scholarly journals Mechanical Behavior of Buried Pipelines Subjected to Faults

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Xiaolong Wei ◽  
Wenshuai Jiao ◽  
Xi Zeng ◽  
Danfu Zhang ◽  
Guofeng Du
Keyword(s):  
Compressive Strain ◽  
Small Deformation ◽  
Dynamic Effect ◽  
Element Model ◽  
Test Model ◽  
Test Results ◽  
Buried Pipelines ◽  
Backfill Soil ◽  
Full Scale Tests ◽  
Lab Test

The length of buried pipelines usually extends thousands of meters or more in engineering, and it is difficult to carry out full-scale tests in the laboratory. Therefore, considering the seriousness of pipeline damage and the difficulty of operating tests and other test limitations, it is necessary to develop a reasonable method to simplify the length of the model for a practical lab test. In this research, an equivalent spring model was established to simulate the small deformation section of the pipeline far away from the fault and the effect of fault displacements, pipeline diameters, wall thicknesses, buried depths, soil materials, and spring constraints on the mechanical properties of pipelines was analyzed. Based on the finite element model using ABAQUS software, the results of the shell model with fixed boundary at both ends were compared; in addition, the dynamic effect of pipelines was investigated. The results show that the two-end spring device can better control the size of the test model and enhance the reliability of the test results. The vibration response of the pipeline mainly depends on the inconsistent movement of soil at both ends of the fault. The analysis results show that choosing a larger pipeline diameter, smaller buried depth, noncohesive backfill soil, and spring with a smaller elastic coefficient is beneficial to reduce pipeline strain and resist pipeline deformation. A simplified formula of the axial compressive strain of buried pipelines across oblique-slip fault is obtained.

Design of Static Test Model for Three-Tower Cable-Stayed Self-Anchored Suspension Composed Bridge

2011 ◽  
Vol 243-249 ◽  
pp. 1528-1535
Author(s):  
Yu Zhao ◽  
Yong Jun Zhou ◽  
Jing Sun ◽  
Jin Tao Tang ◽  
Xu Li
Keyword(s):  
Complex System ◽  
Finite Element ◽  
Element Model ◽  
Test Model ◽  
Test Results ◽  
Static Test ◽  
Whole Process ◽  
Aesthetic Appearance ◽  
Load Carrying ◽  
Novel Structures

Cable-stayed self-anchored suspension composed bridges have novel structures and aesthetic appearance with complex system and difficulty for design and construction. In order to acquire a better knowledge of the load-carrying capability of this type of bridges, based on a real bridge and the theory of abnormal similarity, a full-bridge scaled down(1:20) test model was built to simulate the whole process of construction. The test results were preferably fit the theoretical calculation value. It can be seen that the design of the bridge was reasonable, and the accuracy of the calculation of finite element model was verified at the same time. The test and the related results can be used as the reference for the test and design of the similar bridges.

Study of Alternative Assembly Patterns Using Finite Element Analysis and Lab Tests

2018 ◽  
Author(s):  
Gong H. Jung ◽  
Wesley Pudwill ◽  
Elysia J. Sheu
Keyword(s):  
Finite Element ◽  
Elastic Interaction ◽  
Element Model ◽  
Potential Method ◽  
Test Results ◽  
Element Analysis ◽  
Fea Model ◽  
Assembly Method ◽  
Bolt Stress ◽  
Lab Test

A total of 24 lab tests were performed to evaluate two different joint assembly patterns (legacy and an alternative pattern), two lubricant types (Nickel based and Moly-Disulphide based), and two types of torque wrenches (Hydraulic and Pneumatic). Bolt stress was measured during assembly using load indicating bolts (SPC4). Assembly time was also measured since alternative assembly patterns have been recognized as a potential method for improving assembly efficiency without negatively impacting bolt pre-load scatter. In order to understand the bolt stress distribution in both of the legacy and alternative assembly patterns, a finite element model was developed to simulate wrench sequences specified by ASME PCC-1. The FEA model included the effect of elastic interaction of the bolts and flange. The FEA results indicate similar behavior when compared to the lab test results, and the FEA study was extended to two other alternative assembly patterns. This paper summarizes the results of the FEA and lab tests on a 24” NPS Class 300 flange and may provide validation and supporting information for users who are considering the use of a more efficient assembly method such as the alternative assembly patterns presented in ASME PCC-1.

scholarly journals Experimental study on dynamic effect of freestanding tower of sea-crossing bridge under wave load

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Zhou Daocheng ◽  
Zhang Bo ◽  
Xue Sisi ◽  
Wei Chengxun ◽  
Ou Jinping
Keyword(s):  
Experimental Study ◽  
Dynamic Effect ◽  
Pile Group ◽  
Test Model ◽  
Wave Loads ◽  
Test Results ◽  
Base Shear ◽  
Wave Load ◽  
Vibration Period ◽  
Bridge Tower

