Comparison of Optical Strain Analysis and Circular Grid Analysis in Sheet Metal Forming

2007 ◽  
Author(s):  
K. Hariharan ◽  
S. Suresh
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Strain Analysis ◽  
Grid Analysis ◽  
Optical Strain ◽  
Circular Grid

A new method for circular grid analysis in the sheet metal forming test

2000 ◽  
Vol 40 (2) ◽  
pp. 190-196 ◽  
Author(s):  
C. -C. Wang ◽  
J. Lee ◽  
L. -W. Chen ◽  
H. -Y. Lai
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
New Method ◽  
Grid Analysis ◽  
Circular Grid

A New Approach to the Evaluation of Forming Limits in Sheet Metal Forming

2015 ◽  
Vol 639 ◽  
pp. 333-338 ◽  
Author(s):  
Marion Merklein ◽  
Andreas Maier ◽  
Daniel Kinnstätter ◽  
Christian Jaremenko ◽  
Emanuela Affronti
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Strain History ◽  
Failure Behavior ◽  
Forming Limits ◽  
Optical Strain Measurement ◽  
Optical Strain

The forming limit diagram (FLD) is at the moment the most important method for the prediction of failure within sheet metal forming operations. Key idea is the detection of the onset of necking in dependency of different sample geometry. Whereas the standardized evaluation methods provides very robust and reliable results for conventional materials like deep drawing steels, the determined forming limits for modern light materials are often too conservative due to the different failure behavior. Therefore, within this contribution a new and innovative approach for the identification of the onset of necking will be presented. By using a pattern recognition-based approach in combination with an optical strain measurement system the complete strain history during the test can be evaluated. The principal procedure as well as the first promising results are presented and discussed.

CGA: An image processing based software for surface strain analysis in sheet metal forming

2021 ◽  
pp. 030932472199657
Author(s):  
Wankhede Pankaj ◽  
Tejas Radhakrishnan ◽  
Kurra Suresh ◽  
Sudha Radhika
Keyword(s):  
Image Processing ◽  
Sheet Metal ◽  
Measurement System ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Strain Measurement ◽  
Strain Analysis ◽  
Surface Strain ◽  
Percentage Error ◽  
Flat Sheet

Strain analysis is an essential step in sheet forming applications to understand the deformation behaviour of the material. The strain analysis is conventionally performed by Circle Grid Analysis (CGA). In CGA, a grid of circles with 2 mm–5 mm diameter is printed on a flat sheet and deformed into the required shape. The length of major and minor axes of the deformed ellipses are measured to estimate the strains at different locations of the formed component. The major and minor axes length of the deformed ellipses are measured either by using a manual method or automatic methods. The automated methods are faster and accurate compared to manual methods, but to perform strain measurement using commercially available automatic strain measurement system, is very expensive. Therefore, in this paper, an image processing based software has been developed with user-friendly Graphical User Interface (GUI) for strain measurement and analysis in sheet metal forming operations. The software has been tested on images obtained by printing the ellipses of known dimensions on the flat sheet by laser etching, electrochemical etching and screen printing, which are generally used for printing circular grids on flat sheets for strain analysis in sheet metal forming. It is observed that the edges of the laser engraved ellipse are very slim and easily detected by software compared to other grid printing methods. The developed software can measure the ellipse dimensions with a maximum absolute percentage error of 1.975%. Further, the results of CGA software has been compared with the commercial strain measurement system called Grid Pattern Analyzer (GPA). The mean absolute error in strain measurement using CGA and GPA was found to be 0.0106 and 0.0178, respectively. The statistical test results reveal that there is no evidence to support a claim that there is a difference in mean performance between the two methods.

Strain Analysis of NC Incremental Sheet Metal Forming

2011 ◽  
Vol 418-420 ◽  
pp. 1586-1589 ◽  
Author(s):  
Liu Ru Zhou
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Strain Analysis ◽  
Forming Process ◽  
Strain Calculation ◽  
Incremental Sheet Metal Forming ◽  
Metal Forming Process ◽  
Web Experiment

NC incremental sheet metal forming process is a flexible process which is to form the sheet point by point on NC forming machine according to the prepared program .The forming principle of NC incremental sheet metal forming process is presented. The strain is analysed. A formula of strain calculation is drawn in the NC incremental sheet metal forming process and verified by web experiment.

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