scholarly journals Combining Models to Simulate the Condition of the PVC Distribution Network

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 591
Author(s):  
Karel A. van Laarhoven ◽  
Bas A. Wols
Keyword(s):  
Finite Element ◽  
Drinking Water ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Angular Deflection ◽  
Soil Settlement ◽  
Overall Performance ◽  
Water Companies ◽  
Maintenance And Inspection

The failure of joints plays an important role in the overall performance of mains. One of the prevalent failure modes at polyvinyl chloride (PVC) joints is the rupture of pipe or joint, which may occur due to high angular deflection of the pipe with respect to the joint, caused by differential soil settlement. The present paper reports the construction and use of a finite element model to determine the maximum angular deflection of a variety of PVC joints in different loading situations. The resulting acceptable deflections vary between 3° and 8° per side, which differs significantly from installation guidelines. The results will support drinking water companies in substantiating the prioritization of maintenance and inspection.

Research on seismic behavior of special-shaped CFST column to H-section steel beam joint

2021 ◽  
pp. 136943322110073
Author(s):  
Yu Cheng ◽  
Yuanlong Yang ◽  
Binyang Li ◽  
Jiepeng Liu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Behavior ◽  
Failure Modes ◽  
Joint Stiffness ◽  
Load Ratio ◽  
Element Model ◽  
Steel Tube ◽  
Steel Beam ◽  
Static Test

To investigate the seismic behavior of joint between special-shaped concrete-filled steel tubular (CFST) column and H-section steel beam, a pseudo-static test was carried out on five specimens with scale ratio of 1:2. The investigated factors include stiffening types of steel tube (multi-cell and tensile bar) and connection types (exterior diaphragm and vertical rib). The failure modes, hysteresis curves, skeleton curves, stress distribution, and joint shear deformation of specimens were analyzed to investigate the seismic behaviors of joints. The test results showed the connections of exterior diaphragm and vertical rib have good seismic behavior and can be identified as rigid joint in the frames with bracing system according to Eurocode 3. The joint of special-shaped column with tensile bars have better seismic performance by using through vertical rib connection. Furthermore, a finite element model was established and a parametric analysis with the finite element model was conducted to investigate the influences of following parameters on the joint stiffness: width-to-thickness ratio of column steel tube, beam-to-column linear stiffness ratio, vertical rib dimensions, and axial load ratio of column. Lastly, preliminary design suggestions were proposed.

Thermo-Mechanical Analysis of Instrumentation Guide Tube Failure During a Severe Accident in a Nordic Boiling Water Reactor

2020 ◽  
Author(s):  
Ying Yue ◽  
Walter Villanueva ◽  
Hongdi Wang ◽  
Dingqu Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Boiling Water ◽  
Severe Accident ◽  
Boiling Water Reactor ◽  
Guide Tube ◽  
Water Reactor ◽  
Water Reactors

Abstract Vessel penetrations are important features of both pressurized water reactors and boiling water reactors. The thermal and structural behaviour of instrumentation guide tubes (IGTs) and control rod guide tubes (CRGTs) during a severe accident is vital in the assessment of the structure integrity of the reactor pressure vessel. Penetrations may fail due to welding failure, nozzle rupture, melt-through, etc. It is thus important to assess the failure mechanisms of penetrations with sufficient details. The objective of this paper is to assess the timing and failure modes of IGTs at the lower head during a severe accident in a Nordic boiling water reactor. In this study, a three-dimensional local finite element model was established using Ansys Mechanical that includes the vessel wall, the nozzle, and the weld joint. The thermo-mechanical loads of the finite element model were based on MELCOR results of a station blackout accident (SBO) combined with a large-break loss-of-coolant accident (LBLOCA) including an external vessel cooling by water as a severe accident management strategy. Given the temperature, creep strain, elastic strain, plastic strain, stress and displacement from the ANSYS simulations, the results showed the timing and failure modes of IGTs. Failure of the IGT penetration by nozzle creep is found to be the dominant failure mode of the vessel. However, it was also found that the IGT is clamped by the flow limiter before the nozzle creep, which means that IGT ejection is unlikely.

