Crystal Instruments EDM Modal Correlation Analysis

EDM Modal Correlation Analysis is a module of the Crystal Instruments structural dynamics software suite that compares two modal models - experimental modal analysis (EMA) results and/or finite element analysis (FEA) results - to validate test results and assess the credibility of a simulation model.

The workflow begins by importing geometry and mode shape data from FEA or EMA software, followed by a modal mapping procedure that matches the EMA and FEA models. Mapping can be done manually by pairing three or more points on each model, or automatically using the Auto-Match function. After matching, the new mode shape information from the FEA model is interpolated, and the FEA modal parameters are displayed alongside the EMA results.

To quantify the agreement between the two sets of results, the software calculates and displays a Cross-MAC (cross modal assurance criterion) matrix. Cross-MAC correlates the mode shapes of one model against those of the other; high values near the diagonal indicate that both methods identified the same mode, while off-diagonal values point to missing modes, mode-order mismatches or model discrepancies. This is a key metric for model updating and simulation validation. The software also offers animation comparison, playing the two sets of mode shapes side by side in a left/right or upper/lower layout to make shape differences visually apparent.

The module suits finite element model validation, structural dynamics model updating and test-to-simulation correlation, and typically works together with the EDM Modal structural testing and analysis software on the Crystal Instruments EDM (Engineering Data Management) platform.