The Study About Load Measuring Of The H425 Helicopter Transmission System

The transmission system is one of the key parts in a helicopter, its main function is transferring the power that produced by the engine to the spin wing and the tail oar, the transmission system directly affect the weight of take-off, dependable and life span of the helicopter. Many parts of the transmission system endure changed loading that was happened in the fly, their breakage is disaster to fly the safety. When these parts are enduring period frequent changed loading, the fatigue verification of these parts with safe and tired life span really settle, is one of the most important steps in the transmission system's design.The international last general calculation method of the helicopter transmission system parts' tired life span is based with accumulated-linear hurts assumption or Pahngren—Miner rule. For applying the rule of Miner, two sets of data to the important section of the parts must be abtained, then the loading pedigree and the reduce S—N curve. The loading pedigree of the helicopter transmission system is based on the mission pedigree and the fact-measured loading of the helicopter transmission system, which is a importance calculation basis of the fatigue life span in the transmission system parts.In this text passes by means of summarizing the measured item of the type H425 helicopter transmission system's flight-loading, is researched and explained, the contents include: 1. Helicopter mission pedigree elucidationMission pedigree is the pedigree that the emergence rate between the helicopter's flight appearance or monueveribility, The mission pedigree really settles containment two contents: Flight appearances and to make sure the percentage of each appearance.2. The meaning technique the request of fly-loadingFor the sake knowing of certain helicopter mission pedigree each flight appearance loading, the helicopter transmission system must be measured .Need to analysis to the concerning components, make sure the kinds and class of the loading, choose the measured method, adopt to adapt to changes to account the method to the helicopter transmission system proceeds to measured the loading.3. The experimentation of demarcated components and the request of refitFor guaranteeing the flight-loading fact measured data that get true and valid, request to be in flight-loading fact measuring to guarantee the measured item as far as possible completely, the position of loading to guarantee as far as possible accordance with settle the life document request of the position which for measured the loading .After fixing the strain gauge on the parts, need to proceed to the experimentation of demarcated components' loading, build the equation of the forecast loading and the output of the strain gauge circuit, for improving the precision that is the experimentation of demarcated components' loading, choosing the demarcated components' loading must as possible as approach the components' flight-loading. For transferring the signal which in the strain gauge to the flight-loading data collected-equipments, must proceed to refit the helicopter.4. Flight project and actualizingOrganize the loading to measure the flight, formation the outline of the corresponding-altered measuring .The outline is established by the designing section, the contents includes the design measures the project, kit measure system, put diagraph step etc.The flight work according to the flight mission book puts into practice .The flight experiment mission book established by the outline of the corresponding-altered measuring, ruled the flight experimentation condition (the high degree of the helicopter, speed, power and the estate of the helicopter undercarriage) and the program.5. The collection of flight-loading dataIn-flight, want to collect and note the data of the helicopter transmission system parts' loading in time. From install at the H425 type helicopter transmission system parts strain gauge, we get the lots of information which record the helicopter's flight-parameter in time.6. The handles of the data and the method of organize pedigreeIntroducing prepare handle to rain-flow and the principle of the fact loading pedigree's building.