Load Cell Deformation Correction in Indentation Testing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional indentation testers fail to accurately measure displacement due to the inclusion of load cell deformation in displacement sensor values, leading to inaccurate load-displacement curves and elastic modulus calculations, especially when testing materials with curved surfaces or in high-temperature environments.

Innovation Solution

A method that involves deriving a displacement function of the load cell based on applied load, correcting displacement sensor values for load cell deformation, and deriving a precise load-displacement curve by applying these corrections during the indentation test.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the displacement sensor is positioned above the load cell to enable installation in vacuum chambers or high-temperature environments, then the adaptability of the indentation tester is improved, but the displacement measurement accuracy deteriorates because the measured value includes load cell deformation

Engineering Contradiction:

ImproveadaptabilityVSAvoiddisplacement measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the displacement measurement into two components: the total displacement measured by the sensor and the load cell deformation calculated separately. By dividing the measurement task, the system can use a displacement sensor positioned above the load cell for adaptability while independently calculating and compensating for load cell deformation to maintain measurement accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where the load cell deformation is continuously calculated based on the measured load and a pre-established displacement-load relationship, then this calculated deformation is subtracted from the sensor measurement in real-time. This feedback loop ensures that the corrected displacement accurately reflects the true indenter displacement despite the sensor's position above the load cell.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If the displacement sensor is coupled to the indenter shaft below the load cell, then the displacement measurement accuracy is improved by excluding load cell deformation, but the ease of operation deteriorates due to difficulty in installation in vacuum chambers and high-temperature environments

Engineering Contradiction:

Improvedisplacement measurement accuracyVSAvoidease of operation

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent introduces an intermediary calculation process that acts as a mediator between the displacement sensor and the load cell. By calculating the load cell deformation as an intermediate value and using it to correct the sensor measurement, the system achieves the accuracy of a below-load-cell sensor position while maintaining the operational flexibility of an above-load-cell sensor position.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If conventional indentation testers are used without correcting for load cell deformation, then the device complexity is reduced, but the measurement precision deteriorates due to inaccurate load-displacement curves and elastic modulus calculations

Engineering Contradiction:

Improvedevice complexityVSAvoidmeasurement precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements a self-service approach where the system automatically calculates and corrects for its own measurement errors. The load cell deformation is calculated based on the measured load and the established displacement-load relationship, then automatically subtracted from the sensor measurement. This self-correction mechanism maintains high measurement precision without requiring additional external correction devices or complex manual procedures.

Inventive Principle:

Principle #25Self-service

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 derivation of a precise load-displacement curve by real-time correction of displacement values, effectively accounting for load cell deformation, thereby improving the accuracy of physical property measurements such as elastic modulus.

Implementation Method 1

measuring the applied load and a displacement... deriving a displacement function of the load cell according to a load by applying a load to an indentation module and measuring the applied load and a displacement

Methodology Applied

Scientific EffectDeformation: Deformation

Implementation Method 2

a displacement sensor coupled to the indenter shaft... measure the displacement of the displacement part supported on a material when indented

Methodology Applied

Scientific EffectDisplacement measurement: Displacement

Data Source

PatentUS11921089B2Method for performing press-fitting test in consideration of amount of deformation of load cell

Publication Date: 2024.03.05 FRONTICS

AI summary

According to the embodiments disclosed herein, in a press-fitting test for measuring physical properties of a test object by pressing an indenter against the test object and measuring the load and displacement, the measured displacement value is corrected in real time in consideration of the amount of deformation according to the load of the load cell, and thus an accurate load-displacement curve can be derived, even when the amount of deformation of the load cell is included in a measured value of a displacement sensor.