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GB/T 9239.31-2023: Mechanical vibration - Rotor balancing - Part 31: Susceptibility and sensitivity of machines to unbalance
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| GB/T 9239.31-2023 | English | 444 |
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Mechanical vibration - Rotor balancing - Part 31: Susceptibility and sensitivity of machines to unbalance
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GB/T 9239.31-2023
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Basic data | Standard ID | GB/T 9239.31-2023 (GB/T9239.31-2023) | | Description (Translated English) | Mechanical vibration - Rotor balancing - Part 31: Susceptibility and sensitivity of machines to unbalance | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | J04 | | Classification of International Standard | 21.120.40 | | Word Count Estimation | 24,238 | | Date of Issue | 2023-05-23 | | Date of Implementation | 2023-12-01 | | Older Standard (superseded by this standard) | GB/T 19874-2005 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | GB/T 9239.31-2023: Mechanical vibration - Rotor balancing - Part 31: Susceptibility and sensitivity of machines to unbalance
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ICS21:120:40
CCSJ04
National Standards of People's Republic of China
GB/T 9239:31-2023/ISO 21940-31:2013
Replacing GB/T 19874-2005
Mechanical Vibration Rotor Balancing Part 31:
Machine imbalance variability and imbalance sensitivity
Mechanical vibration-Rotorbalancing-
(ISO 21940-31:2013, IDT)
Released on 2023-05-23
2023-12-01 implementation
State Administration for Market Regulation
Released by the National Standardization Management Committee
table of contents
Preface III
Introduction IV
1 Scope 1
2 Normative references 1
3 Terms and Definitions 1
4 Classification of Machine Variability 1
5 Mode Shape Sensitivity2
6 Experimental determination of vibration mode sensitivity close to a certain resonance speed in running state8
7 Numerical value of local sensitivity 10
8 Experimental determination of local sensitivity 11
9 Sensitivity Analysis of Damped Unbalance 11
Appendix A (Informative) Explanation of Terms 12
Appendix B (Informative) Polar Coordinate (Nyquist) Plot Method Example 14
Appendix C (Informative) Example 15 Classified by Mode Shape Sensitivity
Appendix D (informative) Examples of mathematical models for unbalance16
Reference 17
foreword
This document is in accordance with the provisions of GB/T 1:1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules for Standardization Documents"
drafting:
This document is part 31 of GB/T 9239 "Rotor Balance for Mechanical Vibration": GB/T 9239 has issued the following parts:
--- Part 12: Balance methods and tolerances for rotors with flexible characteristics;
--- Part 13: Criteria and safety protection for on-site balancing of large and medium-sized rotors;
--- Part 14: Evaluation procedures for balance errors;
--- Part 21: Description and evaluation of balancing machines;
--- Part 31: Machine unbalance variability and unbalance sensitivity;
--- Part 32: Key criteria for shaft and mating balance:
This document replaces GB/T 19874-2005 "Mechanical Vibration Machine Unbalance Sensitivity and Unbalance Sensitivity", and
Compared with GB/T 19874-2005, except for structural adjustment and editorial changes, the main technical changes are as follows:
--- Increased machine variability correction factor (see 4:5);
--- Increased mode shape sensitivity value (see 5:4);
--- Increased the working speed (see 5:5);
--- Increased transient speed (see 5:6);
--- Deleted Figure 1 (see Figure 1 of the:2005 edition);
--- Deleted the accelerated rotation of the rotor (see 5:3 of the:2005 edition):
This document is equivalent to ISO 21940-31:2013 "Mechanical Vibration Rotor Balance Part 31: Machine Unbalance Variability and Unevenness
Balancing Sensitivity":
Please note that some contents of this document may refer to patents: The issuing agency of this document assumes no responsibility for identifying patents:
This document is proposed and managed by the National Mechanical Vibration, Shock and Condition Monitoring Standardization Technical Committee (SAC/TC53):
This document is drafted by: Zhengzhou Machinery Research Institute Co:, Ltd:, China Southern Power Grid Electric Power Technology Co:, Ltd:, Henan Jiuyu Enpai Electric Power
Technology Co:, Ltd:, Shanghai Power Generation Equipment Complete Design and Research Institute Co:, Ltd:, Dongfang Electric Group Dongfang Electric Co:, Ltd:, Guangzhou
Deshan CNC Technology Co:, Ltd:
The main drafters of this document: Huang Runhua, Ma Weiping, Liu Shi, Wang Jianhua, Li Wangfan, Chen Changlin, Luo Yingxue, Yang Yi, Guo Yujie:
The previous versions of the documents replaced by this document are as follows:
---GB/T 19874, first released in:2005:
Introduction
Vibration caused by rotor unbalance is one of the most critical issues in the design and maintenance of rotating machinery: The dynamic forces it generates will have an impact on the machine and
adverse effects on human health and safety:
Balancing is the process of checking the mass distribution of a rotor and, if necessary, correcting it so that the remaining unbalance, or
Vibration, or the process in which the forces on a bearing are within specified limits:
GB/T 9239 "Mechanical Vibration Rotor Balance" explains balance in a general way, uses specific terms and definitions, and helps users choose
Choose the appropriate balancing method and provide guidance for the application of balancing techniques: Contains most of the standards in the field of balance, grouped into five main areas:
Introduction, vocabulary, balancing methods and tolerances, balancing machines, and mechanical design for balancing, are intended to consist of the following parts:
--- Part 1: Introduction: The purpose is to give the general background of the use of balancing technology in the GB/T 9239 series of documents, and to guide
