Using Performance Indices

The Performance Index Finder lets you plot performance indices on a chart for a specific design situation, without having to derive an index from first principles.

Use performance indices on a chart by using index lines and performance indices.

Can't find a specific performance index in the Performance Index Finder? Plot it on a chart by creating an attribute expression.

The performance index finder is only available for materials in MaterialUniverse. To create a chart using the performance index finder:
  1. In the Selection Project window under Selection data, select a MaterialUniverse data template.
  2. Under Selection Stages, click Chart/Index.
  3. Select Performance Index Finder at the top of the axis tab.
  4. Select a component from the Function and Loading list.
    The performance index equation will be displayed along side the component notes, and whether the index should be Minimized or Maximized.
  5. Edit the other parameters of the component, if required. They will only be active if further settings are available.
  6. If applicable, select Cyclic loading.
    Cyclic loading only applies to performance indices for strength limited designs, and should be selected when the component is subjected to a high level (10^7 cycles) of cyclic loading. When selected, the performance index uses the fatigue strength (at 10^7 cycles) in place of the yield strength. If cyclic loading is not selected, then the loading condition is taken as static. In cases where cyclic loading is always applicable, the setting will not be visible.
  7. Set the axis settings, if required.

    For effective material selection charts, there are three main types of charts that the performance index finder can be used to create:

    1. A bar chart, to rank the materials based on the performance index value.

    2. A trade-off curve, by plotting two different properties with the same limiting constraint. For example, plot mass per unit of stiffness vs. cost per unit of stiffness.

    3. A coupling line chart, by plotting the same material property with two different constraints, and identify the method by which the materials are likely to fail first. For example, plot mass per unit of strength vs. mass per unit of stiffness.

  8. Optional: To view the expression for a performance index:
    Warning: If you follow these instructions, you must use Cancel to exit both dialogs in order to keep the chart axis unchanged.
    1. In Chart Settings ,click either the X-Axis or Y-Axis tab.
    2. Select Single or Advanced Property.
    3. In the Property Definition section, click Advanced.