Blade Structure Testing Equipment Using Wire Tensile Force
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Solution Overview
Problem
Existing blade structure testing equipment for rotorcraft components fails to accurately apply centrifugal force and moments similar to actual operating conditions, requiring complex sensor calibrations and additional rotational boundary conditions, which complicates the testing process and reduces reliability.
Innovation Solution
A blade structure testing equipment with a mounting jig, grip member, and wire system that applies tensile force at a specific angle using a mass, allowing for rotation to simulate flap and lead-lag moments without additional sensors, utilizing a pulley to adjust load direction and magnitude, and rotating the blade specimen to apply centrifugal, flap, and lead-lag moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic actuators are used to apply load to the blade specimen, then the blade structure can be tested, but additional rotational boundary conditions are added that do not exist in actual operation, making it impossible to predict the moment accurately and requiring complex sensor calibrations
Solution Approach 1:
The patent removes the hydraulic actuators and associated rotational boundary conditions from the testing setup. Instead, it uses only gravitational force from a mass to apply load through a wire, extracting the unnecessary complex components while retaining the essential testing function. This eliminates the need for moment monitoring sensors and their calibrations.
Solution Approach 2:
The testing system uses the gravitational force of a mass to automatically generate the centrifugal force and moments on the blade specimen during rotation. The system serves itself by utilizing the natural physics of rotating a mass-loaded blade rather than requiring external hydraulic actuators to apply forces, thereby simplifying the setup and improving accuracy.
2Measurement precision
If hydraulic actuators with load cells and Wheatstone bridge constructions are used, then load can be applied and measured, but complicated calibration processes are required including calibrating the load cell and constructing and calibrating the Wheatstone bridge
Solution Approach 1:
The patent removes load cells, Wheatstone bridge constructions, and their associated calibration processes from the testing system. It replaces these complex measurement devices with a simple mass-based gravitational force system where the known mass directly provides the applied load without requiring electronic measurement or calibration.
Solution Approach 2:
The patent changes the measurement approach from electronic sensor-based measurement requiring calibration to a direct physical parameter approach where the mass value itself serves as the measurement reference. The gravitational force (F=mg) provides a naturally calibrated load without additional instrumentation.
3Adaptability or versatility
If additional rotational boundary conditions are added through hydraulic actuators, then the blade can be held stationary for testing, but the boundary conditions differ from actual operation where only fixed boundary conditions and air force act on the rotating blade
Solution Approach 1:
Instead of holding the blade stationary and applying forces through hydraulic actuators, the patent inverts the approach by rotating the blade with a fixed mass attached, allowing the centrifugal force to naturally apply the load. This inversion replicates actual operating conditions where the blade rotates under gravitational and aerodynamic forces.
Solution Approach 2:
The patent creates a simplified copy of actual operating conditions by using a mass to represent the aerodynamic forces and centrifugal effects. The rotating blade with attached mass replicates the essential physics of actual operation without requiring complex hydraulic systems to simulate the same boundary conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This setup simplifies the testing process by replicating actual operating boundary conditions using a mass, allowing for accurate application of centrifugal, lead-lag, and flap moments without sensor calibrations, enhancing the reliability of the test results.
Implementation Method 1
A mass is connected to the other end of the wire so that the tensile force is applied to the blade specimen under the load of the mass.
Implementation Method 2
Rotating the rotating member at a certain angle results in a flap moment and a lag moment being applied to the blade specimen by the wire tensile force.
Data Source
AI summary
The present invention provides blade structure testing equipment comprising: a mounting jig to which one end of a blade specimen is mounted; a grip member to which the other end of the blade specimen is coupled; and a wire (W) having one end attached to the grip member to apply a tensile force to the blade specimen in a direction at a certain angle with respect to the ground. Also, the present invention provides a method for testing a blade specimen, the method comprising: a first step of coupling one end of the blade specimen to a mounting jig and the other end of the blade specimen to a grip member; a second step of determining the values of a centrifugal force, a flap moment, and a lag moment that are to be applied to the blade specimen; a third step of determining the magnitude and direction of a tensile force to be applied to the blade specimen, on the basis of the values determined in the second step; and a fourth step of attaching one end of a wire to the grip member and applying a tensile force to the blade specimen by means of the wire at the magnitude and in the direction of the tensile force determined in the third step.