Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Development of Hole Expansion Test for Sheet Materials Using Pattern-Recognition Technique

형태 인식 기술을 이용한 판재의 홀 확장성 평가 시스템 개발

  • Jang, Seung Hyun (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Kim, Chan Il (Institute of Mechanical Engineering Technology, Kyungpook Nat'l Univ.) ;
  • Yang, Seung Han (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Kim, Young Suk (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.)
  • Received : 2012.05.29
  • Accepted : 2012.10.16
  • Published : 2013.02.04
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Abstract

Nowadays, one of the most interested area of automobile industry is the production of vehicle which has collision safety and ability to produce less amount of $CO_2$. The achievement of such a dual performance is done by choosing the materials like dual phase steel, ferrite bainite steel, etc. These steels have been used in automotive chassis and body parts, and also used to be formed by hole flanging to meet the goal of strength and design requirement. The formability of sheet material was experimented by hole expansion test and the judgement relies on human eye and his experience. This manual judgement involves many errors and large deviation. This paper develops the automatic crack recognition system which finds a crack based on CCD image to complement the problem of the current method depending on human's sense.

오늘날 자동차 산업에서 가장 대두되고 있는 충돌 안전성과 배기가스의 감축을 위해서 dual phase 강, ferrite bainite 강 등의 고강도 강판이 개발 되었다. 이러한 강재는 주로 차체 구조부에 적용되며, 적용시에 차체 구조부가 가져야 하는 강도와 디자인 적인 측면에서 사용자의 요구에 맞추기 위하여 홀 플랜징 가공이 자주 사용된다. 이때 재료의 성형성을 알아보기 위한 홀 확장성 평가가 수행된다. 홀 확장실험에서는 크랙 생성 전후의 하중의 차이가 매우 작기 때문에, 단축 인장 시험에서와 같이 하중의 변화로 크랙 발생 유무를 판단하기가 쉽지 않다. 따라서 본 연구에서는 기존의 홀 확장성 평가에서 사람의 눈으로 크랙의 발생 유무를 판단하는 방법의 부정확성을 보완하기 위해 CCD 카메라를 이용하여 크랙의 발생 유무를 판단하는 시스템을 개발하였다.

Keywords

References

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