...Pro<eedIn8' of the First (1990) Elilopean Offshore Mechamo SymposIum Trondhelm, Norway, 20-22 August 1990 CopYlIght © 1990 by The In/flnatlOnal Souery of Offshore and Polat Engineers ISBN 0-9626104-4-5 THE STATIC STRENGTH AND STIFFNESS OF MULTIPLANAR TUBULAR STEEL X-JOINTS G J van del' Vegte and J...

... motion response regular wave aqwanaut amplitude wave frequency well control buoy stiffness annular pressure drilling controls and umbilicals hull EXPERIENCE OF SINGLE TETHER BUOY DYNAMICS M Blooklng Cameron Atkll1s Technology Limited, Epsom E R leffelYs Conoco (UK) Limited London, U K...

... Imaginary unit = A static catenary stiffness elastic, aXial line stiffness frequency dependent geom stiffness stiffness due to drag resistance generalized stiffness coeffiCient local coordinate generalized mass submerged weight of the cable moment arm of drag or inertia forces suspended length of the line...

... (6,7,8) Upheaval buckling is a destructive phenomenon prmcipally affecting laterally restrained small diameter pipelines working at high temperature and pressure BucklIng, which is triggered by seabed Irregularities, is resisted by a combination of pipe bending stiffness and download arising from pipehne...

... to the rela- tive velocity between the structure and the fluid, is considered separately in the exciting force vector. 2.4 Stiffness Matrix The stiffness matrix is calculated from the hydrostatic and ten- don forces required to restore the platform to its equilibrium position for an arbitrary displacement...

... by stretching along its tangential direction. It is therefore evident that, for sufficiently high frequencies, the nonlinear dynamic response of an elastic cable in deep water is dominated by its elastic stiffness, the reduction of which would improve the dynamic performance of the line_ This can be achieved...

... is leading to the capability to predict the service lIfe of dynamic flexible risers. The motions and loads on flexible risers require knowledge of static mechanical properties of the pipe Wellstream has developed a family of simple and accurate methods for calculating static failure and stiffness properties...

... of the anchor damage to failure statistics and stressing its importance for an assessment of safety of pipelines. ship mechanics anchor stiffness operation fluke frequency anchor damage offshore pipeline scenario north sea protection cover deflection interaction deformation procedure...

... behaviour of the platform such as added mass, marine growth and axial pile group stiffness. A parametric structural dynamic identification is achieved by the modal parameter technique, comparing the theoretical and experimental response of the platform. I. INTRODUCTION This paper is concerned with a dynamic...

...; a description of the methodology adopted to inter- pret the results, in particular to define the local parameters of stiffness and damping given by the bearing soil; some relevant findings, where the limits of the adopted techniques with respect to the goals and potential use of the results are defined...

... stiffness properties of the bearing element. 3. Demonstrate sufficient load bearing capacity. 4. Justify adequate fatigue s.trength and wear resistance for 30 years service. - Test Set Up The principles of the test rig used are illustrated in Figure 5. A prototype radial bearing element was mounted...

... hostile environments like the North Sea. The horizontal stiffness of a jack-up platform is typically an order of magnitude less than the stiffness of a corresponding jacket structure. Thus the dynamic effects become significant as the fundamental period of a jack-up may typically be m the range 4-8...