Bladed Rotor Disk Rim Isogrid Pattern Vibration Control
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Solution Overview
Problem
Gas turbine rotor disks experience high vibrational stresses due to coupled vibratory modes, which are challenging to address without increasing the weight of the rotor, especially when tuning vibratory modes to be higher than typical engine operation frequencies, given size constraints.
Innovation Solution
The implementation of an isogrid pattern with geometric intrusions and stiffening ribs on the rotor rim surface, allowing for localized tuning of vibratory modes with minimal weight addition, by varying the depth, cross-sectional area, and corner angles of the intrusions to specifically target and reduce vibrational bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor disk weight is increased to tune vibratory modes higher than engine operation frequencies, then the vibrational stresses are reduced, but the rotor size exceeds acceptable constraints
Solution Approach 1:
The patent applies local quality by implementing non-uniform geometric intrusions (dimples) at specific locations on the rotor disk surface rather than uniform distribution. The intrusions have varying depths, patterns, and densities in different regions to locally tune vibratory modes and reduce stresses at critical areas without adding weight across the entire rotor disk.
Solution Approach 2:
The patent changes physical parameters of the rotor disk by introducing geometric intrusions with specific dimensions, depths, and distributions. These parameter modifications alter the stiffness and mass distribution locally, enabling tuning of vibratory modes to avoid resonance with engine operation frequencies without significantly increasing overall weight.
2Reliability
If geometric intrusions are added to tune specific vibratory modes, then localized vibration control is achieved, but the structural complexity of the rotor rim increases
Solution Approach 1:
The patent segments the rotor rim surface into multiple zones with different intrusion patterns, depths, and geometries. Each segment is designed to address specific vibratory modes or stress concentrations, allowing targeted vibration control while maintaining manufacturing feasibility through modular design approaches.
Data Source
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Figure 2B
AI summary
A rotor disk (200) includes a ring shaped rotor body (240) defining a radially inward opening. Rims (220) protrude radially outward from the rotor body (240), and outwardly facing rotor blade retention slots are defined between circumferentially adjacent rims (220). Each slot is operable to receive and retain a corresponding rotor blade, and each rim (220) of the rims includes an anti-vibratory feature (260). The anti-vibratory feature (260) includes a structure defining an isogrid pattern intruding into a surface of the rim (220).