Earthquake Engineering - Vol 1 | 7. Free Vibration of Single Degree of Freedom (SDOF) System by Abraham | Learn Smarter
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7. Free Vibration of Single Degree of Freedom (SDOF) System

The chapter provides a comprehensive overview of the Free Vibration of Single Degree of Freedom (SDOF) systems, emphasizing foundational concepts such as the definition and equations of motion, solutions to these equations, natural frequency, and the impacts of mass and stiffness on vibration behavior. It also explores real-world applications in earthquake engineering and the significance of understanding both undamped and damped systems in structural design.

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Sections

  • 7

    Free Vibration Of Single Degree Of Freedom (Sdof) System

    This section introduces the concept of free vibration in a Single Degree of Freedom (SDOF) system, focusing on key parameters such as natural frequency and equation of motion.

  • 7.1

    Definition Of Free Vibration

    Free vibration refers to the natural oscillation of a mechanical system without external forces after an initial disturbance.

  • 7.2

    Idealization Of Sdof System

    The idealization of a Single Degree of Freedom (SDOF) system focuses on its core characteristics, such as one mass and one spring, operating without damping or external forces.

  • 7.3

    Equation Of Motion For Free Vibration

    This section introduces the equation of motion for an undamped single degree of freedom (SDOF) system undergoing free vibration.

  • 7.4

    Solution To The Equation Of Motion

    This section presents the solution to the equation of motion for a Single Degree of Freedom (SDOF) system applicable to free vibrations.

  • 7.5

    Natural Frequency And Time Period

    This section discusses the natural frequency and time period of a Single Degree of Freedom (SDOF) system, intrinsic properties that govern its oscillation under free vibration.

  • 7.6

    Initial Conditions And System Response

    This section discusses how initial displacement and velocity define the behavior of a single degree of freedom (SDOF) system during free vibration.

  • 7.7

    Graphical Representation Of Motion

    The section discusses the sinusoidal and periodic motion of an undamped SDOF system, emphasizing the significance of displacement, velocity, and acceleration plots as well as a phase diagram.

  • 7.8

    Energy In Free Vibration

    In undamped free vibration, mechanical energy is conserved, with kinetic and potential energy continually transformed during oscillation.

  • 7.9

    Effect Of Mass And Stiffness

    The effect of mass and stiffness on the natural frequency of a Single Degree of Freedom (SDOF) system is crucial for understanding vibration response in structural dynamics.

  • 7.10

    Resonance In Sdof Systems

    This section explains resonance in Single Degree of Freedom (SDOF) systems, emphasizing the significant impact of natural frequency on structural vibrations.

  • 7.11

    Real-World Application In Earthquake Engineering

    This section discusses how Single Degree of Freedom (SDOF) systems are applied in predicting the behavior of structures during earthquakes.

  • 7.12

    Damped Vs Undamped Free Vibration (Introduction To Damping)

    This section introduces the concept of damping in vibrational systems, contrasting ideal undamped systems with real structures that experience energy dissipation.

  • 7.13

    Logarithmic Decrement (Δ)

    Logarithmic decrement is a method for measuring damping in oscillating systems by evaluating amplitude decay over time.

  • 7.14

    Phase Plane Representation

    Phase plane representation is a method to visualize the motion of dynamical systems by plotting velocity against displacement, illustrating their dynamic behavior.

  • 7.15

    Numerical Solution Of Free Vibration (Finite Difference Method)

    The finite difference method allows for the numerical solution of free vibration problems in systems where analytical solutions are infeasible, by discretizing time and approximating derivatives.

  • 7.16

    Modal Parameters And Experimental Determination

    The section discusses methods to experimentally determine a structure's natural frequency and mode shapes using tools like modal testing and Fast Fourier Transform (FFT).

  • 7.17

    Vibration Isolation And Structural Implications

    This section focuses on vibration isolation techniques to protect structures from ground motion during earthquakes.

  • 7.18

    Role In Seismic Design Codes

    Seismic design codes utilize fundamental natural periods derived from SDOF behavior to ensure structural safety during earthquakes.

  • 7.19

    Case Studies And Real-World Observations

    This section discusses how case studies from past earthquakes inform our understanding of structural response and vibration characteristics.

Class Notes

Memorization

What we have learnt

  • Free vibration occurs witho...
  • Natural frequency and time ...
  • Real-world structures often...

Final Test

Revision Tests