scholarly journals Displacement and Stress Function-based Linear and Quadratic Triangular Elements for Saint-Venant Torsional Problems

2018 ◽  
Vol 20 (2) ◽  
pp. 70 ◽  
Author(s):  
Joko Purnomo ◽  
Wong Foek Tjong ◽  
Wijaya W.C. ◽  
Putra J.S.
Keyword(s):  
Cross Sections ◽  
Stress Function ◽  
Torsional Rigidity ◽  
Structural Members ◽  
Finite Element Program ◽  
Element Program ◽  
Standard Linear ◽  
Triangular Elements ◽  
Displacement Based ◽  
High Degree

Torsional problems commonly arise in frame structural members subjected to unsym­metrical loading. Saint-Venant proposed a semi inverse method to develop the exact theory of torsional bars of general cross sections. However, the solution to the problem using an analytical method for a complicated cross section is cumbersome. This paper presents the adoption of the Saint-Venant theory to develop a simple finite element program based on the displacement and stress function approaches using the standard linear and quadratic triangular elements. The displacement based approach is capable of evaluating torsional rigidity and shear stress distribution of homogeneous and nonhomogeneous; isotropic, orthotropic, and anisotropic materials; in singly and multiply-connected sections.  On the other hand, applications of the stress function approach are limited to the case of singly-connected isotropic sections only, due to the complexity on the boundary conditions. The results show that both approaches converge to exact solutions with high degree of accuracy.

Algorithm and Program for Simulating Heat Transfer in Cavities of Structural Members under Fire Conditions

2011 ◽  
Vol 90-93 ◽  
pp. 3227-3233
Author(s):  
Yong Jun Liu ◽  
Dong Wang ◽  
Xing Tao Ma
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Radiative Heat ◽  
Coefficient Matrix ◽  
System Of Equations ◽  
Structural Members ◽  
Finite Element Program ◽  
Heat Flows ◽  
Element Program ◽  
Fire Conditions

In this paper, an algorithm based on the network method suggested by Oppenheim for calculating the radiative heat flow in a cavity of structural members, say hollow core concrete slabs, exposed to fires is presented. It is assumed that the pressure in a cavity keeps atmospheric pressure through the whole cause of a fire, and the lost heat from the air due to expansion and immediate moving away from a cavity is neglected. The heat in a cavity is transfer via both heat conduction in air and thermal radiation among boundaries, and special regard is paid to modeling heat transfer by radiation. The effective radiative heat flow system of equations is derived and expressed in matrix form. The system of equations features a symmetric coefficient matrix, which can be stored in a one dimensional array, and can be solved using LDLT factorization. Node radiative thermal loads are calculated from effective radiative heat flows at edges of elements located on internal cavities. The nonlinear finite element program TFIELD written by first author has employed the new algorithm. Temperature distribution in two structural members with cavities are calculated using TFIELD, and numerical results demonstrate that the new algorithm is very effective and is useful for further study of structural behavior of structural members under fire conditions.

Behavior of an embankment on New York varved clay

1978 ◽  
Vol 15 (2) ◽  
pp. 250-268 ◽  
Author(s):  
Francis D. Leathers ◽  
Charles C. Ladd
Keyword(s):  
New York ◽  
Cross Sections ◽  
New York State ◽  
Three Dimensional ◽  
Field Measurements ◽  
Finite Element Program ◽  
Pore Pressures ◽  
Element Program ◽  
Prediction Techniques ◽  
Varved Clay

The foundation soils for an embankment in New York State constructed on preconsolidated varved clay were instrumented to determine pore pressures and settlements during and after construction. Four embankment cross sections, three of which had sand drains, are analyzed in this paper. Predictions of the in situ undrained pore pressures, initial settlements and final consolidation settlements are presented and compared with the results of field measurements. Undrained pore pressures and initial settlements are predicted using the finite element program FEECON for plane strain embankment conditions and elastic theory for three-dimensional embankment conditions. Final consolidation settlements are predicted using a modification of the Skempton–Bjerrum approach. At cross sections with sand drains, predicted undrained pore pressures are adjusted to account for the effect of the sand drains. In addition, vertical and horizontal coefficients of consolidation are determined from the field measurements and compared with laboratory values of vertical coefficients of consolidation. The results of the investigation indicate that the proposed prediction techniques yield reasonable predictions of undrained pore pressure and initial settlement. Additional case studies are required in order to evaluate the predictive methods for the rate and amount of consolidation settlement.

Behaviour and resistance of cold-formed steel beams with lipped channel sections under fire conditions

2016 ◽  
Vol 7 (4) ◽  
pp. 365-387 ◽  
Author(s):  
Flávio Arrais ◽  
Nuno Lopes ◽  
Paulo Vila Real
Keyword(s):  
Cross Sections ◽  
Elevated Temperatures ◽  
Numerical Results ◽  
Steel Beams ◽  
Finite Element Program ◽  
Content Type ◽  
Current Design ◽  
Element Program ◽  
Steel Grades ◽  
Cold Formed Steel

Purpose Steel beams composed of cold-formed sections are common in buildings because of their lightness and ability to support large spans. However, the instability phenomena associated to these members are not completely understood in fire situation. Thus, the purpose of this study is to analyse the behaviour of beams composed of cold-formed lipped channel sections at elevated temperatures. Design/methodology/approach A numerical analysis is made, applying the finite element program SAFIR, on the behaviour of simply supported cold formed steel beams at elevated temperatures. A parametric study, considering several cross-sections with different slenderness’s values, steel grades and bending diagrams, is presented. The obtained numerical results are compared with the design bending resistances determined from Eurocode 3 Part 1-2 and its French National Annex (FN Annex). Findings The current design expressions revealed to be too conservative when compared with the obtained numerical results. It was possible to observe that the FN Annex is less conservative than the Annex E, the first having a better agreement with the numerical results. Originality/value Following the previous comparisons, new fire design formulae are tested. This new methodology, which introduces minimum changes in the existing formulae, provides safety and accuracy at the same time when compared to the numerical results, considering the occurrence of local, distortional and lateral torsional buckling phenomena in these members at elevated temperatures.

