Stress Analysis of Arctic Environment Pipelines Using Finite Element Method

Abstract

학위논문 (석사)-- 서울대학교 대학원 : 재료공학부, 2014. 8. 오규환.최근 비교적 에너지자원 확보가 용이했던 육상의 화석연료가 고 갈됨에 따라 이를 확보하기 위한 장소가 육지에서 그 동안 관심을 두지 않았던 극한지로 이동하고 있으며, 극한지 자원확보를 위한 국 가간의 경쟁이 치열하다. 이러한 극한지 에너지자원 개발 시장을 선점하기 위해서는 국내 환경과 상이한 극한지 대상 건설기술 개발이 필수적이다. 극한지 가 스배관의 경우 영하 20℃에서 영상 20℃까지의 온도변화에 따라 국내에서 볼 수 없는 해동침하 등의 새로운 주변 환경의 영향을 많 이 받기 때문에 이에 맞춰 새로운 해석모델개발이 필요하다. 이에 대한 실제 실험을 진행할 경우 엄청난 시간과 비용이 들지만 유한 요소해석법을 활용한다면 배관에 미치는 응력을 빠른 시간에 적은 비용으로 분석할 수 있다. 본 연구에서는 유한요소해석을 활용하여 극한지 가스배관과 외 부환경을 모델링화 시켰으며 극한지의 토양 및 배관의 물성을 적용 하여 이때 발생하는 해동침하에 따른 배관이 받는 응력 및 변위에 대해 알아보고자 한다. 유한요소해석 툴로는 상용 프로그램인 ABAQUS를 사용하였다.초록 ·················································································································· i 목차 ················································································································· ii Figure list ································································································· iv Table list ·································································································· v 1. 서론 ··········································································································· 1 1.1연구의 필요성 ···················································································· 1 1.2 연구의 방향 ······················································································ 3 2. 이론적 배경 ····························································································· 5 2.1 배관에 작용하는 응력 ································································ 5 2.1.1 내압에 의한 응력 ···························································· 5 2.1.2 지반침하에 의한 응력 ···················································· 7 2.1.3 Mohr Coulomb 식 ···················································· 10 2.2 배관두께를 결정하는 식 ·························································· 12 2.3 극한지 토양 환경 ······································································ 13 3. 해동침하에 대한 유한요소법 적용 ··················································· 18 3.1 해석모델 구성 ············································································ 18 3.1.1 배관 모델 및 물성 ························································ 20 3.1.2 토양 모델 및 물성 ························································ 23 3.2 해석방법 및 경계조건 ······························································ 27 3.3 해석 시 가정사항 ······································································ 30 4. 해석결과 ································································································· 32 4.1 배관매설 깊이에 따른 영향 ···················································· 33 4.2 해동침하 길이에 따른 영향 ···················································· 37 4.3 해동침하 깊이에 따른 영향 ···················································· 44 5. 결론 ········································································································· 49 참고문헌 ······································································································· 51 Abstract ···································································································· 53Maste