AbstractThere is a debate over whether the sea-crossing bridges undergo dynamic motions when exposed to wave loads. In order to verify the dynamic effect of the tower of sea-crossing bridge under wave load, an experimental study on dynamic effect of a freestanding tower of sea-crossing bridge is accomplished in this paper. Firstly, a test model for a typical bridge tower of pile group foundation under wave load is established by using a scale of 1:100. Secondly, a typical sea condition is designed for the response test of the bridge tower under wave load. The test results indicated that obvious vibration of top the tower occurs when the wave load period is close to the natural vibration period of the structure, and both displacement and base shear are amplified. The results in this paper will provide an important reference for whether the dynamic effect of wave load should be considered in the designs of bridge structure under wave load.

scholarly journals Experimental and Numerical Investigation on the Steel Reinforced Grout (SRG) Composite-to-Concrete Bond

2020 ◽  
Vol 4 (4) ◽  
pp. 182
Author(s):  
Luciano Ombres ◽  
Salvatore Verre
Keyword(s):  
Bond Length ◽  
Failure Modes ◽  
Peak Load ◽  
Element Model ◽  
Test Results ◽  
Shear Tests ◽  
Bond Slip ◽  
Bond Behavior ◽  
Direct Shear Tests ◽  
Inorganic Matrix

In the paper, the bond between a composite strengthening system consisting of steel textiles embedded into an inorganic matrix (steel reinforced grout, SRG) and the concrete substrate, is investigated. An experimental investigation was carried out on medium density SRG specimens; direct shear tests were conducted on 20 specimens to analyze the effect of the bond length, and the age of the composite strip on the SRG-to-concrete bond behavior. In particular, the tests were conducted considering five bond length (100, 200, 250, 330, and 450 mm), and the composite strip’s age 14th, 21st, and 28th day after the bonding. Test results in the form of peak load, failure modes and, bond-slip diagrams were presented and discussed. A finite element model developed through commercial software to replicate the behavior of SRG strips, is also proposed. The effectiveness of the proposed numerical model was validated by the comparison between its predictions and experimental results.

scholarly journals Certification tests of a protective device such as ROPS to ensure safe usage of tractors

2018 ◽  
Vol 224 ◽  
pp. 02061
Author(s):  
Irina Troyanovskaya ◽  
Anton Kalugin
Keyword(s):  
Strain Curve ◽  
Protective Device ◽  
Test Results ◽  
Experimental Procedure ◽  
Structure Deformation ◽  
Safety Requirements ◽  
Performance Check ◽  
Protective Structures ◽  
Full Scale Tests ◽  
Tractor Plant

According to the safety requirements, all protective devices of tractor units are subject to obligatory certification. One of the main means of protecting the operator during overturning is ROPS system. In accordance with GOST (National State Standard), a performance check of ROPS protective structures is carried out on basis of full-scale tests. The purpose of the presented study is to develop the experimental procedure and to obtain the performance check result of ROPS protective device of the tractor unit’s cabin using B10 bulldozer manufactured by the Chelyabinsk Tractor Plant as an example. The tests were carried out at the Ural Test Center NATI. For this purpose, a special bedplate was used, allowing to test the protective cabins of tractors with the total mass of up to 110 tons. The hydraulic system of the bedplate allowed to carry out the process of lateral loading of ROPS step by step, where each step corresponded to the 10 mm structure deformation. The applied load and structure deformation were recorded at each step. The energy accumulated by the structure was calculated as the area under the stress-strain curve. The energy U = 40867 J, which was required according to GOST, was accumulated during lateral deformation Δ = 270 mm. The force constituted Fy = 243 kN. After removing the lateral load, the structure was subjected to the vertical static and longitudinal loading. During the whole experiment of ROPS protective device, repairs, deformation corrections and adjustments were not allowed. The test results of ROPS structure of B10 bulldozer cabin showed compliance with the GOST safety requirements. During ROPS deformation, penetration of the protective structure elements into the driver’s limited zone was not observed.

Consideration of the Cross-Anisotropy of Different Materials of the Asphalt Surface Layer and Temperature to Determine Pavement Responses

2021 ◽  
Vol 13 (1) ◽  
pp. 140-151
Author(s):  
Minrui Guo ◽  
Xinglin Zhou
Keyword(s):  
Surface Layer ◽  
High Temperatures ◽  
Low Temperatures ◽  
Compressive Strain ◽  
Fatigue Cracking ◽  
Element Model ◽  
Rate Of Change ◽  
Temperature Relationship ◽  
The Cross ◽  
Cross Anisotropy

The effects of the cross-anisotropy of different materials of the asphalt surface layer and the depth-temperature relationship on pavement responses and damage are investigated. A three-dimensional Finite-Element Model (FEM) of the pavement, which considers the depth-temperature relationship of the surface layer under moving tire load, is developed. Pavement damage models are established to evaluate the damage ratio for primary rutting and fatigue cracking. The results show that the compressive strain at the bottom of the surface layer increases as the temperature increases, and the cross-anisotropy (n-value) decreases, indicating that a decrease in the horizontal modulus of different materials of the surface layer increases the damage ratio for primary rutting at high temperatures. The tensile strain at the bottom of the surface layer declines as the n-value increases to 1. For the same change in the n-value, the rate of change of the damage ratio for fatigue cracking is greater at low temperatures than at high temperatures, demonstrating that the number of allowable load repetitions is more sensitive at low temperatures. In addition, the effect of cross-anisotropy and temperature on the vertical stress are larger on the top of the base than in the subbase and subgrade.

