Fixed geometry designs

For fixed geometry designs, you need to convert the design constraints into material property limits using the Engineering Solver. To use the performance index finder, you need to have a design with a free geometric variable.

If there is no free variable, the design is a fixed geometry design, with a fixed volume. In these situations, you need to convert the design constraints into material property limits using the Using Engineering Solver. Use a chart to select materials based on the properties you want to optimize.

For example, in a stiffness-limited design with no free variable (fixed volume), to minimize mass and cost, create a chart of density (or mass per unit volume) vs. price*density (or cost per unit density).

  1. Start the Engineering Solver. Select the required function, enter the engineering requirements, and calculate values for Young’s modulus and yield strength.
  2. Create a limit stage. Enter the values of Young’s modulus and yield strength from the Engineering Solver as minimum values in the limit stage.
    This will filter out materials with values that do not meet these criteria.
  3. Create a chart, and on the axes, plot the properties you want to optimize in the design.
    For example, for a stiffness-limited design with no free variable (fixed volume), and minimizing mass and cost, plot density (or mass per unit volume) vs. price*density (or cost per unit volume). On the chart (below), the materials shown in gray failed the limit stage. The orange line is a trade-off curve.