Integrated Machine Vision System for Evaluating Hole Expansion Ratio of Advanced High-Strength Steels

Abstract

In this paper, we propose a new method to estimate the hole expansion ratio (HER) using an integrated analysis system. To precisely measure the HER, three kinds of analysis methods (computer vision, punch load, and acoustic emission) were utilized to detect edge cracks during a hole expansion test. Cracks can be recognized by employing both computer vision and a punch load analysis system to determine the moment of crack initiation. However, the acoustic emission analysis system has difficulty detecting the instant of crack appearance since the magnitude of the audio signal is drowned out by noise from the press, which interrupts the differentiation of crack configuration. To enhance the accuracy for determining the HER, an integrated analysis system that combines computer vision with punch load analysis, and improves on the shortcomings of each analysis system, is newly suggested.

Application of Digital Image Processing Techniques to Detect Through-Thickness Crack in Hole Expansion Test

“…This algorithm can automatically detect the presence of a through-thickness crack and calculate the corresponding HER value. Park et al [24] developed an integrated analysis system that combines computer vision with punch load analysis to improve the accuracy of the measurements. The system includes an automated image processing algorithm, which reduces the risk of human error and enables more precise prediction of the measurements.…”