Overbraided Carbon Fiber Tension Members for Ultra-High-Rise Elevators
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Solution Overview
Problem
Conventional steel cables are limited to hoisting heights of approximately 700 meters, making them inadequate for modern architectural designs exceeding 1 kilometer, necessitating the development of more advanced tension members with higher specific strength and lighter weight.
Innovation Solution
The use of carbon fiber tension elements with a core of unidirectionally arranged load-carrying fibers in a matrix material, surrounded by a braided or woven outer layer, and embedded within an elastomer belt or cable, providing enhanced strength and flexibility for high-rise elevator systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional steel cable is used, then the cable can support the elevator car, but the cable becomes too heavy and limited to rises of only ~700m
Solution Approach 1:
The patent employs composite materials by combining carbon fiber tension elements with an elastomer matrix to create a tension member that achieves superior strength-to-weight ratio. The carbon fiber provides high tensile strength while the elastomer matrix binds the fibers and provides flexibility, enabling the cable to support elevator cars in high-rise buildings exceeding 700m without excessive weight
Solution Approach 2:
The patent changes the material parameters from conventional steel to carbon fiber reinforced elastomer composite, fundamentally altering the density and strength characteristics. This parameter change enables the tension member to achieve the necessary load-bearing capacity for ultra-high-rise buildings while maintaining a significantly lower weight compared to steel cables
2Strength
If unidirectional fibers are arranged in a rigid matrix composite, then the fibers provide high strength, but the structure lacks flexibility for traction
Solution Approach 1:
The patent changes the matrix material from rigid thermosetting resin to flexible elastomer, fundamentally altering the mechanical properties of the composite. This parameter change enables the tension member to maintain high tensile strength from the carbon fiber while gaining the flexibility and elasticity needed for traction operations and interaction with sheave surfaces
Solution Approach 2:
The patent creates a composite material system where carbon fiber tension elements are embedded in an elastomer matrix. The carbon fiber provides the necessary tensile strength, while the elastomer matrix provides flexibility, elasticity, and traction properties, achieving a balance between strength and operational flexibility that neither material could provide alone
Data Source
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AI summary
A tension member for a lifting and/or hoisting system includes a core including a plurality of load carrying fibers arranged in a matrix material, and an outer layer secured to the core including a plurality of outer fibers arranged around a perimeter of the core. The outer layer includes one or more outer fibers arranged off-axis relative to the load carrying fibers of the core. A method of forming a tension member for an elevator system includes arranging a plurality of load carrying fibers along a length of the tension member, retaining the plurality of load carrying fibers in a matrix material to define a core, and enclosing the core in an outer layer including a plurality of outer fibers arranged around a perimeter of the core. The outer layer includes one or more outer fibers arranged off-axis relative to the load carrying fibers of the core.