Barrel Nut Stress Reduction Grooves for High-Tensile Load Cracking
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Solution Overview
Problem
Barrel nuts used in high-tensile applications, such as aerospace and automobile industries, often crack under heavy loads due to tensile stresses around the threaded hole, necessitating larger diameter bolts and costly re-designs of mounting structures.
Innovation Solution
The improved barrel nut features a partial-cylindrical body with grooves on its planar end surfaces and a flange surrounding the threaded bore, designed to reduce stress concentrations by redistributing peak stresses away from the threaded area, using materials like nickel alloy and applying a solid film lubricant to prevent galling and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard barrel nut design is used in high-tensile applications, then the structure is simple and manufacturing is easy, but the barrel nut cracks under heavy loads due to tensile stresses around the threaded hole
Solution Approach 1:
The patent applies local quality by adding stress reduction features (such as relief grooves or notches) specifically at the threaded hole area where tensile stresses concentrate. This localized modification improves strength at the critical stress point without requiring complex changes to the entire barrel nut structure, thereby resolving the contradiction between strength and structural simplicity.
2Strength
If larger diameter bolts and barrel nuts are used to accommodate heavy loads, then the barrel nut can withstand higher stresses, but the mounting structures require expensive re-design
Solution Approach 1:
The patent changes the geometric parameters of the barrel nut by introducing stress reduction features such as relief grooves, notches, or modified thread profiles. These parameter changes allow the barrel nut to withstand higher loads without increasing the overall diameter, thereby maintaining compatibility with existing mounting structures and avoiding expensive re-design while still achieving the required load capacity.
3Reliability
If the barrel nut is subjected to vibration and heavy loads, then the preload fluctuates causing the nut to become loose or fail, but adding locking mechanisms increases complexity
Solution Approach 1:
The patent applies beforehand cushioning by incorporating stress reduction features that preemptively mitigate the effects of vibration-induced preload fluctuations. These features (such as relief grooves or compliant elements) absorb or dampen stress variations before they can cause the nut to become loose or fail, thereby improving reliability under vibration without adding complex locking mechanisms.
Data Source
AI summary
A barrel nut with features for reducing tensile stresses under heavy load within the barrel nut has a partial-cylindrical body having a first planar end surface and a second planar end surface. A threaded bore extends through the partial-cylindrical body with a central axis substantially parallel to the first planar end surface and the second planar end surface. At least one groove is formed in each of the first planar end surface and the second planar end surface, the groove having a rounded surface extending at least a part of a distance between a curved upper surface of the partial-cylindrical body to a bottom surface thereof in a direction substantially parallel to the central axis of the threaded bore.