Program and request for test and operation life of aeroengine bearings
1 Scope
This standard specifies the program and request for test and operation life determination of spindle bearings for military aeroengines (hereinafter referred to as "bearings").
This standard is applicable to the test and operation life determination of spindle bearings for aeroengines, as well as to those of spindle bearings for aerospace auxiliary power units (APUs) with independent system functions. It may also serve as a reference for the test and operation life determination of other aerospace bearings.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However parties using this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GJB 269 The general specification for aerospace rolling bearings
3 Terms and definitions
For the purposes of this standard, the terms and definitions given in GJB 269 and the followings apply.
3.1 bearing life determination
process of determining the operational life of an aeroengine bearing in accordance with specified program and request
3.2 leader operational life
pre-specified time for flight test evaluation of a bearing installed in an engine, in an organized and planned manner, to determine the operational life of the bearing
3.3 unconventionality
defects in a bearing, such as early damage, wear, fatigue, part failure, or significant reduction in accuracy, that render it unsuitable for continued use
3.4 failure
phenomenon where a bearing or its parts lose their specified function
3.5 bearing of retrofit manufacture
bearing of the same model used in other retrofitted engines of the same model series
3.6 bearing of select model development
bearing of the same model used in newly developed engines of other models
3.7 performance test
test conducted on a bearing test rig primarily to simulate high-speed light-load or high-speed heavy-load operating conditions of the bearing, to verify the rationality of the bearing structure and design parameters
3.8 durability test
bearing life test based on the engine's overhaul interval, conducted on a bearing test rig by simulating its main operating parameters and operational conditions in an engine, to evaluate the bearing's operational life
3.9 oil refused test
test conducted on a bearing test rig to evaluate the operating performance of the bearing under short-term lubricating oil interruption conditions, by simulating the bearing's operation during a short-term interruption of engine lubricating oil
Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
4.1 Test objective
4.2 Test items
5 Test program
5.1 Classification of bearings under development
5.2 Basic test program
5.3 Test program for independently developed bearings
5.4 Test program for reverse-engineered bearings
5.5 Test program for bearings of retrofit manufacture
5.6 Test program for bearings of select model development
5.7 Test program for bearings of transferred manufacture
6 Test requirements
6.1 General
6.2 Rig tests
6.3 Engine test runs
6.4 Flight tests
7 Bearing life determination
Program and request for test and operation life of aeroengine bearings
1 Scope
This standard specifies the program and request for test and operation life determination of spindle bearings for military aeroengines (hereinafter referred to as "bearings").
This standard is applicable to the test and operation life determination of spindle bearings for aeroengines, as well as to those of spindle bearings for aerospace auxiliary power units (APUs) with independent system functions. It may also serve as a reference for the test and operation life determination of other aerospace bearings.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However parties using this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GJB 269 The general specification for aerospace rolling bearings
3 Terms and definitions
For the purposes of this standard, the terms and definitions given in GJB 269 and the followings apply.
3.1 bearing life determination
process of determining the operational life of an aeroengine bearing in accordance with specified program and request
3.2 leader operational life
pre-specified time for flight test evaluation of a bearing installed in an engine, in an organized and planned manner, to determine the operational life of the bearing
3.3 unconventionality
defects in a bearing, such as early damage, wear, fatigue, part failure, or significant reduction in accuracy, that render it unsuitable for continued use
3.4 failure
phenomenon where a bearing or its parts lose their specified function
3.5 bearing of retrofit manufacture
bearing of the same model used in other retrofitted engines of the same model series
3.6 bearing of select model development
bearing of the same model used in newly developed engines of other models
3.7 performance test
test conducted on a bearing test rig primarily to simulate high-speed light-load or high-speed heavy-load operating conditions of the bearing, to verify the rationality of the bearing structure and design parameters
3.8 durability test
bearing life test based on the engine's overhaul interval, conducted on a bearing test rig by simulating its main operating parameters and operational conditions in an engine, to evaluate the bearing's operational life
3.9 oil refused test
test conducted on a bearing test rig to evaluate the operating performance of the bearing under short-term lubricating oil interruption conditions, by simulating the bearing's operation during a short-term interruption of engine lubricating oil
Contents of GJB 7268-2011
Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
4.1 Test objective
4.2 Test items
5 Test program
5.1 Classification of bearings under development
5.2 Basic test program
5.3 Test program for independently developed bearings
5.4 Test program for reverse-engineered bearings
5.5 Test program for bearings of retrofit manufacture
5.6 Test program for bearings of select model development
5.7 Test program for bearings of transferred manufacture
6 Test requirements
6.1 General
6.2 Rig tests
6.3 Engine test runs
6.4 Flight tests
7 Bearing life determination
