조선 해양 구조물용 강재의 소성 및 파단 특성 V: 온도 의존성을 고려한 변형률 속도에 관한 실험적 연구
Plasticity and Fracture Behaviors of Marine Structural Steel, Part V: Effects of Strain Rate and Temperature
2
조회
0
다운로드
4
인용
0
참고문헌
키워드
초록
This is the fifth in a series of companion papers dealing with the dynamic hardening properties of various marine structural steels at intermediate strain rates. Five steps of strain rate levels (0.001, 1, 10, 100, 200/s) and three steps of temperature levels (LT (-40℃), RT, and HT (200℃)) were taken into account for the dynamic tensile tests of three types of marine structural steels: API 2W50 and Classifications EH36and DH36. The total number of specimens was 180 pieces. It was seen that the effects of dynamic hardening became clearer at LT than at RT. Dynamic strain aging accompanying serrated flow stress curves was also observed from high temperature tests for all kinds of steels. The dynamic hardening factors (DHFs) at the two temperature levels of LT and RT were derived at the three plastic strain levels of 0.05, 0.10, 0.15 from dynamic tensile tests. Meanwhile, no DHFs were found for the high temperature tests because a slight negative strain rate dependency due to dynamic strain aging had occurred. A new formulation to determine material constant D in a Cowper-Symonds constitutive equation is provided as a function of the plastic strain rate, as well as the plastic strain level. The proposed formula is verified by comparing with test flow stress curves, not only at intermediate strain rate ranges but also at high strain rate ranges.
Abstract
This is the fifth in a series of companion papers dealing with the dynamic hardening properties of various marine structural steels at intermediate strain rates. Five steps of strain rate levels (0.001, 1, 10, 100, 200/s) and three steps of temperature levels (LT (-40℃), RT, and HT (200℃)) were taken into account for the dynamic tensile tests of three types of marine structural steels: API 2W50 and Classifications EH36and DH36. The total number of specimens was 180 pieces. It was seen that the effects of dynamic hardening became clearer at LT than at RT. Dynamic strain aging accompanying serrated flow stress curves was also observed from high temperature tests for all kinds of steels. The dynamic hardening factors (DHFs) at the two temperature levels of LT and RT were derived at the three plastic strain levels of 0.05, 0.10, 0.15 from dynamic tensile tests. Meanwhile, no DHFs were found for the high temperature tests because a slight negative strain rate dependency due to dynamic strain aging had occurred. A new formulation to determine material constant D in a Cowper-Symonds constitutive equation is provided as a function of the plastic strain rate, as well as the plastic strain level. The proposed formula is verified by comparing with test flow stress curves, not only at intermediate strain rate ranges but also at high strain rate ranges.
참고문헌 (16)
- American Society for Testing and Materials (ASTM), "E 8－04 Standard Test Methods for Tension Testing of Metallic Materials", ~ (2004)
- American Petroleum Institute (API), "Recommended Practice 2FB: Design of Offshore Facilities Against Fire and Blast Loading", ~ (2006)
- British Standard (BS), "BS 5950: Part 8. Code of Practice for Fire Resistance Design", ~ (1990)
- Choung, J, "Impact test simulations of stiffened plates using the micromechanical porous plasticity model", OCEAN ENGINEERING, 37, pp.749~756 (2010), PERGAMON-ELSEVIER SCIENCE LTD
- 정준모, "조선 해양 구조물용 강재의 소성 및 파단 특성 I: 변형률 경화 및 변형률 속도 경화의 이론적 배경", 한국해양공학회지, 25(2), pp.134~144 (2011), 한국해양공학회
- 정준모, "조선 해양 구조물용 강재의 소성 및 파단 특성 II: 파단의 이론적 배경", 한국해양공학회지, 25(2), pp.92~100 (2011), 한국해양공학회
- 정준모, "조선 해양 구조물용 강재의 소성 및 파단 특성 III: 파단 변형률에 관한 실험적 연구", 한국해양공학회지, 25(3), pp.53~65 (2011), 한국해양공학회
- 정준모, "조선 해양 구조물용 강재의 소성 및 파단 특성 IV: 고온 기계적 물성치에 관한 실험적 연구", 한국해양공학회지, 25(3), pp.66~72 (2011), 한국해양공학회
- Eurocode 3: Design of Steel Structures. Part 1-2: General Rules－Structural Fire Design, "European Committee for Standardisation (CEN)", Belgium. CEN, ~, pp.EN 1993-2-1 (1995)
- Offshore Technology Report OTO 2001, "020-Elevated Temperature and High Strain Rate Properties of Offshore Steels", Health and Safety Executive, 2001
- H.HUH, "CRASHWORTHINESS ASSESSMENT OF SIDE IMPACT OF AN AUTO-BODY WITH 60TRIP STEEL FOR SIDE MEMBERS", International Journal of Automotive Technology, 4(3), pp.149~156 (2003), 한국자동차공학회
- Huh, H, "Dynamic tensile characteristics of TRIP-type and DP-type steel sheets for an auto-body", INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 50(5), pp.918~931 (2008), PERGAMON-ELSEVIER SCIENCE LTD
- Lee, H. J, "A Study on the Application of Material Properties in Ship Collision Analysis", Proceedings of the Annual Autumn Meeting SNAK, pp.1050~1057 (2007)
- Effect of Strain Rate in Full Vehicle Grontal Crash Analysis, "Mahadevan, K", SAE, ~, pp.SAE Paper No. 2000-01-0625 (2000)
- Nemat-Nasser, S, "Thermomechanical Response of DH-36 Structural Steel over a Wide Range of Strain Rates and Temperature", Mech. Mat, 35, pp.1023~1047 (2003)
- Paik, J.K, "Ship-Shaped Offshore Installations: Design, Building, and Operation" (2007), Cambridge University Press