Numerical Simulation of Stress Relief of Buried Pipeline at Pembina River Crossing

2006 ◽  
Author(s):  
Bing Song ◽  
J. J. Roger Cheng ◽  
Dave H. Chan ◽  
Joe Zhou
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Large Strain ◽  
Element Model ◽  
Stress Relief ◽  
Nonlinear Material ◽  
Soil Conditions ◽  
Buried Pipeline ◽  
Soil Movement ◽  
Pembina River

Pipelines in operation often experience various loadings due to operational and environmental conditions. Large strain may be accumulated in the pipes under these loadings, and it may eventually induce local buckling or even fractures on the pipes. It is a common practice that a stress relief procedure is applied to a pipe by removing the soil around the pipe, allowing the pipe to spring back to a zero load state. The frequency of stress relief procedure is dependent on the severity of loading and soil conditions. This project is intended to study the behavior of buried pipes subjected to repeated stress relief procedures. The buried pipeline at Pembina River Crossing in Lodgepole, Alberta was simulated using the finite element method and the results were compared with field measured data. The pipeline at Pembina River Cross is situated at the active soil movement locations. A finite element model was developed to simulate the slope movement and the pipeline response. The correlation between soil movement and precipitation was investigated. With shell elements for pipe, 3D-solid elements for soil, this model captures the global and local behavior of pipeline. Soil-pipe interaction was simulated by setting a weak layer of soil surrounding the pipeline. The model incorporates nonlinear material, slope soil creep and water table change. Modified Drucker-Prager Cap Model was applied to soils based on direct shear test results. The finite element model was calibrated by slope indicator data and strain gauge data with satisfactory agreement. The model was used to simulate the strain accumulation and the stress relief in the pipeline, before and after the stress relief operation. Reasonable agreement was achieved when compared to the field data. The model can be used to further understand the behavior of pipe under repeated soil movement and stress relief procedure. It can also be used to develop the optimum stress relief procedure and operating schedule.

A materially nonlinear finite element model for the analysis of curved reinforced concrete box-girder bridges

1993 ◽  
Vol 20 (5) ◽  
pp. 754-759 ◽  
Author(s):  
S. F. Ng ◽  
M. S. Cheung ◽  
J. Q. Zhao
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Element Model ◽  
Nonlinear Material ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Girder Bridges ◽  
Concrete Box Girder ◽  
Concrete Box Girder Bridges

A layered finite element model with material nonlinearity is developed to trace the nonlinear response of horizontally curved reinforced concrete box-girder bridges. Concrete is treated as an orthotropic nonlinear material and reinforcement is modeled as an elastoplastic strain-hardening material. Due to the fact that the flanges and webs of the structure are much different both in configuration and in the state of stresses, two types of facet shell elements, namely, the triangular generalized conforming element and the rectangular nonconforming element, are adopted to model them separately. A numerical example of a multi-cell box-girder bridge is given and the results are compared favourably with the experimental results previously obtained. Key words: finite element method, curved box-girder bridges, reinforced concrete, nonlinear analysis.

Evaluation for RC Column Confined Partially with Externally FRP Wrapping Sheet Using Nonlinear FE Analysis

2019 ◽  
Vol 972 ◽  
pp. 129-133
Author(s):  
Yasmeen Taleb Obaidat
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Load Capacity ◽  
Element Model ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Number Of Layers

Little research has been carried out in validating, fiber reinforced polymer (FRP) concrete strengthened column and the effective using partial wrapping. Also the effect of several parameter on strengthen column using the partial wrapping sheet of desired width and thickness around column have not been found out. To this end, a nonlinear 3D finite element model has been developed in current study for CFRP strengthened reinforced concrete column to simulate the behavior accompanied by the effect of partial wrapping with emphasis on load capacity and failure mode. The finite element simulation of CFRP strengthened RC columns is performed using commercial finite element program ABAQUS. Modelling was conducted on reinforced concrete columns with dimensions of 160 x 250 x 960 mm. The finite element model incorporates the nonlinear material behavior of concrete, bilinear stress-strain curve of steel and linear elastic behavior of CFRP material. The concrete was modeled using a plastic damage model. The performance of the FE model was studied by simulating experimental columns from the literature. The load, and strain of CFRP obtained from the FE study were compared with the corresponding experimental results. The FEM results agreed well with the experiments. In addition, to enhance our understanding of the behavior of strengthened reinforced concrete column capacity using partial wrapping the effect of changing the spacing between the CFRP sheets and number of layers were examined. The increase number of layers and decrease spacing give a higher ultimate load capacity, and delay the failure.

