Propagation of Buckles in Sandwich Pipes Under External Pressure

2005 ◽  
Author(s):  
I. P. Pasqualino ◽  
M. I. Lourenc¸o ◽  
T. A. Netto
Keyword(s):  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
External Pressure ◽  
Core Material ◽  
Small Scale ◽  
Ongoing Research ◽  
Scale Models ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Sandwich pipes have been considered feasible conceptions for ultra deepwater pipelines, since they are capable to work at low temperatures and withstand high hydrostatic pressures. Sandwich pipelines are composed by inner and outer metallic pipes and a suitable core material which must provide high compression strength and good thermal insulation. The aim of this ongoing research is to study the quasi-static propagation of buckles in sandwich pipes. In this paper, a three-dimensional finite element model considering material and geometric nonlinear behavior is presented. The mesh discretization is determined through a detailed mesh sensitivity analysis. Some experiments with small scale models combining aluminum pipes and polypropylene as core material were carried out to calibrate the numerical model. The propagation pressure is evaluated under different bonding conditions between pipe layers.

scholarly journals Numerical and Experimental Study on Modular-Based Timber Structures

2019 ◽  
pp. 471-478
Author(s):  
Sigurdur Ormarsson ◽  
Johan Vessby ◽  
Marie Johansson ◽  
Le Kua
Keyword(s):  
Three Dimensional ◽  
Shear Stiffness ◽  
Element Model ◽  
Structural Safety ◽  
Test Results ◽  
Structural Behaviour ◽  
Ongoing Research ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Connection Design

Building with prefabricated light-frame volume modules is a prevalent and innovative construction method for low and mid-rise timber buildings. Compared to traditionally site-built constructions this method is very advantageous due to its high prefabrication level and the fast on-site assembly of the modules. The focus of this project is to study and optimise the global shear stiffness of the volume modules and to secure a large enough shear and uplift stiffness of the mechanical (or friction based) connections between the modules. Some companies assume that the friction between the modules is sufficient to transfer the wind stabilization forces down through the entire building. Regarding structural safety, connection design is an important task that needs to be numerically studied and experimentally verified. The paper presents numerical and experimental results obtained from two ongoing research projects concerning modular-based timber buildings in Sweden. The final aim of this work is to develop an efficient three dimensional finite-element model to analyse both the global and detailed structural behaviour of these types of buildings. To study the overall shear stiffness of the volume modules, eight different test-modules are to be tested. The test results will be used to calibrate the numerical model.

scholarly journals 3D FEM Soil-Structure Interaction Analysis for Kashiwazaki–Kariwa Nuclear Power Plant Considering Soil Separation and Sliding

2021 ◽  
Vol 7 ◽  
Author(s):  
Yoshitaka Ichihara ◽  
Naohiro Nakamura ◽  
Hiroshi Moritani ◽  
Byunghyun Choi ◽  
Akemi Nishida
Keyword(s):  
Seismic Data ◽  
Nuclear Power ◽  
Soil Structure ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Soil Structure Interaction ◽  
Reactor Building ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In the 2007 Niigataken Chuetsu-oki earthquake, soil settlement, considered to be a result of the relative displacement between the soil and the structure, occurred alongside buildings at Kashiwazaki–Kariwa nuclear power plant. The objective of this study is to evaluate accurately the influence of the nonlinear behavior of the soil-structure interface on the response of the reactor building using a three-dimensional finite element model. To achieve this, we modeled the separation and sliding from sidewalls during a severe earthquake using joint elements, and evaluated the effect on the horizontal response of the structure. Through the soil-structure interaction analyses based on the recorded seismic data on the foundation for unit 7 reactor building using the three-dimensional finite element model, it was confirmed that the simulated horizontal responses of the building corresponded to the recorded seismic data. In addition, the comparison of the cases with and without separation and sliding revealed that the separation and sliding of soil from sidewalls reduces the embedment effects of the structure and that the reduction causes an occurrence of the foundation uplift. Moreover, in this study, it was clarified that the increase of the foundation uplift affected both the soil pressure characteristics beneath the foundation and along the sidewalls, and the maximum acceleration response of structures. In this study, the separation and sliding of soil from sidewalls had only a limited influence on the structural responses; however, under severe seismic excitation, it is expected that the embedment effects will be significantly reduced due to the separation and sliding of soil. Therefore, a precise response evaluation of the building including the nonlinear behavior due to separation and sliding should be considered in the seismic response analyses under severe seismic excitation.

