Multi-Strand Cable Structure for Endurance and Structural Elongation

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Solution Overview

Problem

Existing cables with a 1xN structure have a high structural elongation but lack an improved endurance criterion, particularly in applications requiring reduced shear in the polymer matrix and enhanced endurance to withstand cyclic stresses.

Innovation Solution

A multi-strand cable configuration with a single layer of multi-strands, each comprising at least two layers of metal wires wound helically, optimized for structural elongation and endurance criterion, reducing bending stress and increasing metal mass relative to cable diameter to enhance endurance performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a 1xN cable structure with single layer of strands is used, then structural elongation is improved (2.8%), but endurance criterion deteriorates (3635 N x m/g)

Engineering Contradiction:
Improvestructural elongationVSAvoidendurance criterion
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The cable is divided into multiple layers of strands (first layer, second layer, third layer) with different winding directions and pitches. Each layer contains multiple strands (e.g., 4 strands in first layer, 6 strands in second layer), creating a segmented structure that simultaneously achieves high structural elongation (≥2.5%) and improved endurance criterion (≥3800 N x m/g) by distributing stresses across multiple segments with different orientations.

Inventive Principle:
Principle #1Segmentation

2Reliability

If cable metal mass is increased to relieve tensile stresses, then endurance performance improves, but cable diameter increases

Engineering Contradiction:
Improveendurance performanceVSAvoidcable diameter
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

Different layers of strands are assigned different local qualities through varying winding pitches and directions. The first layer has pitch p1, the second layer has pitch p2, and the third layer has pitch p3, where these pitches differ to optimize local stress distribution. This allows the cable to achieve high metal mass (M/D ratio ≥ 10 kg/m²) for improved endurance while maintaining a compact diameter by optimizing the local arrangement and winding parameters of each layer.

Inventive Principle:
Principle #3Local quality

3Reliability

If bending stress is reduced to improve endurance, then cable flexibility improves, but structural integrity may deteriorate

Engineering Contradiction:
Improveendurance criterionVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The cable employs asymmetric winding configurations where odd-numbered layers (first, third) wind in one direction while even-numbered layers (second) wind in the opposite direction. The winding pitches are also asymmetric (p1, p2, p3 are different). This asymmetric multi-layer structure reduces bending stresses by distributing curvature across layers with different orientations, improving endurance while maintaining structural integrity through the balanced asymmetric configuration.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4540458B1Multi-strand cable with a multi-strand layer
Publication Date: 2026.04.15 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP4540458B1 patent drawingFigure 1
  • EP4540458B1 patent drawingFigure 2
  • EP4540458B1 patent drawingFigure 3

AI summary

The invention relates to a multi-strand cable with a multi-strand layer of structure 1 x X comprising a single layer (51) of X helically wound multi-strands (M1), each multi-strand (M1) comprising K > 1 strands (T1) helically wound around a main axis (A), each strand (T1) being a strand with at least two layers (C1, C3), with the strands (T1) being helically wound around an axis (A'). The cable (50) has an endurance criterion V1 = Δσ bending (M/D) < 3500 N x m/g. The cable (50) has a structural elongation As such that As ≥ 1.0%.