Co-lecturer: Dr. J.R.Kermode
Module Ambassadors: Marina Shcherbakora (Systems) Anglina Bhambra (Mechanical)
This 15 CATS module is one of the third year modules for:
This module is a pre-requisite for ES480 Dynamic Analysis of Mechanical Systems and is recommended for students on the optional courses who wish to take the Robotics Elective in Year 4.
Vibrations exert a significant influence on the performance of the majority of engineering systems. All engineers should understand the basic concepts and all mechanical engineers should be familiar with the analytical techniques for the modelling and quantitative prediction of behaviour. Thus, this module provides students with fundamental skills necessary for the analysis of the dynamics of mechanical systems, as well as providing opportunities to apply these skills to the modelling and analysis of vibration.
This third-year module is mandatory for students pursuing a degree in Mechanical Engineering, building upon competences acquired earlier in the course. This module introduces students to the use of Lagrange’s equations (applied to 1D and 2D systems only for this module) and to techniques for modelling both lumped and continuous vibrating systems. It includes some coverage of approximate methods both as an aid to physical understanding of the principles and because of their continuing usefulness. The module assumes basic understanding of mechanics and linear algebra consistent with the level of Year 2 modules.
At the end of the module students should have a sound understanding of the wide application of vibration theory and of the underlying physical principles. In particular, they should be able to use either Newtonian or Lagrangian mechanics to analyse 2D systems, and to determine the response of simple damped and undamped multi-degrees of freedom (DOF) systems to both periodic and aperiodic excitation. They should also be familiar with engineering solutions for measuring and influencing vibrational behaviour.
By the end of the module the student should be able to...
- Identify and apply an appropriate co-ordinate system for the modelling of planar mechanical systems by Newton’s or Lagrange’s equations, and consolidate this information to analyse the vibration of planar systems.
- Make simplifying abstractions to complex engineering mechanisms to enable analysis using a lumped system model or a simple distributed mass and stiffness model.
- Determine the natural frequencies and modes of vibration of a multi-DOF damped or undamped linear system using standard matrix methods, devising computational routines as appropriate to the problem.
- Determine estimates for the fundamental natural frequency of an undamped or lightly damped vibrating mechanism using approximate methods.
- Determine the response of a single DOF system to aperiodic excitation and of a multi-DOF system to periodic excitation.
- Apply the methods referred to above to important current engineering systems.
- Generalised co-ordinates, Lagrange's equation (including preliminary study of other classical methods)
- General application of the Lagrange equation to vibrating systems
- Multi-degree of freedom systems: lumped system models, continuous system models; geared and branched systems; reduction of an n-DOF system to a set of n single-DOF systems; principal co-ordinates
- Matrix methods of analysis: conservative and non-conservative (damped) systems; determination of principal co-ordinates
- Modelling of damping: hysteretic, Coulomb, viscous; measurement of damping factor
- Forced vibration: harmonic excitation of multi-DOF systems; shaft whirling; transmissibility; vibration isolation; non-harmonic and arbitrary excitation (convolution integral)
- Approximate methods e.g. Rayleigh's method, Dunkerley's method
This module includes 30 hours of lectures and 2 hours of revision classes.
Required self-study: 118 hours
A 15 CATS module: 80% examined via a 3 hour paper:
Exam rubric information
- 4 Compulsory Questions
and 20% assessed consisting of a computational assignment.