Thin Plate Residual Stress Mapping by Fin Cutting
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Solution Overview
Problem
Existing methods for measuring residual stress in thin plates are qualitative, failing to provide a quantitative characterization of the stress distribution, which hinders the optimization of manufacturing processes for high-performance thin plates used in aerospace and chip packaging.
Innovation Solution
A method involving prearranging fins parallel to the length of the thin plate, cutting these fins at intervals, and measuring strain and residual stress to determine the distribution of residual stress in both the width and thickness directions, allowing for accurate quantification of residual stress through computational formulas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single-side corrosion method is used to evaluate residual stress, then the measurement process is simple, but the measurement precision is insufficient as it can only qualitatively determine stress magnitude
Solution Approach 1:
The thin plate is segmented into multiple fins along the width direction, with each fin independently measuring residual stress at its location. This segmentation enables quantitative characterization of residual stress distribution across the plate width, transforming the qualitative single-side corrosion method into a quantitative multi-point measurement system.
Solution Approach 2:
The measurement approach transitions from single-side qualitative assessment to multi-dimensional quantitative characterization by measuring residual stress not only in the width direction through multiple fins but also in the thickness direction through sequential cutting, achieving comprehensive spatial distribution mapping.
2Measurement precision
If multiple fins are cut and measured to obtain quantitative residual stress distribution, then the measurement precision improves, but the device complexity and measurement time increase
Solution Approach 1:
The plate is divided into multiple fins that can be independently measured, allowing parallel or sequential measurement of residual stress at different width positions. This segmentation strategy achieves comprehensive spatial coverage while maintaining relatively simple individual measurement procedures.
Solution Approach 2:
The fins are pre-cut along the width direction before thickness-direction cutting, establishing a systematic measurement framework. This preliminary segmentation prepares the structure for subsequent sequential thickness cutting, organizing the complex multi-dimensional measurement into manageable staged operations.
3Measurement precision
If sequential cutting in thickness direction is performed to obtain stress distribution, then the measurement precision improves, but the measurement time increases
Solution Approach 1:
The thickness-direction measurement is performed through periodic sequential cutting at regular intervals, systematically exposing different thickness layers for residual stress measurement. This periodic cutting approach enables comprehensive thickness-direction characterization while maintaining a structured, efficient measurement rhythm.
Solution Approach 2:
The width-direction fin segmentation is completed as a preliminary action before thickness-direction cutting begins. This pre-organization of measurement units (fins) allows efficient sequential thickness cutting without requiring re-positioning or re-setup, reducing overall measurement time.
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
Enables accurate and reliable quantification of residual stress distribution in thin plates, facilitating better deformation control during processing and enhancing manufacturing efficiency.
Implementation Method 1
computing x-direction strain εi0 and x-direction residual stress σi0 in the length direction of the thin plate borne by each fin according to lengths of each fin before and after cutting
Implementation Method 2
The thin plates have low bending stiffness on account of thinness, and will largely deform even under low residual stress during a removal process
Data Source
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AI summary
Provided is a method for measuring residual stress in a thin plate. The method includes: S1: prearranging and cutting a plurality of fins that have the same length and are parallel to a length direction of the thin plate at equal intervals in a width direction of the thin plate, where the fins have fixed ends and movable ends, computing x-direction strain εi0 and x-direction residual stress σi0 in the length direction of the thin plate borne by each fin according to lengths of each fin before and after cutting, and obtaining distribution of x-direction residual stress in the width direction of the thin plate according to all σi0; S2: repeatedly cutting the fixed ends in a thickness direction of the thin plate, computing a total cutting depth Zij and x-direction residual stress σij of each fin after each cutting, and obtaining distribution of x-direction residual stress in the thickness direction of the thin plate borne by an ith fin according to all σij; and S3: computing distribution σx, σx = σi0 + σij, of x-direction residual stress on a yz cross section of the thin plate according to σi0 obtained in S1 and corresponding σij in S2. According to this solution, a distribution rule of the residual stress in a thickness of the thin plate is quantitatively characterized.