Centrifugal Compressor Fixing Bolt Vibration Resistance
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Solution Overview
Problem
Centrifugal compressors experience vibration issues due to the rotation of the rotary shaft and impellers, leading to potential damage and reduced reliability of through bolts and fixing bolts, which are weaker than other components.
Innovation Solution
A fixing bolt design with alternating large and small diameter sections corresponding to vibration modes, combined with vibration dampers, is used to reduce deflection and stress concentration, enhancing vibration resistance and preventing damage such as cracks and fractures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fixing bolt is made with uniform diameter, then the manufacturing is simple, but the vibration resistance is poor due to stress concentration at boundaries
Solution Approach 1:
The fixing bolt columnar portion is designed with varying diameter along its length, creating large diameter parts and small diameter parts at specific locations. This non-uniform structure distributes stress more effectively during vibration, preventing stress concentration at boundaries while maintaining manufacturing feasibility.
2Reliability
If the fixing bolt uses standard uniform design, then the manufacturing cost is low, but deflection occurs under vibration leading to potential damage
Solution Approach 1:
The bolt's geometric parameter (diameter) is changed along its length to create large and small diameter parts. This parameter variation optimizes the bolt's mechanical properties under vibration, reducing deflection and preventing damage while remaining manufacturable through conventional processes.
3Reliability
If the fixing bolt is designed with alternating large and small diameter parts, then the vibration resistance is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The columnar portion is segmented into multiple sections with different diameters (large diameter parts and small diameter parts). This segmentation allows each section to be optimized for its specific function while maintaining overall manufacturability through standard machining processes.
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 design effectively reduces deflection and stress concentration, improving the vibration resistance of the fixing bolt, thereby reducing the likelihood of damage and enhancing the reliability of the bolt's performance over time.
Implementation Method 1
the columnar portion includes one or more large diameter parts and a plurality of small diameter parts. The one or more large diameter parts correspond to a position of an antinode of a primary vibration mode of the fixing bolt
Implementation Method 2
strength of each of the large diameter parts and the small diameter parts is suppressed low, it is possible to reduce deflection of the columnar portion, and to suppress stress concentration to a boundary between the head portion and the columnar portion and to a boundary between the columnar portion and the threaded portion
Data Source
AI summary
A fixing bolt for a stationary member, the bolt extending through and fixing a plurality of stationary members in a multistage centrifugal compressor, includes a head portion, a columnar portion connected to the head portion, and a threaded portion connected to the columnar portion. The columnar portion includes one or more large diameter parts and a plurality of small diameter parts, the one or more large diameter parts each corresponding to a position of an antinode of a primary vibration mode of the fixing bolt for the stationary member, or to the position of the antinode of the primary vibration mode and positions of antinodes of a secondary vibration mode of the fixing bolt for the stationary member, and each of the plurality of small diameter parts having a diameter smaller than each of the large diameter parts.