The factors that affect the natural frequencies and mode shapes, such as length, diameter, lumped mass, and boundary conditions, were analyzed. Four drill pipe models of different sizes were used in the experiments which were measured using piezoelectric acceleration sensors and fiber Bragg grating sensors, respectively. The natural frequencies and mode shapes are obtained by using the differential transformation method. A fourth-order partial differential equation with variable coefficients was established based on Euler–Bernoulli beam theory. This expands the current practice of riser fatigue analysis of only using the regular wave approach, to using an irregular wave approach employing the rainflow counting method.In this study, experimental and numerical investigations on the vibration characteristics of a drill pipe during the lowering of a subsea Xmas tree were presented. This development permits more realistic riser structural properties to be modeled in the dynamic simulation, and reports detailed time history stress or strain results of the strength components of the riser. A study is presented to illustrate the difference in the riser dynamic responses with and without consideration of the bending hysteresis behaviour, and to assess the difference in the dynamic responses between the Wellstream and Orcina 3D bending hysteresis models. Both models are implemented using the analysis program OrcaFlex the Wellstream model is a detailed model that calculates both the total bending moment and the stresses in the tensile armour the Orcina model is a simpler model that only calculates the total bending moment.
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This paper introduces two 3D flexible riser bending hysteresis models, developed by Wellstream and Orcina respectively, and their calibrations against the bending hysteresis loops measured in full scale tests. Because of this technical obstacle, the current industry practice is to model the riser as a linear structure, with certain conservatism enforced, and then to extract the global dynamic loads to a detailed local model for stress and life assessment. The main technical challenge is to understand and model the riser tensile armour behaviour under continuous changes in both the magnitude and direction of bending, and its subsequent impact on the riser’s bending hysteresis characteristics. This paper presents a ‘state of art’ in the development of the time domain dynamic simulation of 3D bending hysteresis behaviour of a flexible riser under offshore environment loading. Journal of Verification, Validation and Uncertainty Quantification.Journal of Thermal Science and Engineering Applications.Journal of Offshore Mechanics and Arctic Engineering.Journal of Nuclear Engineering and Radiation Science.Journal of Nondestructive Evaluation, Diagnostics and Prognostics of Engineering Systems.Journal of Nanotechnology in Engineering and Medicine.Journal of Micro and Nano-Manufacturing.Journal of Manufacturing Science and Engineering.Journal of Engineering Materials and Technology.Journal of Engineering for Sustainable Buildings and Cities.Journal of Engineering for Gas Turbines and Power.Journal of Engineering and Science in Medical Diagnostics and Therapy.Journal of Electrochemical Energy Conversion and Storage.Journal of Dynamic Systems, Measurement, and Control.Journal of Computing and Information Science in Engineering.Journal of Computational and Nonlinear Dynamics.Journal of Autonomous Vehicles and Systems.ASME Letters in Dynamic Systems and Control.ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part B: Mechanical Engineering.Mechanical Engineering Magazine Select Articles.