Laminate optimization

You can optimize laminate performance by modifying ply angles, ply thickness, ply materials, or by adding or removing plies. The optimizer uses a genetic algorithm to provide the five best candidates to replace the original laminate.

Note:

Laminate optimization does not support ply materials and orthotropic materials with predefined ply thicknesses.

The optimization process includes the following three components:

• The design variables are ply parameters that are allowed to change in the optimization of a laminate.

• The design constraints are limits that the optimization must respect.

• The design objectives are the laminate parameters that the optimization process is minimizing or maximizing.

Design variables

You can specify the following types of design variables for a laminate:

• Ply thickness

• Ply angle

• Material assigned to the ply.

• Whether or not a ply can be removed from the laminate (ply existence).

You define the ply thickness and angle design variables as either discrete or continuous. Ply materials and ply existence are inherently discrete design variables.

• For the discrete design variables you specify a list of acceptable values.

• For continuous design variable you specify the lower and upper bounds of the domain containing acceptable values.

A star (*) to the right of the thickness, angle, material and ply ID of a ply in the Ply Layup group of the Laminate Modeler dialog box identifies the existence of a design variable.

The allowable values for discrete variables, and the limits for continuous variables, automatically become optimization constraints.

For the Nastran SOL 200 Design Optimization solution, continuous ply angle and ply thickness design variables can be exported as Design Variable — Composite Property modeling objects.

Design constraints

You can place the following types of design constraints on a laminate:

• The total mass of the laminate, which is defined as the laminate density multiplied by the laminate plate area.

• The buckling factor, which is the first buckling eigenvalue of a laminate plate under an arbitrary load condition.

• The ply failure index, which is the smallest ply failure index, for all plies, for the laminate under an arbitrary load condition.

• The natural frequency, which is the first out-of-plane eigenvalue of the laminate plate.

• The ply contiguity, which is the value for the maximum number of consecutive plies having the same ply angle.

• The X and Y Young's moduli, which are the equivalent laminate membrane Young's moduli in the X and Y directions, respectively.

• The shear modulus, which is the equivalent laminate membrane shear modulus in the XY direction.

• The Poisson's ratio, which is the equivalent laminate Poisson's ratio in the XY direction.

• The X, Y, and XY thermal expansion coefficients, which are the equivalent laminate membrane thermal expansion coefficients in the X, Y, and XY directions, respectively.

You can specify one or more constraints for the same optimization process.

Note:

The software creates an implicit constraint when you define a Stacking Recipe (in the Laminate Properties group of the Laminate Modeler dialog box) as anything other than Regular or Inherited from layup for the entire laminate, or ply groups.

Design objectives

You can define the following criteria as a design objective when you optimize a laminate:

• The total mass of the laminate, which is defined as the laminate density multiplied by the laminate plate area.

• The buckling factor, which is the first buckling eigenvalue of a laminate plate under an arbitrary load condition.

• The X and Y Young's moduli, which are the equivalent laminate membrane Young's moduli in the X and Y directions, respectively.

• The shear modulus, which is the equivalent laminate membrane shear modulus in the XY direction.

• The Poisson's ratio, which is the equivalent laminate Poisson's ratio in the XY direction.

• The X, Y, and XY thermal expansion coefficients, which are the equivalent laminate membrane thermal expansion coefficients in the X, Y, and XY directions, respectively.

You can specify one or more objectives for the same optimization process, but the software must maximize all of them or minimize all of them. It is not currently possible to define a problem where the optimization process maximizes an objective and minimizes another. The optimization process uses all existing objectives.

Load cases

You must also specify load cases to perform the optimization when you define:

• Buckling factor objectives or constraints.

• Ply failure index constraints.

The load cases that you can specify are:

• Loads per unit length in the laminate X and Y directions. These are equivalent to shell stress resultants.

• Temperature loads, in the form of a temperature delta from the laminate reference temperature. This is a temperature delta, not an absolute temperature.

All the load components are applied simultaneously to the laminate. You can define one or more load cases for the same optimization process. The software applies each load case independently to the laminate. The optimization uses the worst case failure index or buckling factor.

Note:

If you select Stress or Strain Output Request, PCOMP from the Output Format list, and, MEM, BEND, SMEAR, or SMCORE from the Laminate Options list (in Solver Properties group of the Laminate Modeler dialog box), the calculated ply stresses and strains may be incorrect due to the approximations imposed by these options.

Where do I find it?

With a FEM file displayed:

• Choose Laminates tab→Laminate group→Laminate Physical Property . In the Laminate Modeler dialog box, select Enable Optimization under Optimization group.

• Insert→Laminate→Physical Property→Optimization group.

How do I

Optimize a laminate

Define a design variable

Export a design variable as a modeling object

Export all design variables as modeling objects

Learn more

Genetic algorithm for laminate optimization

Ply materials

Look up more details

Laminate plate geometric properties

Shell stress resultants

Quick links

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Pre/Post video examples

Bulk Entry Descriptions

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Related Topics

Laminates failure analysis

Laminate optimization, Simcenter 3D 2021.1 Series

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