Simulation of Cold Bends by Finite Element Method

2004 ◽  
Author(s):  
M. Behbahanifard ◽  
J. J. R. Cheng ◽  
D. W. Murray ◽  
Joe Zhou ◽  
K. Adams ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Local Buckling ◽  
Element Model ◽  
Shell Elements ◽  
University Of Alberta ◽  
Main Pipe ◽  
Residual Curvature ◽  
Residual Strains ◽  
The Moment

A composite finite element model for cold bend simulation of energy pipelines is presented in this paper. Four-node shell elements with material and geometric nonlinearity are used to model a pipe in straight condition. An elastic pipe, having the same nodal coordinates as the main pipe along with elastic radial links are used as a tool to prevent local buckling and ovalization of the main pipe during the cold bend process. By dividing the elastic pipe into series of rings along the axis of the pipe and by conducting a four-step procedure, residual curvature is developed in a specific segment of a pipe. Based on the proposed concept, different methods of cold bending are discussed and the results are presented. University of Alberta cold bend trials were used to validate the proposed finite element model. The moment-curvature response, pattern of imperfections, and distribution of maximum residual strains are obtained by the finite element model and compared with the test results.

Finite Element Modeling of Unidirectional Non-Crimp Fabric for Manufacturing of Composites with Embedded Cabling

2013 ◽  
Vol 554-557 ◽  
pp. 484-491 ◽  
Author(s):  
Alexander S. Petrov ◽  
James A. Sherwood ◽  
Konstantine A. Fetfatsidis ◽  
Cynthia J. Mitchell
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Explicit Finite Element ◽  
Shell Elements ◽  
Beam Elements ◽  
Hybrid Finite Element ◽  
International Benchmarking ◽  
Unidirectional Glass ◽  
Forming Simulations

A hybrid finite element discrete mesoscopic approach is used to model the forming of composite parts using a unidirectional glass prepreg non-crimp fabric (NCF). The tensile behavior of the fabric is represented using 1-D beam elements, and the shearing behavior is captured using 2-D shell elements into an ABAQUS/Explicit finite element model via a user-defined material subroutine. The forming of a hemisphere is simulated using a finite element model of the fabric, and the results are compared to a thermostamped part as a demonstration of the capabilities of the used methodology. Forming simulations using a double-dome geometry, which has been used in an international benchmarking program, were then performed with the validated finite element model to explore the ability of the unidirectional fabric to accommodate the presence of interlaminate cabling.

Quick Aeromechanical Assessment of Turbine Blades Based on Shell Element Based Models

2014 ◽  
Author(s):  
Suryarghya Chakrabarti ◽  
Letian Wang ◽  
K. M. K. Genghis Khan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Computation Time ◽  
Shell Element ◽  
Element Model ◽  
Shell Elements ◽  
Barrier Coating ◽  
Order Of Magnitude

A fast finite element model based tool has been developed to calculate the natural frequencies of fundamental modes of cooled gas turbine bladed disk assemblies during conceptual design. The tool uses shell elements to model the airfoil, shank, and disk, and achieves order of magnitude reduction in computation time allowing exploration of a wide design space at the preliminary design stages. The analysis includes prestress effects due to centrifugal loading and approximate temperature loading on the parts. Sensitivity studies are performed to understand the relative impact of design features such as airfoil internal geometry, bond coat, and thermal barrier coating on the system natural frequencies. Critical features are selected which need to be modeled to get an accurate natural frequency estimate. The results obtained are shown to be within 5% of the frequencies obtained from a full-fidelity finite element model. A case study performed on seven blade designs illustrates the use of this tool for quick aeromechanical assessment of a large number of designs.

Seismic analysis of elevated pure conical tanks under vertical excitation

2014 ◽  
Vol 41 (10) ◽  
pp. 909-917 ◽  
Author(s):  
Michael Jolie ◽  
Ayman M. El Ansary ◽  
Ashraf A. El Damatty
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Vertical Component ◽  
Element Model ◽  
Shell Elements ◽  
Vertical Excitation ◽  
Analysis And Design ◽  
Conical Tanks

Truncated conical vessels are commonly used as liquid containers in elevated tanks. Despite the widespread use of this type of structure worldwide, no direct code provisions are currently available covering its seismic analysis and design. The purpose of the current study is to assess the importance of considering the vertical component of ground accelerations when analyzing and designing this type of water-storage structure. The study is conducted using an equivalent mechanical model that estimates the normal forces that develop in the tank walls when subjected to vertical excitation. In addition, a three-dimensional finite element model has been developed by modeling the walls of the tank using shell elements. The finite element model has been employed to predict maximum membrane and overall meridional stresses due to both hydrodynamic and hydrostatic pressure distributions. Comparisons have been conducted to assess the significance of considering vertical excitation and to identify the magnification in meridional stresses due to bending effects associated with support conditions and large deformations.

A numerical investigation of overstrength and ductility factors of moment resisting steel frames retrofitted with GFRP plates

2014 ◽  
Vol 41 (1) ◽  
pp. 17-31 ◽  
Author(s):  
Mohammad Al Amin Siddique ◽  
Ashraf A. El Damatty ◽  
Ayman M. El Ansary
Keyword(s):  
Steel Frames ◽  
Local Buckling ◽  
Element Model ◽  
Steel Beams ◽  
Shell Elements ◽  
Glass Fiber Reinforced ◽  
Moment Resisting ◽  
Spring System ◽  
The Moment ◽  
Nonlinear Finite Element Model

This paper reports the results of an investigation conducted to assess the effectiveness of using glass fiber reinforced polymer (GFRP) plates to enhance the overstrength and ductility factors of moment resisting steel frames. The GFRP plates are bonded to the flanges of steel beams of the frame with an aim to enhance their local buckling capacities and consequently their ductility. The flexural behaviour of GFRP retrofitted beams is first determined using a nonlinear finite element model developed in-house. In this numerical model, consistent shell elements are used to simulate the flanges and web of the steel beam as well as the GFRP plate. The interface between the steel and the GFRP plate is simulated using a set of continuous linear spring system representing both the shear and peeling stiffness of the adhesive based on values obtained from a previous experimental study. The moment–rotation characteristics of the retrofitted beams are then implemented into the frame model to carry out nonlinear static (pushover) analyses. The seismic performance level of the retrofitted frames in terms of overstrength and ductility factors is then compared with that of the bare frame. The results show a significant enhancement in strength and ductility capacities of the retrofitted frames, especially when the beams of the frame are slender.