scholarly journals Engineering our Favorite Pastime

2010 ◽  
Vol 132 (04) ◽  
pp. 44-48
Author(s):  
Lloyd Smith ◽  
James Sherwood
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Layer By Layer ◽  
Ball Impact ◽  
Support Mechanism ◽  
Bat Performance ◽  
Technology Advances

This article describes the equipment and technology advances in baseball and softball games. Research efforts are currently being pursued by the authors to develop a layer-by-layer finite element model of a baseball. While work on improved ball models is ongoing, a number of significant accomplishments have been made with current models. These include comparing bat performance, describing the plastic deformation (denting) observed in metal bats, and the failure modes observed with wood bats. To simulate the bat/ball impact at game-like speeds, a durability machine is used to fire balls at a bat at speeds up to 200 mph, at the rate of 10 per minute. After a ball is shot, it falls into a trough and is loaded back into the magazine, which holds up to 36 balls. The bat-support mechanism simulates the grip and flexibility of a batter and can be programmed to rotate the bat between hits to simulate the use of hollow bats or to remain “label up” as is needed for wood bats.

Simulating Responses of Buried Steel Pipe Crossing Reverse Fault

2011 ◽  
Vol 90-93 ◽  
pp. 825-828
Author(s):  
Lei Zhao ◽  
Jian Zhong Yang ◽  
Jin Xin Zhao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Local Buckling ◽  
Element Model ◽  
Pipe Diameter ◽  
Reverse Fault ◽  
Shell Finite Element ◽  
Dip Angle ◽  
The Finite Element Model

The responses of the buried pipeline due to reverse fault dislocating are studied by a 3-dimension shell finite element model with equivalent boundary spring in ANSYS program. The calculating length of the model is determined by dip angle of the reverse fault: The length is 150 times pipe diameter when the angle is equal to or bigger than 45°; but the length is 240 times pipe diameter when the angle is less than 45°. The finite element model is fit for computing that dip angle is less than 80°. Results show: Failure modes of the pipes are determined by dip angle and dislocation value of the fault. When the angle is gentle and the dislocation is small, either local buckling(wrinkling) or beam buckling can be happened. The angle is equal to or bigger than 75°, local buckling and beam buckling can be happened at same time.

scholarly journals A Double-Acting Piezoelectric Actuator for Helicopter Active Rotor

Actuators ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 247
Author(s):  
Jinlong Zhou ◽  
Linghua Dong ◽  
Weidong Yang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Piezoelectric Actuator ◽  
Performance Test ◽  
Failure Modes ◽  
Element Model ◽  
Test Results ◽  
Trailing Edge ◽  
Trailing Edge Flaps ◽  
Piezoelectric Stacks

An active rotor with trailing-edge flaps is an effective approach to alleviate vibrations and noise in helicopters. In this study, a compact piezoelectric actuator is proposed to drive trailing-edge flaps. The two groups of piezoelectric stacks accommodated in the actuator operate in opposition, and double-acting output can be realized through the differential motion of these stacks. A theoretical model and a finite element model are established to predict the output capability of this actuator, and structural optimization is performed using the finite element model. A prototype is built and tested on a benchtop to assess its performance. Test results demonstrate that the actuator stiffness reaches 801 N/mm, and its output stroke is up to ± 0.27 mm when subjected to actuation voltage of 120 V. Agreement between measurements and simulations validates the accuracy of the established models. In addition, actuator outputs in failure modes are measured by canceling the supply voltage of one group of piezoelectric stacks. In this condition, the actuator can still generate acceptable outputs, and the initial position of the output end remains unchanged. Simulations and test results reveal that the proposed actuator achieves promising performance, and it is capable to be applied to a helicopter active rotor.

Stress Analysis of a Novel MEMS Microphone Chip Using Finite Element Analysis

2005 ◽  
Author(s):  
Jia Gao ◽  
Ronald N. Miles ◽  
Weili Cui
Keyword(s):  
Finite Element ◽  
Low Temperature ◽  
Tensile Stress ◽  
Finite Element Model ◽  
Oxide Layer ◽  
Compressive Stress ◽  
Failure Modes ◽  
Element Model ◽  
Mems Devices ◽  
Mems Microphone

