Testing Technique Of Strain Gauge Applicated In The Aero-engine And Helicopter Transmission System

According to related standards, tens of static tests and fatigue tests are compulsory in aero-engine and transmission system research for increasing fatigue life, reliability and maintainability. Strain measurement and analysis of reliability and maintainability of the loads of the parts which are the fundaments of the experiments play an important role in helicopter flight test.The strength of parts or assembly which is complex in structure and bearing multiple loads in aero-engine or helicopter transmission system (HTS) is crucial to the safety of flight. Therefore, it is significant for fatigue life management and optimization of prototype that the life of parts in flight test comes from the load spectrums in flight and fatigue life of tests. To achieve this goal, Strain measurement and analysis should be seriously taken.Test and analysis is difficult because of all kinds of parts with complex structure and variable loads. An effective method should be applied to test and analysis guaranteeing their correctness and accuracy. This thesis focuses on the methods of strain measurement of important parts in aero-engine or HTS.It is discussed that corrected strain data in the use of standard gauge install method and advanced protect technique, utilization of the Wheatstone bridge, all kinds of correction methods of gauge sensitivity, relationship between load and strain as well as stress, strain and real load of parts results from all kinds of strain bridges, life of parts results from four-parameter S-N curve and data from fatigue test and flight test.Strain measurement is widely applied in load condition measurement of aero-engine or HTS; stress distribution and stress concentration analysis of local area; strength design supported by strain data contrast prototype to upgraded type; rationality and correctness check of design contrast test to simulation; life management of parts supported by flight load spectrum from flight test and data from fatigue test.