Composite Sucker Rod Wedge Connection for Creep Resistance
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Solution Overview
Problem
Structural members, particularly sucker rods, face issues with premature failure due to non-ideal fiber alignment leading to stress concentrations and vulnerability to creep when loads are applied to the resin rather than the fibers, and there is a need for improved connection methods to enhance performance under cyclic loads.
Innovation Solution
The design incorporates a sucker rod segment with an uphole and downhole wedge configuration that applies tensile and compressive forces effectively to a composite rod, utilizing integral wedge configurations and connectors to distribute stress uniformly and prevent creep, while also providing a method of overmolding thermoplastic polymers to integrate the wedge configurations with the composite rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite rod is used to reduce weight and cost, then manufacturing cost and weight are reduced, but premature failure occurs due to stress concentrations from non-ideal fiber alignment
Solution Approach 1:
The sucker rod is divided into multiple composite rod segments, each with controlled fiber alignment. By segmenting the rod, the patent ensures that each segment maintains ideal fiber orientation to resist tensile loads, while connection elements join these segments to form a complete rod assembly, thereby preventing premature failure due to stress concentrations.
Solution Approach 2:
The patent uses fiber-reinforced composite materials with specifically oriented fibers arranged to align with the primary stress directions in each rod segment. This composite material structure ensures that fibers carry the tensile loads efficiently, preventing premature failure while maintaining the weight advantages of composite materials.
2Ease of operation
If connection elements are added to join composite rod segments, then the rod can be assembled and connected, but the connection may cause creep when loads are applied to the resin rather than fibers
Solution Approach 1:
Connection elements serve as intermediaries between composite rod segments, designed to transfer loads directly to the fibers rather than the resin matrix. These connectors engage with fiber reinforcement layers, ensuring that applied loads are carried by the high-strength fibers, thereby preventing creep that would occur if loads were applied to the resin.
Solution Approach 2:
The connection elements are designed with local quality features that specifically engage the fiber reinforcement layers at the connection points. The connectors have surfaces or structures that interface with fibers, ensuring that loads are applied locally to the fibers rather than the resin, thereby preventing creep at the connection interfaces.
3Strength
If metal structural members are used, then strength and durability are achieved, but manufacturing cost, transport cost, and installation cost increase
Solution Approach 1:
The patent employs fiber-reinforced composite materials to achieve the structural strength previously obtained only from metal. The composite rod segments with properly oriented fibers provide high strength-to-weight ratio, reducing both manufacturing costs and transport costs while maintaining the necessary structural strength for sucker rod applications.
Solution Approach 2:
By segmenting the composite rod into multiple sections that can be manufactured separately and then joined with connection elements, the patent reduces manufacturing complexity and cost. Each segment can be manufactured using cost-effective composite processing methods, avoiding the high costs associated with manufacturing large metal components.
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
This configuration enhances the structural integrity and durability of sucker rod segments by evenly distributing forces and preventing creep, thereby improving their performance under cyclic loads and reducing the risk of premature failure.
Implementation Method 1
the uphole rod segment connector, the uphole wedge configuration counterpart, the uphole wedge configuration, the composite rod, the downhole wedge configuration, the downhole wedge configuration counterpart, and the downhole rod segment connector are co-operatively configured such that, while a tensile force, having a downhole direction, is being applied to the downhole rod segment connector, and while a tensile force, having an uphole direction, is being applied to the uphole rod segment connector: wedging of the uphole wedge configuration, between the composite rod and the uphole wedge configuration counterpart, is effectuated
Implementation Method 2
a method of overmolding thermoplastic polymers to integrate the wedge configurations with the composite rod
Data Source
AI summary
Disclosed herein is a sucker rod segment, comprising a composite rod, an uphole rod segment connector for connection to an adjacent segment, an uphole wedge configuration counterpart, an uphole wedge configuration wedged between the uphole wedge configuration counterpart and an uphole rod portion, a downhole wedge configuration counterpart, a downhole wedge configuration wedged between the downhole wedge configuration counterpart and a downhole rod portion, and a downhole rod segment connector for connection to an adjacent segment. While a tensile force directed downhole is being applied to the downhole connector and a tensile force directed uphole is being applied to the uphole connector: the uphole wedge configuration and the downhole wedge configuration are wedging between the rod and the respective uphole and downhole counterpart and the uphole and downhole rod portions are compressed; and a tensile force, directed downhole, and a tensile force, directed uphole, are applied to the rod.