Nuclear Reactor Head Lifting Shackle Stress Reduction
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Solution Overview
Problem
Nuclear reactors with increased earthquake acceleration and heavier reactor heads require a shackle design that reduces weight while maintaining lifting ability, as existing shackles are inefficient and prone to stress concentration.
Innovation Solution
A lifting shackle with parallel members of constant thickness and length, featuring stress reduction portions and connection units with optimized curvature and angle configurations to minimize bending stress, coupled to a tripod assembly for adjustable support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the shackle weight is decreased to meet earthquake acceleration requirements, then the lifting ability and stress resistance deteriorate
Solution Approach 1:
The patent applies curvature by forming stress reduction portions with curved surfaces at the connection member and member interfaces. These curved transitions replace sharp corners with smooth radii, distributing stress more evenly and preventing stress concentration while maintaining structural strength with reduced material usage.
Solution Approach 2:
The patent implements local quality by creating stress reduction portions only at specific high-stress areas (connection member interfaces and member connection points) rather than uniformly thickening the entire shackle. This localized reinforcement maintains overall weight reduction while providing targeted strength where needed.
2Weight of moving object
If the shackle design is optimized for weight reduction, then the stress concentration increases at connection points
Solution Approach 1:
The patent directly addresses stress concentration by forming stress reduction portions with curved surfaces at all connection points between members and the connection member. These curved transitions distribute loads evenly and eliminate stress concentration points that would otherwise occur at sharp corners or abrupt geometry changes.
Solution Approach 2:
The patent changes geometric parameters by optimizing the curvature radius and shape of stress reduction portions through finite element analysis. This parameter optimization ensures minimum stress concentration while maintaining weight reduction goals, balancing structural integrity with weight efficiency.
Data Source
AI summary
A lifting shackle of a head assembly for a nuclear reactor according to one embodiment of the present invention comprises: a first member and a second member which extend in parallel to each other in a predetermined thickness and length and respectively have an upper portion and a lower portion; a first connection member which connects the upper portion of the first member and the upper portion of the second member to each other and is coupled to a hook; coupling sections which are respectively provided at the lower portions of the first member and the second members and has a hollow portion so as to be coupled to the head assembly for a nuclear reactor via pins; and stress reducing sections which are formed at the upper portions of the first member and the second member such that the stress reducing sections extend from the first connection member to the first member and the side end of the second member at a predetermined curvature and protrudes upwards so as to reduce bending stress that is applied to the first connection member.