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.

Mesh Convergence Studies for Thick Shell Elements Developed by the ASME Special Working Group on Computational Modeling

2013 ◽  
Author(s):  
David P. Molitoris ◽  
Gordon S. Bjorkman ◽  
Chi-Fung Tso ◽  
Michael Yaksh
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Working Group ◽  
Element Model ◽  
Thick Shell ◽  
Shell Elements ◽  
Special Working ◽  
Special Working Group

The ASME Special Working Group on Computational Modeling for Explicit Dynamics was founded in August 2008 for the purpose of creating a quantitative guidance document for the development of finite element models used to analyze energy-limited events using explicit dynamics software. This document will be referenced in the ASME Code Section III, Division 3 and the next revision of NRC Regulatory Guide 7.6 as a means by which the quality of a finite element model may be judged. One portion of the document will be devoted to a series of element convergence studies that can aid designers in establishing the mesh refinement requirements necessary to achieve accurate results for a variety of different element types in regions of high plastic strain. These convergence studies will also aid reviewers in evaluating the quality of a finite element model and the apparent accuracy of its results. In this paper, the authors present the results of a convergence study for an impulsively loaded propped cantilever beam constructed of LS-DYNA thick shell elements using both reduced and selectively reduced integration. A large load is applied to produce large deformations and large plastic strains in the beam. The deformation and plastic strain results are then compared to similar results obtained using thin shell elements and hexahedral elements for the beam mesh.

scholarly journals Finite Element Analysis of Glass Fiber-Reinforced Polymer-(GFRP) Reinforced Continuous Concrete Beams

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4468
Author(s):  
Hazem Ahmad ◽  
Amr Elnemr ◽  
Nazam Ali ◽  
Qudeer Hussain ◽  
Krisada Chaiyasarn ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Shear Capacity ◽  
Experimental Results ◽  
Beam Specimen ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
Moment Distribution ◽  
The Moment

Fiber-reinforced concrete (FRC) is a competitive solution for the durability of reinforced structures. This paper aims to observe the moment redistribution behavior occurring due to flexural and shear loading in Glass Fiber-Reinforced Polymer- (GFRP) reinforced continuous concrete beams. A rectangular cross-section was adopted in this study with dimensions of 200 mm in width and 300 mm in depth with a constant shear span-to-depth ratio of 3. The reinforcement ratio for the top and bottom were equal at sagging and hogging moment regions. A finite element model was created using Analysis System (ANSYS) and validated with the existing experimental results in the literature review. Based on the literature review, the parametric study was conducted on twelve beam specimens to evaluate the influence of concrete compressive strength, transversal GFRP stirrups ratio, and longitudinal reinforcement ratio on the redistribution of the moment in beams. Several codes and guidelines adopted different analytical models. The Canadian Standards Association (CSA) S806 adopted the modified compression field theory in predicting the shear capacity of the simply supported beams. Recently, various researchers encountered several factors and modifications to account for concrete contribution, longitudinal, and transverse reinforcement. A comparison between the predicting shear capacity of the generated finite element model, the analytical model, and the existing data from the literature was performed. The generated finite element model showed a good agreement with the experimental results, while the beam specimens failed in shear after undergoing significant moment redistribution from hogging to sagging moment region. The moment distribution observed about 21.5% from FEM of beam specimen GN-1.2-0.48-d, while the experimental results achieved 24% at failure load. For high strength concrete presented in beam specimen GH-1.2-0.63-d, the result showed about 20.2% moment distribution, compared to that achieved experimentally of 23% at failure load.

Mesh Convergence Studies for Thin Shell Elements Developed by the ASME Task Group on Computational Modeling

2011 ◽  
Author(s):  
Gordon S. Bjorkman ◽  
David P. Molitoris
Keyword(s):  
Finite Element ◽  
Computational Modeling ◽  
Finite Element Model ◽  
Thin Shell ◽  
Element Model ◽  
Task Group ◽  
Plastic Strains ◽  
Shell Elements ◽  
Explicit Dynamics

The ASME Task Group on Computational Modeling for Explicit Dynamics was founded in August 2008 for the purpose of creating a quantitative guidance document for the development of finite element models used to analyze energy-limited events using explicit dynamics software. This document will be referenced in the ASME Code Section III, Division 3 and the next revision of NRC Regulatory Guide 7.6 as a means by which the quality of a finite element model may be judged. One portion of the document will be devoted to a series of element convergence studies that can aid designers in establishing the mesh refinement requirements necessary to achieve accurate results for a variety of different elements types in regions of high plastic strain. These convergence studies will also aid reviewers in evaluating the quality of a finite element model and the apparent accuracy of its results. In this paper the authors present the results of a convergence study for an impulsively loaded propped cantilever beam constructed of LS-DYNA thin shell elements using both reduced and full integration. Three loading levels are considered; the first maintains strains within the elastic range, the second induces moderate plastic strains, and the third produces large deformations and large plastic strains.

Sign in / Sign up

Export Citation Format

Share Document