EBOOK - Engineering Vibrations (William J. Bottega)

EBOOK - Kỹ thuật rung động (William J. Bottega) - 750 Trang.

The effects of vibrations on the behavior of mechanical and structural systems are often of critical importance to their design, performance, and survival. For this reason the subject of mechanical vibrations is offered at both the advanced undergraduate level and graduate level at most engineering schools. I have taught vibrations to mechanical and aerospace engineering students, primarily seniors, for a number of years and have used a variety of textbooks in the process. As with many books of this type, the emphasis is often a matter of taste. Some texts emphasize mathematics, but generally fall short on physical interpretation and demonstrative examples, while others emphasize methodology and application but tend to oversimplify the mathematical development and fail to stress the fundamental principles. Moreover, both types fail to stress the underlying mechanics and physics to a satisfactory degree, if at all.

For these reasons, there appeared to be a need for a textbook that couples thorough mathematical development and physical interpretation, and that emphasizes the mechanics and physics of the phenomena. The book would need to be readable for students with the background afforded by a typical university engineering curriculum, and would have to be self-contained to the extent that concepts are developed, dvanced and abstracted using that background as a base. The present volume has been written to meet these goals and fill the apparent void.

1.  PRELIMINARIES1
 1.1  Degrees of Freedom……………………………………………………. 2
1.2  Equivalent Systems…………………………………………………….. 6
1.2.1 Extension/Contraction of Elastic Rods…………………………… 6
 1.2.2 Bending of Elastic Beams………………………………………... 8
 1.2.3 Torsion of Elastic Rods…………………………………………. 16
1.2.4 Floating Bodies…………………………………………………. 20
 1.2.5 The Viscous Damper…………………………………………… 22
 1.2.6 Aero/Hydrodynamic Damping (Drag)………………………….. 24
1.3  Springs Connected in Parallel and in Series…………………………… 25
 1.3.1 Springs in Parallel………………………………………………. 26
 1.3.2 Springs in Series…………………………………………………26
1.4  A Brief Review of Complex Numbers………………………………… 28
1.5  A Review of Elementary Dynamics…………………………………... 30
 1.5.1 Kinematics of Particles…………………………………………. 31
 1.5.2 Kinetics of a Single Particle…………………………………….. 38
 1.5.3 Dynamics of Particle Systems…………………………………... 49
1.5.4 Kinematics ofRigid Bodies…………………………………….. 56
1.5.5 (Planar) Kinetics of Rigid Bodies………………………………. 60
1.6  Concluding Remarks………………………………………………….. 66
 Bibliography…………………………………………………………... 67
 Problems………………………………………………………………. 67
2.  FREE VIBRATION OF SINGLEDEGREE OF FREEDOM SYSTEMS 75
2.1  Free Vibration of Undamped Systems………………………………… 75
2.1.1 Governing Equation and SystemResponse……………………... 76
2.1.2 The Effect of Gravity…………………………………………… 87
 2.1.3 Work and Energy……………………………………………….. 93
 2.1.4 The Simple Pendulum…………………………………………... 94
2.2  Free Vibration of Systems with Viscous Damping…………………... 109
 2.2.1 Equation of Motion and GeneralSystem Response…………… 109
2.2.2 Underdamped Systems………………………………………… 111
2.2.3  Logarithmic Decrement………………………………………. 115
2.2.4 Overdamped Systems………………………………………….. 119
 2.2.5 Critically Damped Systems……………………………………. 121 
2.3  Coulomb (Dry Friction) Damping…………………………………….127
2.3.1 Stick-Slip Condition…………………………………………… 127
2.3.2 SystemResponse……………………………………………….129
2.4 Concluding Remarks………………………………………………… 133
  Bibliography…………………………………………………………. 135
Problems…………………………………………………………….. 135
3.  FORCED VIBRATION OF SINGLE DEGREE OF FREEDOM 
SYSTEMS – 1: PERIODIC EXCITATION143
3.1  Standard Form of the Equation of Motion…………………………… 143
3.2  Superposition………………………………………………………… 144
3.3  Harmonic Forcing……………………………………………………. 147
3.3.1 Formulation……………………………………………………. 147
3.3.2 Steady State Response of Undamped Systems………………… 149
 3.3.3 Steady State Response of Systems with Viscous Damping……. 162
3.3.4 Force Transmission and Vibration Isolation……………………179
3.4  StructuralDamping………………………………………………….. 184
3.4.1 Linear Hereditary Materials…………………………………… 185
3.4.2 Steady State Response of Linear Hereditary Materials………... 186
 3.4.3 Steady State Response of Single Degree of FreedomSystems... 189
3.5  Selected Applications………………………………………………... 192
 3.5.1 Harmonic Motion of the Support……………………………… 192
3.5.2 Unbalanced Motor…………………………………………….. 201
 3.5.3 Synchronous Whirling of Rotating Shafts…………………….. 206
3.6  Response to General Periodic Loading……………………………… 211
 3.6.1 General Periodic Excitation…………………………………… 211
 3.6.2 Steady State Response………………………………………… 213
3.7 Concluding Remarks………………………………………………… 219
 Bibliography…………………………………………………………. 220
 Problems……………………………………………………………... 220
4.  FORCED VIBRATION OF SINGLE DEGREE OF FREEDOM 
SYSTEMS – 2: NONPERIODIC EXCITATION229
4.1  Two Generalized Functions………………………………………….. 229

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EBOOK - Kỹ thuật rung động (William J. Bottega) - 750 Trang.

