Structural Performance of Buried Steel Pipelines Crossing Strike-Slip Faults

2014 ◽  
Author(s):  
Polynikis Vazouras ◽  
Panos Dakoulas ◽  
Spyros A. Karamanos
Keyword(s):  
Closed Form ◽  
Local Buckling ◽  
Closed Form Solution ◽  
Strike Slip ◽  
Form Solution ◽  
Strike Slip Fault ◽  
Performance Criteria ◽  
Cross Sectional ◽  
Soil System ◽  
Inelastic Material

The performance of pipelines subjected to permanent strike-slip fault movement is investigated by combining detailed numerical simulations and closed-form solutions. A closed-form solution for the force-displacement relationship of a buried pipeline subjected to tension is presented and used in the form of nonlinear springs at the two ends of the pipeline in a refined finite element model, allowing an efficient nonlinear analysis of the pipe-soil system at large strike-slip fault movements. The analysis accounts for large deformations, inelastic material behaviour of the pipeline and the surrounding soil, as well as contact and friction conditions on the soil-pipe interface. Appropriate performance criteria of the steel pipeline are adopted and monitored throughout the analysis. It is shown that the end conditions of the pipeline have a significant influence on pipeline performance. For a strike-slip fault normal to the pipeline axis, local buckling occurs at relatively small fault displacements. As the angle between the fault normal and the pipeline axis increases, local buckling can be avoided due to longitudinal stretching, but the pipeline may fail due to excessive axial tensile strains or cross sectional flattening.

A closed-form solution for the bending analysis of composite sandwich pipe with compliance core based on high-order sandwich theory

2018 ◽  
Vol 22 (6) ◽  
pp. 1786-1811 ◽  
Author(s):  
I Maleki ◽  
O Rahmani
Keyword(s):  
Closed Form ◽  
Shell Theory ◽  
Variational Principles ◽  
Closed Form Solution ◽  
Form Solution ◽  
High Order ◽  
Geometrical Parameters ◽  
Cross Sectional ◽  
Nonlinear Distortions ◽  
Flexible Core

In this paper, bending of cylindrical sandwich pipes based on the high-order theory of sandwich structures with flexible core is investigated. The cylindrical sandwich pipe is composed of a flexible core and two composite face sheets. Behavior of the cylindrical sandwich pipe is described by a high-order sandwich shell theory, which explains nonlinear distortions of cross-sectional plane of the flexible core as well as changes in its height. The theory based on variational principles and using an extremely thorough systematic closed-form approach is formulated. In this model, no assumption has been considered for displacement distribution of core components. In this study, stress and displacement of the flexible core are obtained through a three-dimensional elasticity solution and the face sheets are modeled using classical shell theory. Also, a comparison is made in order to verify high-order solution results between a closed-form solution, which is expanded for simply supported boundary conditions and results that are obtained from the commercial finite element method. Finally, influences of physical and geometrical parameters on behavior of the cylindrical sandwich pipe are investigated.

Spine Fin Efficiency – A Three Sided Pyramidal Fin of Isosceles Triangular Cross-Sectional Area

2007 ◽  
Author(s):  
Richard G. Carranza
Keyword(s):  
Closed Form ◽  
Governing Equation ◽  
Heat Balance ◽  
Bessel Functions ◽  
Closed Form Solution ◽  
Form Solution ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fin Efficiency

An analytical, closed form, solution is presented for determining the fin efficiency of a spine fin with the geometry of a three sided pyramid with isosceles triangular cross-sectional area (from here on referred to as TSPICA). The solution is presented purely in terms of Bessel functions. The TSPICA is modeled using fundamental formulas of geometry. The governing equation is derived from a heat balance around the fin.

scholarly journals Analytical Solution of Laterally Loaded Free-Head Long Piles in Elasto-Plastic Cohesive Soils

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1961
Author(s):  
Ayman Abd-Elhamed
Keyword(s):  
Closed Form ◽  
Closed Form Solution ◽  
Bending Moment ◽  
Cohesive Soil ◽  
Form Solution ◽  
Cohesive Soils ◽  
Fe Model ◽  
Soil System ◽  
Soil Medium ◽  
Laterally Loaded

This research study presents a closed form solution of responses of laterally loaded long piles embedded on cohesive soils with a constant subgrade modulus. The surrounding soil medium is modelled as elastic-perfectly plastic. The closed form solution is derived by solving the governing differential equation of the pile–soil system. The most popular numerical computation software package MATLAB is utilized for the implementation of solutions. The provided analytical method reliably calculates the pile head deflection and bending moment required for engineering design purposes. Results are discussed and verified with solutions of an equivalent three-dimensional finite element (FE) model developed using ANSYS software. It was concluded that the proposed analytical model could efficiently provide the exact solution of embedded piles in elasto-plastic cohesive soil under lateral loads.

On a Closed-Form Solution of Prandtl's System of Equations

2013 ◽  
Vol 40 (2) ◽  
pp. 106-114
Author(s):  
J. Venetis ◽  
Aimilios (Preferred name Emilios) Sideridis
Keyword(s):  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
System Of Equations

scholarly journals A Closed-Form Solution to Planar Feature-Based Registration of LiDAR Point Clouds

2021 ◽  
Vol 10 (7) ◽  
pp. 435
Author(s):  
Yongbo Wang ◽  
Nanshan Zheng ◽  
Zhengfu Bian
Keyword(s):  
Closed Form ◽  
Closed Form Solution ◽  
Simulated Data ◽  
Real Data ◽  
Point Clouds ◽  
Form Solution ◽  
Spatial Transformation ◽  
Dual Quaternions ◽  
Feature Based ◽  
Planar Feature

Since pairwise registration is a necessary step for the seamless fusion of point clouds from neighboring stations, a closed-form solution to planar feature-based registration of LiDAR (Light Detection and Ranging) point clouds is proposed in this paper. Based on the Plücker coordinate-based representation of linear features in three-dimensional space, a quad tuple-based representation of planar features is introduced, which makes it possible to directly determine the difference between any two planar features. Dual quaternions are employed to represent spatial transformation and operations between dual quaternions and the quad tuple-based representation of planar features are given, with which an error norm is constructed. Based on L2-norm-minimization, detailed derivations of the proposed solution are explained step by step. Two experiments were designed in which simulated data and real data were both used to verify the correctness and the feasibility of the proposed solution. With the simulated data, the calculated registration results were consistent with the pre-established parameters, which verifies the correctness of the presented solution. With the real data, the calculated registration results were consistent with the results calculated by iterative methods. Conclusions can be drawn from the two experiments: (1) The proposed solution does not require any initial estimates of the unknown parameters in advance, which assures the stability and robustness of the solution; (2) Using dual quaternions to represent spatial transformation greatly reduces the additional constraints in the estimation process.

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