Lever Frame Load Frame for Combined Tension and Bending
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Solution Overview
Problem
Current load frame designs for testing subsea oilfield equipment are limited by the need for increasingly larger and more expensive hydraulic cylinders to apply higher loads, which leads to deformation and cost issues, as they rely on the test article for support and cannot efficiently apply combined tension and bending loads without becoming excessively large and costly.
Innovation Solution
A load frame test device utilizing a lever frame assembly with pivot pins and hydraulic cylinders to apply axial and bending forces independently, using split clamps for secure attachment and leveraging forces to apply tensile and bending stresses without relying on the test article for support, allowing for higher load magnitudes without increasing the test structure's size or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional hydraulic cylinders are used to apply higher loads, then the test load capacity increases, but the test structure becomes too large and too expensive
Solution Approach 1:
A lever arm is introduced as an intermediary mechanical element between the hydraulic cylinder and the test article. The lever arm pivots on the test structure and uses mechanical leverage to multiply the force from a smaller hydraulic cylinder, enabling high load capacity without requiring a proportionally large test structure
Solution Approach 2:
The system changes the mechanical advantage parameter by adjusting the lever arm configuration and pivot positions. This allows the same hydraulic cylinder to produce different effective load magnitudes on the test article, achieving high test loads without proportionally increasing cylinder or structure size
2Force
If hydraulic cylinders are increased in size to apply higher loads, then the test load capacity increases, but the cost increases exponentially
Solution Approach 1:
The lever arm serves as a force multiplication intermediary, allowing a smaller, less expensive hydraulic cylinder to generate the same effective test load as a much larger, more expensive cylinder would provide through direct connection
Solution Approach 2:
Instead of using a large hydraulic cylinder that directly applies force, the system creates a mechanical copy/representation of the force application through the lever arm system, where a smaller cylinder's force is replicated and amplified at the test article interface
3Strength
If the test structure is made stronger to avoid deformation under high loads, then the rigidity increases, but the structure becomes larger and more expensive
Solution Approach 1:
The lever arm acts as a force distribution intermediary that redirects and multiplies forces through pivot points on the test structure, allowing the structure to experience reduced localized stresses while still applying high loads to the test article
Solution Approach 2:
The force application is segmented into multiple pivot points and lever arms rather than a single direct connection. This distributes the structural loads across multiple attachment points, reducing the required strength and size of any single structural component
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
Enables the testing of subsea equipment at higher load magnitudes with maintained rigidity, reducing costs by utilizing existing hydraulic cylinders and minimizing deformation, while applying a variety of stress combinations effectively, including pure bending and tension, without the need for oversized test structures.
Implementation Method 1
The hydraulic cylinder can be pressurized to apply an axial load
Implementation Method 2
The moment arms can apply a bending moment to the test article
Implementation Method 3
a first lever rotatable about a first pivot pin and a second lever rotatable about the first pivot pin
Data Source
AI summary
The present invention includes a load frame test device using a plurality of levers about a common pivot point for applying combinations of tensile loading and bending on test articles at magnitudes seen in offshore applications.