Finite Element Analysis of Buried Polyethylene Pipe Subjected to Seismic Landslide

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Xiangpeng Luo ◽  
Jinjin Ma ◽  
Jinyang Zheng ◽  
Jianfeng Shi
Keyword(s):  
Finite Element ◽  
Failure Criterion ◽  
Urban Areas ◽  
Deformation Behavior ◽  
Transportation Systems ◽  
Uniaxial Tensile ◽  
Seismic Load ◽  
Pipe Length ◽  
Quartic Polynomial ◽  
Seismic Landslide

Polyethylene (PE) pipes are widely used in natural gas transportation systems in urban areas nowadays. As landslide caused by earthquake would cause destructive damage to buried pipes, increasing attention is attracted to the safety of buried PE pipes under seismic load. In this paper, the deformation behavior of PE pipe subjected to seismic landslide was investigated and a related failure criterion due to yielding was proposed. Based on extensive uniaxial tensile tests, a rate-dependent constitutive model of PE was applied to simulate the mechanical behavior of PE pipes. The extended Drucker-Prager model was used for surrounding soil. In our proposed finite element model, a quartic polynomial bending deflection displacement normal to the pipeline was loaded along the axial direction of PE pipe. The numerical simulation results revealed that the main failure mode of buried PE pipe subjected to seismic landslide shifted from bending deformation to ovalization deformation with increasing bending deflection. On the basis of deformation behavior analysis, failure criterion curves were put forward, which depicts the maximum relative deflection of the pipe cross-section, and the maximum displacement of the pipe versus pipe length subjected to seismic landslide. The results may be referable for design and safety assessment of PE pipes due to seismic landslide.

Safety Investigation of Buried Polyethylene Pipe Subject to Seismic Landslide

2012 ◽  
Author(s):  
Jinjin Ma ◽  
Jianfeng Shi ◽  
Jinyang Zheng
Keyword(s):  
Mechanical Behavior ◽  
Failure Criterion ◽  
Axial Direction ◽  
Tensile Tests ◽  
Seismic Load ◽  
Engineering Practice ◽  
Acceptance Criterion ◽  
Quartic Polynomial ◽  
Seismic Landslide ◽  
Pipe Deflection

As polyethylene (PE) pipes are widely used in the gas transportation system nowadays, increasing attention is attached to the safety of buried PE pipe under seismic load. In this paper, the related failure criterion is proposed and mechanical behavior of PE pipe subject to seismic landslide is investigated. Based on extensive tensile tests, an appropriate constitutive model of PE is selected and the parameters are estimated to simulate mechanical behavior of PE pipes using finite element method. The pipe is assumed to be loaded with a quartic polynomial bending deflection displacement along the axial direction and the soil acts linear elastic. From the numerical simulation results, it is concluded that cross-section deformation is the governing failure mode of buried PE pipe subject to seismic landslide and the critical pipe deflection is about 0.048. Failure criterion curves of seismic landslide are put forward with the combination of failure criterion and engineering practice. The proposed failure criterion curves serve as a foundation available not only for the safety design and assessment also for engineering acceptance criterion of the failure of PE pipe due to seismic landslide.

MULTISCALE COMPUTATIONAL EVALUATION OF ELASTO-VISCOPLASTIC DEFORMATION BEHAVIOR OF AMORPHOUS POLYMER CONTAINING MICROSCOPIC HETEROGENEITY DURING UNIAXIAL TENSILE TEST

2010 ◽  
Vol 02 (03n04) ◽  
pp. 235-255 ◽  
Author(s):  
MAKOTO UCHIDA ◽  
NAOYA TADA
Keyword(s):  
Finite Element ◽  
Deformation Behavior ◽  
Volume Fraction ◽  
Amorphous Polymer ◽  
Element Model ◽  
Strength Distribution ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Viscoplastic Deformation ◽  
Heterogeneous Microstructures

The two-scale elasto-viscoplastic deformation behavior of amorphous polymer was investigated using the large deformation finite element homogenization method. In order to enable a large time increment for the simulation step in the plastic deformation stage, the tangent modulus method is introduced into the nonaffine molecular chain network theory, which is used to represent the deformation behavior of pure amorphous polymer. Two kinds of heterogeneous microstructures were prepared in this investigation. One was the void model, which contains uniformly or randomly distributed voids, and the other was the heterogeneous strength (HS) model, which contains a distribution of initial shear strength. In the macroscopic scale, initiation and propagation processes of necking during uniaxial tension were considered. The macroscopic nominal stress–strain relation was strongly characterized by the volume fraction and distribution of voids for the void model and by the width of the strength distribution for the HS model. Non-uniform deformation behaviors in microscopic and macroscopic scales are closely related to each other for amorphous polymers because continuous stretching and hardening in the localized zone of the microstructure brings about an increase in macroscopic deformation resistance. Furthermore, computational results obtained from the homogenization model are compared to those obtained from the full-scale finite element model, and the effect of the scale difference between microscopic and macroscopic fields is discussed.