Nonlinear Piezoelectric Material Properties and Non-Uniform Poling in a Flexible Electro-Active Composite Finite Element Model

2016 ◽  
Author(s):  
Joseph Calogero ◽  
Hassene Ben Atitallah ◽  
Nicholas Wyckoff ◽  
Zoubeida Ounaies ◽  
Mary Frecker
Keyword(s):  
Finite Element ◽  
Electric Field ◽  
Finite Element Model ◽  
Electric Fields ◽  
Lead Zirconate Titanate ◽  
Material Properties ◽  
Electromechanical Coupling ◽  
Element Model ◽  
Nonlinear Material ◽  
Interdigitated Electrodes

Active Fiber Composites (AFCs) are piezoelectric devices comprised of long cylindrical fibers, typically made of ceramic lead zirconate titanate (PZT), embedded in an epoxy polymer. AFCs use interdigitated electrodes to produce electric field lines parallel to the fibers (33-mode) rather than across the diameter, exploiting the stronger out-of-plane electromechanical coupling. Nonlinear piezoelectric and dielectric terms and non-uniform poling are often neglected in modeling AFCs due to the added complexity, however including the terms improves accuracy for strong electric fields and where the electrode geometry causes non-uniform electric fields. For that reason, a new finite element model of the AFC is developed which includes the effect of nonlinearities in piezoelectric strain constants and electric permittivity due to a non-uniform applied electric field resulting from two sets of interdigitated electrodes. The methods used to apply the nonlinear constitutive equations and poling are described. A comparison of the AFC response with linear and nonlinear material properties, with non-uniform poling, is shown for increasing applied electric fields. The difference in AFC response illustrates the necessity to include Rayleigh Law terms and non-uniform poling in the model.

Dynamic response of a historical armory building using the finite element model validated by the ambient vibration test

2018 ◽  
Vol 24 (22) ◽  
pp. 5472-5484 ◽  
Author(s):  
Ahmet Can Altunişik ◽  
Ali Fuat Genç ◽  
Murat Günaydin ◽  
Fatih Yesevi Okur ◽  
Olguhan Şevket Karahasan
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Finite Element Model ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Element Model ◽  
Ambient Vibration ◽  
Nonlinear Material ◽  
Mode Shapes ◽  
Nonlinear Dynamic Response

In this paper, the aim was to determine the nonlinear dynamic response of historical masonry armory buildings using a validated finite element model. Eight ambient vibration tests were conducted on the building, using three different measurement test setups to extract the dynamic characteristics using the Enhanced Frequency Domain Decomposition method. A finite element model was constructed in ANSYS and the dynamic characteristics were obtained numerically. It can be seen that there is a good correlation between the mode shapes, but there are differences in natural frequencies with maximum values of 10.1%, 7.4% and 13.4% for first the three modes. To determine the nonlinear dynamic response, the validated finite element model was analyzed using the Kocaeli earthquake motion. The Drucker–Prager criterion and Willam–Warnke surface were considered for the nonlinear material models. At the end of the analyses, maximum displacements, principal stresses and strains are given in detail using contour diagrams. It is evident that the displacements show an increasing trend from the base to the top point of the building. Stresses occurred on the corners, openings and transition segments. In addition, crack distribution diagrams were drawn up to illustrate the stress accumulation points.

Gusset plate connections under monotonic and cyclic loading

2005 ◽  
Vol 32 (5) ◽  
pp. 981-995 ◽  
Author(s):  
S S Walbridge ◽  
G Y Grondin ◽  
J J.R Cheng
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Finite Element Model ◽  
Element Model ◽  
Nonlinear Material ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Cyclic Behaviour ◽  
Plate Connections ◽  
Simplified Finite Element Model

A numerical investigation of the monotonic and cyclic behaviour of steel gusset plate connections is conducted using a nonlinear finite element model. Successive versions of the model, which include the effects of framing member stiffness, nonlinear material behaviour, initial imperfections, and bolt slip, are formulated and validated by comparison with test results. A parametric study is then conducted to examine the effects of the load sequence and the interaction between the gusset plate and the brace member under cyclic loading. This investigation demonstrates that the cyclic behaviour of gusset plate connections can be modelled accurately using a simplified finite element model. Gusset plate – brace member subassemblies, wherein the gusset plate is designed as the weak element in compression rather than the brace member, are shown to have stable behaviour under cyclic loading and better energy absorption characteristics than similar subassemblies with the brace member designed as the weak element in compression.Key words: steel, connections, gusset plates, cyclic loading, concentric bracing, buckling.

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