Finite element modeling of guyed back spars in cable logging

2004 ◽  
Vol 34 (4) ◽  
pp. 817-828 ◽  
Author(s):  
Albert Saravi ◽  
C Kevin Lyons
Keyword(s):  
Finite Element ◽  
Normal Stress ◽  
Cross Section ◽  
A Priori ◽  
Element Model ◽  
Transverse Cross Section ◽  
Stress Fields ◽  
Stress Concentrations ◽  
Maximum Normal Stress ◽  
Tree Method

In this study a finite element model of a back spar system was developed with three guylines opposing the skyline strap tension. In this paper the allowable skyline strap tension is the tension in the skyline strap that results in the maximum normal stress on a transverse cross section of the tree being equal to an assumed allowable stress. An iterative routine was developed to find the allowable skyline strap tension, and this routine was found to converge rapidly from initial values that were below and above the allowable skyline strap tension. Two algorithms were developed for finding the maximum normal stress on a transverse cross section of a tree, method 1 and method 2. If the plane that the tree displaced in was known a priori, then method 2 could be used, and it was found to be less sensitive to mesh coarseness. If the plane that the tree displaced in was not known a priori, then method 1 had to be used with a less coarse mesh. It was found that the stress concentrations due to simplified cable connections were not significant for rigging configurations that allowed a larger rigging point displacement. The rigging configurations that allowed larger rigging point displacements have stress fields that are dominated by bending, while for rigging configurations that allow only small rigging point displacements, the stress fields are dominated by axial compression.

Stress analysis of a plain orthogonally woven textile composite under tension along the warp direction

2019 ◽  
Vol 53 (20) ◽  
pp. 2809-2829
Author(s):  
M Keith Ballard ◽  
John D Whitcomb
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Normal Stress ◽  
Local Coordinate System ◽  
Mesh Refinement ◽  
Element Model ◽  
Stress Concentrations ◽  
Textile Composite ◽  
Volume Average ◽  
Woven Textile

A non-idealized finite element model of a plain orthogonally woven textile composite was subjected to tension along the warp direction, and the predicted stress state was investigated. The effect of refining the geometry and mesh on the volume average stresses and the percentage of each constituent at different stress levels was explored. For the particular textile architecture considered, which consisted of large reinforcement tows and complex tow cross sections, it was shown that the typical mesh refinement in the literature might suffice for volume average stresses, but a higher mesh refinement is needed to accurately capture stress concentrations. The locations of stress concentrations within each constituent were identified. For the three types of tows, [Formula: see text], transverse normal stress in the local coordinate system, in the wefts was predicted to be the most severe component of stress. For the layers of wefts that are crossed over or under by a binder, stress concentrations developed where the warps were the most distorted. Whereas, for the interior layer of wefts, stress concentrations developed where a binder came closest to the weft. In the matrix, [Formula: see text], the normal stress in the direction of the load, concentrations developed where a binder came close to a warp or weft. The locations of peak cross-sectionally averaged stresses along the tow paths were shown to match the locations of local stress concentrations. However, it was observed that many of the stress concentrations might be sensitive to the method used to create the finite element model, boundary conditions, or accounting for the variation of local fiber-volume fraction that results from a variation of cross-sectional area.

Numerical Simulation of the Effects of Preheating on Electron Beam Additive Manufactured Ti-6Al-4V Build Plate

2016 ◽  
Vol 879 ◽  
pp. 274-278 ◽  
Author(s):  
Jun Cao ◽  
Philip Nash
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Finite Element ◽  
Electron Beam ◽  
Cross Section ◽  
Element Model ◽  
Normal Direction ◽  
Thermal Residual Stresses ◽  
Longitudinal Residual Stress ◽  
Middle Cross Section

In an earlier study, a 3-D thermomechanical coupled finite element model was built and experimentally validated to investigate the evolution of the thermal residual stresses and distortions in electron beam additive manufactured Ti-6Al-4V build plates. In this study, an investigation using this robust and accurate model was focused on an efficient preheating method, in which the electron beam quickly scanned across the substrate to preheat the build plate prior to the deposition. Various preheat times, beam powers, scan rates, scanning paths and cooling times (between the end of current preheat scan/deposition layer and the beginning of the next preheat scan/deposition layer) were examined, and the maximum distortion along the centerline of the substrate and the maximum longitudinal residual stress along the normal direction on the middle cross-section of the build plate were quantitatively compared. The results show that increasing preheat times and beam powers could effectively reduce both distortion and residual stress for multiple layers/passes components.

Free Vibration Analysis for Tapered Cross-Section Steel-Concrete Composite Material Beam

2017 ◽  
Vol 893 ◽  
pp. 380-383
Author(s):  
Jun Xia ◽  
Z. Shen ◽  
Kun Liu
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Cross Section ◽  
Vibration Analysis ◽  
Free Vibration Analysis ◽  
Element Model ◽  
Composite Beams ◽  
Shear Connection ◽  
The Common ◽  
Interlayer Slip

The tapered cross-section beams made of steel-concrete composite material are widely used in engineering constructions and their dynamic behavior is strongly influenced by the type of shear connection jointing the two different materials. The 1D high order finite element model for tapered cross-section steel-concrete composite material beam with interlayer slip was established in this paper. The Numerical results for vibration nature frequencies of the composite beams with two typical boundary conditions were compared with ANSYS using 2D plane stress element. The 1D element is more efficient and economical for the common tapered cross-section steel-concrete composite material beams in engineering.