The user understands the corresponding part of the series, including vocabulary, balancing methods and tolerances, balancing machines and mechanical design for balancing:
--- Part 2: Vocabulary: The purpose is to define the vocabulary used for balancing, giving an alphabetical index of the balancing vocabulary and a diagram of the balancing machine term
solution guide:
--- Part 11: Balance methods and tolerances for rotors with rigid characteristics: The aim is to give a balancing method for rigid rotors and
Tolerance: It specifies the allowable value of residual unbalance, the necessary number of correction surfaces, the allocation of residual unbalance tolerances of correction surfaces and how
How to account for errors in the balancing process:
--- Part 12: Balance methods and tolerances for rotors with flexible characteristics: The purpose is to give a balancing method for flexible rotors and
Tolerance: The typical structural forms of flexible rotors are given, the balance requirements according to their own characteristics are specified, and the balance methods are listed:
method, provides a method for assessing the final state of equilibrium and gives guidance on tolerances for unbalance:
--- Part 13: Criteria and safety protection for on-site balancing of large and medium-sized rotors: The purpose is to give large and medium-sized rotors in their own bearings
The procedure for in-field balancing: Describes the conditions suitable for on-site balancing, the required instruments, the contents of safety measures, reports and
Requirements for maintaining records:
--- Part 14: Evaluation procedures for balance errors: The purpose is to give a procedure for evaluating the balance error and to specify the rotor
Requirements for the identification of errors during balance measurements, the evaluation of identified errors and the consideration of errors in the determination of residual unbalance:
--- Part 21: Description and evaluation of balancing machines: The purpose is to give the requirements for the performance evaluation of the balancing machine:
--- Part 23: Balancing machine guards and other protective measures for measuring stations: The purpose is to give balancing machine shields and other protection
Requirements for protective measures, define the different levels of protection provided by protective covers and other protective measures, and give the application of each level of protection
scope:
--- Part 31: Machine unbalance variability and unbalance sensitivity: The purpose is to give the determination of machine vibration sensitive to unbalance
It provides a method for evaluating vibration sensitivity considering that the resonant speed is close to the operating speed:
--- Part 32: Key criteria for shaft and mating balance: The purpose is to give a keyed rotor assembly when the individual components are balanced
the only criterion:
Mechanical Vibration Rotor Balancing Part 31:
Machine imbalance variability and imbalance sensitivity
1 Scope
This document describes a method for determining the sensitivity of a machine to vibration to unbalance, and for this sensitivity (which is the relation between resonant speed and operating speed)
function of speed proximity), providing evaluation guidelines: This document focuses only on fundamental frequency vibrations caused by unbalance and shows how to convert sensitive
Degree values are recommended for use in some special cases:
This document includes a classification system for classifying machines according to their unbalanced variability: Divide machines into three categories by variability
Type, divided into five ranges according to sensitivity: This sensitivity value is intended for simple mechanical systems, where the rotor is preferably only
There is a resonant speed: These sensitivity values can also be used for machines with multiple resonant speeds in the operating speed range, but these resonant speeds are required
The speeds are far apart from each other (for example, more than 20% apart):
These sensitivity values given are not intended to be used as acceptance criteria for any type of machine, but rather as an indication of how to avoid oversized defects or avoid
Guidelines for avoiding excessive, unattainable requirements: It can also be used as the basis for more related investigations, for example, in some specific cases it may be necessary to
To determine the sensitivity more accurately: If due consideration is given to the sensitivity values given, the machine is expected to perform satisfactorily in most cases
run:
Considering only the sensitivity value does not guarantee that the vibration will not exceed the given vibration limit during operation, many other vibration sources may also cause vibration:
activities, but these are beyond the scope of this document:
2 Normative references
The contents of the following documents constitute the essential provisions of this document through normative references in the text: Among them, dated references
For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to
this document:
Part 2:Vocabulary)
Note: GB/T 6444-2008 Mechanical Vibration Balance Vocabulary (ISO 1925:2001, IDT)
3 Terms and Definitions
The terms and definitions defined in ISO 21940-2 apply to this document:
Note: Some terms used are explained in Appendix A:
4 Classification of Machine Variability
4:1 General
Machine variability is classified in terms of the probability that a machine will experience significant unbalanced changes in operation: Machines with low variability allow for
Higher sensitivity (requiring less damping), while machines with high variability are limited to lower sensitivity (requiring greater damping):
4:2 Class I: low variability
Such machines have a low probability of experiencing significant unbalance changes during operation: Typically, the mass of the rotor is larger than the mass of the support, and the
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