Strip Flatness Prediction with Lateral Spread Coupling

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Solution Overview

Problem

Traditional strip flatness prediction methods based on crown ratio simplifications fail to accurately account for lateral metal flow, leading to inaccurate predictions and neglecting the influence of lateral spread on strip elongation, which affects the quality of rolled strips.

Innovation Solution

A strip flatness prediction method that considers lateral spread during rolling by constructing a 3D finite element model to simulate strip rolling, incorporating parameters like strip and roll properties, friction, and rolling speed, and calculating flatness based on the coupling of flatness, crown, and lateral spread, using equations to derive longitudinal strain and residual tensile stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional strip flatness prediction method based on crown ratio simplification is used, then the calculation process is simple, but the prediction accuracy is low due to neglecting lateral metal flow

Engineering Contradiction:
Improvecalculation simplicityVSAvoidprediction accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transforms the prediction approach by changing from simplified crown ratio parameters to a comprehensive model incorporating lateral spread parameters. The lateral spread parameter ξ is introduced to quantify lateral metal flow, and the prediction model is reformulated to include this new parameter, thereby improving accuracy while maintaining computational feasibility through parameter expansion rather than complex structural changes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces the lateral spread parameter ξ as an intermediary variable that mediates between the crown ratio and the actual flatness prediction. This intermediary parameter captures the effect of lateral metal flow that was previously neglected, serving as a bridge between simplified theoretical models and actual rolling behavior, enabling more accurate predictions without requiring complete model restructuring

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If lateral spread is considered in flatness prediction, then the prediction accuracy is improved, but the model complexity increases

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

Solution Approach 1:

The patent segments the flatness prediction problem into distinct components: crown ratio effects, lateral spread effects, and their coupling relationship. By dividing the prediction model into these manageable segments with the lateral spread parameter ξ as a separate consideration, the complexity is organized and handled systematically rather than as an intractable whole

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent manages model complexity by introducing the lateral spread parameter ξ as an additional but well-defined parameter rather than requiring complete model restructuring. This parameter change approach allows the incorporation of lateral metal flow effects while maintaining a relatively straightforward prediction framework that builds upon existing crown ratio theory

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If geometric similarity conditions (constant crown ratio principle) are applied, then the flatness control is simplified, but the prediction results are inaccurate when lateral metal flow is significant

Engineering Contradiction:
Improveflatness control simplicityVSAvoidflatness prediction accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies preliminary anti-action by introducing the lateral spread parameter ξ to counteract the inaccuracies introduced by the constant crown ratio assumption. This parameter预先 compensates for the effects of lateral metal flow that would otherwise cause prediction errors, allowing the simplified constant crown ratio principle to remain useful while correcting its inherent limitations

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent modifies the constant crown ratio principle by introducing the lateral spread parameter ξ as a correction factor. This parameter change transforms the original simplified model into an enhanced version that accounts for lateral metal flow while maintaining the operational simplicity of the crown ratio approach, thereby improving accuracy without sacrificing ease of control

Inventive Principle:
Principle #35Parameter changes

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 method improves prediction accuracy and applicability by comprehensively considering lateral metal flow, allowing for precise calculation of strip flatness and identification of defects like edge waves and center buckles, enhancing the quality control of rolled strips.

Implementation Method 1

simulating strip rolling by the 3D FEM, extracting lateral displacement and thickness data of the strip during a stable rolling stage

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

constructing a 3D finite element model (FEM) of a rolling mill and a strip... simulating strip rolling

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

the rolling process parameters include friction and rolling speed

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentUS11745236B2Strip flatness prediction method considering lateral spread during rolling
Publication Date: 2023.09.05 NORTHEASTERN UNIV CHINA
  • US11745236B2 patent drawing
  • US11745236B2 patent drawing
  • US11745236B2 patent drawing

AI summary

The present disclosure provides a strip flatness prediction method considering lateral spread during rolling. The method includes: step 1: acquiring strip parameters, roll parameters and rolling process parameters; step 2: introducing a change factor of a lateral thickness difference before and after rolling and a lateral spread factor by considering lateral metal flow, and constructing a strip flatness prediction model based on the coupling of flatness, crown and lateral spread; step 3: constructing a three-dimensional (3D) finite element model (FEM) of a rolling mill and a strip, simulating strip rolling by the 3D FEM, extracting lateral displacement and thickness data of the strip during a stable rolling stage, calculating parameters of the strip flatness prediction model based on the coupling of flatness, crown and lateral spread; and step 4: predicting the flatness of the strip by the strip flatness prediction model based on the coupling of flatness, crown and lateral spread.