Max Feature Size Constraint

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About this Block

The Max Feature Size Constraint block can be used as a constraint in the Topology Optimization block to maintain the feature sizes of the optimized design space below a user-defined value. This block can be used with the Min Feature Size Constraint to enforce an upper and lower limit to the feature sizes generated from Topology Optimization. This block can be added to an Optimization Constraint List to enforce the desired feature size specification on the design space. Here is a summary of the recommendations described in detail in the Min Feature Size Constraint section of the documentation that applies to the Max Feature Size Constraint :

• Use the Remap Constraint to enforce symmetry in the Topology Optimization
• Use an element edge length that is at least 1/3rd the desired feature size
• When using the Passive Region Constraint , limit the thickness of the passive region to ½ the feature size specification

| The progress of the Max Feature Size Constraint can be tracked from the Display panel in the Topology Optimization block (similar to the Min Feature Size Constraint). The Min/Max Projection Beta (image on the left) tracks our main constraint filter parameter, which is updated through the course of the optimization to not over-constrain the optimization right from the start. It is recommended to set the Max Iterations to a value that ensures the blue line meets the yellow dotted line. This is typically achieved at iterations that are greater than the default of 200 iterations in the block. It is recommended to set this parameter to at least 250 iterations when using the Feature Size Constraints. The image on the right shows another convergence plot for the Max Feature Size Constraint that can be used to track constraint satisfaction. Since the Max Feature Size Constraint is an inequality-based constraint that tracks the features sizes at each point in the design space, the value indicated in the chart should always be below 1 (the yellow dotted line) to obey the feature size input.

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Example Files

Download Examples: Simple Bracket Example Swing Arm Extrusion Define a constraint on the maximum feature size. Inputs

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Output