Integrally Bladed Rotor Damping Structure for HCF Stress Reduction
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Solution Overview
Problem
Integrally bladed rotors (IBRs) in gas turbine engines suffer from high vibratory stresses leading to High Cycle Fatigue (HCF) damage due to lack of mechanical damping, limiting their lifespan.
Innovation Solution
A damper system is integrated into the rotor blades, comprising a damper pocket and damper body with tapered configurations, along with a plug and weld collar, to provide mechanical damping and reduce vibratory stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If integrally bladed rotors are used in gas turbine engines, then the structural integrity and aerodynamic performance are improved, but high vibratory stresses lead to High Cycle Fatigue damage and reduced lifespan
Solution Approach 1:
The patent converts the harmful vibratory stresses that cause fatigue damage into beneficial damping effects. By incorporating damper bodies within damper pockets in the integrally bladed rotor structure, the system utilizes the vibrational energy itself to generate frictional forces that dissipate the harmful vibrations, transforming the harmful mechanical stress into a protective damping mechanism that extends component lifespan
2Device complexity
If traditional integrally bladed rotor design is used, then manufacturing complexity is reduced, but mechanical damping is insufficient leading to high vibratory stresses
Solution Approach 1:
The patent segments the integrally bladed rotor structure by introducing discrete damper bodies within damper pockets at strategic locations. This segmentation allows the addition of damping functionality without fundamentally changing the integral manufacturing process, as the dampers can be installed as separate components within the existing blade structure, thereby reducing vibratory stresses while maintaining manufacturing feasibility
Solution Approach 2:
The damper bodies act as intermediary elements between the vibrating blade structure and the damper pockets. These intermediaries provide the necessary mechanical damping through frictional contact, mediating the vibratory energy dissipation without requiring complex modifications to the primary integrally bladed rotor manufacturing process
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 damper system effectively reduces high vibratory stresses and HCF damage by dissipating vibrational energy, enhancing the reliability and flexibility of blade design.
Implementation Method 1
The damper body is disposed within the damper pocket, and has a second tapered configuration. The second tapered configuration of the damper body mates with the first tapered configuration of the damper pocket.
Data Source
AI summary
An integrally bladed disk is provided that includes a disk and a plurality of rotor blades. The disk has an outer radial hub and is configured for rotation around a rotational axis. Each rotor blade of the plurality of rotor blades has an airfoil that extends chordwise between a leading edge and a trailing edge, and extends spanwise between a base end and a blade tip. Each rotor blade includes a damper pocket, a damper body, and a plug. The damper pocket extends into the airfoil from the base end and has a first tapered configuration. The damper body is disposed within the damper pocket, and has a second tapered configuration. The second tapered configuration of the damper body mates with the first tapered configuration of the damper pocket. The plug is disposed to retain the damper body within the damper pocket.