Residual stress produces major challenges in the fabrication of MEMS devices. This is particularly true in the development of MEMS microphones since the response of the thin sound-sensitive diaphragm is strongly affected by stress. It is important to predict the effects of fabrication stress on the microphone chip and identify the failure modes to ensure a satisfactory fabrication yield. In this study, a finite element model of the microphone chip is developed to analyze the laminated structure under different fabrication stresses. The model of the microphone chip includes the diaphragm, backplate and sacrificial oxide layers on top of the silicon substrate. Fabrication stresses are included through the use of an equivalent thermal stress. The stresses in the different layers have been estimated based on measurements performed on fabricated test structures. The estimated stresses are simulated in the finite element model. An important factor in determining the process reliability is the compressive stress of the low temperature sacrificial oxide layer (LTO). A variety of stress combinations between different layers with the low temperature oxide layer are investigated. It is found that an adequate level of tensile stress in the backplate is crucial to ensure the fabrication yield. In the designs considered here, silicon nitride in combination with a thin conductive layer is identified as a favorable material for the backplate considering its high modulus and tensile stress in ‘as deposited’ film. In addition, the presence of a LTO layer on the backside of the wafer turns out to be very helpful in reducing the deflection of the unreleased chip and the stress in the diaphragm. In the case where there is a net compressive stress in the laminate, the failure mode is identified by nonlinear analysis. This analysis provides a guideline to select robust materials and tune the fabrication process to ensure a satisfactory fabrication yield.

scholarly journals Bending Experiment and Mechanical Properties Analysis of Composite Sandwich Laminated Box Beams

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2959 ◽  
Author(s):  
Xiujie Zhu ◽  
Chao Xiong ◽  
Junhui Yin ◽  
Dejun Yin ◽  
Huiyong Deng
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Analytical Model ◽  
Failure Modes ◽  
Ultimate Load ◽  
Element Model ◽  
Three Point Bending ◽  
Composite Sandwich ◽  
Box Beam ◽  
Box Beams

The failure modes, ultimate load, stiffness performance, and their influencing factors of a composite sandwich laminated box beam under three-point bending load are studied by an experiment, finite element model, and analytical method. The three-point bending experiment was carried out on three different core composite sandwich laminated box beams, and the failure modes and bearing capacity were studied. With the use of composite progressive damage analysis and the core elastoplastic constitutive model, the finite element model of the composite sandwich laminated box beam was established, and the three-point bending failure process and failure modes were analyzed. The analytical model was established based on the Timoshenko beam theory. The overall bending stiffness and shear stiffness of the composite sandwich laminated box beam were calculated by the internal force–displacement relationship. The results show that the composite sandwich laminated box beam mainly suffers from local crushing failure, and the errors between the finite element simulation and the experiment result were within 7%. The analytical model of the composite sandwich laminated box beam can approximately predict the overall stiffness parameters, while the maximum error between theoretic results and experimental values was 5.2%. For composite aluminum honeycomb sandwich laminated box beams with a ratio of span to height less than 10, the additional deflection caused by shear deformation has an error of more than 25%. With the ratio of circumferential layers to longitudinal layers increasing, the three-point bending ultimate load of the composite sandwich laminated box beam increases, but the ratio of the overall stiffness to mass reduces. The use of low-density aluminum foam and smaller-wall-thickness cell aluminum honeycombs allows for the more obvious benefits of light weight.

Finite element modelling and design of composite bridges with profiled steel sheeting

2016 ◽  
Vol 20 (9) ◽  
pp. 1406-1430 ◽  
Author(s):  
Ehab Ellobody
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Finite Element Models ◽  
Test Results ◽  
Composite Bridges ◽  
European Code ◽  
Composite Bridge

This article discusses the non-linear analysis and design of highway composite bridges with profiled steel sheeting. A three-dimensional finite element model has been developed for the composite bridges, which accounted for the bridge geometries, material non-linearities of the bridge components, bridge boundary conditions, shear connection, interactions among bridge components and bridge bracing systems. The simply supported composite bridge has a span of 48 m, a width of 13 m and a depth of 2.3 m. The bridge components were designed following the European code for steel–concrete composite bridges. The live load acting on the bridge was load model 1, which represents the static and dynamic effects of vertical loading due to normal road traffic as specified in the European code. The finite element model of the composite bridge was developed depending on additional finite element models, developed by the author, and validated against tests reported in the literature on full-scale composite bridges and composite bridge components. The tests had different geometries, different boundary conditions, different loading conditions and different failure modes. Failure loads, load–mid-span deflection relationships, load–end slip relationships, failure modes, stress contours of the composite bridge as well as of the modelled tests were predicted from the finite element analysis and compared well against test results. The comparison with test results has shown that the finite element models can be effectively used to provide more accurate analyses and better understanding for the behaviour and design of composite bridges with profiled steel sheeting. A parametric study was conducted on the composite bridge highlighting the effects of the change in structural steel strength and concrete strength on the behaviour and design of the composite bridge. This study has shown that the design rules specified in the European code are accurate and conservative for the design of highway steel–concrete composite bridges.

