AS 60068.2.64-2003

1 - AS 60068.2.64-2003 ENVIRONMENTAL TESTING-TESTS-TEST Fh: VIBRATION, BROAD-BAND RANDOM (DIGITAL CONTROL) AND GUIDANCE
4 - PREFACE
5 - CONTENTS
7 - INTRODUCTION
9 - 1 Object
9 - 2 Normative references
10 - 3 Definitions
10 - 3.1 –3 dB bandwidth,
10 - 3.2 acceleration spectral density
10 - 3.3 bias error:
10 - 3.4 checkpoint:
10 - 3.5 control acceleration spectral density:
10 - 3.6 control system loop:
10 - 3.7 crest factor
11 - 3.8 damping ratio:
11 - 3.9 distortion:
11 - 3.10 drive signal clipping:
11 - 3.11 effective frequency range:
11 - 3.12 error acceleration spectral density:
11 - 3.13 equalization:
11 - 3.14 final slope:
11 - 3.15 frequency resolution:
11 - 3.16 “gn"
11 - 3.17 indicated acceleration spectral density:
11 - 3.18 initial slope:
11 - 3.19 instrument error:
11 - 3.20 multipoint control, averaging:
11 - 3.21 multipoint control, extremal:
12 - 3.22 preferred testing axes:
12 - 3.23 random error:
12 - 3.24 record:
12 - 3.25 reference point:
12 - 3.26 reproducibility
12 - 3.27 response points:
12 - 3.28 root-mean-square value
12 - 3.29 standard deviation,
12 - 3.30statistical accuracy:
12 - 3.31 statistical degrees of freedom
12 - 3.32 sweep cycle
12 - 3.33 true acceleration spectral density:
13 - 3.34 window function
13 - 4 Requirements for testing
13 - 4.1 General
13 - 4.2 Vibration response investigation
13 - 4.3 Testing with random excitation
13 - 4.3.1 Basic motion
13 - 4.3.2 Transverse motion
13 - 4.3.3 Distribution
14 - 4.3.4 Vibration tolerances
14 - 4.3.5 Statistical accuracy
14 - 4.3.6 Frequency resolution
15 - 4.4 Mounting
15 - 5 Severities
15 - 5.1 General
15 - 5.2 Test frequency range
16 - 5.3 Acceleration spectral density
16 - 5.4 Shape of acceleration spectral density curve
16 - 5.5 Duration of testing
16 - 6 Preconditioning
16 - 7 Initial measurements
16 - 8 Testing
16 - 8.1 General
17 - 8.2 Vibration response investigation
18 - 8.3 Low-level excitation for equalization prior to testing
18 - 8.4 Random vibration testing
18 - 8.5 Intermediate measurements
18 - 8.6 Final vibration response investigation
18 - 9 Recovery
18 - 10 Final measurements
19 - 11 Information to be given in the relevant specification
20 - Annex A - Vibration response investigation
20 - A.1 Introduction
20 - A.2 Sinusoidal vibration
22 - A.3 Random excitation
23 - Annex B - Guidance
23 - B.1 General introduction
24 - B.2 Requirements for testing
30 - B.3 Testing procedures
31 - B.4 Equipment normally used with vibration isolators
32 - B.5 Test severities
32 - B.6 Equipment performance
32 - B.7 Initial and final measurements
33 - Annex C - Conversion between percentage values and dB

Provides two standard test methods (Method 1 and Method 2) for determining the ability of a specimen to withstand specified severities of broad-band random vibration.

The object of this International Standard is to provide two standard test methods (Method 1 and Method 2) for determining the ability of a specimen to withstand specified severities of broad-band random vibration. Neither test method can be considered more severe than the other, the difference being primarily that Method 2 provides more information to quantify the applied test, and is therefore more reproducible.It is also to reveal the accumulated effects of stress induced by random vibration, and the resulting mechanical weakness and degradation in specified performance and to use this information, in conjunction with the relevant specification, to assess the acceptability of specimens. In some cases, this standard may also be used to demonstrate the mechanical robustness of specimens and/or to study their dynamic behaviour.This standard is applicable to specimens which may be subjected to vibration of a stochastic nature resulting from transportation or operational environments, for example in aircraft, space vehicles and land vehicles. It is primarily intended for unpackaged specimens, and for items in their transportation container when the latter may be considered as part of the specimen itself.Although primarily intended for electrotechnical products, this standard is not restricted to them and may be used in other fields where desired.

First published as AS 60068.2.64-2003.