Square Hopkinson Bar Fixture for Precise Strain Gauge Alignment

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Solution Overview

Problem

The dynamic true triaxial electromagnetic Hopkinson bar test system requires precise and consistent placement of strain gauges on multiple square waveguide bars to ensure accurate synchronization and measurement of stress waves, which is challenging due to the transverse dispersion effect and horizontal position deviations of the strain gauges.

Innovation Solution

A specialized strain gauge sticking fixture is designed for square waveguide bars, incorporating a laser rangefinder assembly, elastic material layers, and strain gauge positioning stickers to ensure consistent and accurate placement of strain gauges across multiple bars, maintaining synchronization and reducing data deviation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a traditional sticking method is used for strain gauges on circular waveguide bars, then the placement is simple and quick, but the position consistency cannot be ensured for multiple square waveguide bars

Engineering Contradiction:

Improveposition consistency of strain gaugesVSAvoidcomplexity of sticking fixture

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The fixture is divided into multiple independent modules: laser rangefinder assembly for positioning, elastic material layers for cushioning and alignment, positioning stickers for marking locations, and clamping mechanisms for securing. Each module performs a specific function, allowing the complex positioning task to be broken down into manageable segments that work together to achieve precise strain gauge placement on multiple square waveguide bars.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If strain gauges are placed manually on multiple square waveguide bars, then the process is fast, but horizontal position deviations occur causing data dispersion

Engineering Contradiction:

Improveaccuracy of stress wave measurementVSAvoidtime for strain gauge placement

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The fixture performs preliminary positioning actions before the actual strain gauge sticking process. The laser rangefinder pre-determines the axial positions, the elastic material layers pre-align the horizontal positions, and the positioning stickers pre-mark the exact locations. This preliminary preparation ensures that when strain gauges are placed, they are automatically positioned correctly, eliminating the need for time-consuming manual alignment while ensuring measurement accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual mechanical positioning with an automated optical-mechanical system. The laser rangefinder uses optical principles to precisely measure and determine axial positions, eliminating manual measurement errors. This substitution of manual mechanical operations with automated optical positioning significantly improves both the accuracy of stress wave measurements and the efficiency of the placement process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a specialized fixture with laser rangefinder and positioning mechanisms is used, then position consistency is ensured, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improvereliability of test resultsVSAvoidease of manufacturing fixture

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The fixture is designed as a universal platform that can accommodate multiple square waveguide bars of different sizes and configurations. The laser rangefinder assembly can measure various axial positions, the elastic material layers can adapt to different bar dimensions, and the positioning stickers can be adjusted for different horizontal locations. This multi-functionality allows a single fixture design to reliably position strain gauges across all six waveguide bars in the dynamic true triaxial electromagnetic Hopkinson bar test system, improving reliability without requiring six different specialized fixtures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 fixture ensures position consistency of strain gauges, improving the accuracy and reliability of test results by reducing data deviation caused by position errors, and is specifically tailored for the complex multi-axial loading conditions of the dynamic true triaxial electromagnetic Hopkinson bar test system.

Implementation Method 1

a laser rangefinder assembly frame, an elastic material layer, a laser rangefinder

Methodology Applied

Scientific EffectLaser: Laser

Data Source

PatentUS12345581B1Fixture applied to sticking strain gauge on Hopkinson square bar and use method thereof

Publication Date: 2025.07.01 SHENZHEN UNIV

AI summary

Provided is a fixture applied to sticking a strain gauge on a Hopkinson square bar and a use method of the fixture. The invention is specially designed for a square waveguide bar, and the fixture further ensures consistency of the same group of strain gauges along a cross-section position of the bar. The fixture has important practical value in application in a dynamic true triaxial electromagnetic Hopkinson bar test, especially in a high-end material testing field requiring high-precision and high-reliability test data.