Method for testing static strength of helicopter blade

Abstract

The invention provides a method for testing static strength of a helicopter blade, wherein the method belongs to the field of helicopter blade static strength testing. The method comprises the steps of obtaining a waving and swinging calibration equation according to a direct proportion relation between a stress and a bending moment; determining a testing section; determining a plurality of wavingand swinging loads according to a preset waving and shaking bending moment and the testing section; determining each waving and swinging strain value which corresponds with the waving and shaking load; connecting a blade loading end with actuators in a centrifugal force direction, a waving direction and a swinging direction through loading joints, and applying multiple grades of load to the blade. The strain value in the invention reflects a real load bearing condition of the blade on the condition of the corresponding load. The method effectively settles a problem of difference between an actual load bearing condition and applied force load in each direction at the loading end of an actuator. The method can be widely applied to subsequent static strength testing for different types of blades.

Description

technical field [0001] The invention belongs to the field of static strength tests of helicopter blades, and relates to a test method for the static strength of helicopter blades. Background technique [0002] Helicopter development and design as a system engineering is a very complex task, and strength design, as one of the important contents of helicopter development, is often the coordination and compromise of multiple conflicting requirements. In order to ensure the strength requirements of the structure and system , usually conflicts with aerodynamic requirements, process requirements, and use requirements. The compromise solution is to select and determine the optimal solution to ensure structural strength at the cost of minimum weight under the premise of meeting the strength requirements. Rotor blades are the main source of lift for helicopters. Their strength and performance are related to the performance and safety of the entire rotor system, and even the entire ma...

AI Technical Summary

Problems solved by technology

[0003] The assessment parts of the static strength test of the blade mainly include: the root of the blade, the sleeve and the typical sections of the blade. The traditional static strength test of the blade is usually based on the load of the centrifugal force Fx, flapping load Fz and shimmy load Fy according to the test task. requires direct application of loads, such as figure 2 As shown, the test load is applied step by step in the direction of centrifugal force, flapping direction and shimmy direction of the blade. The load required for the test is the same as the load of each actuator at the test loading end. The influence of centrifugal force on flapping load and shimmy is not considered. Effect of load

However, when the blade is subjected to centrifugal force Fx, flapping load Fz, and shimmy load Fy at the same time, the blade is deformed due to the action of flapping load Fz and shimmy load Fy, resulting in a certain angle θ between the direction of centrifugal force Fx and the blade Rather than along the direction of the blade, due to the existence of the angle θ, the centrifugal force Fx will generate corresponding component forces F1 and F2 in both the waving direction and the shimmy direction, thus weakening the true force of the blade in the waving direction and the shimmy direction. Force, the real force of the blade in each direction is formed by the superposition of the load components in the direction of the load in the three directions of flapping, shimmy and centrifugal force. However, since the angle θ is unknown, the real force acting on the blade The load of the examined section is also unknown, resulting in the inconsistency between the actual load on the blade and the force load applied in all directions of the actuator, and the test did not meet the assessment requirements. Therefore, a new test method is needed to have an impact on the static strength of the blade. more accurate assessment

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