API SPEC 16R:1997 pdf download.Specification for Marine Drilling Riser Couplings
1 SCOPE
1.1 Purpose
This specification pertains to the design, rating, manufac- turing and testing of marine drilling riser couplings. Cou- pling capacity ratings are established to enable the grouping of coupling models according to their maximum stresses developed under specific levels of loading, regardless of man- ufacturer or method of make-up. This specification relates directly to API Recommended Practice 16Q, which pertains to the design, selection, and operation of the marine drilling riser system as a whole.
1.2 Organization
This specification is organized into distinct sections for easy reference. Section 3 contains a description of the func- tion of marine riser couplings, along with the definition of rel- evant terms. Section 4 includes service classifications and design criteria. Materials and welding requirements are included in Section 5 and dimensions in Section 6. Section 7 covers quality control. Design qualification testing require- ments are spelled out in Section 8, and product marking requirements are provided in Section 9. Section 10 defines requirements for operation and Maintenance manuals. Appendixes A, B, and C provide analysis, testing, and design, information.
4.4 Stress Distribution Verification Test
After completion of the design studies, a prototype (or multiple prototypes) of the riser coupling shall be tested to verify the stress analysis. The testing has two primary objec- tives: to verify any assumptions which were made about pre- loading, separation behavior, and friction coefficients and to substantiate the analytical stress predictions. Strain gauge data shall be used to measure preload stresses as they relate to make-up load or displacement. Friction coef- ficients shall be varied (including at least two values) to estab- lish sensitivity. The coupling design load shall be applied to verify any assumption made in the analysis regarding separation. Strain gauges shall be placed as near as physically possible to at least five of the most highly stressed regions as predicted by the finite element analyses performed in accordance with 4.3 and in five locations away from stress concentrations. Rosettes shall be used. All strain gauge readings and the asso- ciated loading conditions shall be recorded in a manner that they may be retained as part of the coupling design documentation. Normal design qualification tests may be performed simul- taneously with this stress distribution verification testing. These are defined in 8.2. Note: It is often difficult to acquire sufficient strain data to totally correlate with the analytical results. High stress areas may be inaccessible and are sometimes so small that a strain gauge gives an average rather than the peak value. The testing should serve to verify the pattern of strain in regions sur- rounding the critical points.
API SPEC 16R:1997 pdf download
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