FSW Joint Tensile Strength Prediction Using Temperature and Axial Force

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Solution Overview

Problem

Existing methods for predicting the tensile strength of friction stir welding (FSW) joints fail to accurately consider the dynamic influence of welding process parameters, particularly axial force and temperature, leading to incomplete understanding of their impact on joint quality.

Innovation Solution

A one-dimensional convolutional neural network (1D CNN) model is employed to predict tensile strength by using time series data of temperature and axial force from the advancing and retreating sides of the weldment surface, processed through infrared thermal imaging and force sensing, with data normalization and model training using a Huber robust loss function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional welding parameter prediction methods are used, then the prediction process is simple, but the prediction accuracy is insufficient and cannot accurately reflect the dynamic influence of welding parameters on tensile strength

Engineering Contradiction:
Improveprediction accuracyVSAvoidmodel complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical/statistical prediction methods with an intelligent 1D CNN deep learning model. This substitution enables the system to automatically learn complex nonlinear relationships between welding parameters (temperature, axial force) and tensile strength, achieving high prediction accuracy (average relative error of 2%) without requiring manual feature engineering or simplified assumptions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces dynamic time-series data collection during the FSW process, capturing temperature and axial force variations at different welding stages. The 1D CNN model processes these temporal sequences to reflect the dynamic influence of welding parameters on tensile strength, moving from static parameter analysis to dynamic process characterization.

Inventive Principle:
Principle #15Dynamics

2Loss of information

If welding process parameters are used directly for prediction, then the measurement process is simple, but the influence of axial force and temperature time series data on tensile strength is not comprehensively considered

Engineering Contradiction:
Improveinformation completenessVSAvoiddata collection complexity
Core Design Contradiction:
Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements a feedback mechanism by collecting real-time temperature and axial force data during the FSW process using infrared thermal imagers and force sensors. This feedback loop captures the actual welding process state, enabling the model to learn the true relationship between process parameters and joint quality, thereby preventing information loss about the dynamic welding behavior.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces infrared thermal imagers and force sensors as intermediary devices to indirectly measure temperature and axial force that are difficult to access directly during welding. These intermediaries convert physical quantities into measurable signals, enabling comprehensive data collection without interfering with the welding process.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If destructive tensile tests are performed to evaluate joint quality, then the measurement is direct and accurate, but the assessment process is time-consuming and not suitable for real-time quality control

Engineering Contradiction:
Improvequality assessment efficiencyVSAvoidquality evaluation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent creates a virtual copy of the tensile strength property through the 1D CNN prediction model. Instead of physically testing each joint, the model generates a predicted tensile strength value based on processed welding parameter data, providing a non-destructive alternative that maintains accuracy while dramatically improving assessment efficiency and enabling real-time quality control.

Inventive Principle:
Principle #26Copying

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 model achieves accurate prediction of tensile strength with an average relative error of approximately 2%, providing a non-destructive assessment of FSW joint quality.

Implementation Method 1

the temperature of the AS and RS feature points of the weldment surface... are obtained by infrared thermal imager

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

axial force... obtained by infrared thermal imager and force sensor

Methodology Applied
Scientific EffectForce sensing: Force

Implementation Method 3

The shoulder provides heat through friction during FSW process, which softens the welded metal

Methodology Applied
Scientific EffectFriction heating: Friction

Data Source

PatentUS12504326B2Intelligent prediction method for tensile strength of FSW joints considering welding temperature and axial force
Publication Date: 2025.12.23 DALIAN UNIV OF TECH
  • US12504326B2 patent drawing
  • US12504326B2 patent drawing

AI summary

The invention belongs to the field of friction stir welding (FSW) quality prediction and relates to an intelligent prediction method for the tensile strength of FSW joints considering welding temperature and axial force. The invention uses a combination of experiment and theory. FSW experiment is carried out, the infrared thermal imager and force sensor are used to obtain the temperature of the feature points on the advancing side and retreating side of the outside of the shoulder of the weldment surface and the axial force during FSW process. The obtained data is used to train and test the one-dimensional convolutional neural network. The tensile strength prediction of friction stir welding is realized, which provided a reference for welding process control.