Understanding Support Excitation — Lesson 1

This lesson covers the response of a system when subjected to support excitation. It explains how forces are induced throughout the body of a structure or machine parts due to the displacement of the support or base. The lesson provides examples of such scenarios, like an earthquake affecting a multi-story building or the jerking felt by passengers in a vehicle moving on a rough road. It also discusses the concept of base excitation and how it causes force in the structure, leading to dynamic stresses. The lesson further delves into the response of continuous systems to base excitation, using a cantilever beam as an example.

Video Highlights

03:19 - Analyzing a system subjected to base motion.
08:17 - Deriving the equation of motion for a system subjected to base motion.
14:03 - Concept of transmissibility of base motion.
33:22 - Calculating the force transmitted due to base motion.
37:55 - Response of a continuous system to base excitation using a cantilever beam as an example.

Key Takeaways

- Support excitation can induce forces throughout a structure or machine parts.
- Base excitation can cause force in the structure, leading to dynamic stresses.
- The response of continuous systems to base excitation can be analyzed using mathematical models.
- The displacement of the support or base can be calculated using the equation of motion.
- The transmissibility of base motion can be calculated using the frequency ratio and the damping ratio.