Fracture Risk Extraction via Adaptive Element Discretization

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Solution Overview

Problem

Conventional methods for predicting fractures using the finite element method face challenges in accurately determining fracture risk portions due to dependence on element size, leading to over or under estimation, and require extensive calculation time, making it difficult to reliably extract fracture risk areas.

Innovation Solution

The method involves discretizing the analysis target into two areas of different sizes, calculating maximum principal strain or sheet thickness reduction rate, and extracting the fracture risk portion based on the difference between these values, allowing for precise determination without the need for very small element sizes, thereby reducing processing time and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If element discretization is performed with small area to improve prediction accuracy, then measurement precision is improved, but calculation time increases significantly

Engineering Contradiction:
Improvefracture prediction accuracyVSAvoidcalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the analysis target into multiple regions based on deformation characteristics. High-accuracy analysis with small elements is applied only to regions with large deformation gradients (potential fracture zones), while low-accuracy analysis with large elements is applied to regions with small deformation gradients. This segmentation allows accurate fracture prediction in critical areas without the computational cost of applying fine discretization to the entire model.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different element sizes and analysis accuracies to different regions of the analysis target based on local deformation characteristics. Regions with large deformation gradients receive high-accuracy analysis with small elements, while regions with small deformation gradients receive low-accuracy analysis with large elements. This local differentiation optimizes the balance between prediction accuracy and calculation efficiency.

Inventive Principle:
Principle #3Local quality

2Productivity

If element discretization is performed with large area to reduce calculation time, then productivity is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveanalysis efficiencyVSAvoidfracture prediction accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The analysis target is segmented into regions with large deformation gradients and regions with small deformation gradients. By applying large elements only to regions with small deformation gradients, the patent reduces calculation time while maintaining adequate accuracy in non-critical areas. The critical regions with large deformation gradients are analyzed with small elements to ensure accurate fracture prediction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different element sizes are assigned based on local deformation characteristics. Large elements are used in regions with small deformation gradients where high accuracy is not critical, improving computational efficiency. Small elements are used only in regions with large deformation gradients where accurate fracture prediction is essential.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If conventional fracture prediction methods are used, then analysis can be performed, but reliability deteriorates due to over or under estimation

Engineering Contradiction:
Improveanalysis feasibilityVSAvoidprediction reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent dynamically adjusts the analysis approach based on deformation characteristics. By calculating deformation gradients and identifying regions with large gradients, the method adaptively determines where high-accuracy analysis is needed. This dynamic adaptation ensures reliable fracture prediction in critical regions while avoiding unnecessary computational overhead in non-critical regions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses deformation gradient calculation as an intermediary step to identify potential fracture zones. This intermediary analysis guides the subsequent high-accuracy fracture prediction analysis, ensuring that computational resources are focused on regions where they are most needed for reliable prediction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2136197B1Breakage prediction method, calculation processing device, program, and recording medium
Publication Date: 2018.12.05 NIPPON STEEL & SUMITOMO METAL CORP
  • EP2136197B1 patent drawingFigure 1
  • EP2136197B1 patent drawingFigure 2
  • EP2136197B1 patent drawingFigure 3

AI summary

When discretizing an analysis target part into plural elements and performing analysis, sheet thickness reduction rate or maximum principal strain at an equivalent position including a same element is compared by either a manner of combining two adjacent elements after the analysis or a manner of changing an element discretization size with two types and performing the analysis, and the element where the difference is large is extracted as a fracture risk portion. With this structure, a fracture risk portion can be extracted reliably when a fracture is predicted by a finite element method.