14 11 Analysis of Experimental Data 11.1 Typical Test Data 11.2 Transforming to the Frequency Domain – The CFT 11.3 Transforming to the Frequency Domain – The DFT 11.4 Transforming to the Frequency Domain – A Faster DFT 11.5 Transforming to the Frequency Domain – The FFT 11.6 Transforming to the Frequency Domain – An Example 11.7 Sampling and Aliasing 11.8 Leakage and Windowing 11.9 Decimating Data 11.10 Averaging FFTs Exercises Notes
15 12 Topics in Vibrations 12.1 What About the Mass of the Spring? 12.2 Flow‐induced Vibrations 12.3 Self‐Excited Oscillations of Railway Wheelsets 12.4 What is a Rigid Body Mode? 12.5 Why Static Deflection is Very Useful Exercises Notes
16 Appendix A: Least Squares Curve Fitting
17 Appendix B: Moments of Inertia B.1 Parallel Axis Theorem for Moments of Inertia B.2 Moments of Inertia for Commonly Encountered Bodies Notes
18 Index
List of Tables
1 Chapter 6Table 6.1 Effective viscous damping coefficients.
2 Chapter 10Table 10.1 Inertia coefficients.
3 Chapter 11Table 11.1 Fourier Transforms Computational Effort.Table 11.2 Sampled Data.Table 11.3 DFT Coefficients.Table 11.4 DFT Coefficients.
4 Chapter 12Table 12.1 The Routh Table.Table 12.2 The Routh Table for the wheelset.
5 Appendix ATable A.1 Sample data points.
List of Illustrations
1 Chapter 1Figure 1.1 A bead on a wire.Figure 1.2 Free Body Diagram of a bead on a wire.Figure 1.3 A 2D representation of the bead on a wire.Figure 1.4 A linear viscous damper.Figure 1.5 A simple pendulum.Figure 1.6 Nonlinear structural element – Linearization and effective stiffn...Figure E1.1 Figure E1.2 Figure E1.5 Figure E1.6
2 Chapter 2Figure 2.1 A mass on a spring.Figure 2.2 Independent front suspension.Figure 2.3 Assembly of the mass/spring system.Figure 2.4 FBD of the mass/spring system.Figure 2.5 A spring element.Figure 2.6 The linear spring constitutive relationship.Figure 2.7 A mass on a spring.Figure 2.8 A mass on a spring – FBD.Figure 2.9 A simple pendulum.Figure 2.10 Spring deflection due to a large angle of rotation.Figure 2.11 A body with a rotational DOF: How to deal with a spring, a dampe...Figure 2.12 Gravitational effects.Figure E2.2 Figure E2.3 Figure E2.4 Figure E2.5 Figure E2.6
3 Chapter 3Figure 3.1 Simple harmonic motion.Figure 3.2 Simple harmonic motion with a phase shift.Figure 3.3 Mass/spring/damper system.Figure 3.4 Mass/spring/damper FBD.Figure 3.5 The underdamped response.Figure 3.6 The critically damped response.Figure 3.7 The overdamped response.Figure 3.8 The root locus.Figure E3.1 Figure E3.2 Figure E3.3 Figure E3.4 Figure E3.5 Figure E3.6 Figure E3.7
4 Chapter 4Figure 4.1 SDOF system with a harmonically applied force.Figure 4.2 SDOF system with a harmonically applied force – FBD.Figure 4.3 Widely separated frequencies.Figure 4.4 The Beating phenomenon.Figure 4.5 Resonance.Figure E4.2
5 Chapter 5Figure 5.1 SDOF system with a harmonically applied force.Figure 5.2 Frequency response – SDOF undamped system.Figure 5.3 Magnification Factor ‐ SDOF undamped system.Figure 5.4 Damped SDOF system with a harmonically applied force.Figure 5.5 Magnification Factor – SDOF damped system.Figure 5.6 Damped SDOF system with harmonic base motion.Figure 5.7 Free body diagram – damped SDOF system with harmonic base motion.Figure 5.8 Magnification Factor – Harmonic base motion.Figure 5.9 Force transmissibility – Harmonic base motion.Figure 5.10 Damped SDOF system with a rotating unbalance.Figure 5.11 Free body diagram – Damped SDOF system with a rotating unbalance...Figure 5.12 Amplitude Ratio – SDOF rotating unbalance.Figure 5.13 Schematic layout of a typical piezoelectric accelerometer.Figure 5.14 Model of a typical piezoelectric accelerometer.Figure 5.15 Free body diagram of the accelerometer model.Figure 5.16 Piezoelectric accelerometer – % error.Figure E5.1 Figure E5.3 Figure E5.8 Figure E5.9
6 Chapter 6Figure 6.1 A linear viscous damper.Figure 6.2 Test setup for energy removed by a linear viscous damper.Figure 6.3 Hysteresis loop for a linear viscous damper.Figure 6.4 Experimental hysteresis loops for two shock absorbers.Figure 6.5 Friction force magnitude and direction.Figure 6.6 A system with Coulomb friction.Figure 6.7 Response with Coulomb friction.Figure 6.8 The underdamped