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# Note for Structural Dynamics and Earthquake Engineering - SDEE By Biswajit Jena

• Structural Dynamics and Earthquake Engineering - SDEE
• Note
• Dhaneswar Rath Institute of Engineering and Management Studies (DRIEMS) -
• Civil Engineering
• 9 Topics
• 18410 Views
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#### Note for Structural Dynamics and Earthquake Engineering - SDEE By Biswajit Jena

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STRUCTURAL DYNAMICS AND EARTHQUKE ENGINEERING UNIT I THEORY OF VIBRATIONS UNIT-I 1. 1

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CONTENTS No TITLE TECHNICAL TERMS 1.1 INTRODUCTION TO STRUCTURAL DYNAMICS 1.2 IMPORTANCE OF STRUCTURAL DYNAMICS 1.3 TYPES AND SOURCES OF DYNAMIC LOADS 1.4 DISTINGUISHING FEATURES OF A DYNAMIC PROBLEMS 1.5 METHODOLOGY FOR DYNAMIC ANALYSIS 1.6 TYPES OF STRUCTURAL VIBRATION QUESTION BANK UNIT-I 1. 2

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TECHNICAL TERMS 1. Mass: Mass is obtained by dividing the weight on body by the acceleration of gravity. Unit of mass is given in kilograms (kgs) 2. Stiffness: It is defined as the force required producing unit deformation. It is an elastic property that describes the level of resisting force that results when a body undergoes change in length. 3. Natural Period: It is defined as the time required to complete one cycle of free vibration 4. Natural frequency: When no external force acts on the system after giving it an initial displacement, the body vibrates. These vibrations are called free vibration and their frequency is natural frequency 5. Simple Harmonic Motion: The motion of a body to and fro about fixed point is called simple harmonic motion (SHM) 6. Amplitude: The maximum displacement or deformation of a vibrating system from its mean position is called as amplitude. 7. Mode of Vibration: The structure possesses as many natural frequencies as it has the degree of freedom. For each frequency the structure has its own way of vibration is known as mode of vibration 8. Fundamental mode of vibration: The fundamental mode of vibration of a structure is the mode having the lowest natural frequency. 9. Resonance: When the frequency of external force is equal to or matches with one of the natural frequencies of the vibrating system, the amplitude of vibration becomes excessively large. This phenomenon is called resonance. 10. Free Vibration: Free vibration is a vibration in which energy is neither added to nor removed from the vibrating system. It will just keep vibrating forever at the same amplitude. Except from some superconducting electronic oscillators, or possibly the motion of an electron in its orbit about an atomic nucleus, there are no free vibrations in nature. They are all damped to some extent. 11. Forced Vibration: Forced vibration is one in which energy is added to the vibrating system, as for example in a clockwork mechanism where the energy stored in a spring is UNIT-I transferred a bit at a time to the vibrating element. 1. 3