the model, at the end of the analysis.

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

Poisson's ratio (v13) (3D fiber) (overmolding) result

The Poisson's ratio (v13) (3D fiber) (overmolding) result indicates the strain in the third principal direction for the overmolded component, caused by stress in the first principal direction. This result is recorded for each tetrahedral element in the model, at the end of the analysis.

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

Poisson's ratio (V23) (3D fiber) (overmolding) result

The Poisson's ratio (v23) (overmolding) result indicates the strain in the third principal direction for the overmolded component, caused by stress in the second principal direction. This result is recorded for each tetrahedral element in the model, at the end of the analysis.

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

Orthotropic assumption

The thermo-mechanical property calculation for fiber-filled composites is 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.

The Orthotropic set option is set by default and 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. 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 Home tab > Molding Process Setup panel > Process Settings.
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.
4. Click Composite property calculation options, and then from the Fiber-filled property output drop-down list, select Orthotropic set.

Using this result

These results are recorded for each tetrahedral element in the model at the end of the analysis and are used in the thermal loading calculation of subsequent Stress analyses.

Click (Results tab > Plots panel > New Plot) and under Plot type click Path plot so that you can view the Poisson’s ratio distribution with respect to the model geometry.