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Mechanical Vibrations (Spring 2013)

Course code : ME-MEV-U1
ECTS Credits : 5 Status : Optional
Revised : 22/04 2013 Written : 24/08 2009
Placement : 6. semester Hours per week : 4
Length : 1 semester Teaching Language : English

Objective : To provide the students with a firm foundation for solving vibration problems related to structures and machines, using analytical and numerical methods. To give the students a basic background for advanced studies in dynamics and vibrations.

A student who has met the objectives of the course will be able to:

• Identify sources for inertia, stiffness, energy-dissipation and external loads in some standard mechanical systems.
• Use Newton"s second law, free body diagrams and the energy method to derive the equations of motion (scalar or matrix-vector form) for simple models of mechanical systems with a finite or infinite number of degrees of freedom
• Determine the natural frequencies for mechanical systems with a finite or infinite number of degrees of freedom.
• Use analytical and numerical methods to solve standard equations of motion for mechanical system models.
• Understand and explain eigenfunctions, eigenvectors and eigenvalues.
• Identify resonance problems for mechanical systems whose dynamics (i.e. inertia and energy dissipation) can not be neglected.
• Account for the limitations in the models and methods used, and predict the possible consequences of making simplified assumptions, especially linearization and limitation of the number of degrees of freedom.
• Write technical reports, with correct description of theoretical and experimental procedures, in a clear way, using technical terms, giving physical interpretations and evaluations of results.
• Use the computer software DAMA and MATLAB for solving vibration problems.
• To give the students a basic background for advanced studies in dynamics and vibrations.
• Read engineering literature on mechanical vibrations.
Principal Content : Equations of motion with initial conditions.

Vibrations of linear single-degree-of-freedom systems: Free and forced vibrations for translation and rotation. Viscous damped systems and vibration isolators.

Pendulums and mass moment of inertia.

Vibrations of linear two-degree-of-freedom systems: Free and forced vibrations. Vibration absorbers. Viscous damping.

Vibrations of continuous systems: Equations of motion for strings, bars and beams. Boundary and initial conditions. Eigenfunctions, eigenvectors and eigenvalues. Whirling shafts and Dunkerley’s formula.

Finite Element Methods: Mass and Stiffness matrices and equations of motion for bar and beam expressed in Matrix form.

Introduction to non-linear vibration.

The software “DAMA” will be used to generate computer simulations and animations in order to enhance the students’ understanding of the motion and vibration of mechanical systems.
Teaching method : The teaching is both project-oriented and problem-based, using realistic systems. There will be lectures. 4 assignments and a project based upon experiments with Frequency Analyzer must both be handed in. MATLAB simulation will be use in the project.
Required prequisites : ME-MAT1-U5 and ME-MEK2-U5
Recommended prerequisites : ME-MEK1-U5
Relations : Courses in numerical methods, control systems and advanced dynamics.
Type of examination : Look under remarks
External examiner : Internal
Marking : 7 step scale
Remarks : 30 minute oral examination based upon the assignments, setting up equations of motion and demonstrating how to solve practical vibration problems. 50 % of the grade will be based on the 4 assignments and the Project.
This is a relevant course in the study of control systems and advanced dynamics and especially when doing bachelor project concerning vibration and noise.
Teaching material : Dynamics and Vibration: An Introduction, ISBN-13: 978-0-470-72300-5, by Magd Abdel Wahab, Wiley 2008.
- Lecture notes on CampusNet.
Responsible teacher :