These Matlab scripts calculate the natural frequencies of a beam via the finite element method: beam_base_accel_fea.zip
They also have options for base excitation:
1. frequency response function
2. half-sine base input
3. arbitrary base input
A ramp invariant digital recursive relationship is used for the case of arbitrary base excitation.
The main function is: beam_base_accel_fea.m
The remaining functions are supporting functions.
* * *
The reference papers are:
The numerical engine is taken from the applied force model because the temporal response is needed in its modal absolute form. See: Modal Transient Analysis of a System Subjected to an Applied Force via a Ramp Invariant Digital Recursive Filtering Relationship: force_ramp_invariant.pdf
* * *
– Tom Irvine