Variable-Lattice Turbomachinery Shaft for Stress and Deflection Control
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Solution Overview
Problem
Traditional rotating shafts for cabin air compressors in aircraft environmental control systems suffer from high stress, strain, and deflection, leading to increased failure rates and reduced efficiency due to their solid cross-sections and manufacturing processes.
Innovation Solution
The use of a rotating shaft with a variable lattice structure manufactured via additive manufacturing, which varies in density to optimize mechanical properties locally, reducing stress and strain in high-stress regions and deflection regions, thereby enhancing stiffness and reducing failure rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional solid cross-section shafts are used, then manufacturing simplicity is maintained, but stress, strain, and deflection increase leading to higher failure rates
Solution Approach 1:
The shaft employs a variable lattice structure where the lattice density varies along the length of the shaft. Regions experiencing higher stress or deflection have denser lattice structures, while regions with lower stress have sparser lattices. This local variation in structural density optimizes mechanical properties at each specific location, reducing overall stress and deflection while maintaining manufacturing efficiency through additive manufacturing.
2Strength
If variable lattice density is implemented, then stress and deflection are reduced, but manufacturing complexity increases
Solution Approach 1:
The invention changes the structural parameter of the shaft by implementing a variable lattice density distribution along its length. This parameter change allows the shaft to achieve optimized stiffness and strength characteristics in different regions, reducing stress and deflection. The additive manufacturing process enables this complex variable geometry to be produced efficiently, transforming a previously difficult-to-manufacture structure into one that can be created through digital modeling and layer-by-layer fabrication.
3Weight of moving object
If solid shaft sections are used, then manufacturing simplicity is maintained, but weight increases
Solution Approach 1:
The shaft is segmented into multiple regions along its length, with each region having a different lattice density. This segmentation allows the structure to be divided into functional zones that can be independently optimized for weight and strength requirements. The additive manufacturing process creates these segmented lattice structures by varying the lattice parameters in different build zones, achieving weight reduction while maintaining the precision needed for the specific application.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A rotating shaft for a rotary machine includes a first shaft portion (118) centered on a central axis (A) and a variable lattice structure (142) in an interior of the rotating shaft. The variable lattice structure includes a first region (150) of the rotating shaft having a first lattice structure and a second region (152) of the rotating shaft having a second lattice structure. The second lattice structure of the second region is denser than the first lattice structure of the first region. The second region is a deflection region or a stress region of the rotating shaft.