충격시험

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충격시험에 대한 레포트 입니다.

목차

Ⅰ. 서론 ················································································ 1
1.1. 충격시험 목적································································ 1
1.2. 관련이론··········································································· 1
1.3. 용어정리·································································· 5
1.3.1 연성··································································· 5
1.3.2 취성··································································· 5
1.3.3 인성································································· 6
1.3.4 파단에너지························································6
1.4. 충격 측정 방법····································································· 7
1.4.1 샤르피(Charpy) 충격시험기···················································· 7
1.4.2 아이조드(izod) 충격시험기················································· 8
1.5. 충격시험종류···································································9

Ⅱ. 본론 ··············································································· 11
2.1 시험기구 및 재료································································ 11
2.2 시험편···································································· 12
2.3 시험 순서 및 방법·······························································13
2.4 시험시 주의사항·······························································14
2.5 시험결과에 영향 주는 인자····················································15


Ⅲ. 결과 및 고찰 ································································· 18
3.1 실험값························································· 18
3.2 실험 결과 고찰························································· 19
3.3 고찰··············································································20


Ⅳ. 참고문헌········································································ 20

Ⅰ. 서론

본문내용

Ⅰ. 서론
1.1 충격시험 목적
구조물이나 기계 장치를 개발하는 경우, 개발자들은 이들 장치가 받게 될 하중의 형태에 대한 고려를 해야 한다. 하중은 통상적으로 정적하중과 동적하중으로 구분할 수 있다. 그 중에서 동적하중의 대표적인 예로 충격하중을 꼽을 수 있다. 충격시험의 목적은 어떤 재료가 충격하중 내에서 취성으로 인해 파괴하는지 연성으로 인해 파괴하는지 즉, 인성(toughness)정도를 확인하고자 하는 것이다.
충격시험은 충격하중을 가하는 방법에 따라 충격 인장시험, 충격압축시험, 충격 비틀림 시험등으로 구분하며 공업적으로 시험하는 것은 주로 노치가 되어있는 시험편을 사용하는 충격 굽힘시험으로 가장 광범위하게 사용한다.
충격에 의한 시험편의 파괴에 요하는 0.001∼0.00005초 정도의 시험으로 충격굽힘을 제외한 충격인장이나 충격 압력은 충격 파괴 에너지를 구하기 위한 시험법으로 주로 고속 변형할 때 재료의 구성비를 구하는 학술적 연구의 시험이다.
1.2 관련이론
a) 충격하중
일반적으로 구조물 또는 기계의 부재들은 동적 하중을 받게 되므로 동적 하중에 대한 저항력 즉, 취성이나 인성은 재료의 중요한 기계적 성질이 된다. 충격하중은 동적 하중의 하나로서 재료가 충격하중을 받게 되면 하중만큼의 최대 변형이 일어나고 그 이후 즉시 원상태로 돌아가려는 거동을 보인다. 이것은 마치 스프링 위에 질량을 떨어뜨리는 것과 유사하게 충격방향에 대해 진동이 일어날 것이다.
이 진동은 감쇄효과 때문에 곧 중단될 것이고 곧 정지상태로 들어간다. 이와 같이 재료가 충격하중을 받았을 때의 거동은 대단히 복잡하고 이에 대한 해석 역시 고도의 수학적 능력이 필요하게 된다. 그러나 변형 에너지의 개념을 도입하고 약간의 과정을 단순화하면 대략적인 해석이 가능하게 된다.
b) 충격 실험
일반적으로 충격 시험은 에너지의 개념으로 실행되며, 충격 시험(impact test)에서 나타나는 특수한 점은 다음과 같다.
- 보통 충격 시험은 동적 시험이므로 정적하중에 대한 에너지와 차이가 많다.
- 상온에서 연성 파괴(ductile fracture)되는 재료라 할지라도 어떤 온도 이하에 서는 급격히 여린 성질을 가져 깨짐 파괴(brittle fracture)를 이루는 일이 있다.
- 시편의 노치효과(notch impact)를 많이 받는다.

참고 자료

- 재료기초실험교과서