Circle Grid Analysis (CGA)

Circle Grid Analysis is a sophisticated diagnostic technique used to measure the strain distribution in sheet metal after a forming operation. A pattern of small circles is etched onto the flat strip. After the part is formed, these circles deform into ellipses. By measuring the change in the major and minor axes, engineers can calculate the exact elongation and thinning the metal underwent. This data is plotted on a Forming Limit Diagram (FLD) to predict where the material is likely to fail or tear.