Support Excitation in Continuous Systems — Lesson 2

This lesson covers the concept of support excitation in continuous systems, focusing on its common occurrence in structures like aircraft wings. It delves into the types of excitations that cause significant responses in these systems, particularly tangent excitation. The lesson also introduces the concept of a basic oscillator and its response to tangent forces. It further discusses the construction of a shock spectrum, commonly known as a response spectrum. The lesson concludes with the application of these concepts in solving problems related to continuous systems with numerical data. For instance, it explains how the response of an aircraft wing during landing can be calculated using these principles.

Video Highlights

02:42 - Three cases of tangent excitations: step input with finite rise time, step rectangular pulse, and half sine pulse.
05:09 - Response of a single degree freedom system to different types of excitations using Duhamel's integral.
07:15 - Concept of response spectrum and its application in the design methodology of structures.
14:40 - Construction of the response spectrum for different types of excitations.
65:37 - Concept of modal participation factor and its calculation for different modes.

Key Takeaways

- Support excitation is common in many structures, such as an aircraft wing attached to the fuselage.
- Tangent excitation, though short in duration, can have a significant impact on continuous systems and must be considered in design.
- The response of a basic oscillator to tangent forces can be calculated using the Duhamel's integral.
- The shock or response spectrum is a useful tool in understanding the response of a system to different excitations.
- The response of continuous systems to various excitations can be calculated using principles of support excitation and response spectrum.