Ground Whirl Flutter Testing With Full-Scale Force Loading
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Solution Overview
Problem
Current methods for predicting whirl flutter in rotorcraft, such as wind tunnel tests, face challenges due to size limitations, high costs, and the inability to accurately simulate dynamic features and nonlinear elements, leading to instability risks and flight safety concerns.
Innovation Solution
A ground whirl flutter test system and method using force loading devices and industrial control systems to simulate rotor aerodynamics and inertia forces on a full-scale rotorcraft, enabling accurate reproduction of whirl flutter phenomena without wind tunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If wind tunnel tests are used for whirl flutter testing, then aerodynamic loading can be simulated, but the test cannot be conducted on full-scale rotorcraft due to size limitations
Solution Approach 1:
The patent replaces the wind tunnel aerodynamic system with a ground-based mechanical loading system. Force loading devices equipped with load cells directly apply aerodynamic and inertia forces to the rotorcraft structure on the ground, eliminating the need for a wind tunnel environment and enabling full-scale testing.
Solution Approach 2:
The patent introduces force loading devices as intermediaries between the control system and the rotorcraft structure. These devices, equipped with load cells, serve as mediators that can apply and measure forces directly on the structure, bypassing the need for full-scale wind tunnel facilities.
2Reliability
If dynamic scaling method is used for model testing, then full-scale testing can be avoided, but dynamic features and nonlinear elements are ignored
Solution Approach 1:
The patent creates a semi-physical test system that copies the essential dynamic characteristics of full-scale rotorcraft whirl flutter without requiring geometric scaling. The force loading devices reproduce the aerodynamic and inertia forces acting on the full-scale structure, preserving all dynamic features and nonlinear elements.
Solution Approach 2:
The patent changes the testing parameters from scaled geometric models to full-scale structural parameters. By directly testing the full-scale rotorcraft structure with simulated aerodynamic and inertia forces, the system maintains accurate dynamic features without the complications of dynamic scaling laws.
3Productivity
If wind tunnel tests are conducted for whirl flutter, then aerodynamic loading can be applied, but the test cycle is long and cost is high
Solution Approach 1:
The patent replaces the complex wind tunnel system with a ground-based mechanical loading system. This substitution eliminates the need for large-scale wind tunnel facilities, reducing both the test cycle time and the economic costs associated with wind tunnel operations.
Solution Approach 2:
The test system uses industrial control computers and force loading devices that can be rapidly configured and operated. The system serves itself by directly applying forces to the full-scale structure without requiring extensive facility setup, thereby reducing test cycle time and operational costs.
Data Source
AI summary
The present invention belongs to the technical field of flutter tests for rotorcrafts, and discloses a ground whirl flutter test system and test method for a rotorcraft. The ground whirl flutter test system for the rotorcraft comprises a hardware part and a software part. The hardware part comprises a rotor test article, a support system, force loading devices, vibration signal sensors, load cells, vibration signal acquisition cards, an industrial control computer, force signal output cards, a power amplifier and load cell signal acquisition cards. The software part of the ground whirl flutter test system for the rotorcraft comprises a rotor force and moment calculation program and a multi-input multi-output force control program running on the industrial control computer. The method can reserve all dynamic characteristics of the aircraft structure, is not restricted by the size of a wind tunnel test chamber section, does not require dynamic scaling of aircraft structures.