Nonrectangular Band Layer Edges for Non-Pneumatic Tire Fatigue Life
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Solution Overview
Problem
Existing non-pneumatic tires are susceptible to failure from surface imperfections and have reduced fatigue life due to orthogonal axial edges in the band layer, leading to potential cracks and reduced robustness.
Innovation Solution
The band layer in the non-pneumatic tire features a nonrectangular cross-section with continuously curved or chamfered edges, combined with a surface roughness of less than 25 microns, to enhance fatigue life and reduce sensitivity to surface imperfections, using materials like ultra-high strength steel or composite materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the band layer has orthogonal axial edges with a rectangular cross-section, then the manufacturing process is simple, but the tire is susceptible to failure from surface imperfections and has reduced fatigue life
Solution Approach 1:
The band layer is designed with continuously curved edges instead of orthogonal axial edges. The edges extend along the circumferential direction and have a continuous curvature that eliminates sharp corners, thereby reducing stress concentration points and improving fatigue life while maintaining structural integrity.
Solution Approach 2:
The band layer cross-section is designed as nonrectangular with asymmetric edge geometries. The edges may be chamfered or curved with different radii on opposite sides, creating an asymmetric shape that eliminates orthogonal corners and reduces sensitivity to surface imperfections while maintaining load-bearing capacity.
2Reliability
If the band layer has a rectangular cross-section with orthogonal edges, then the manufacturing process is straightforward, but cracks propagate easily from surface imperfections
Solution Approach 1:
The edges of the band layer are formed with continuous curvature instead of sharp orthogonal corners. This curvature distributes stress more evenly and eliminates stress concentration points where cracks would initiate and propagate, thereby improving crack propagation resistance.
Solution Approach 2:
The geometry parameters of the band layer edges are changed from orthogonal (90-degree angles) to curved or chamfered configurations. This parameter change modifies the stress distribution pattern and reduces the likelihood of crack initiation and propagation from surface imperfections.
3Strength
If the band layer uses high-strength materials like ultra-high strength steel, then the load-carrying capacity increases, but the manufacturing complexity and cost increase
Solution Approach 1:
The band layer may be constructed from composite materials that combine high-strength components with more manageable materials. This allows achieving the required load-carrying capacity while improving manufacturability and reducing processing complexity compared to using solely ultra-high strength steel.
Solution Approach 2:
The material parameters are optimized to achieve the necessary strength properties. By carefully selecting material composition and mechanical properties, the band layer achieves high load-carrying capacity while maintaining reasonable manufacturability and avoiding excessive processing complexity.
Data Source
Figure 1~2
Figure 3a
Figure 3b
AI summary
A non-pneumatic tire includes an inner ring having an axis of rotation and an outer ring coaxial with the inner ring. The non-pneumatic tire further includes support structure extending from the inner ring to the outer ring and a circumferential tread extending about the outer ring. The circumferential tread includes a band layer constructed of a single material and a tread rubber layer directly attached to the band layer. The band layer has a first face and a second face opposite the first face, and a first axial edge and a second axial edge, the first and second axial edges spacing the first face from the second face. At least one of the first edge and the second edge has a geometry that provides the band layer with a nonrectangular cross section.