217,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Written by two experts across multiple disciplines, this is the perfect reference on structural dynamics for veteran engineers and introduction to the field for engineering students.
Across many disciplines of engineering, dynamic problems of structures are a primary concern. Civil engineers, mechanical engineers, aircraft engineers, ocean engineers, and engineering students encounter these problems every day, and it is up to them systematically to grasp the basic concepts, calculation principles and calculation methods of structural dynamics. This book focuses on the basic theories and concepts, as well as the application and background of theories and concepts in engineering.
Since the basic principles and methods of dynamics are applied to other various engineering fields, this book can also be used as a reference for practicing engineers in the field across many multiple disciplines and for undergraduate and graduate students in other majors as well. The main contents include basic theory of dynamics, establishment of equation of motion, single degree of freedom systems, multi-degree of freedom systems, distributed-parameter systems, stochastic structural vibrations, research projects of structural dynamics, and structural dynamics of marine pipeline and risers.
Whether for the veteran engineer or student, this is a must-have for any scientific or engineering library.
Useful for students and veteran engineers and scientists alike, this is the only book covering these important issues facing anyone working with coastal models and ocean, coastal, and civil engineering in this area.
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 484
Veröffentlichungsjahr: 2019
Ähnliche
Contents
Cover
Preface
About the Authors
Chapter 1: Introduction
1.1 Overview of Structural Dynamics
1.2 Dynamic Loads
1.3 Characteristics of a Dynamic Problem
1.4 Application of Structural Dynamics
Exercises
References
Chapter 2: Establishment of the Structural Equation of Motion
2.1 General
2.2 Formulation of the Equations of Motion
2.3 Theory of Total Potential Energy Invariant Value of Elastic System Dynamics
2.4 Influence of Gravitational Forces
2.5 Influence of Support Excitation
Exercises
References
Chapter 3: Single Degree of Freedom Systems
3.1 Response of Free Vibrations
3.2 Response to Harmonic Loading
3.3 Periodic Load Response
3.4 Impulsive Loading Response
3.5 Response of Arbitrary Load
3.6 Energy in Vibration
3.7 Structural Vibration Test
3.8 Vibration Isolation Principle
3.9 Structural Vibration Induced Fatigue
Exercises
References
Chapter 4: Multi-Degree of Freedom System
4.1 Two Degrees of Freedom System
4.2 Free Vibrations of Undamped System
4.3 Practical Calculation Method of Dynamic Characteristics
4.4 Mode Superposition Method for Damped System
4.5 Numerical Analysis of Damping System
4.6 Stability and Accuracy Analysis of Stepwise Integration Method
Exercises
References
Chapter 5: Distributed-Parameter System
5.1 Overview
5.2 Establish Differential Equations for Motion
5.3 Free Vibration of a Beam
5.4 Orthogonality Relationships
5.5 Modal Decomposition
References
Chapter 6: Stochastic Structural Vibrations
6.1 Overview
6.2 Stochastic Process
6.3 Stochastic Response of Linear SDOF System
6.4 Stochastic Response of Linear MDOF System
6.5 Nonlinear Structural Stochastic Response Analysis
6.6 State Space Method for Structural Stochastic Response Analysis
Exercises
References
Chapter 7: Research Topics of Structural Dynamics
7.1 Analysis of Structural Seismic Response
7.2 Structural Vibration Control
7.3 Modal Analysis and Theory
7.4 Structural Dynamic Damage Identification
7.5 Nonlinear Problems of Dynamic Analysis
7.6 Sub-Structure Method
7.7 Dynamics of Offshore Structures
Exercises
References
Chapter 8: Structural Dynamics of Marine Pipeline and Riser
8.1 Overview
8.2 Environmental Conditions
8.3 Hydrodynamic Loads
8.4 Structural Response Analysis
8.5 Vortex Induced Vibrations
Exercises
References
Answers to Exercises
Index
End User License Agreement
Guide
Cover
Table of Contents
Begin Reading
List of Tables
Chapter 7
Table 7. 1
Application of viscoelastic dampers in wind-resistant earthquake engineering.
Table 7.2
Experimental study on the structure with viscoelastic dampers.
Chapter 8
Table 8.1
Parameters of model data in Chaplin’s test.
Table 8.2
The modal frequencies from modal analysis.
Pages
ii
iii
iv
xi
xii
xiii
xiv
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106
Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])
Structural Dynamics
Yong Bai
Zhao-Dong Xu
This edition first published 2019 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA © 2019 Scrivener Publishing LLC For more information about Scrivener publications please visit www.scrivenerpublishing.com.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.
Wiley Global Headquarters111 River Street, Hoboken, NJ 07030, USA
For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.
Limit of Liability/Disclaimer of WarrantyWhile the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials, or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read.
