Me mv-16-17 unit-2
- 1. Mechanical Department COURSE NAME: MECHANICAL VIBRATIONS Prepared By: MD ATEEQUE KHAN (Assistant Professor) Mechanical Engineering Department JIT,Barabanki,U.P. INDIA 12/31/2016 1NME-013 MA KHAN
- 2. Table of Contents Unit-2 1. Single Degree Freedom: Forced Vibration 2. Harmonic excitation with viscous damping 3. steady state vibrations 4. Forced vibrations with rotating unbalance 5. Forced vibrations with reciprocating unbalance 6. Support excitation 7. Vibration isolation 8. Transmissibility 9. Vibration measuring instruments 10.Displacement measuring instruments 11.Velocity measuring instruments 12.Acceleration measuring instruments 13.Objective Questions 12/31/2016 2NME-013 MA KHAN
- 3. Unit-2: Mechanical Vibrations SDoF: Forced Vibration Undamped forced vibration : k m m 0F 0F xk .. xm 0 .. Fkxxm n nn m F tCtCx 2 0 21 sincos 12/31/2016 3NME-013 MA KHAN
- 4. Unit-2: Mechanical Vibrations SDoF: Forced Vibration Damped forced vibration : m m 0F xk .. xm 0 ... Fxckxxm k 0F c . xc 12/31/2016 4NME-013 MA KHAN
- 5. Unit-2: Mechanical Vibrations Harmonic excitation with viscous damping k tF sin0 c tFxckxxm sin0 ... 12/31/2016 5NME-013 MA KHAN
- 6. Unit-2: Mechanical Vibrations Forced vibrations with rotating unbalance One may find many rotating systems in industrial applications. The unbalanced force in such a system can be represented by a mass m with eccentricity e , which is rotating with angular velocity as shown in below Figure: 2 k 2 kc m x 12/31/2016 6NME-013 MA KHAN
- 7. Unit-2: Mechanical Vibrations Forced vibrations with reciprocating unbalance 2 2 2 2 2 1 2 tan 21 n n nn r em A 12/31/2016 7NME-013 MA KHAN
- 8. Unit-2: Mechanical Vibrations Support excitation Free Body Diagram Solution of Excitation 12/31/2016 8NME-013 MA KHAN
- 9. Unit-2: Mechanical Vibrations Vibration isolation In various industrial applications, we may find the vibrating machine transmit forces to ground which in turn vibrate the neighboring machines. So in that case it is necessary to calculate how much force is transmitted to ground from the machine or from the ground to the machine otherwise it may cause mechanical damage in the machine. Vibrating Machine part 12/31/2016 9NME-013 MA KHAN
- 10. Unit-2: Mechanical Vibrations Transmissibility Transmissibility defining the transmissibility TR as the ratio of the force transmitted Force to the disturbing force one obtains When damping is negligible 12/31/2016 10NME-013 MA KHAN
- 11. Unit-2: Mechanical Vibrations Vibration measuring instruments 12/31/2016 11NME-013 MA KHAN
- 12. Unit-2: Mechanical Vibrations Displacement measuring instruments 12/31/2016 12NME-013 MA KHAN
- 13. Unit-2: Mechanical Vibrations Acceleration measuring instruments 12/31/2016 13NME-013 MA KHAN