Sheave Structured Web Design for Buckling Resistance
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Solution Overview
Problem
Large sheaves used in material handling systems face issues with buckling due to compressive forces, leading to weight inefficiencies and potential fatigue, especially as sizes increase.
Innovation Solution
A sheave design featuring a structured web with profiles such as wavy, corrugated, or staggered sections that increase the section modulus, allowing for a thinner web thickness while maintaining strength, thereby reducing weight and rotational inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the web thickness is increased to resist compressive forces and prevent buckling, then the strength and stability of the sheave is improved, but the weight of the sheave increases
Solution Approach 1:
The web is formed with a corrugated profile featuring curved wave patterns instead of a flat structure. This curvature increases the section modulus and moment of inertia, allowing the web to better resist compressive forces and prevent buckling while maintaining a thinner overall thickness, thereby reducing weight without sacrificing strength
Solution Approach 2:
The web transitions from a two-dimensional flat plate to a three-dimensional corrugated structure with varying thickness and profile. This dimensional change adds structural complexity in the radial direction, creating regions of increased material concentration where stresses are highest, which improves load-bearing capacity while keeping the average web thickness reduced
2Stability of the object's composition
If the web thickness is increased to prevent buckling under compressive forces, then the stability of the sheave is improved, but the rotational inertia increases making rotation more difficult
Solution Approach 1:
The corrugated web profile with its curved wave patterns increases the moment of inertia about the rotational axis, enhancing buckling resistance and structural stability. This curved geometry allows the web to maintain stability under compressive loads while the optimized amplitude and wavelength of the corrugations control the added mass distribution, minimizing the increase in rotational inertia
Solution Approach 2:
The corrugated profile creates local variations in web thickness and material distribution, concentrating material where compressive stresses are highest (near the hub and outer rim) while reducing material in intermediate regions. This non-uniform quality distribution optimizes stability where needed while minimizing overall weight and rotational inertia
3Stress or pressure
If a thicker web is used to handle large sheave sizes, then the resistance to bending stresses is improved, but the weight and material usage increase
Solution Approach 1:
The corrugated web profile with its characteristic wave pattern increases the section modulus and moment of inertia, providing enhanced resistance to bending stresses. The curved geometry creates a more efficient structural form that distributes bending loads more effectively across the web, allowing for reduced material usage while maintaining or improving bending strength
Solution Approach 2:
The corrugated profile effectively segments the web into a series of connected arches or ribs that work together to resist bending loads. This segmentation creates multiple load paths and distributes stresses more evenly throughout the structure, improving bending resistance while using less material than a solid thick web would require
Data Source
AI summary
A sheave may include a body portion with a circular circumference and defining a center plane, a bore extending through the body portion and configured for receiving a shaft and allowing the body portion to rotate in the center plane, and a rope groove arranged on the circular circumference, wherein, the body portion comprises a structured profile.