The starting point of a dynamic structural analysis is often modal analysis or eigenfrequency analysis. This determines the influence of vibrations on a structure. The natural frequencies and the corresponding eigenforms of the structure are calculated. The natural frequency of a structure susceptible to vibration is the frequency with which the system can vibrate as its own form after a single excitation. If a weakly damped structure is excited from the outside with this frequency (excitation frequency), high amplitudes can occur. This is referred to as resonance effects.