scholarly journals Effect of Cyclic Loadings on the Shear Strength and Reinforcement Slip of RC Beams

2017 ◽  
Vol 3 (2) ◽  
pp. 111-123 ◽  
Author(s):  
Mohammed A Sakr
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Failure Mode ◽  
Failure Modes ◽  
Concrete Beams ◽  
Kinematic Hardening ◽  
Element Model ◽  
Reinforced Concrete Beams

Numerous studies of the response of reinforced concrete members under cyclic loadings, many of which have been summarized and have indicated that, in general, the flexural strength of under-reinforced beams remains unimpaired under cyclic loadings consisting of a reasonable number of cycles. However, there is a body of evidence indicating that their shear strength may suffer under such loadings. The first objective of the current study is to construct an accurate 2D shell finite element model of reinforced concrete beams under cyclic loadings. The second objective is carrying out a parametric study on reinforced concrete beams, using the suggested 2D shell model.  The objective of this study was to observe the effect of the stirrup spacing, steel-to-concrete bond properties on the performance of reinforced concrete beams under cyclic loadings. For this purpose, an efficient and accurate finite element model was established taking into account the compression and tensile softening introducing damage in the concrete material, the Baushinger effect using nonlinear isotropic/kinematic hardening in the steel and an adequate bond-slip law for the concrete–steel interface. The simulated results of numerical models were verified by experimental results available in literature in order to validate the proposed model, including hysteretic curves, failure modes, crack pattern and debonding failure mode. The model provided a strong tool for investigating the performances of reinforced concrete beam. The results showed that: Cyclic loadings may change the failure mode of the beam to bond failure even though it has sufficient bond length to resist static loadings. So that under cyclic loadings additional anchorage length must be taken, cyclic loadings also influence the ductility and peak load for beams fail in shear. All these topics are of the utmost importance to RC behaviour to be considered by construction codes.

Beam Shear Connections

2018 ◽  
Vol 763 ◽  
pp. 207-215
Author(s):  
Raharuhi Koia ◽  
Jack Needham ◽  
Saeid Alizadeh ◽  
John Scarry ◽  
Gregory A. MacRae
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Vertical Plane ◽  
Element Model ◽  
Shear Loading ◽  
Side Plate ◽  
Design Practices ◽  
Current Design ◽  
And Performance

Web side plate (WSP) connections consist of a WSP bolted to the web of a beam. The WSP and the beam web not lying in the same vertical plane cause a load eccentricity under shear or axial loading. However, common design practices in New Zealand do not explicitly consider the effects of this load eccentricity. Therefore, the purpose of this research paper was to investigate the effect this load eccentricity can have on the capacity of a WSP connection when it is subjected to shear loading alone. To do this, a finite element model was developed to predict the behaviour and performance of WSP connections under monotonic shear loading. Via the use of experimental data gathered from previous research into web side plate connections the performance of the model could be validated. It was shown that the finite element model could replicate the behaviour and performance of WSP connections well. Using the validated model procedure two different standard WSP connections were modelled and subjected to various parametric studies. It was found that for some typical NZ configurations the failure modes were identified to be bearing failure of the WSP or beam web and bolt tear out. The failure modes most susceptible to eccentric effects were considered to be bearing of the WSP and bolt shear failure. In general the effects of the eccentricity was considered to not be significant, however, there was one exception. The strength of the WSP connection was seen to decrease by 24% when the WSP was extended. It was concluded that the current design practices were appropriate for all WSP connections investigated except for those with extended WSPs. For extended WSP connections additional guidance was developed. Thus, considering the additional guidance in conjunction with current design practices will result in good behaviour for extended WSP connections.

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