scholarly journals Nonsymmetric Nonlinear Dynamics of Piezoelectrically Actuated Beams

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Mergen H. Ghayesh ◽  
Hamed Farokhi
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Piezoelectric Patch ◽  
Beam System ◽  
Piezoelectric Beam ◽  
Dimensional Finite Element ◽  
Differential Type ◽  
Three Dimensional Finite Element

The nonlinear behavior of a piezoelectrically actuated clamped–clamped beam has been examined numerically while highlighting the nonsymmetric response of the system. The nonlinearly coupled electromechanical model of the piezoelectric beam system is developed employing the Bernoulli–Euler theory along with the piezoelectric stress–voltage equations. A general nonsymmetric configuration is considered with a piezoelectric patch partially covering the beam. The geometric nonlinearities of stretching type are taken into account for both the piezoelectric patch and the beam. Through use of the generalized Hamilton's principle, the nonlinearly coupled electromechanical equations of transverse and longitudinal motions of the piezoelectrically actuated beam are derived. A high-dimensional Galerkin scheme is utilized to recast the equations of partial differential type into ordinary differential type. For comparison and benchmark purposes, a three-dimensional finite element model is developed using abaqus/cae to verify the model developed in this study. It is shown that the response of the system is strongly nonsymmetric and that it is essential to retain many degrees-of-freedom to ensure converged results.

Core Material Performance on the Propagation Pressure of Sandwich Pipes

2008 ◽  
Author(s):  
Marcelo Igor Lourenc¸o ◽  
Ilson Paranhos Pasqualino ◽  
Tiago da Silva Palermo
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Core Material ◽  
The Core ◽  
Bonding Condition ◽  
Dimensional Finite Element ◽  
Actual Contribution ◽  
Three Dimensional Finite Element ◽  
Perfect Adherence ◽  
High Hydrostatic Pressures

Due to their insulative nature and ability to withstand high hydrostatic pressures, sandwich pipes have been considered feasible for use in ultra deepwater pipelines. As defined here, sandwich pipes consist of an inner and outer metallic pipe with a suitable core material in the annulus. In this paper, a non linear three-dimensional finite element model, previously presented and compared with experiments, is used in an extensive parametric study of the quasi-static propagation of buckles in sandwich pipes. The primary purpose of this study is to investigate the actual contribution of the core material to the propagation pressure. Parameters addresses include bonding condition (no adherence, perfect adherence), metallic pipe thickness, and core material thickness.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
High Strength ◽  
Element Model ◽  
Internal Force ◽  
Foundation Pit ◽  
Dimensional Finite Element ◽  
Influence Of Temperature On ◽  
Scale Experiment ◽  
Three Dimensional Finite Element

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

Process Modeling in Laser Deposition of Multilayer SS410 Steel

2007 ◽  
Vol 129 (6) ◽  
pp. 1028-1034 ◽  
Author(s):  
Liang Wang ◽  
Sergio Felicelli
Keyword(s):  
Phase Transformation ◽  
Temperature Distribution ◽  
Three Dimensional ◽  
Element Model ◽  
Traverse Speed ◽  
Processing Parameters ◽  
Dimensional Finite Element ◽  
Net Shaping ◽  
Three Dimensional Finite Element ◽  
Continuous Cooling Transformation Diagram

A three-dimensional finite element model was developed to predict the temperature distribution and phase transformation in deposited stainless steel 410 (SS410) during the Laser Engineered Net Shaping (LENS™) rapid fabrication process. The development of the model was carried out using the SYSWELD software package. The model calculates the evolution of temperature in the part during the fabrication of a SS410 plate. The metallurgical transformations are taken into account using the temperature-dependent material properties and the continuous cooling transformation diagram. The ferritic and martensitic transformation as well as austenitization and tempering of martensite are considered. The influence of processing parameters such as laser power and traverse speed on the phase transformation and the consequent hardness are analyzed. The potential presence of porosity due to lack of fusion is also discussed. The results show that the temperature distribution, the microstructure, and hardness in the final part depend significantly on the processing parameters.

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