Recent Developments in the Ultimate Strength Assessment of Tubular Joints: A Nonlinear Numerical Treatment

Abstract

From an ul timate strength standpoi nt, research to date on tubul ar joi nts has concentrated on testing work.However, the high costs associated with testing has directed recent efforts towards non-l i near anal ys is techni ques to generate data and information. This paper gives a background to these efforts and descri bes the current status.The manner of application of numerical techniques is described and discussed by reference to various separate investigations which have been carried out, or are currently underway.New strength data generated using the non-linear finite-element program FINAS are presented and discussed. These data, together with others generated el sewhere, are compared where appropri ate with existing experimental data and API RP2A recommendations.Areas where future effort needs to be directed are identified and presented.The non-linear techni~ues (and the results) discussed herein demonstrate their applicability to generate, new information in a much more cost-effective manner than the high-cost and difficult experimentation that has been undertaken to date. Further, the flexibil ity offered by such techniques can be applied in practical areas where experimentation becomes prohibitively expensive and difficult, ego for complex joints and joints with realistic load scenarios (hydrostatic loading for example). Notwithstanding this aspect, it is recognised that non-linear numerical techniques represent a developing technology, and the need for experimental data will remain for a variety of reasons, not 1east the need to have rel evant test results to assist in the all-important calibration of the numerical techniques.References and illustrations at end of paper. 399