scholarly journals Membrane analogy for multi-material bars under torsion

2019 ◽  
Vol 475 (2225) ◽  
pp. 20190124 ◽  
Author(s):  
Laura Galuppi ◽  
Gianni Royer-Carfagni
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Elastic Problem ◽  
Two Dimensional ◽  
Torsion Problem ◽  
Linear Elastic ◽  
Physical Apparatus

Prandtl's membrane analogy for the torsion problem of prismatic homogeneous bars is extended to multi-material cross sections. The linear elastic problem is governed by the same equations describing the deformation of an inflated membrane, differently tensioned in regions that correspond to the domains hosting different materials in the bar cross section, in a way proportional to the inverse of the material shear modulus. Multi-connected cross sections correspond to materials with vanishing stiffness inside the holes, implying infinite tension in the corresponding portions of the membrane. To define the interface constrains that allow to apply such a state of prestress to the membrane, a physical apparatus is proposed, which can be numerically modelled with a two-dimensional mesh implementable in commercial finite-element model codes. This approach presents noteworthy advantages with respect to the three-dimensional modelling of the twisted bar.

Support-Condition Analyses of Rotating Beams Under Distributed Imbalance Loading

2011 ◽  
Author(s):  
Kai Jokinen ◽  
Erno Keskinen ◽  
Marko Jorkama ◽  
Wolfgang Seemann
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cross Section ◽  
Cross Sections ◽  
Natural Frequencies ◽  
Element Model ◽  
Mode Shapes ◽  
Constant Cross Section ◽  
Support Condition ◽  
Beam Elements

In roll balancing the behaviour of the roll can be studied either experimentally with trial weights or, if the roll dimensions are known, analytically by forming a model of the roll to solve response to imbalance. Essential focus in roll balancing is to find the correct amount and placing for the balancing mass or masses. If this selection is done analytically the roll model used in calculations has significant effect to the balancing result. In this paper three different analytic methods are compared. In first method the mode shapes of the roll are defined piece wisely. The roll is divided in to five parts having different cross sections, two shafts, two roll ends and a shell tube of the roll. Two boundary conditions are found for both supports of the roll and four combining equations are written to the interfaces of different roll parts. Totally 20 equations are established to solve the natural frequencies and to form the mode shapes of the non-uniform roll. In second model the flexibility of shafts and the stiffness of the roll ends are added to the support stiffness as serial springs and the roll is modelled as a one flexibly supported beam having constant cross section. Finally the responses to imbalance of previous models are compared to finite element model using beam elements. Benefits and limitations of each three model are then discussed.

Residual stress distribution in built-in beams

2020 ◽  
pp. 146442072095861
Author(s):  
FA de Castro ◽  
Paulo P Kenedi ◽  
LL Vignoli ◽  
I I T Riagusoff
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Cross Section ◽  
Cross Sections ◽  
Element Model ◽  
Residual Stress Distribution ◽  
Concentrated Load ◽  
Load Growth ◽  
Final Failure

Metallic hyperstatic structures, like beams, submitted to excessive loads, do not fail completely before fully yielding in more than one cross section. Indeed, for built-in beams, three cross sections must be fully yielded before the final failure can occur. So, modeling the evolution of the cross-section residual stress distribution is an important subject that should be addressed to guarantee the stress analysis modeling correctness. This paper analyses the residual stress distribution evolution, in critical cross sections, of built-in beams during a transversal concentrated load growth, until the final failure through hinges formation. A finite element model is also presented. The results show good matches with the numerical model, used as a reference.

scholarly journals Hierarchical Beam Finite Elements Based Upon a Variables Separation Method

2016 ◽  
Vol 08 (02) ◽  
pp. 1650026 ◽  
Author(s):  
Gaetano Giunta ◽  
Salim Belouettar ◽  
Olivier Polit ◽  
Laurent Gallimard ◽  
Philippe Vidal ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Cross Section ◽  
Three Dimensional ◽  
Finite Element Solution ◽  
Stress Fields ◽  
Element Solution ◽  
One Dimensional ◽  
Kinematic Approximation ◽  
The Cross

A family of hierarchical one-dimensional beam finite elements developed within a variables separation framework is presented. A Proper Generalized Decomposition (PGD) is used to divide the global three-dimensional problem into two coupled ones: one defined on the cross-section space (beam modeling kinematic approximation) and one belonging to the axis space (finite element solution). The displacements over the cross-section are approximated via a Unified Formulation (UF). A Lagrangian approximation is used along the beam axis. The resulting problems size is smaller than that of the classical equivalent finite element solution. The approach is, then, particularly attractive for higher-order beam models and refined axial meshes. The numerical investigations show that the proposed method yields accurate yet computationally affordable three-dimensional displacement and stress fields solutions.

Performance Analysis of CFST Column and RC Column Subjected to Eccentric Load

2011 ◽  
Vol 94-96 ◽  
pp. 805-809
Author(s):  
Yu Yong Fu ◽  
Shu Wang Yan ◽  
Chuang Du
Keyword(s):  
Finite Element ◽  
Performance Analysis ◽  
Bearing Capacity ◽  
Cross Section ◽  
Slenderness Ratio ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Eccentric Load ◽  
Rc Column ◽  
Nonlinear Finite Element Model

A nonlinear finite element model is developed to study the behavior of square concrete-filled steel tubular(CFST) column and reinforced concrete (RC) column with the same quantity of material and cross-section sizes under eccentric load using ANSYS software.The results indicate that the bearing capacity of CFST column is about 30% greater than RC column and the ductility of CFST column is much greater than RC column under the same conditions. Eccentricity and slenderness ratio have same effect on the bearing capacity of both, which are drop.

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