Linear Analysis

Introduction

Linear Analysis tools let you analyze the structural properties of a dynamic system in the frequency domain. It works by linearizing the dynamic system around a specified operating point; the resulting linearized system is far easier to analyze, and conclusions about its dynamic properties become clear with far less CPU time than a time-domain analysis.

Tools available in Linear Analysis:

• Eigenvalues
• FRF — Modal analysis
• Modal shapes
• Root locus
• Frequency diagram

The underlying concepts are described in the manual but are entirely invisible to the end user in practice — using the Linear Analysis tools is simple and yields powerful, efficient insight into a system's dynamic properties.

Benefits of using Linear Analysis

• Extracts the significant (influential) parameters of a system.
• Frequency-domain correlation implies time-domain correlation: performing an FFT on a time-domain oscillation always matches the resonance frequency identified via Eigenvalues analysis or a Bode plot in the frequency domain (demonstrated with a mass-spring-damper example where both approaches agree on a ~5 Hz natural mode).
• Frequency-domain analysis is faster than time-domain analysis, since it avoids long-CPU-time time-domain excitations — dynamic properties of the system are obtained almost instantaneously.