MECH 375 LAB 3 (Experiment 3: Characteristics of a Two Degrees of Freedom System) 2025|2026 Concordia University

MECH 375 LAB 3 (Experiment 3: Characteristics of a Two Degrees
of Freedom System) 2025|2026 Concordia University
Experiment 3:
Characteristics of a Two Degrees of Freedom System




Submitted by




Lab Section EI – X
Summer 2025
Professor Subhash Rakheja




Concordia University
Montreal, QC, Canada




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,Table of Contents
Objective ............................................................................................ 4
Introduction ......................................................................................... 4
Experiment 3.1 ................................................................................... 4
Experiment 3.2 ................................................................................... 6
Procedure ........................................................................................... 8
Experiment 3.1: Characteristics of a two degrees-of-freedom semidefinite system ....... 8
Experiment 3.2: Characteristics of an undamped torsional vibration absorber............. 8
Results ............................................................................................... 9
Experiment 3.1 ................................................................................... 9
Experiment 3.2 .......................................................................................................................... 14
Discussion ......................................................................................... 23
Experiment 3.1 ................................................................................. 23
Experiment 3.2 ................................................................................. 24
Conclusion......................................................................................... 25
Experiment 3.1 ................................................................................. 25
Experiment 3.2 ................................................................................. 25
References ........................................................................................ 25




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, List of Figures
Figure 1: Schematic of a two degree-of-freedom semi-definite system [1] .................... 4
Figure 2: Rigid body motion of the two rotors (ω = ω1)............................................................... 5
Figure 3: Mode shape (ω = ω2) .................................................................... 5
Figure 4: SDOF undamped torsion system [1] .................................................... 6
Figure 5: Schematic of an undamped torsion vibration absorber [1] ........................... 6
Figure 6: Non- Drifting Response of Rotors ....................................................... 9
Figure 7: Experimental Phase Angle Vs Frequency For Semi- Definite System............... 10
Figure 8: Theoretical Mode Shape of the Anti-Phase Motion .................................. 12
Figure 9: Amplitude Ratio (θ2/θ1) Vs Frequency of Undamped SDOF System ............... 16
Figure 10: Steady State Amplitude ( θ2/θ1) SDOF and 2DOF Vs Frequency ........................... 17
Figure 11: Experimental and Theoretical Amplitude (θ2/θ1) for 2DOF System Vs Frequency
. .................................................................................................... 18
Figure 12: Experimental Amplitude Ratio (θ2/θ1) SDOF and 2DOF Vs Frequency ........... 19
Figure 13: Experimental And Theoretical Amplitude (θ3/θ1) for 2DOF System Vs Frequency
. .................................................................................................... 20



List of Tables
Table 1: Experimental Data Experiment 3.1..................................................... 11
Table 2: Experimental and theoretical data for system without an absorber ................. 21
Table 3: Experimental and theoretical data for system without an absorber ................. 22




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