1shock and vibration testing

... are used to evaluate shock and vibration environments, to devise testing procedures and testing machines, and to design and operate equipment and machinery Shock and/ or vibration may be either wanted ... frequencies f1 and f2 They involve the periodic increase and decrease of amplitude at the beat frequency (f1 − f2) beats broadband random vibration Broadband random vibration is random vibration having ... degree-of-freedom system narrow-band random vibration (random sine wave) Narrow-band random vibration is random vibration having frequency components only within a narrow band It has the appearance...

Ngày tải lên: 11/08/2014, 07:23

... are used to evaluate shock and vibration environments, to devise testing procedures and testing machines, and to design and operate equipment and machinery Shock and/ or vibration may be either wanted ... frequencies f1 and f2 They involve the periodic increase and decrease of amplitude at the beat frequency (f1 − f2) beats broadband random vibration Broadband random vibration is random vibration having ... degree-of-freedom system narrow-band random vibration (random sine wave) Narrow-band random vibration is random vibration having frequency components only within a narrow band It has the appearance...

Ngày tải lên: 29/06/2014, 09:21

... equations, Eqs (3.31e) and (3.31f ), and two sets each consisting of two coupled equations [Eqs (3.31a) and (3.31d); Eqs (3.31b) and (3.31c)] The planes of symmetry are the XZ and YZ planes For example, ... Z″ are transferred to the mutually paralay; that between Z″ and Z′ is az The lel axes X′, Y′, Z′ by Eqs (3.14) and (3.15), and moments and products of inertia of the then to the inclined axes X, ... oscillations about X and Z are uncoupled The angle θ0 and the moment of inertia about the Z axis give Ixz by Eq (3.28) When the moments and product of inertia with respect to a pair of axes X and Z in a...

Ngày tải lên: 11/08/2014, 07:23

... Mounting Systems,” J of Vibration and Acoustics, 117(B):117–161, 1995 Choi, Y S., and S T Noah: “Forced Periodic Vibration of Unsymmetric Piecewise-Linear Systems,” J of Sound and Vibration, 121(3):117–126, ... NONLINEAR VIBRATION 4.45 Ehrich, F F.: “Observations of Subcritical Superharmonic and Chaotic Response in Rotordynamics,” J of Vibration and Acoustics, 114(1):93–100, 1992 Nayfeh, A H., B Balachandran, ... Rubs and Chatter Instabilities in Forced Vibrations Bistable vibration Unstable imbalance In each instance, the physical mechanism is described and aspects of its prevention or its diagnosis and...

Ngày tải lên: 11/08/2014, 07:23

... frequencies and normal modes of small vibration of a rectangular plate of length a, width b, and thickness h are to be calculated All edges are hinged and subjected to unchanging normal forces Nx and ... executing lateral vibration (B) Element of beam showing shear forces and bending moments 8434_Harris_07_b.qxd 09/20/2001 11:24 AM Page 7.14 7.14 CHAPTER SEVEN and that caused by the vibration. The ... if the amplitude of the vibration is known EXAMPLE 7.4 The natural frequencies and modes of vibration of the rectangular steel beam shown in Fig 7.6 are to be determined and the fundamental frequency...

Ngày tải lên: 11/08/2014, 07:23

... measurements and shock and vibration data should not be taken until stabilization is reached 8434_Harris_12_b.qxd 09/20/2001 11:15 AM Page 12.29 VIBRATION TRANSDUCERS 12.29 Input and Output Resistance ... required to band-limit the signal, possibly to integrate it (to velocity and/ or displacement), and to adjust the gain High- and low-pass filters normally are required to remove extraneous low- and high-frequency ... replace the rectifier VIBRATION METERS Vibration meters are instruments which receive a signal from a vibration transducer and process it so as to give an indication of relevant vibration parameters...

Ngày tải lên: 11/08/2014, 07:23

... of vanes and blades in pumps and fans, number of motor poles, and number of stator slots and rotor bars Vibratory forces such as misalignment, mass unbalance, and reciprocating masses Vibration ... to the frequency and amplitude ranges for which the secondary standard has been calibrated and for which the vibration exciter has adequate rectilinear motion The secondary standard accelerometer ... in the vibration spectrum at the machine speed and in the radial direction However, dynamic unbalance may also result in a rocking motion and consequently in vibration in both radial and axial...

