Strain Gauge Web for Screw Force Measurement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing force measurement technologies struggle to accurately measure force components deviating from the main direction in mechanical components, such as screws, due to the need for precise positioning of strain gauge sensors, which is challenging and often impossible in complex or already installed mechanical components like machine elements in wind turbines, leading to incorrect loading and potential failure.

Innovation Solution

A mechanical component design featuring an elongate web on its mounting surface with strain gauge sensors aligned to detect forces along the web's longitudinal direction, filtering out transverse stresses and allowing for universal application without precise positioning requirements, enabling effective measurement of operating forces in multiple directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strain gauge sensors are positioned to measure force components deviating from the main direction, then measurement precision is improved, but manufacturing precision requirements increase significantly

Engineering Contradiction:
Improveforce component measurementVSAvoidsensor positioning accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent introduces a mounting surface with a specific geometric structure (featuring a longitudinal axis and transverse axis) as an intermediary between the mechanical component and the strain gauge sensor. This mounting surface structure guides the sensor orientation, allowing the strain gauge to measure force components deviating from the main direction without requiring high-precision manual positioning. The mounting surface acts as a mechanical mediator that translates arbitrary force directions into measurable strain along the sensor's sensitive axis.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If strain gauge sensors are positioned to measure force components deviating from the main direction, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveforce component measurementVSAvoidsensor alignment requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The mounting surface with its defined longitudinal and transverse axes serves as a simplifying intermediary that eliminates complex alignment procedures. Instead of requiring complex positioning equipment and procedures to orient the strain gauge at specific angles relative to the force vector, the mounting surface provides a pre-defined reference frame that simplifies the installation process while enabling measurement of force components in any direction within the plane.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If strain gauge sensors are positioned to measure force components deviating from the main direction, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveforce component measurementVSAvoidsensor installation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The mounting surface acts as an operational intermediary that simplifies sensor installation. By providing a pre-fabricated structure with defined axes and mounting features, it eliminates the need for operators to perform complex measurements and calculations to determine sensor orientation. The strain gauge can be installed using simple alignment features provided by the mounting surface, making the process accessible to personnel without specialized measurement expertise.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If strain gauge sensors are positioned to measure force components deviating from the main direction, then measurement precision is improved, but adaptability deteriorates

Engineering Contradiction:
Improveforce component measurementVSAvoidretrofitting existing components
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The mounting surface serves as a versatile intermediary that can be adapted to various existing mechanical components. Rather than requiring direct integration of strain gauges into the component geometry, the mounting surface provides a standardized interface that can be attached to different component types (screws, beams, machine elements). This intermediary approach enables retrofitting of existing components with force measurement capabilities without modifying the original component design or requiring precise knowledge of force vector directions.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for reliable measurement of operating forces in mechanical components, including those already installed, by eliminating the need for precise sensor alignment and reducing manufacturing effort, while providing a robust and easy-to-install solution for various mechanical components.

Implementation Method 1

a strain gauge sensor comprising at least one strain gauge arranged in a plane with a piezoelectric coefficient axis is used to detect the force perpendicular to the plane

Methodology Applied
Scientific EffectStrain gauge measurement: Piezoresistive Effect

Implementation Method 2

at least one strain gauge arranged in a plane with a piezoelectric coefficient axis

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3650825B1Operational force measurement of a mechanical component
Publication Date: 2021.11.03 CIS FORSCHUNGSINST FUR MIKROSENSORIK & PHOTOVOLTAIK GMBH
  • EP3650825B1 patent drawingFigure 1~2
  • EP3650825B1 patent drawingFigure 3~4
  • EP3650825B1 patent drawingFigure 5~6

AI summary

A screw with a screw head (2) is described, on which a longitudinally extended strain gauge (28) is mounted for measuring mechanical stress, wherein a web (30) is arranged on the screw head (2) that is freed along its longitudinal sides and extends on or parallel to the top (6) of the screw head (2), has a web height (H) of at least 100 µm and a web width (B) of at most 2 mm, and the strain gauge (28) is fixedly connected to the web (30), wherein the longitudinal extension of the strain gauge (28) is aligned along the longitudinal sides of the web (30).