Library of Congress Cataloging-in-Publication Data
ISBN 978-1-119-60560-7
Preface
Dynamic problems of structures are ubiquitous in research. Therefore, it is very important for students majoring in civil engineering, mechanical engineering, aircraft engineering and ocean engineering to systematically grasp the basic concepts, calculation principles and calculation methods of structural dynamics. This book focuses on the basic theories and concepts, as well as the application and background of theories and concepts in engineering. Since the basic principles and methods of dynamics are applied to other various engineering fields, this book can also be used as a reference for undergraduate and graduate students in other majors.
The main contents include basic theory of dynamics, establishment of equation of motion, single degree of freedom systems, multi-degree of freedom systems, distributed-parameter systems, stochastic structural vibrations, research projects of structural dynamics, and structural dynamics of marine pipeline and riser.
This book was co-authored by Professor Yong Bai of Southern University of Science and Technology and Professor Zhao-Dong Xu of Southeast University. The authors would like to appreciate Dr. Yong Bai’s and Dr. Zhao-Dong Xu’s graduate students and postdoctoral fellows who provided the initial technical writing. The students in Southern University of Science and Technology are Ms. Xinyu Sun (Chapters 1 & 3), Mr. Jiannan Zhao (Chapters 2 & 4), Mr. Zhao Wang (Chapters 5, 6, & 7), and Mr. Wei Qin (Chapter 8). The students in Southeast University are Mr. Yanwei Xu (Chapter 1 and proofread all), Mr. Hao Hu (Chapter 3), Mr. Yun Yang (Chapter 6), Mr. Shi Chen (Chapter 7), and Mr. Qiangqiang Li (proofread all). The students in Xi’an University of Architecture and Technology are Mr. Zefeng He (Chapter 3), Mr. Zhenhua He (Chapter 4), and Ms. Tian Zhang (proofread all). Thanks to all persons involved in reviewing the book.
About the Authors
Professor Bai received a doctorate from Hiroshima University in Japan and engaged in postdoctoral work in the field of ocean engineering in Technical University of Denmark, Norwegian University of Science and Technology and University of California at Berkeley. He has published over 100 research papers, 9 English academic treatises and 8 Chinese books on Ocean Engineering. Bai served as a professor at University of Stavanger, Harbin Engineering University, Zhejiang University and Southern University of Science and Technology. He guided more than 50 graduate students and 30 doctoral students.
Professor Bai has a wealth of engineering experience and management skills. He worked in Det Norske Veritas, American Bureau of Shipping, JP KENNY Company in Norway, Shell E & P Company and MCS in the United States. He has presided over dozens of large projects in the field of ship structures, submarine pipelines and risers, design analysis and risk assessment of offshore platforms. Bai put forward the design concept of buckling and ultimate load carrying capacity of deepwater submarine pipelines. He improved the design methods, analytical tools and design standards of marine pipelines and reached the international leading level. He significantly improved the design methodology and criteria for subsea pipelines and risers such as ultimate strength design, use of risk and reliability methods.
He contributed to subsea technology by publishing many papers and a recognized book entitled Subsea Engineering Handbook and promoted limit-state design and use of risk and reliability by teaching at universities and publishing a book entitled Marine Structural Design.
Professor Zhao-Dong Xu is the professor at the Civil Engineering School of Southeast University, serving as doctoral tutor. His major research fields are Anti-earthquake of Structures, Structural Control and Health Monitoring, Smart Material and Structures. Professor Xu got his Ph.D. in China, followed by a series of teaching and research positions at Xi’an Jiaotong University, Ibaraki University, North Carolina State University and University of Illinois at Urbana-Champaign. He is the Vice President of RC & PC Key Laboratory of Education Ministry. He has also been Changjiang Scholar Distinguished Professor and the National Science Fund for Distinguished Young Scholars in China.
Professor Xu engaged in teaching and research on structural dynamics for more than 20 years. He has published more than 200 papers on the subject of structure dynamics research, numerical analysis and application of civil engineering, etc. He has been honored with many awards—the 43rd Geneva International Patents Exhibition Gold Award, the Second Award of National Award for Technological Invention in China, the Top Award of Chinese Building Materials Technology Invention, etc. He has completed many significant research projects in the areas of structural vibration control and structural health monitoring, and many research outcomes have been utilized in major real applications.
Chapter 2Establishment of the Structural Equation of Motion
The purpose of structural dynamics analysis is to calculate the dynamic response of the structure under dynamic load, that is, to solve the history of displacement, velocity, acceleration, strain, etc., of the structure over time. In most cases, applying an approximate analysis method with a finite number of degrees of freedom is accurate enough. In this way, the problem becomes to find the time-history curve of the selected component. Before solving the time-history curve, the equation of motion of the dynamical system under dynamic load must be established. This chapter will briefly introduce some of the basic concepts of structural dynamics and the methods for establishing the structural equations of motion.