Finite Element Analysis of Four-Roll Pass Cold Rolling

1992 ◽  
Vol 206 (2) ◽  
pp. 133-141 ◽  
Author(s):  
S W Wen ◽  
P Hartley ◽  
I Pillinger ◽  
C E N Sturgess
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cold Rolling ◽  
Cross Sections ◽  
Rolling Process ◽  
Roll Pass ◽  
Element Analysis ◽  
Finite Element Program ◽  
Iron And Steel ◽  
Element Program

This paper presents a study of the mechanics of deformation of the four-roll pass cold rolling using an elastic-plastic finite element program. This process has been developed at the Anshan Institute of Iron and Steel Technology, People's Republic of China, where a new four-roll pass small section cold rolling mill has been built. The initial finite element analysis has been carried out for the rolling of 8 mm square section bar from 10 mm diameter round stock under dry friction conditions. The results show clearly how the areas of plastic deformation develop during the rolling process. The distributions of the generalized stress and the generalized plastic strain, both on the longitudinal symmetrical plane and on the transverse cross-sections of the workpiece, have been obtained, and the pressure distribution along the arc of contact has been determined. In addition, the roll separation force and the pass elongation of the workpiece predicted by the finite element program have been compared with the corresponding values measured in experiments when rolling 6.5 mm square section bar from 8 mm round material with machine oil lubrication. Good agreement has been obtained.

Implementation of Likhachev’s Model into a Finite Element Program

2013 ◽  
Vol 738-739 ◽  
pp. 160-164 ◽  
Author(s):  
Patrick Terriault ◽  
Vladimir Brailovski
Keyword(s):  
Finite Element ◽  
Stress And Strain ◽  
Complex Behavior ◽  
Element Analysis ◽  
Finite Element Program ◽  
The Past ◽  
Design Engineers ◽  
Element Program ◽  
Displacement Based ◽  
Proportional Controller

Shape memory alloys have become very popular over the past few decades, mainly as actuators or superelastic devices. Their complex behavior complicates the design process of these applications, and several models have been developed to assist design engineers in this endeavor. One of these models, the structure-analytical theory proposed by Likhachev, is particularly attractive because it is physically grounded and capable of dealing with tensorial stress and strain states. Unfortunately, its stress-controlled formulation has hindered its implementation in displacement-based finite element programs. This paper presents an adaptation of Likhachev’s model leading to a strain-controlled formulation based on an iterative algorithm and a proportional controller. The resulting model is implemented in ANSYS and a simple finite element analysis is carried out to illustrate its appropriate functioning.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

scholarly journals The impact of drilling and slitting construction on damage field: evolution characteristics in low-permeability coal seam

2021 ◽  
Vol 37 ◽  
pp. 205-215
Author(s):  
Heng Chen ◽  
Hongmei Cheng ◽  
Aibin Xu ◽  
Yi Xue ◽  
Weihong Peng
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Damage Mechanics ◽  
Effective Strain ◽  
Secondary Development ◽  
Distribution Area ◽  
Finite Element Program ◽  
Element Program ◽  
Mining Face ◽  
The Impact

ABSTRACT The fracture field of coal and rock mass is the main channel for gas migration and accumulation. Exploring the evolution law of fracture field of coal and rock mass under the condition of drilling and slitting construction has important theoretical significance for guiding efficient gas drainage. The generation and evolution process of coal and rock fissures is also the development and accumulation process of its damage. Therefore, based on damage mechanics and finite element theory, the mathematical model is established. The damage variable of coal mass is defined by effective strain, the elastoplastic damage constitutive equation is established and the secondary development of finite element program is completed by FORTRAN language. Using this program, the numerical simulation of drilling and slitting construction of the 15-14120 mining face of Pingdingshan No. 8 Mine is carried out, and the effects of different single borehole diameters, different kerf widths and different kerf heights on the distribution area of surrounding coal fracture field and the degree of damage are studied quantitatively. These provide a theoretical basis for the reasonable determination of the slitting and drilling arrangement parameters at the engineering site.

Mechanical Property Analysis and Numerical Simulation of Honeycomb Sandwich Structure’s Core

2013 ◽  
Vol 631-632 ◽  
pp. 518-523 ◽  
Author(s):  
Xiang Li ◽  
Min You
Keyword(s):  
Numerical Simulation ◽  
Elastic Constants ◽  
Sandwich Structure ◽  
Optimization Design ◽  
Simulation Analysis ◽  
Finite Element Program ◽  
Honeycomb Sandwich ◽  
Calculation Results ◽  
Element Program ◽  
Typical Satellite

Owing to the lack of a good theory method to obtain the accurate equivalent elastic constants of hexagon honeycomb sandwich structure’s core, the paper analyzed mechanics performance of honeycomb sandwich structure’s core and deduced equivalent elastic constants of hexagon honeycomb sandwich structure’s core considering the wall plate expansion deformation’s effect of hexagonal cell. And also a typical satellite sandwich structure was chose as an application to analyze. The commercial finite element program ANSYS was employed to evaluate the mechanics property of hexagon honeycomb core. Numerical simulation analysis and theoretical calculation results show the formulas of equivalent elastic constants is correct and also research results of the paper provide theory basis for satellite cellular sandwich structure optimization design.

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