MORPACK Interface Functionality for importing FE Structures into MBS-Code via alternative Model Order Reduction Methods

摘要

The Matlab-based MORPACK (Model Order Reduction PACK age) interface is presented and its functionality is outlined for importing Reduced Order Models (ROMs) into Multi Body System (MBS) codes. MOR methods, such as the Guyan reduction and the Component Mode Synthesis (CMS), have been used for the past decades as standard approaches implemented in commercial Finite Element (FE) software, e.g. ANSYS and MSC Nastran. When importing the ROMs into MBS-codes, e.g. from ANSYS into SIMPACK, the necessary FE-MBS data conversion takes place based on the FEMBS interface. MORPACK, consisting of two inner interfaces, combines all necessary procedures required for the automatic import of ANSYS FE models into SIMPACK. The FE discretized model's system information is converted into the Matrix Market file format, the ROM is created based on a user selected variety of physical, non-physical, and hybrid MOR methods, the ROM's dynamic properties and structure preservation are validated by certain Model Correlation Criteria (MCC), and finally the necessary Standard Input Data (SID) file is generated for further usage of the ROM in SIMPACK. In all the above mentioned levels various numeric and modelling schemes have been conceived, e.g. the diagonal perturbation method or the back-transformation approach, which constitute feasibly the application of the selected MOR method overcoming difficulties such as: the ill-conditionality of system matrices when iteratively producing the ROM, non-stable matrix polynomials by certain non-physical and hybrid MOR methods and the import of non-physical space ROMs into SIMPACK. All the above is applied for free or fixed models originating from the field of structural mechanics.