Hybrid Rope Copolyester Elastomer Coating Fatigue Resistance
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Solution Overview
Problem
Hybrid ropes with fiber cores, especially those under high stress or low bending radius conditions, face issues with abrasion and fatigue due to the extruded plastomer coating deteriorating and being pressed out between steel wire strands, leading to reduced performance and lifespan.
Innovation Solution
A hybrid rope design featuring a core element made of synthetic fibers coated with a copolyester elastomer containing soft blocks, which forms a hard transition layer between the core and metallic outer layer, enhancing fatigue resistance and preventing the coated material from flowing during use, while maintaining compatibility with both the fiber core and metallic layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If extruded plastomer coating is used on the fiber core, then abrasion resistance is improved, but the coating deteriorates and is pressed out between steel wire strands under high stress or low bending radius conditions
Solution Approach 1:
The patent changes the material parameters of the coating from conventional plastomer to copolyester elastomer with specific soft block content (10-70 wt%), achieving optimal balance between hardness and flexibility. This parameter optimization prevents the coating from being pressed out while maintaining abrasion resistance, resolving the contradiction between coating protection and structural stability.
Solution Approach 2:
The patent uses composite material structure with copolyester elastomer containing both soft blocks and hard blocks. The soft blocks provide flexibility and adhesion to the fiber core, while the hard blocks provide resistance to deformation and prevent material extrusion under stress. This composite approach simultaneously achieves abrasion resistance and coating stability.
2Strength
If high modulus fibers are used in the core to increase breaking load, then strength is improved, but the fiber core is easily abraded due to movement relative to the steel outer layer
Solution Approach 1:
The copolyester elastomer coating acts as an intermediary layer between the high modulus fiber core and the steel wire strands. It reduces direct friction and movement between the fiber core and steel strands, thereby protecting the high modulus fibers from abrasion while maintaining the high breaking load capability.
Solution Approach 2:
By optimizing the soft block content (10-70 wt%) in the copolyester elastomer, the patent achieves the right balance of hardness and flexibility. The coating is soft enough to cushion the fiber core against abrasion but hard enough to prevent excessive deformation, thereby protecting high modulus fibers while maintaining strength.
3Ease of manufacture
If conventional plastomer coating is used, then manufacturing is simplified, but the coating is insufficient to protect the core under critical applications with huge compressive stresses
Solution Approach 1:
The patent optimizes the chemical composition parameters of the coating material by specifying copolyester elastomer with soft blocks in the range of 10-70 wt%. This parameter optimization enhances the coating's mechanical properties, enabling it to withstand huge compressive stresses in critical applications while remaining manufacturable using conventional extrusion processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The hybrid rope exhibits improved resistance to flexural and bending fatigue at various temperatures, maintains high breaking loads, and extends the lifespan by preventing the coated material from being pressed out, making it suitable for critical applications like crane ropes.
Implementation Method 1
the core element is coated with a polymer having copolyester elastomer containing soft blocks in the range of 10 to 70 wt %. Preferably, the hardness Shore D of the copolyester elastomer as measured according to ISO 868 is larger than 50
Data Source
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AI summary
Hybrid rope (20) comprising a core element (22) containing high modulus fibers surrounded by at least one outer layer (24) containing wirelike metallic members (26). The core element (22) is coated (23) with a thermoplastic polyurethane or a copolyester elastomer, preferably the copolyester elastomer containing soft blocks in the range of 10 to 70 wt %. The coated material (23) on the inner core element (22) is inhibited to be pressed out in-between the wirelike members (26) of the hybrid rope (20) and the hybrid rope (20) has decreased elongation and diameter reduction after being in use.