1、 GUIDE FOR SPECTRAL-BASED FATIGUE ANALYSIS FOR FLOATING PRODUCTION, STORAGE AND OFFLOADING (FPSO) INSTALLATIONS MAY 2010 NOTICE NO. 2 January 2018 The following Changes were approved by the ABS Rules Committee on 30 May 2017 and become EFFECTIVE AS OF 1 JANUARY 2018. (See http:/www.eagle.org for the
2、 consolidated version of the Guide for Spectral-Based Fatigue Analysis for Floating Production, Storage and Offloading (FPSO) Installations, 2010, with all Notices and Corrigenda incorporated.) Notes - The date in the parentheses means the date that the Rule becomes effective for new construction ba
3、sed on the contract date for construction. (See 1-1-4/3.3 of the ABS Rules for Conditions of Classification Offshore Units and Structures (Part 1).) SECTION 9 FATIGUE LIFE (DAMAGE) CALCULATION AND ACCEPTANCE CRITERIA 5 Low Cycle Fatigue Damage 5.5 Stress Range Calculation (Revise Subparagraph 9/5.5.
4、1, as follows.) 5.5.1 Elastic Hot Spot Stress Range Calculation (2018) (Preceding text remains unchanged.) The number of cycles for installations loading and unloading, nLCF, is assumed to be not less than 1200 for 20 years. The actual cycles of loading/offloading may be used for historical sites in
5、 FPSO phase. Assume there are 108wave cycles within 20 years, n is then equal to: LCFn2108In general, it is expected that the time in tension will not equal the time in compression. For a conservative analysis, the larger of the two might be selected. ABSGUIDE FOR SPECTRAL-BASED FATIGUE ANALYSIS FOR
6、 FPSO INSTALLATIONS .2010 1 Notice No. 2 January 2018 (Revise Subparagraph 9/5.5.3, as follows.) 5.5.3 Low Cycle S-N Curve and Damage Calculation (2018) The design S-N curve in the low cycle region is defined in Section 9, Figure 4. It may be considered to be a modified D-Curve. The low cycle fatigu
7、e (LCF) design S-N curve is given as: NSq= B for 100 N 104where q = 2.4 B = 3.51 1010(MPa units) It is assumed that the LCF design S-N curve is applicable to static induced stresses. Basic application of Miners rule produces the expression of static stress damage DMLCFis: DMLCF= BSNqLLCFnLCFis the total cycles of loading/offloading, which is not to be less than 1200 for a ship-type installation to be operated for 20 years. The actual cycles of loading/offloading may be used for historical sites in FPSO phase. 2 ABSGUIDE FOR SPECTRAL-BASED FATIGUE ANALYSIS FOR FPSO INSTALLATIONS .2010