A Finite Element Model for Ultrasonic Cutting of Toffee

2006 ◽  
Vol 5-6 ◽  
pp. 519-526 ◽  
Author(s):  
E. McCulloch ◽  
Alan MacBeath ◽  
Margaret Lucas
Keyword(s):  
Finite Element ◽  
Failure Criterion ◽  
Uniaxial Tensile ◽  
Test Machine ◽  
Fe Model ◽  
Temperature Dependent ◽  
Erosion Model ◽  
Element Erosion ◽  
Element Removal ◽  
Ultrasonic Cutting

The performance of an ultrasonic cutting device critically relies on the interaction of the cutting tool and the material to be cut. A finite element (FE) model of ultrasonic cutting is developed to enable the design of the cutting blade to be influenced by the requirements of the toolmaterial interaction and to allow cutting parameters to be estimated as an integral part of designing the cutting blade. In this paper, an application in food processing is considered and FE models of cutting are demonstrated for toffee; a food product which is typically sticky, highly temperature dependent, and difficult to cut. Two different 2D coupled thermal stress FE models are considered, to simulate ultrasonic cutting. The first model utilises the debond option in ABAQUS standard and the second uses the element erosion model in ABAQUS explicit. Both models represent a single blade ultrasonic cutting device tuned to a longitudinal mode of vibration cutting a specimen of toffee. The model allows blade tip geometry, ultrasonic amplitude, cutting speed, frequency and cutting force to be adjusted, in particular to assess the effects of different cutting blade profiles. The validity of the model is highly dependent on the accuracy of the material data input and on the accuracy of the friction and temperature boundary condition at the blade-material interface. Uniaxial tensile tests are conducted on specimens of toffee for a range of temperatures. This provides temperature dependent stress-strain data, which characterises the material behaviour, to be included in the FE models. Due to the difficulty in gripping the tensile specimens in the test machine, special grips were manufactured to allow the material to be pulled without initiating cracks or causing the specimen to break at the grips. A Coulomb friction condition at the bladematerial interface is estimated from experiments, which study the change in the friction coefficient due to ultrasonic excitation of a surface, made from the same material as the blade, in contact with a specimen of toffee. A model of heat generation at the blade-toffee interface is also included to characterise contact during ultrasonic cutting. The failure criterion for the debond model assumes crack propagation will occur when the stress normal to the crack surface reaches the tensile failure stress of toffee and the element erosion model uses a shear failure criterion to initiate element removal. The validity of the models is discussed, providing some insights into the estimation of contact conditions and it is shown how these models can improve design of ultrasonic cutting devices.

Finite Element Modeling of Deformation Behavior of Steel Specimens under Various Loading Scenarios

2015 ◽  
Vol 651-653 ◽  
pp. 969-974 ◽  
Author(s):  
Dilip Banerjee ◽  
Mark Iadicola ◽  
Adam Creuziger ◽  
Tim Foecke
Keyword(s):  
Finite Element ◽  
Deformation Behavior ◽  
Stress Measurement ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Fe Model ◽  
Strain Paths

Lightweighting materials (e.g., advanced high strength steels, aluminum alloys etc.) are increasingly being used by automotive companies as sheet metal components. However, accurate material models are needed for wider adoption. These constitutive material data are often developed by applying biaxial strain paths with cross-shaped (cruciform) specimens. Optimizing the design of specimens is a major goal in which finite element (FE) analysis can play a major role. However, verification of FE models is necessary. Calibrating models against uniaxial tensile tests is a logical first step. In the present study, reliable stress-strain data up to failure are developed by using digital image correlation (DIC) technique for strain measurement and X-ray techniques and/or force data for stress measurement. Such data are used to model the deformation behavior in uniaxial and biaxial tensile specimens. Model predictions of strains and displacements are compared with experimental data. The role of imperfections on necking behavior in FE modeling results of uniaxial tests is discussed. Computed results of deformation, strain profile, and von Mises plastic strain agree with measured values along critical paths in the cruciform specimens. Such a calibrated FE model can be used to obtain an optimum cruciform specimen design.

