Journal of Ocean Engineering and Technology (한국해양공학회지)

Korean Society of Ocean Engineers (한국해양공학회)
권호 표지
DOI QR코드

DOI QR Code

Plasticity and Fracture Behaviors of Marine Structural Steel, Part V: Effects of Strain Rate and Temperature

조선 해양 구조물용 강재의 소성 및 파단 특성 V: 온도 의존성을 고려한 변형률 속도에 관한 실험적 연구

  • Choung, Joon-Mo (Dep't of Naval Architecture and Ocean Engineering, INHA University) ;
  • Im, Sung-Woo (Steel Structure Research Lab., RIST) ;
  • Kim, Kyung-Su (Dep't of Naval Architecture and Ocean Engineering, INHA University)
  • 정준모 (인하대학교 조선해양공학과) ;
  • 임성우 (포항산업과학연구원 강구조연구소) ;
  • 김경수 (인하대학교 조선해양공학과)
  • Received : 2011.04.21
  • Accepted : 2011.06.20
  • Published : 2011.06.30
Download PDF
⟨ Previous Next ⟩

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 ($-40^{\circ}C$), RT, and HT ($200^{\circ}C$)) were taken into account for the dynamic tensile tests of three types of marine structural steels: API 2W50 and Classifications EH36 and 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.

Keywords

References

  1. American Society for Testing and Materials (ASTM) (2004). E 8－04 Standard Test Methods for Tension Testing of Metallic Materials.
  2. American Petroleum Institute (API) (2006), Recommended Practice 2FB: Design of Offshore Facilities Against Fire and Blast Loading.
  3. British Standard (BS) (1990). BS 5950: Part 8. Code of Practice for Fire Resistance Design.
  4. Choung, J., Cho, S. R., Kim, K. S. (2010). "Impact Test Simulations of Stiffened Plates Using the Micromechanical Porous Plasticity Model". Ocean Engineering, Vol 37, pp 749-756. https://doi.org/10.1016/j.oceaneng.2010.02.015
  5. Choung, J., Shim, C.S., and Kim, K.S. (2011a). "Plasticity and Fracture Behaviors of a Marine Structural Steel, Part I: Technical Backgrounds of Strain Hardening and Rate Hardening". Journal of Ocean Engineering and Technology (to be published).
  6. Choung, J., Shim, C.S., and Kim, K.S. (2011b). "Plasticity and Fracture Behaviors of a Marine Structural Steel, Part II: Theoretical Backgrounds of Fracture". Journal of Ocean Engineering and Technology (to be published).
  7. Choung, J., Shim, C.S., and Kim, K.S. (2011c). "Plasticity and Fracture Behaviors of a Marine Structural Steel, Part III: Experimental Study on Failure Strain". Journal of Ocean Engineering and Technology (to be published).
  8. Choung, J., Im, S.W., Kim, K.S. (2011d). "Plasticity and Fracture Behaviors of a Marine Structural Steel, Part IV: Experimental Study on Mechanical Properties at ElevatedTemperatures". Journal of Ocean Engineering and Technology (to be published).
  9. European Committee for Standardisation (CEN) (1995).
  10. Eurocode 3: Design of Steel Structures. Part 1-2: General Rules－Structural Fire Design (EN 1993-2-1). Brussels, Belgium. CEN
  11. Health and Safety Executive (2001), Offshore Technology Report OTO 2001/020-Elevated Temperature and High Strain Rate Properties of Offshore Steels
  12. Huh, H., Lim, J. H., Song, J. H., Lee, K. S., Lee, Y. W., Han, S. S. (2003). "Crashworthiness Assessment of Side Impact of an Auto-Body with 60trip Steel for Side Members". International Journal of Automotive Technology, Vol 4, No 3, pp 149.156.
  13. Huh, H., Kim, S.B., Son, J.J., Lim, J.H. (2008). "Dynamic Tensile Characteristics of TRIP-type and DP-type Steel Sheets for an Auto-body". International Journal of Mechanical Sciences, Vol 50, pp 918-931 https://doi.org/10.1016/j.ijmecsci.2007.09.004
  14. Lee, H. J. and Kim, B. J. (2007). "A Study on the Application of Material Properties in Ship Collision Analysis", Proceedings of the Annual Autumn Meeting SNAK, pp 1050-1057
  15. Mahadevan, K., Liang, P., Fekete, J. (2000). "Effect of Strain Rate in Full Vehicle Grontal Crash Analysis". SAE Paper No. 2000-01-0625.
  16. Nemat-Nasser, S. and Guo, W.G. (2003). "Thermomechanical Response of DH-36 Structural Steel over a Wide Range of Strain Rates and Temperature", Mech. Mat., Vol 35, pp 1023-1047. https://doi.org/10.1016/S0167-6636(02)00323-X
  17. Paik, J.K., Thayamballi, A.T. (2007). Ship-Shaped Offshore Installations: Design, Building, and Operation. Cambridge University Press. New York, USA.