The effects of vibrations on the behavior of mechanical and structural systems are often of critical importance to their design, performance, and survival. For this reason the subject of mechanical vibrations is offered at both the advanced undergraduate level and graduate level at most engineering schools. I have taught vibrations to mechanical and aerospace engineering students, primarily seniors, for a number of years and have used a variety of textbooks in the process. As with many books of this type, the emphasis is often a matter of taste. Some texts emphasize mathematics, but generally fall short on physical interpretation and demonstrative examples, while others emphasize methodology and application but tend to oversimplify the mathematical development and fail to stress the fundamental principles. Moreover, both types fail to stress the underlying mechanics and physics to a satisfactory degree, if at all.

For these reasons, there appeared to be a need for a textbook that couples thorough mathematical development and physical interpretation, and that emphasizes the mechanics and physics of the phenomena. The book would need to be readable for students with the background afforded by a typical university engineering curriculum, and would have to be self-contained to the extent that concepts are developed, dvanced and abstracted using that background as a base. The present volume has been written to meet these goals and fill the apparent void.

1.  PRELIMINARIES1
 1.1  Degrees of Freedom……………………………………………………. 2
1.2  Equivalent Systems…………………………………………………….. 6
1.2.1 Extension/Contraction of Elastic Rods…………………………… 6
 1.2.2 Bending of Elastic Beams………………………………………... 8
 1.2.3 Torsion of Elastic Rods…………………………………………. 16
1.2.4 Floating Bodies…………………………………………………. 20
 1.2.5 The Viscous Damper…………………………………………… 22
 1.2.6 Aero/Hydrodynamic Damping (Drag)………………………….. 24
1.3  Springs Connected in Parallel and in Series…………………………… 25
 1.3.1 Springs in Parallel………………………………………………. 26
 1.3.2 Springs in Series…………………………………………………26
1.4  A Brief Review of Complex Numbers………………………………… 28
1.5  A Review of Elementary Dynamics…………………………………... 30
 1.5.1 Kinematics of Particles…………………………………………. 31
 1.5.2 Kinetics of a Single Particle…………………………………….. 38
 1.5.3 Dynamics of Particle Systems…………………………………... 49
1.5.4 Kinematics ofRigid Bodies…………………………………….. 56
1.5.5 (Planar) Kinetics of Rigid Bodies………………………………. 60
1.6  Concluding Remarks………………………………………………….. 66
 Bibliography…………………………………………………………... 67
 Problems………………………………………………………………. 67
2.  FREE VIBRATION OF SINGLEDEGREE OF FREEDOM SYSTEMS 75
2.1  Free Vibration of Undamped Systems………………………………… 75
2.1.1 Governing Equation and SystemResponse……………………... 76
2.1.2 The Effect of Gravity…………………………………………… 87
 2.1.3 Work and Energy……………………………………………….. 93
 2.1.4 The Simple Pendulum…………………………………………... 94
2.2  Free Vibration of Systems with Viscous Damping…………………... 109
 2.2.1 Equation of Motion and GeneralSystem Response…………… 109
2.2.2 Underdamped Systems………………………………………… 111
2.2.3  Logarithmic Decrement………………………………………. 115
2.2.4 Overdamped Systems………………………………………….. 119
 2.2.5 Critically Damped Systems……………………………………. 121 
2.3  Coulomb (Dry Friction) Damping…………………………………….127
2.3.1 Stick-Slip Condition…………………………………………… 127
2.3.2 SystemResponse……………………………………………….129
2.4 Concluding Remarks………………………………………………… 133
  Bibliography…………………………………………………………. 135
Problems…………………………………………………………….. 135
3.  FORCED VIBRATION OF SINGLE DEGREE OF FREEDOM 
SYSTEMS – 1: PERIODIC EXCITATION143
3.1  Standard Form of the Equation of Motion…………………………… 143
3.2  Superposition………………………………………………………… 144
3.3  Harmonic Forcing……………………………………………………. 147
3.3.1 Formulation……………………………………………………. 147
3.3.2 Steady State Response of Undamped Systems………………… 149
 3.3.3 Steady State Response of Systems with Viscous Damping……. 162
3.3.4 Force Transmission and Vibration Isolation……………………179
3.4  StructuralDamping………………………………………………….. 184
3.4.1 Linear Hereditary Materials…………………………………… 185
3.4.2 Steady State Response of Linear Hereditary Materials………... 186
 3.4.3 Steady State Response of Single Degree of FreedomSystems... 189
3.5  Selected Applications………………………………………………... 192
 3.5.1 Harmonic Motion of the Support……………………………… 192
3.5.2 Unbalanced Motor…………………………………………….. 201
 3.5.3 Synchronous Whirling of Rotating Shafts…………………….. 206
3.6  Response to General Periodic Loading……………………………… 211
 3.6.1 General Periodic Excitation…………………………………… 211
 3.6.2 Steady State Response………………………………………… 213
3.7 Concluding Remarks………………………………………………… 219
 Bibliography…………………………………………………………. 220
 Problems……………………………………………………………... 220
4.  FORCED VIBRATION OF SINGLE DEGREE OF FREEDOM 
SYSTEMS – 2: NONPERIODIC EXCITATION229
4.1  Two Generalized Functions………………………………………….. 229

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Chuyên mục: C. Bài giảng C. Bài giảng chuyên ngành Điện - Điện tử (Electrical & Electronic) C. Bài giảng kỹ thuật