Microscale deformation behavior of rheocast Al–7Si–0.3 Mg alloy

2016 ◽  
Vol 230 (6) ◽  
pp. 1041-1061
Author(s):  
Prosenjit Das ◽  
Sk. Tanbir Islam ◽  
Sudip K Samanta ◽  
Santanu Das
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Failure Mode ◽  
Strain Localization ◽  
Deformation Behavior ◽  
Uniaxial Tensile ◽  
Process Conditions ◽  
Plastic Strain Localization ◽  
Representative Volume ◽  
Representative Volume Elements

In the present work, microscale deformation behavior, plastic strain localization, and plastic instability of rheocast Al–Si–Mg (A356) alloy have been investigated using micromechanical approach. For this purpose, two-dimensional microscale models (representative volume elements) have been developed using actual microstructure of the cast samples made under three different process conditions. Microstructure of the above-mentioned alloy consists of two different phases, such as aluminum-rich primary phase and silicon-rich eutectic phase. In line with that, composite micromechanical models have been developed to analyze them within the finite element framework. Rheocasting has been performed using cooling slope with two different slope angles of 45° and 60°, and comparison has been made with the conventional cast samples of the alloy that has been cast directly from the superheated molten state. Different boundary conditions have been assumed to perform finite element based simulation, using a popular finite element solver ABAQUS, depending upon the position of representative volume elements on the cylindrical tensile specimen. Under uniaxial tensile loading, ductile failure mode is predicted in the form of plastic strain localization due to incompatible deformation between the phases. This indicates inhomogenity of microstructure that determines the damage initiation process within this material, as there is no damage or failure criterion specified during the finite element analysis. Grain size, shape, and orientation of the primary aluminum phase are found to play a vital role on deformation behavior and failure mode of the materials investigated in this study.

Analysis of the Contact Deformation of Tread Blocks

1992 ◽  
Vol 20 (4) ◽  
pp. 230-253 ◽  
Author(s):  
T. Akasaka ◽  
K. Kabe ◽  
M. Koishi ◽  
M. Kuwashima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deformation Behavior ◽  
Contact Deformation ◽  
The Finite Element Method ◽  
The Road ◽  
Loss Of Contact ◽  
Tread Rubber ◽  
Good Agreement ◽  
Rubber Block

Abstract The deformation behavior of a tire in contact with the roadway is complicated, in particular, under the traction and braking conditions. A tread rubber block in contact with the road undergoes compression and shearing forces. These forces may cause the loss of contact at the edges of the block. Theoretical analysis based on the energy method is presented on the contact deformation of a tread rubber block subjected to compressive and shearing forces. Experimental work and numerical calculation by means of the finite element method are conducted to verify the predicted results. Good agreement is obtained among these analytical, numerical, and experimental results.

Quality indicator of the smart city transportation and logistics system

2020 ◽  
Vol 19 (11) ◽  
pp. 2116-2135
Author(s):  
G.V. Savin
Keyword(s):  
Intelligent Transportation Systems ◽  
Smart City ◽  
Urban Areas ◽  
Human Life ◽  
Life Quality ◽  
Intelligent Transportation ◽  
Transportation Systems ◽  
Logistics System ◽  
Organization And Management

Subject. The article considers functioning and development of process flows of transportation and logistics system of a smart city. Objectives. The study identifies factors and dependencies of the quality of human life on the organization and management of stream processes. Methods. I perform a comparative analysis of previous studies, taking into account the uniquely designed results, and the econometric analysis. Results. The study builds multiple regression models that are associated with stream processes, highlights interdependent indicators of temporary traffic and pollution that affect the indicator of life quality. However, the identified congestion indicator enables to predict the time spent in traffic jams per year for all participants of stream processes. Conclusions. The introduction of modern intelligent transportation systems as a component of the transportation and logistics system of a smart city does not fully solve the problems of congestion in cities at the current rate of urbanization and motorization. A viable solution is to develop cooperative and autonomous intelligent transportation systems based on the logistics approach. This will ensure control over congestion, the reduction of which will contribute to improving the life quality of people in urban areas.

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