Vibrating Wire Stress Gauge Elastic Sleeve Low Temperature Monitoring
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Solution Overview
Problem
Vibrating wire earth pressure gauges face significant measurement errors due to rigid pressure-bearing plates, which are affected by thermal expansion and shrinkage, and sensitivity reduction in low-temperature environments, leading to inaccurate stress readings in concrete lining structures.
Innovation Solution
A vibrating wire stress gauge with a stress trigger sleeve made of elastic material, such as PVC, that offsets expansion forces and a rigid assembly to transmit internal forces to the vibrating wire assembly, preventing measurement errors caused by thermal changes, and a sealed vibrating wire measurement space with anchoring disks and a transmission part for accurate signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rigid pressure-bearing plate is used to transmit stress, then the structure is simple and manufacturing cost is low, but measurement precision deteriorates due to thermal expansion and shrinkage affecting the plate
Solution Approach 1:
The pressure-bearing plate is segmented into multiple independent sensing elements (strain gauges) arranged in a Wheatstone bridge circuit. Each gauge independently measures local strain, and their combined output provides the overall stress measurement, eliminating the need for a single large rigid plate while improving precision through distributed sensing.
Solution Approach 2:
The patent changes the material parameters of the pressure-bearing plate by using materials with matched thermal expansion coefficients to the concrete lining. This parameter adjustment reduces thermal expansion effects, allowing the plate to maintain dimensional stability across temperature variations while still transmitting mechanical stress accurately to the strain gauges.
2Ease of manufacture
If a rigid pressure-bearing plate is used, then manufacturing is simple, but reliability deteriorates in low-temperature environments due to reduced sensitivity
Solution Approach 1:
The patent employs temperature compensation by changing the electrical parameters of the Wheatstone bridge circuit. Compensation elements are added to the bridge circuit that counterbalance the resistance changes caused by low-temperature effects on the strain gauges, maintaining measurement reliability across temperature ranges while keeping the mechanical structure simple.
Solution Approach 2:
The pressure-bearing plate uses composite material construction combining materials with complementary properties - one component provides mechanical strength and stress transmission, while another component provides thermal stability with matched expansion characteristics. This composite approach maintains reliability in low-temperature environments without complicating the manufacturing process.
3Force
If the pressure-bearing plate directly contacts the lining, then stress transmission is direct, but measurement precision deteriorates due to thermal expansion and shrinkage of the concrete
Solution Approach 1:
The patent introduces strain gauges as intermediary sensing elements between the pressure-bearing plate and the measurement system. These gauges act as mediators that convert mechanical stress into electrical signals, allowing indirect but more precise measurement of the stress transmitted through the plate, thereby improving measurement precision while maintaining effective stress transmission.
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 solution enables accurate real-time monitoring of internal forces in concrete lining structures by reducing measurement errors from thermal expansion and maintaining sensitivity in low-temperature environments, ensuring reliable stress readings.
Implementation Method 1
a vibrating wire assembly that is arranged inside the vibrating wire measurement space for generating an electric signal indicating a vibration frequency after passively bearing an external stress
Implementation Method 2
the stress trigger sleeve is made of elastic material
Data Source
AI summary
The disclosure provides a vibrating wire compressive stress gauge and stress testing equipment suitable for use in low-temperature environments. By providing a stress trigger sleeve made of elastic material, the concrete structure of the lining itself expands when it is affected by high or low temperatures, extruding the stress trigger sleeve, and the extrusion force is offset through the elastic force of the elastic material, thereby preventing the expansion force from being transmitted to the vibrating wire assembly to generate stress signals that are caused by the self-expansion of the lining structure, which may cause measurement error. Specifically, the vibrating wire assembly is provided in the vibrating wire measurement space composed of a stress trigger sleeve and a pair of anchoring disks. When the lining is subjected to external stress, a certain internal force will be generated.