Carbon Composite Extension Element for Rock Displacement Measurement

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Solution Overview

Problem

Conventional measuring devices for rock displacements are sensitive to temperature influences and require laborious calculations to differentiate between thermal expansion and actual rock movement, limiting their accuracy and efficiency.

Innovation Solution

The measuring device employs a carbon composite extension element with low thermal expansion, combined with rock anchors and a linear potentiometer, featuring standardized pins, ball joints, and a communication element for precise and reproducible measurements, minimizing temperature sensitivity and allowing easy calibration and verification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If aluminum extension elements are used in conventional measuring devices, then the device can measure rock displacements, but the measurements are sensitive to temperature influences requiring laborious calculations to differentiate thermal expansion from actual rock movement

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidtemperature sensitivity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter of the extension element from aluminum to carbon fiber composite, which has a fundamentally different thermal expansion coefficient. This parameter change eliminates the need for temperature compensation calculations while maintaining measurement capability, directly resolving the contradiction between measurement precision and temperature sensitivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs carbon fiber composite material for the extension element, which combines mechanical strength with negligible thermal expansion. This composite material solution simultaneously provides the structural integrity needed for measurement while being immune to temperature-induced dimensional changes, thereby eliminating the harmful temperature sensitivity

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If standardized pins and adapters are used with rock anchors, then the measuring device allows easy removal and reattachment of the linear potentiometer, but requires additional components increasing device complexity

Engineering Contradiction:
Improveease of assembly and disassemblyVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent divides the measuring device into separable modules: rock anchors with pins remain permanently installed in the rock, while the linear potentiometer with adapters can be easily attached and detached. This segmentation allows the measurement system to be reconfigurable and maintainable without disturbing the permanently installed anchor points, achieving ease of operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The standardized pins and adapters create a universal interface that works with different linear potentiometer models and measurement systems. This universality allows the same rock anchor setup to be used with various measuring instruments, reducing the need for multiple specialized components and justifying the added complexity through increased versatility

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If ball joints are used between the linear potentiometer and rock anchors, then transverse stresses are prevented, but the device requires additional articulated connection components

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ball joints are installed in advance to provide articulated connections that automatically accommodate misalignments and prevent transverse stresses before they can affect the linear potentiometer. This preemptive protection ensures measurement reliability by eliminating a potential source of error without requiring complex active compensation mechanisms

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 provides a measuring device with high mechanical stability and rigidity, reducing temperature-induced errors and enabling accurate, easy verification and calibration of rock displacement measurements over long periods.

Implementation Method 1

Carbon composite, for example, has a thermal expansion coefficient 240 times lower than that of aluminum

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a linear potentiometer mounted between the rock anchors with an extension element, which measures a change in length in a straight connecting line between the rock anchors

Methodology Applied
Scientific EffectLinear potentiometer measurement:

Data Source

PatentEP4249848B1Measuring device and method
Publication Date: 2025.07.09 AARTESYS AG
  • EP4249848B1 patent drawingFigure 1~2

AI summary

A measuring device (1) comprising two rock anchors (2) and a linear potentiometer (3) connected between the rock anchors (2) by an extension element (4) is disclosed. The potentiometer measures changes in length along a straight line connecting the rock anchors (2). A measuring method to be performed with such a measuring device (1) is also disclosed. To make the measuring device (1) less sensitive to temperature influences, it is proposed that the extension element (4) be made of a carbon composite.