Ngày tải lên: 11/08/2014, 07:23

... of tests and experiments, transmissibility of gloves and resilient materials, and terminology (See Chap 42.) Testing Numerous standards and handbooks that cover shock and vibration testing have ... visco-elastic materials using vibration NASA Standards and Handbooks NASA has issued three standards (STD) and two handbooks (HDBK) related to shock and vibration testing that are approved for ... International Standard (NAIS) ANSI S2.1 Use and Calibration of Transducers and Instrumentation The use and calibration of shock and vibration transducers and instrumentation, including standardized...

Ngày tải lên: 11/08/2014, 07:23

... signal has random amplitude and random phase distribution and contains energy throughout the frequency spectrum The difference between this signal and the periodic random signal is that the random ... Time-history and line spectrum for almost-periodic vibration STATIONARY RANDOM VIBRATIONS By definition, random vibrations cannot be described by an explicit mathematical function and, hence, ... 12:06 PM Page 22.9 CONCEPTS IN VIBRATION DATA ANALYSIS 22.9 (A) (B) FIGURE 22.6 Time-histories and autospectra for wide-bandwidth (A) and narrow-bandwidth (B) random vibrations Wxy(f) = |Wxy(f)|e−jθxy(f)...

Ngày tải lên: 11/08/2014, 07:23

... Harris and C E Crede (eds.), “Shock and Vibration Handbook,” 1st ed., vol III, chap 50, McGrawHill Book Company, Inc., New York, 1961 Richart, F E., Jr., J R Hall, Jr., and R D Woods: Vibration ... mind when selecting a vibration testing machine for a specific application Digital control systems for vibration testing are described in Chap 27 Applications of vibration testing machines are ... electrodynamic vibration test system is comprised of an electrodynamic vibration machine, electrical power equipment which drives the vibration machine, and electrical controls and vibration monitoring...

Ngày tải lên: 11/08/2014, 07:23

... shock and vibration data Multiple input/output analysis of shock and vibration data Average values and tolerance limits for shock and vibration data Other statistical analysis of shock and vibration ... stationary random vibration test.31 This is called sine-on-random vibration testing or swept-sine-on-random vibration testing Systems are also available that can control swept narrow bandwidths ... of nonstationary random superimposed on a stationary random vibration test This is called swept-narrow-bandwidth-random-on-random testing It uses a variation of the random vibration control methods,...

Ngày tải lên: 11/08/2014, 07:23

... THEORY OF VIBRATION ISOLATION 30.43 ISOLATION OF RANDOM VIBRATION In random vibration, all frequencies exist concurrently, and the amplitude and phase relations are distributed in a random manner ... sinusoidal motion with a continuously and irregularly varying envelope; it is described as narrow-band random vibration or a random sine wave The characteristics of random vibration are defined by a frequency ... rotational stiffness of the system NONLINEAR VIBRATION ISOLATORS In vibration isolation, the vibration amplitudes generally are small and linear vibration theory usually is applicable with sufficient...

Ngày tải lên: 11/08/2014, 07:23

... periodic vibration sinusoidal continuos motion or acceleration occurring at discrete frequencies, (2) random vibration the simultaneous existence of any and all frequencies and amplitudes in any and ... damping of the gas, and nonlinearity 8434_Harris_32_b.qxd 09/20/2001 12:32 PM Page 32.15 SHOCK AND VIBRATION ISOLATORS AND ISOLATION SYSTEMS 32.15 The damping varies with the vibration amplitude; ... and 32.9B, can be used to better advantage than a helical spring when the energy to be absorbed is high and 8434_Harris_32_b.qxd 09/20/2001 12:32 PM Page 32.11 SHOCK AND VIBRATION ISOLATORS AND...

Ngày tải lên: 11/08/2014, 07:23

... for static and residual strength and stiffness testing and for the proof load specification Similar difficulties would arise in the case of all candidate methodologies considered here, and indeed ... temperature (magnitude and variation) and the surrounding medium and its (corrosive, erosive, and chemical) effects Factors tabulated above, such as stress magnitude, history, and frequency, may ... rotating shafts and of error in sensitive instruments Resonant vibrations of large amplitude are encountered in a variety of modern devices, frequently causing rough and noisy operation and, in extreme...

