Hollow Cylindrical Strain Sensor for Bore-Mounted Fatigue Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing strain sensing technologies face challenges in comprehensively monitoring fatigue damage in structural components, particularly due to difficulties in accessing internal damage, inaccuracies from external mounting, and practical limitations in harsh environments, as well as complexities in retrofitting internally mounted devices.
Innovation Solution
A strain sensing device comprising a hollow, cylindrical member with strain sensing elements attached to its inner surface, designed to be inserted into a structural component's cylindrical bore, allowing for accurate strain measurement and fatigue evaluation by translating strain from the component into the member, which can be fixed using methods like press fit, adhesive, or welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges are mounted on the exterior surface of a structural component, then strain measurement can be performed, but measurement precision deteriorates due to bending deflection errors when offset from the neutral axis
Solution Approach 1:
The patent inverts the conventional approach by placing strain sensing elements on the interior surface of a hollow cylindrical member that is inserted into a bore of the structural component, rather than mounting gauges on the exterior surface. This inversion allows the sensing elements to be positioned at the neutral axis where bending deflection does not cause measurement errors, while the exterior surface serves as the interface for strain translation.
Solution Approach 2:
The hollow cylindrical member acts as an intermediary element that bridges the structural component and the strain sensing elements. It translates strain from the structural component into strain in the cylindrical member, which is then detected by the sensing elements attached to the inner surface, solving both the accessibility and precision problems.
2Measurement precision
If strain sensing devices are mounted externally on structural components, then strain measurement is possible, but reliability deteriorates in harsh environments with branches and debris
Solution Approach 1:
The strain sensing device is nested within a bore of the structural component, with the hollow cylindrical member inserted inside the structural component and strain sensing elements attached to its inner surface. This nesting protects the sensing elements from environmental hazards such as branches and debris while maintaining strain detection capability through the cylindrical member.
3Measurement precision
If strain sensing elements are mounted directly to the inner surface of a cylindrical bore, then internal strain measurement is achieved, but device complexity increases due to difficult mounting procedures
Solution Approach 1:
The device is segmented into a hollow cylindrical member and strain sensing elements that can be attached separately to the inner surface. This segmentation allows the cylindrical member to be inserted into the bore first, followed by attachment of the sensing elements, simplifying the overall installation process compared to attempting to mount integrated devices directly.
Solution Approach 2:
The hollow cylindrical member is prepared in advance with its outer diameter corresponding to the inner diameter of the bore, allowing it to be inserted and positioned before the strain sensing elements are attached. This preliminary preparation of the cylindrical member separates the insertion and sensing element attachment steps, reducing installation complexity.
4Ease of operation
If manual direct visual inspection is performed on structural components, then visible fatigue damage can be detected, but measurement precision deteriorates for internal damage and early-stage cracks
Solution Approach 1:
The patent replaces manual visual inspection with an electronic strain sensing system that uses strain sensing elements to detect strain in the structural component. This substitution enables detection of internal damage and early-stage cracks through electrical signals, maintaining operational simplicity while dramatically improving detection precision for internal and early-stage fatigue damage.
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 solution provides comprehensive and accurate strain measurement, reduces errors from bending deflection, protects the device from environmental hazards, and facilitates easy installation and retrofitting, enabling effective fatigue life prediction and damage detection.
Implementation Method 1
The hollow, cylindrical member may be configured to mate to the inner surface of the cylindrical bore of the structural component such that strain in the structural component is translated into strain in the hollow, cylindrical member
Implementation Method 2
one or more strain sensing elements attached to the inner surface of the hollow, cylindrical member and configured to detect strain exhibited by the hollow, cylindrical member
Data Source
AI summary
A strain sensing device is provided, which may include a hollow, cylindrical member having an inner surface and an outer surface. The outer surface may have an outer diameter corresponding approximately in size to an inner diameter of an inner surface of a cylindrical bore of a structural component configured to undergo mechanical loading. The hollow, cylindrical member may be configured to mate to the inner surface of the cylindrical bore of the structural component such that strain in the structural component is translated into strain in the hollow, cylindrical member. The strain sensing device may also include one or more strain sensing elements attached to the inner surface of the hollow, cylindrical member and configured to detect strain exhibited by the hollow, cylindrical member.