Structural Dynamics Software

Type 8421 (Replaces Type 8722) BK Connect Correlation Analysis

Type 8421 (Replaces Type 8722) BK Connect Correlation Analysis

This application allows you to perform a complete visual and numerical comparison of two modal models, typically a test model versus a finite element (FE) model. The complete workflow process is intuitive, yet flexible, and guides you efficiently through geometry alignment, degree of freedom (DOF) mapping, comparison, vector comparison, mode pairing and reporting. In addition, test planning and test validation tools help you design optimal test conditions and evaluate different modelling strategies.


  • Identifying shortcomings in modal tests and areas of insufficient modelling quality in finite element (FE) models
  • Applying information that can only be measured or simulated, such as applying measured modal damping to analytical modes and scaling operational mode shapes using the scaling from analytical mode shapes
  • Defining targets and updating variables for FE model updating
  • Structural health monitoring (SHM) and damage detection by correlating (operational) modal test results with the analysis results of a reference FE model
  • Test planning: Decimation of an FE model to a test model for identification of optimal excitation and response locations.
  • Investigation of frequency range of interest, mode density and critical modes for the modal test
  • Test validation by comparing test and finite element analysis (FEA) results


The software helps you to scale and orientate the two geometric models in order to align them for easy comparison. You can animate the various test and FE mode shapes and view mode tables, to clearly compare their modal parameters. Mode pairing is automatically done between the two modal models according to their degree of frequency or shape correlation.


  • Import test modal models in standard formats
  • Import FE models such as Nastran® (MSC, NX, NEi), ANSYS®, ABAQUS® or UFF files
  • Select and validate test nodes from FE models for test planning
  • Decimate finite element models to create test models
  • DOF mapping to match the DOFs from the two models being correlated
  • AutoMAC, CrossMAC, auto-orthogonality and cross-orthogonality tables and 3D plots calculated in reduced test space
  • Import reduced mass matrix from Nastran or ABAQUS
  • SEREP algorithm can be used if no reduced mass matrix is available
  • Expand test modal vectors to FE space using the SEREP algorithm
  • Integrated Microsoft® Office reporting capabilities


We offer BK Connect Finite Element Interfaces for importing FE models:

  • BK Connect Nastran Interface Type 8400-D
  • BK Connect Ansys Interface Type 8400-E
  • BK Connect Abaqus Interface Type 8400-F