Ngày tải lên: 11/08/2014, 07:23

... 12:26 PM Page 38.15 TORSIONAL VIBRATION IN RECIPROCATING AND ROTATING MACHINES 38.15 causing the vibration Vibration amplitudes and stresses around the operating range and at the critical speeds ... rpm and multiples No plungers × rpm and multiples No vanes × rpm No poles or blades × rpm Depends on engine design and operating conditions; can be 0.5n and n × rpm Depends on engine design and ... TORQUES Torsional vibration, like any other type of vibration, results from a source of excitation The mechanisms that introduce torsional vibration into a machine system are discussed and quantified...

Ngày tải lên: 11/08/2014, 07:23

... platform Isolation and protection against vibration and short-time accelerations; ballistocardiography Hand-arm impedance Isolation and protection against handtransmitted vibration; design of ... maintain and not available to many small companies and agencies Commercial test facilities are available for such organizations Chapter 19 describes general shock and vibration standards and Chap ... 13 Nigam, N C.: “Introduction to Random Vibrations,” MIT Press, Cambridge, Mass., 1983 14 Wirsching, P H., T L Paez, and H Ortiz: “Random Vibrations: Theory and Practice,” John Wiley & Sons,...

Ngày tải lên: 11/08/2014, 07:23

... kế:  Seismic (Inertial)  Piezoelectric  Piezoresistive and strain gages  Electromechanical  Capacitive and electrostatic  Micro- and nanosensors  Velocity sensors  Noncontact proximity ... (rad/s) - undamped critical frequency    c /  km hệ số tắt dần - damping ratio Vibration & shock  Độ rung (vibration) thể dạng độ dịch chuyển (displacement), tốc độ (velocity) hay gia tốc ... Chuyển động rung mô tả miền thời gian (time domain) miền tần số (frequency domain) Stationary Random Vibrations  Chuyển động rung loại ngẫu nhiên, dừng (tại chỗ):  Chuyển động rung ngẫu nhiên...

Ngày tải lên: 09/09/2014, 01:38

... Revised and Expanded, Earl Logan, Jr 86 Vibrations of Shells and Plates: Second Edition, Revised and Expanded, Werner Soedel 87 Steam Plant Calculations Manual: Second Edition, Revised and Expanded, ... Selection and Application, Duane Tandeske 73 Zinc Handbook: Properties, Processing, and Use in Design, Frank Porter 74 Thermal Fatigue of Metals, Andrzej Weronski and Tadeusz Hejwowski 75 Classical and ... Understanding Gear Noise, J Derek Smith Chains for Power Transmission and Material Handling: Design and Applications Handbook, American Chain Association Corrosion and Corrosion Protection Handbook,...

Ngày tải lên: 05/08/2014, 09:20

... Revised and Expanded, Earl Logan, Jr 86 Vibrations of Shells and Plates: Second Edition, Revised and Expanded, Werner Soedel 87 Steam Plant Calculations Manual: Second Edition, Revised and Expanded, ... Selection and Application, Duane Tandeske 73 Zinc Handbook: Properties, Processing, and Use in Design, Frank Porter 74 Thermal Fatigue of Metals, Andrzej Weronski and Tadeusz Hejwowski 75 Classical and ... Understanding Gear Noise, J Derek Smith Chains for Power Transmission and Material Handling: Design and Applications Handbook, American Chain Association Corrosion and Corrosion Protection Handbook,...

Ngày tải lên: 05/08/2014, 09:20

... effectiveness of vibration isolators Of these approaches, (c) and (d) are very expensive and tend to be temperamental and delicate or impracticable so this book concentrates on (a) and (b) as the ... Stiffnesses Damping I GEARCASE FOOT VIBRATIONS ^ Antivibration Mounts I TRANSMITTED STRUCTURE VIBRATION Sound Radiating Panel AIRBORNE NOISE Fig 1.4 Vibration excitation and transmission path 1.6 T.E ... transmission and losses over a broad frequency band can give a clearer description than the conventional transfer function approach when frequencies are high and there are multiple inputs and resonances...

Ngày tải lên: 05/08/2014, 09:20