2.1 General
The degree of freedom is often talked about in structural dynamics, and it is necessary to be familiar with the concept of particles before describing degrees of freedom. Particles are ideal models for simplifying objects. The model is considered as objects which have only mass and no size.
2.1.1 Dynamic Freedom
The number of independent geometric parameters required to describe the position of the system at any moment of mass during motion is called the number of degrees of dynamic freedom of the structure. The number of structural degrees of freedom is not fixed, changes as the structural calculation hypothesis changes for a structure. As shown in Figure 2.1, the single mass is depicted in Figure 2.1(a), and the mass which has two degrees of freedom can move in x-axis and y-axis; cantilever beam ignoring axial effect is shown in Figure 2.1(b), where the right mass can move in x-axis, and the left one can move in y-axis; a rigid beam is shown in Figure 2.1(c), if the stiffness is assumed to be infinite, whose three masses has single degree of freedom, namely angle of rotation θ; the sketch of four-layered frame is shown in Figure 2.1(d), each mass can move in horizontal direction and the structure has four degrees of freedom.
Figure 2.1 Definition of degree of freedom.
When analyzing a dynamic system, the first step is to determine the degree of power freedom and establish the differential equation of motion. Before describing how to establish the differential equation of motion of a dynamic system, it is necessary to understand the basic components of the dynamic system.
2.1.2 Basics of Dynamic System
A dynamic system is a simple representation of physical systems and is modeled by mass, damping and stiffness. For any system subjected to a dynamic load, the main physical characteristics are the mass of the system, elastic recovery characteristics, energy dissipation characteristics or damping, and the external disturbance or load of the system.
Inertia Force
Mass is a fundamental property of matter and is present in all physical systems. This is simply the weight of the structure divided by the gravity acceleration. Mass contributes an inertia force (equal to mass times acceleration) in the dynamic equation of motion, which can be expressed as,
(2.1)
where, FI(t) represents the inertia force; m represents the mass; ü(t) is the acceleration.
Elastic Restoring Force
Stiffness makes the structure more rigid, lessens the dynamic effects and makes it more dependent on static forces and displacements. Usually, structural systems are made stiffer by increasing the cross-sectional dimension, making the structures shorter or using stiffer materials. Stiffness is the resistance it provides to deformations, mass is the matter it contains and damping represents its ability to decrease its own motion with time. Assuming that the relationship between the force and displacement is linear, the restoring force of the spring is also referred to as the elastic restoring force, which is equal to the product of the spring stiffness and displacement,
(2.2)
where, FS(t) represents the restoring force; k represents the stiffness of the spring; u(t) is the displacement.
Damping Force
Damping, in physics, is restraining of vibratory motion, such as mechanical oscillations, noise, and alternating electric currents, by dissipation of energy. Unless a child keeps pumping a swing, its motion dies down because of damping. Shock absorbers in automobiles and carpet pads are examples of damping devices. Whereas the mass and the stiffness are well-known properties and measured easily, damping is usually determined from experimental results or values assumed from experience. There are several sources of damping in a dynamic system. Viscous damping is the most used damping system and provides a force directly proportional to the structural velocity. This is a fair representation of structural damping in many cases and for the purpose of analysis, and it is convenient to assume viscous damping (also known as linear viscous damping). For the single degree of freedom system, the viscous damping can be written as,
(2.3)
where, FD(t) represents the damping force; c represents the damping coefficient; is the velocity of mass.
Viscous damping is caused by such energy losses as occur in liquid lubrication between moving parts or in a fluid forced through a small opening by a piston, as in automobile shock absorbers. The viscous-damping force is directly proportional to the relative velocity between the two ends of the damping device. Viscous damping is usually an intrinsic property of the material and originates from internal resistance to motion between different layers within the material itself.
The motion of a vibrating body is also checked by its friction with the gas or liquid through which it moves. The damping force of the fluid in this case is directly proportional to a quantity slightly less than the square of the body’s velocity and, hence, is referred to as velocity-squared damping. Besides these external kinds of damping, there is energy loss within the moving structure itself that is called hysteresis damping or, sometimes, structural damping. In hysteresis damping, some of the energy involved in the repetitive internal deformation and restoration to original shape is dissipated in the form of random vibrations of the crystal lattice in solids and random kinetic energy of the molecules in a fluid.
There are other types of damping. Resonant electric circuits, in which an alternating current is surging back and forth, as in a radio or television receiver, are damped by electric resistance. The signal to which the receiver is tuned supplies energy synchronously to maintain resonance. In radiation damping, vibrating energy of moving charges, such as electrons, is converted to electromagnetic energy and is emitted in the form of radio waves or infrared or visible light. In magnetic damping, energy of motion is converted to heat by way of electric eddy currents induced in either a coil or an aluminum plate (attached to the oscillating object) that passes between the poles of a magnet.
