Structural dynamics is the study of the behavior of structures subjected to dynamic loads such as earthquakes, wind, and vibrations. It involves analyzing the response of a structure to these dynamic loads and understanding its dynamic characteristics. Some specific principles covered in the optional subject of structural dynamics are as follows:


- Free vibration refers to the natural oscillations of a structure without any external forces acting on it.
- The principles of free vibration analyze the behavior of structures when they are disturbed from their equilibrium position and then left to vibrate freely.
- It involves studying the natural frequencies, mode shapes, and damping of the structure.


- Forced vibration occurs when a structure is subjected to external dynamic loads such as wind, earthquakes, or machinery vibrations.
- The principles of forced vibration analyze the response of the structure to these external loads.
- It involves determining the dynamic amplification factor, resonant frequencies, and mode shapes under forced vibration conditions.


- Modal analysis is a technique used to determine the dynamic characteristics of a structure, including its natural frequencies, mode shapes, and damping.
- It involves the calculation of eigenvalues and eigenvectors of the structure's mass, stiffness, and damping matrices.
- Modal analysis helps in understanding the dynamic behavior, identifying critical modes, and optimizing the design of structures.


Vibration analysis is the study of vibrations in mechanical systems and structures. It involves analyzing the causes and effects of vibrations, as well as the methods to control and mitigate them. Some specific principles covered in the optional subject of vibration analysis are as follows:


- Single degree of freedom (SDOF) systems are simplified models used to analyze the dynamic behavior of structures.
- The principles of SDOF systems involve studying the response of a structure to harmonic, transient, and random vibrations.
- It includes the calculation of natural frequency, damping ratio, and response amplitude under different types of excitations.


- Multiple degree of freedom (MDOF) systems are more complex models used to analyze the dynamic behavior of structures with multiple degrees of freedom.
- The principles of MDOF systems involve studying the modes of vibration, mode shapes, and modal superposition.
- It includes the calculation of natural frequencies, mode shapes, and participation factors of the structure.


- Vibration control and mitigation techniques aim to reduce the harmful effects of vibrations on structures and their occupants.
- The principles of vibration control involve understanding the sources of vibrations, designing isolation systems, and implementing damping techniques.
- It includes the analysis of vibration isolators, absorbers, and active control systems to reduce the transmitted vibrations.