scholarly journals STUDY OF THE FIRE PERFORMANCE OF HYBRID STEEL-TIMBER CONNECTIONS WITH FULL-SCALE TESTS AND FINITE ELEMENT MODELLING

2016 ◽  
Author(s):  
Aaron O. Akotuah ◽  
Sabah G. Ali ◽  
Jeffrey Erochko ◽  
Xia Zhang ◽  
George V. Hadjisophocleous
Keyword(s):  
Finite Element ◽  
Load Ratio ◽  
Full Scale ◽  
Test Results ◽  
Structural Members ◽  
Fire Performance ◽  
Shear Connection ◽  
Timber Connections ◽  
Full Scale Tests ◽  
Connection Design

Connection design is critical in timber buildings since the connections tend to have lower strength than the structural members themselves and they tend to fail in a brittle manner. The effect of connection geometry on the fire performance of a hybrid steel-timber shear connection is investigated by full-scale testing. These tests were conducted by exposing the test specimens to the standard time-temperature curve defined by CAN/ULC-S101 (CAN/ULC-S101, 2007). Test results showed that the fire resistance of these connections depends on the load ratio, the type of connection and the relative exposure of the steel plate to fire. Finite element models of the connections under fire were constructed using ABAQUS/CAE and these were validated using the test results. These numerical model results correlate well with test results with ±8.32% variation.

Modified Equation to Predict Leak/Rupture Criteria for Axially Through-Wall Notched X80 and X100 Linepipes Having Higher Charpy Energy

2004 ◽  
Author(s):  
Shinobu Kawaguchi ◽  
Naoto Hagiwara ◽  
Mitsuru Ohata ◽  
Masao Toyoda
Keyword(s):  
Fracture Toughness ◽  
Flow Stress ◽  
Pipe Material ◽  
Test Results ◽  
Absorbed Energy ◽  
Bending Tests ◽  
Full Scale Tests ◽  
Hoop Stresses ◽  
The Relationship ◽  
Modified Equation

A method of predicting the leak/rupture criteria for API 5L X80 and X100 linepipes was evaluated, based on the results of hydrostatic full-scale tests for X60, X65, X80 and X100 linepipes with an axially through-wall (TW) notch. The TW notch test results clarified the leak/rupture criteria, that is, the relationship between the initial notch lengths and the maximum hoop stresses during the TW notch tests. The obtained leak/rupture criteria were then compared to the prediction of the Charpy V-notch (CVN) absorbed energy-based equation, which has been proposed by Kiefner et al. The comparison revealed that the CVN-based equation was not applicable to the pipes having a CVN energy (Cv) greater than 130 J and flow stress greater than X65. In order to predict the leak/rupture criteria for these linepipes, the static absorbed energy for ductile cracking, (Cvs)i, was introduced as representing the fracture toughness of a pipe material. The (Cvs)i value was determined from the microscopic observation of the cut and buffed Charpy V-notch specimens after static 3-point bending tests. The CVN energy in the original CVN-based equation was replaced by an equivalent CVN energy, (Cv)eq’ which was defined as follows: (Cv)eq = 4.5 (Cvs)i. The leak/rupture criteria for the X80 and X100 linepipes with higher CVN energies were reasonably predicted by the modified equation using the (Cvs)i value.

Non-Linear Analysis and Modeling of the Structure with Bolted Joints

2015 ◽  
Vol 656-657 ◽  
pp. 694-699
Author(s):  
Xin Liao ◽  
Jian Run Zhang ◽  
Dong Lu
Keyword(s):  
Dynamic Stiffness ◽  
Element Model ◽  
Outer Radius ◽  
Bolted Joints ◽  
Structure Model ◽  
Test Results ◽  
Bolted Joint ◽  
Joint Structure ◽  
Non Linear ◽  
Simulation Results

In this study, a non-linear finite element model for a simplified single-bolted joint structure model is built. Static analysis on the structure under different shear force and pretension effect is done, and the non-linear contact behavior is analyzed. Through comparing datum, it is found that interface area of each bolted joint region can be described an annular region around bolt hole, whose outer radius has increased by 85% compared with radius of bolt hole. Also, the frequency responses of the multi-bolted joint structure under sinusoidal excitation are investigated. Simulation results show that the resonance regions basically remain unchanged in different pretension effect and the largest amplitude will increase with the increasing preloads. Finally, the vibration experiments are conducted. Interface nonlinear affect dynamic stiffness considerably. The test results illustrate that dynamic behaviors of bolted joint agree with the simulation results and the proposed non-linear contact model was reasonable.

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