Two-Layer Multi-Strand Cable Structure for Puncture-Resistant Tires
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Solution Overview
Problem
Existing tire cables are prone to punctures and breaks due to perforations and deformations when encountering obstacles, leading to reduced lifespan and performance.
Innovation Solution
A two-layer, multi-strand cable design with specific wire configurations and geometric properties to enhance surface breaking energy, including an inner layer of 2-4 internal metallic wires and an outer layer of 3-layer strands with optimized contact angles and helix angles, resulting in improved tensile strength and resistance to embrittlement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional cable designs are used, then manufacturing simplicity is maintained, but the cable exhibits low surface breaking energy and is prone to punctures and breaks
Solution Approach 1:
The cable is divided into multiple independent strands (inner strands and outer strands), each with its own two-layer or three-layer wire configuration. This segmentation allows each strand to independently absorb and distribute stress, preventing catastrophic failure and increasing overall surface breaking energy while maintaining manageable structural complexity through modular design
Solution Approach 2:
The cable employs a nested multi-layer structure where inner layers of wires are surrounded by outer layers, which are in turn surrounded by strands. This nested arrangement (wires within strands, strands within cable) creates a hierarchical structure that maximizes surface breaking energy by ensuring that energy is distributed through multiple concentric layers, each contributing to the overall strength
2Strength
If cable breaking force is increased, then puncture resistance improves, but the cable becomes more susceptible to embrittlement at inter-wire contacts
Solution Approach 1:
The patent applies different wire diameters (d1, d2, d3) to different positions within the cable structure. Inner wires have different dimensions than outer wires, creating local variations in mechanical properties. This local quality optimization ensures that contact points between wires have enhanced strength and reduced stress concentration, thereby reducing embrittlement while maintaining high breaking force
Solution Approach 2:
The invention systematically varies critical parameters including wire diameters (d1, d2, d3), contact angles (αf), and helix angles (αt) to optimize performance. By adjusting these parameters, the cable achieves a balance between high breaking force and reduced embrittlement, as the optimized geometric parameters minimize stress concentration at inter-wire contacts while maximizing overall structural strength
3Strength
If more outer metal wires are added to increase breaking strength, then puncture resistance improves, but the cable weakening coefficient increases due to more contact points
Solution Approach 1:
The patent optimizes the diameter parameter d3 of outer metal wires to achieve the optimal balance between breaking strength and cable weakening. By carefully selecting d3 and the contact angle αf, the design maximizes the contribution of outer wires to breaking strength while minimizing the weakening effect at contact points, thereby increasing breaking strength without proportionally increasing cable weakening
Data Source
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AI summary
The invention relates to a multi-strand cable (50) comprising a cable core (Cl) consisting of K=1 inner strand (Tl) that has two plies (C1, C3), wherein the inner ply (C1) consists of Q inner metal wires (F1) and the outer ply (C3) consists of N outer metal wires (F3), and an outer layer (CE) of the cable consisting of L>1 outer strands (TE) that have three plies (C1', C2', C3') and are wound around the cable core (Cl), wherein the inner ply (C1') consists of Q' inner metal wires (F1'), the intermediate ply (C2') consists of M' intermediate metal wires (F2') and the outer ply (C3') consists of N' outer metal wires (F3'). The cable (50) has a fracture surface energy ES > 155 N.mm-1, where ES = (a), where (b) is the sum of the forces at break for Ne wires, (c) is the sum of the total elongation of the Nc wires, Cfrag is the embrittlement coefficient of the cable (50), and D is the diameter of the cable (50).