Publications

Implementing experimental substructuring in abaqus

Moldenhauer, Benjamin; Allen, Matt; Roettgen, Daniel R.; Owens, Brian

In many applications, components that are difficult or inconvenient to represent as a finite element model (FEM) are instead experimentally characterized to capture their contribution to the overall dynamics of an assembly. A recent advance in experimental substructuring, the Transmission Simulator method, has proven promising for coupling an experimentally identified model to analytical FEMs. While in typical applications all experimental and FEM data is imported into MATLAB and assembled in modal coordinates, it would be preferable to perform equivalent operations in finite element software where large models are readily handled and results are easily visualized and post-processed. This work details a process for importing experimental modal models into the Dassault Systèmes® SIMULIA™ Abaqus finite element analysis software suite through an application of the Transmission Simulator method. In this approach, after decoupling the TS from the experimental subsystem in MATLAB, the result is represented as single degree-of-freedom (DOF) spring-mass oscillators in Abaqus. These are coupled to the native Abaqus FEM by implementing the substructuring constraint equations as linear equation multipoint constraints between the necessary DOF. This approach is shown to perform very well in an analytical test case and reasonably well in an experimental test case. The limiting factors appear to be the quality of measured data and curve fitting used in defining the modal properties of the experimental subsystem, the quantity and location of constraint DOF, and the selection of modes used to represent each subsystem. These determine the quality of the decoupled experimental model, which dictates how accurate the result will be after coupling it to the FEM subsystem.