Introduction to Vibration and Dynamics
Structural vibration is both fascinating and infuriating. Whether you’re watching the wings of an aircraft or the blades of a wind turbine as they flex to absorb turbulence, you have to admire the elegant engineering that discriminates between a structure’s ability to absorb loads against its desire to resonate and shake itself to pieces.
Of course we remember learning about vibration at University. We mostly remember hours spent solving differential equations and matrices, and the look of joy on a young academic’s face as he or she finally proves the natural frequencies of a drum skin or the volumetric modes of a cup of coffee. It can’t be denied the mathematics of vibration are wonderfully elegant and perhaps even beautiful, so that when we finally master all the techniques we can genuinely take pride that we are part of that top 1% of the world’s population who actually understands such stuff. However, in the course of our careers we often forget this knowledge and the sheer thought of revising all that maths is particularly daunting. So that’s the purpose of this short webinar: to introduce (or revise) the principle concepts of structural vibration and dynamics without all the equations.
The webinar is divided in three parts: Part 1 introduces the principle concepts of structural vibration applied to a trivially simple structure, while parts 2 & 3 extends these concepts to more complex examples.
Part 1 - Structural dynamics
- What is the Dynamic Equilibrium and Natural Frequency?
- What is the ‘Frequency Response Function (FRF)’ of a vibrating structure?
- What's the effect of Damping?
- What is meant by ‘quasi-static’ response?
- What are 'linear' and 'non-linear' structures?
Part 2 - Vibration loading & structural response
- What is Power Spectral Density (PSD)
- How do I calculate structural response using PSD and FRF?
Part 3 – Vibration and Dynamics of real structures – Multi-degree of freedom systems
- What are ‘Modal frequencies’, ‘Mode Shapes’, ‘nodes’ and ‘anti-nodes’?
- How to calculate the Frequency Response Function (FRF) of a multi-modal structure
- What is anti-resonance?
- What is modal damping and how do we estimate it using:
- Experimental Modal Analysis (EMA)
- Operational Modal Analysis (OMA)
Originally presented on October 30, 2013