Rotor Blade Vibration Jig Centrifugal Load Simulation
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Solution Overview
Problem
Conventional vibration testing devices for rotor blades in aircraft engines fail to apply a load equivalent to centrifugal force, limiting the amplitude of vibration and thus the evaluation of high cycle fatigue characteristics, which can lead to incomplete testing and potential failure to detect high cycle fatigue failure.
Innovation Solution
A jig for vibration testing that includes a jig body holding the rotor blade's dovetail portion and a force applying section to simulate centrifugal force, allowing the rotor blade to be excited at large amplitudes by an electromagnetic shaker, thereby reaching the deformation region where high cycle fatigue failure occurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional fatigue testing device uses pulsed air to collide with the rotor blade surface, then the blade can be excited, but the deformation amount is limited and air cannot be applied perpendicularly to the blade surface at large amplitudes
Solution Approach 1:
The patent replaces the conventional pulsed air collision method with an electromagnetic shaker system. The shaker directly applies mechanical vibration forces to the rotor blade through a specialized jig, enabling controlled large-amplitude vibrations without the limitations of air pulse methods. This substitution allows the blade to be excited to larger deformations while maintaining perpendicular force application.
2Force
If the rotor blade is excited to large amplitudes without applying centrifugal force, then the vibration amplitude increases, but the test does not simulate actual operation conditions
Solution Approach 1:
The patent merges two previously separate testing approaches into one integrated system. The jig simultaneously applies centrifugal force through the force applying section (simulating operation conditions) and transmits vibration from the electromagnetic shaker (achieving large amplitudes). This combination allows the blade to vibrate at large amplitudes while under centrifugal load, accurately simulating actual engine operation conditions during high cycle fatigue testing.
3Device complexity
If a conventional fixing jig is used without force applying section, then the setup is simpler, but it cannot apply load equivalent to centrifugal force
Solution Approach 1:
The patent introduces dynamic load application capability to the fixing jig through the force applying section. This section includes movable components that can apply and adjust centrifugal force dynamically during the vibration test. The force applying section works in conjunction with the electromagnetic shaker to create a dynamic testing environment that simulates actual operation conditions, transforming the static fixing jig into a dynamic testing system capable of applying realistic loads.
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
The jig enables a vibration test that simulates actual operating conditions, efficiently exciting the rotor blade to reach large deformation regions, ensuring comprehensive evaluation of high cycle fatigue characteristics and preventing test failures.
Implementation Method 1
an electromagnetic shaker, and a jig for the vibration test of the rotor blade
Implementation Method 2
the force applying section applies, to the dovetail portion of the rotor blade, the load equivalent to a centrifugal force in the span direction
Data Source
AI summary
Provided is a jig for a vibration test of a rotor blade, for use in the vibration test for evaluating high cycle fatigue characteristics of the rotor blade for an aircraft engine, and the jig is provided with a jig body holding a dovetail portion of a fan blade and fixed onto an excitation table of a shaker, and a hydraulic jack that applies a load in a blade span direction to the fan blade to fix the fan blade to the jig body. Consequently, in the vibration test for evaluating the high cycle fatigue characteristics of the rotor blade, a test simulating an actual operation state can be carried out, the rotor blade can be efficiently excited to reach a large deformation region, and high cycle fatigue failure can occur without any increase in test cost.