Appendix B. Ansys Interface to AVL EXCITE

The EXCITE program by AVL is used mainly by the automotive industry to perform engine structural dynamics analysis. An AVL EXCITE multi-body dynamic simulation calculates the dynamic response of multiple components (engine block, crankshaft, and so on) coupled to each other by joints.

The Mechanical APDL program provides a CMS generation pass procedure to create a condensed substructure that can be used in an AVL EXCITE simulation. The generation pass outputs an EXB (EXCITE body property) file that contains all body properties for the substructure, which represents one component for the AVL EXCITE transient analysis. It is then assembled with other components, joints, and loads in an EXCITE simulation. The file also provides geometry and recovery matrix information for the simulation.

File.EXB contains the following data:

  • DOFT table and GEOM table for retained degrees of freedom (A-SET)

  • DOFT table of omitted degrees of freedom (O-SET), as well as GEOM table of all degrees of freedom (F-SET)

  • Rigid body properties that have total mass, total inertia tensors at the center of gravity and at the origin

  • Flexible body matrices of the substructure, including stiffness, mass, and damping (if available)

  • Selections of existing node and element components in the finite element model (see OUTCOMP on the EXBOPT command)

  • Fifteen inertia invariant matrices that are linearly dependent on CMS conduction modes: M1, M2, M3, M4, R1, R2, R3, Q1, Q2, Q3, Q4, Q5, Q6, PHI, and GFAS (see NOINV on the EXBOPT command)

  • Nine quadratic invariants: T1, T2, T3, F1, F2, F3, F4, F5, and F6 (see OUTINV2 and NOINV on the EXBOPT command)

  • Recovery matrix (see OUTRM on the EXBOPT command)

  • Element data, including connectivity, material properties, and element properties (see OUTELE on the EXBOPT command)

The generation pass procedure is described in: