Welding Process Control Using FE-Based Nominal Stress Estimation
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Solution Overview
Problem
Existing methods for estimating nominal stress in welded structures are time-consuming, error-prone, and often require hand calculations, specific mesh density in finite element (FE) analysis, and identification of geometric parameters, which can be tedious and arbitrary.
Innovation Solution
A welding control system that uses FE analysis algorithms to calculate stresses at multiple points along a base line of a welded structural component, spline-fits the stresses, identifies points with consistent second derivatives, and extrapolates these points to estimate nominal stress at the base point, thereby controlling welding process variables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (hand calculations, coarse FE mesh, geometric parameter extrapolation) are used to estimate nominal stress, then the estimation can be obtained, but the process becomes time-consuming and error-prone
Solution Approach 1:
The patent replaces conventional mechanical calculation methods (hand calculations, coarse mesh approaches) with an automated computational system that uses FE analysis algorithms combined with spline-fitting and second derivative evaluation to automatically identify and extrapolate nominal stress points, eliminating manual intervention and reducing time consumption
Solution Approach 2:
The system performs self-service by automatically identifying nominal stress points through algorithmic evaluation of second derivatives of FE-calculated stresses, without requiring external geometric parameter inputs or manual point selection, thereby reducing both time and potential human error
2Ease of manufacture
If conventional methods require identification of geometric parameters (such as plate thickness) for stress extrapolation, then the estimation can be performed, but the process becomes tedious and arbitrary
Solution Approach 1:
The patent extracts and eliminates the requirement for geometric parameter identification by directly using FE-calculated stress values at multiple points along a base line, applying spline-fitting and second derivative evaluation to automatically identify nominal stress points without needing plate thickness or other geometric inputs
Solution Approach 2:
The system achieves universality by creating a general-purpose algorithm that can estimate nominal stress for various welded structural configurations without requiring configuration-specific geometric parameters, making the process applicable across different weld types and geometries
3Device complexity
If coarse FE mesh is used to minimize local stress raising effects, then the calculation is simpler, but the approach becomes somewhat arbitrary and tedious
Solution Approach 1:
The patent applies preliminary action by performing spline-fitting on the FE-calculated stress values before evaluating second derivatives to identify nominal stress points, ensuring that the stress field is smoothly interpolated and that the identification process is not sensitive to mesh density variations
Solution Approach 2:
The system uses feedback by evaluating second derivatives of the spline-fitted stress values to automatically identify points where the curvature changes, providing an objective criterion for nominal stress point identification that reduces arbitrariness and improves reliability
Data Source
AI summary
Systems and methods described herein are configured to control welding systems, for example, controlling welding process variables based at least in part on nominal stresses estimated using finite element (FE) algorithms. The systems and methods described herein may be utilized to identify nominal stress in welded structures and components to enable adjustment of welding process variables for the manufacture of subsequent welded structures and components, for example, performed by the same welding system. The systems and methods described herein also allow readily available FE stress results to be utilized in a consistent manner, as well as providing user feedback regarding the accuracy of the nominal stress approximations. Furthermore, the systems and methods described herein are generally faster and less error prone than conventional techniques, and are relatively insensitive to mesh density of the FE stress calculations.