Stress Function Calibration for Workpiece Distortion Prediction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for predicting residual stress in workpieces resulting from manufacturing operations are inadequate and time-consuming, requiring iterative adjustments and costly reworking due to the difficulty in accurately estimating and verifying residual stress without physically measuring it.
Innovation Solution
A method involving the calculation of a moment coefficient representative of residual stress induced in a plate coupon, calibration of a stress function, and application to a workpiece model to predict distortion and residual stress, allowing for adjustments in manufacturing parameters without physical measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current methods for predicting residual stress are used, then residual stress can be estimated, but the prediction accuracy is inadequate and requires iterative adjustments
Solution Approach 1:
The patent applies preliminary action by pre-calculating stress influence coefficients and distortion coefficients before actual machining operations. These pre-computed coefficients are stored in a database and can be directly applied to predict residual stress and distortion without requiring iterative adjustments during production, thereby improving prediction accuracy while reducing time loss.
Solution Approach 2:
The patent creates a virtual model (copy) of the workpiece and machining process through finite element analysis. This digital twin allows prediction of residual stress and distortion without physical iteration, enabling accurate predictions to be made on the virtual model and then applied to actual machining operations.
2Measurement precision
If physical measurement of residual stress is performed to verify predictions, then measurement accuracy can be improved, but the verification process becomes time-consuming
Solution Approach 1:
The patent replaces physical measurement systems with a computational prediction system. By using pre-calculated stress influence coefficients and applying them through finite element analysis, the system substitutes mechanical/physical verification methods with computational methods, maintaining accuracy while dramatically improving verification efficiency.
3Manufacturing precision
If machining parameters are adjusted to reduce residual stress, then distortion can be minimized, but the adjustment process requires costly reworking
Solution Approach 1:
The patent applies preliminary action by predicting residual stress and distortion before machining operations using pre-computed coefficients. This allows machining parameters to be optimized in advance based on predictions, avoiding the need for costly reworking after distortion occurs. The stress influence coefficients are calculated beforehand and used to predict outcomes and adjust parameters proactively.
Solution Approach 2:
The patent implements feedback by comparing predicted residual stress and distortion with acceptable thresholds. Based on this feedback, machining parameters are automatically adjusted before production, creating a closed-loop system that prevents distortion rather than correcting it, thereby eliminating reworking costs.
4Productivity
If high-speed machining is performed to increase productivity, then manufacturing speed improves, but residual stress and distortion increase
Solution Approach 1:
The patent creates virtual models of workpieces at different machining speeds using finite element analysis. By simulating high-speed machining in the virtual model and applying the stress influence coefficients, the system can predict residual stress and distortion outcomes before actual high-speed machining, allowing parameter optimization to maintain precision while achieving high productivity.
Data Source
AI summary
A method of predicting distortion in a workpiece may include measuring residual stress induced in a coupon surface of a plate coupon by a selected manufacturing operation. The induced residual stress measurements may be fitted to a curve shape function. A moment coefficient may be calculated based upon the fitted induced residual stress measurements. The moment coefficient may be used to calibrate a stress function and corresponding stress magnitude. The calibrated stress function may be applied to a model of the workpiece such that the distortion of the workpiece may be predicted.