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The Study about Load Measuring of the H425 Helicopter Transmission System

Author: LinJun
Tutor: SunZuoFeng；YangJingXin
School: Harbin Engineering University
Course: Power Engineering
Keywords: Mission spectrum Load spectrum Demarcate Flight loads
CLC: V275.1
Type: Master's thesis
Year: 2006
Downloads: 214
Quote: 1
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Abstract

The drive system is the key components of the helicopter, its main role is to pass the power generated by the engine to the rotor and tail rotor, transmission system directly affects the helicopter take-off weight, reliability and longevity. In many parts of the helicopter transmission system to withstand the flight alternating load catastrophic damage to flight safety. These parts when subjected to repeated cycles of alternating load, the fatigue verification and security of the determination of the fatigue life of these parts is the most important one of the steps in a helicopter transmission system design. Common international helicopter Transmission System Parts fatigue life calculation method is based on the assumption of linear cumulative damage or Palmgren-Miner rule-based. To apply Miner's rule, an important part profile must be two sets of data, the load spectrum and reduced the S-N curve. Helicopter transmission system load spectrum helicopter mission spectrum and transmission system based on the measured flight loads is an important basis for the calculation of the fatigue life of the drive system parts. In this paper, on the the H425 type of drive system flight load measurement project summary, research and description of the measurement method helicopter transmission system load spectrum, including content, including: 1. The helicopter mission spectra instructions mission spectrum is prepared according to the helicopter flying state or the emergence of the motor state rate spectrum. The determination of the task spectrum contains two elements: to determine flight status and determine the percentage of each state. 2. Flight load measurement technology is required in order to determine the status of each flight helicopter mission spectrum load on the transmission system must be flight load measurement. Required to carry out the relevant parts under load analysis to determine the load of the nature and magnitude, the appropriate choice of measurement method, strain gauge load measurement for helicopter transmission system. 3. Helicopter components and calibration tests and modification requirements in order to ensure real and effective measurement of flight loads measured data, round the measurement position of the load as much as possible to ensure that the position of the load measurement with the given Shou file requires measurement project to try to ensure that the flight loads measured. Installed strain gauges on the part you need in the face of the part load calibration tests to establish the forecast load and strain gauge circuit output relationship equation, in order to improve the accuracy of the load calibration tests, calibration load should be chosen to be as close as possible to the parts of the by flight load. To the strain gauge the strain signal transmission to the flight load the data acquisition devices, the appropriate modified work must helicopter. 4. Flight program and the implementation of the organization load measurement flight, formation flight strain measurement outline. Flight strain measurement outline developed by the design department, including the measurement of content, design measurement solutions, supporting measurement system, the implementation of the measurement procedures. Flight work in accordance with the implementation of the mission book. The flight test mission statement is formulated according to the outline of the flight strain measurement provisions of the test conditions (the height of the helicopter, the speed and power of the state as well as helicopter landing gear) flight tests and procedures. 5. Flight load data acquisition in flight, the helicopter transmission system parts load data real-time acquisition and recording. Real-time recording information from strain gauges mounted in the the H425 type of drive system parts on to the helicopter flight parameters. 6. Data processing and compilation spectral method introduced the rainflow pretreatment and measured load spectrum generated principle.

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CLC: > Aviation, aerospace > Aviation > Various types of aircraft > Short-range and vertical - lift aircraft > Helicopters, rotorcraft
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