scholarly journals Large deformation coupled analysis of embedded pipeline – Soil lateral interaction

2021 ◽  
Vol 78 ◽  
pp. 102971
Author(s):  
Xiaoyu Dong ◽  
Wangcheng Zhang ◽  
Hodjat Shiri ◽  
Mark F. Randolph
Author(s):  
Abhijit A. Tanksale ◽  
Prasanna S. Gandhi

Compliant mechanisms are highly preferred in applications demanding motion with high precision. These mechanisms provide friction-less, backlash-free precise motion obtained through deformation of flexible members. The double parallelogram compliant mechanism (DPCM) is one the most important compliant mechanisms to obtain highly precise straight-line motion. DPCM when operated in horizontal plane yield high precision straight-line motion (even with large deformations) useful in several engineering applications. However, constraints such as space, dead loads, etc. may demand DPCMs to be used in the vertical plane. For DPCMs operating in a vertical plane, the axial load due to gravity causes tension and compression in flexible beams which get coupled to bending under large deformations. This ultimately affects the parasitic error of straight-line motion. This paper presents a coupled analysis, along with experimental validation, of DPCM operating in vertical plane considering gravity effects with large deformation.


Author(s):  
Qilin Yin ◽  
Jinjin Zhai ◽  
Sheng Dong

Safety problems may occur to the jack-up rig when it is installed near the old footprint. In this study, three-dimensional large deformation finite element simulations using the Coupled Eulerian–Lagrangian (CEL) method have been carried out on the spudcan–footprint interaction problem. The correctness of the CEL method is verified through comparison with existing centrifuge tests. Uniform and non-uniform clays with different shear strength profiles encompassing the typical strength range of practical interest are considered as the subsea soil. The principle of thermo-mechanical coupled analysis is provided, after which this method is used to realize the updating of clay strength profiles in non-uniform clays. The influences of initial penetration depth, offset distance and shear strength profile on horizontal and moment loads are investigated. Distributions of soil load on the spudcan are presented, and their effect on the resulted inclined loads during spudcan reinstallation is analyzed. In both uniform and non-uniform clays, two peak values are obtained on the horizontal and moment load profiles during the reinstallation near the footprint. The relationship between the normalized maximum value of the horizontal load and initial penetration depth is described as a combination of linear and quadratic equations. While for the peak moment load, the offset distance is the main influencing factor. Finally, failure mechanisms of the surrounding soil during the penetration influenced by the footprint are discussed by defining four failure mechanism stages.


2017 ◽  
Vol 2017.30 (0) ◽  
pp. 141
Author(s):  
Tatsuhiro SHONO ◽  
Gaku HASHIMOTO ◽  
Hiroshi OKUDA

2021 ◽  
Author(s):  
Василий Садовников

This monograph is a continuation of the monograph by V.V. Sadovnikov. Lateral interaction. Moscow 2006. Publishing house "Anta-Eco", 2006. ISBN 5-9730-0017-6. In this work, the foundations of the theory of heterogeneous catalysis and the theory of chemisorption are more easily formulated. The book consists of two parts, closely related to each other. These are the theoretical foundations of heterogeneous catalysis and chemisorption. In the theory of heterogeneous catalysis, an experiment is described in detail, which must be carried out in order to isolate the stages of a catalytic reaction, to find the stoichiometry of each of the stages. This experiment is based on the need to obtain the exact value of the specific surface area of the catalyst, the number of centers at which the reaction proceeds, and the output curves of each of the reaction products. The procedures for obtaining this data are described in detail. Equations are proposed and solved that allow calculating the kinetic parameters of the nonequilibrium stage and the thermodynamic parameters of the equilibrium stage. The description of the quantitative theory of chemisorption is based on the description of the motion of an atom along a crystal face. The axioms on which this mathematics should be based are formulated, the mathematical apparatus of the theory is written and the most detailed instructions on how to use it are presented. The first axiom: an atom, moving along the surface, is present only in places with minima of potential energy. The second axiom: the face of an atom is divided into cells, and the position of the atom on the surface of the face is set by one parameter: the cell number. The third axiom: the atom interacts with the surrounding material bodies only at the points of minimum potential energy. The fourth axiom: the solution of the equations is a map of the arrangement of atoms on the surface. The fifth axiom: quantitative equations are based on the concept of a statistically independent particle. The formation energies of these particles and their concentration are calculated by the developed program. The program based on these axioms allows you to simulate and calculate the interaction energies of atoms on any crystal face. The monograph is intended for students, post-graduate students and researchers studying work and working in petrochemistry and oil refining.


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