Modeling Multi-Point Wheel/Rail Contact in the Analysis of Turnout Negotiation of Multibody Railroad Vehicles

2012 ◽  
Author(s):  
Akihiro Terao ◽  
Hiroyuki Sugiyama
Keyword(s):  
Numerical Procedure ◽  
Numerical Results ◽  
Elastic Contact ◽  
Cross Sectional ◽  
Railroad Vehicles ◽  
Curve Negotiation

In this investigation, a numerical procedure that accounts for multipoint contact for the analysis of vehicle/turnout interactions is developed. To this end, the multiple look-up contact table approach that can be used for modeling the change in the rail cross sectional shapes on turnout along the track is generalized for multipoint contact scenarios. The numerical results are compared with those of the online constraint/elastic contact approach for the analysis of curve negotiation first, and then it is demonstrated that the numerical procedure developed in this investigation can be used for predicting the multipoint contact between the wheel and rail for the analysis of vehicle/turnout interactions.

Numerical Procedure for Dynamic Simulation of Two-Point Wheel/Rail Contact and Flange Climb Derailment of Railroad Vehicles

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Shunpei Yamashita ◽  
Hiroyuki Sugiyama
Keyword(s):  
Point Contact ◽  
Numerical Procedure ◽  
Contact Problems ◽  
Detection Algorithm ◽  
Elastic Contact ◽  
Switching Algorithm ◽  
Railroad Vehicles ◽  
Contact Formulation ◽  
Contact Constraint ◽  
Contact Detection Algorithm

In this investigation, a numerical procedure for wheel/rail contact problems in the analysis of curve negotiation of railroad vehicles is developed using constraint/elastic contact approach. In particular, this work focuses on the flange contact detection algorithm using the two-point look-up contact table and the switching algorithm from the elastic to constraint contact for the flange climb simulation. The two-point look-up contact table is used for the contact search of the second point of contact modeled using the elastic contact, while the constraint contact is used for the first point of contact on the wheel tread. Furthermore, in the flange climb simulation using the constraint contact formulation, loss of a tread contact modeled using the constraint contact occurs. Therefore, the elastic contact used for modeling the flange contact in the two-point contact state needs to be switched to the constraint contact as soon as loss of the tread contact occurs. For this reason, if the Lagrange multiplier associated with the contact constraint becomes greater than or equal to zero, the elastic contact used for the flange is switched to the constraint contact. The computational algorithm for the proposed switching algorithm is also presented. Several numerical examples are presented in order to demonstrate the use of the numerical procedure developed in this investigation for modeling the two-point tread/flange contact as well as the flange climb behavior. Numerical results are in good agreement with those of the existing fully elastic contact formulation. Furthermore, it is shown that significant reduction in CPU time is achieved using the numerical procedure developed in this investigation.

scholarly journals Bonding widths of Deposited Polymer Strands in Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 871
Author(s):  
Cheng Luo ◽  
Manjarik Mrinal ◽  
Xiang Wang ◽  
Ye Hong
Keyword(s):  
Polymer Melt ◽  
Acrylonitrile Butadiene Styrene ◽  
High Viscosity ◽  
Numerical Results ◽  
Fused Filament Fabrication ◽  
Cross Sectional ◽  
Nozzle Height ◽  
Special Cases ◽  
Cross Sectional Profile ◽  
Sectional Profile

In this study, we explore the deformation of a polymer extrudate upon the deposition on a build platform, to determine the bonding widths between stacked strands in fused-filament fabrication. The considered polymer melt has an extremely high viscosity, which dominates in its deformation. Mainly considering the viscous effect, we derive analytical expressions of the flat width, compressed depth, bonding width and cross-sectional profile of the filament in four special cases, which have different combinations of extrusion speed, print speed and nozzle height. We further validate the derived relations, using our experimental results on acrylonitrile butadiene styrene (ABS), as well as existing experimental and numerical results on ABS and polylactic acid (PLA). Compared with existing theoretical and numerical results, our derived analytic relations are simple, which need less calculations. They can be used to quickly predict the geometries of the deposited strands, including the bonding widths.

Vibro-Stone Column Reinforcement Mechanism and Numerical Analysis

2012 ◽  
Vol 446-449 ◽  
pp. 1940-1943
Author(s):  
Yang Liu ◽  
Hong Xiang Yan
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Pore Pressure ◽  
Numerical Procedure ◽  
Numerical Results ◽  
Excess Pore Pressure ◽  
Stone Column ◽  
Reinforcement Mechanism ◽  
Consolidation Theory ◽  
Excess Pore

Numerical simulation of vibro-stone column is taken to simulate the installation of vibro-stone column. A relationship based on test is adopted to calculate the excess pore pressure induced by vibratory energy during the installation of vibro-stone column. A numerical procedure is developed based on the formula and Terzaghi-Renduric consolidation theory. Finally numerical results of composite stone column are compared single stone column.

Thermal Results for Forced Heat Convection Through Elliptical Ducts

1962 ◽  
Vol 29 (1) ◽  
pp. 165-170 ◽  
Author(s):  
N. T. Dunwoody
Keyword(s):  
Heat Transfer ◽  
Viscous Fluid ◽  
Cross Section ◽  
Constant Temperature ◽  
Fluid Flows ◽  
Numerical Results ◽  
Heat Convection ◽  
Elliptic Cross Section ◽  
Cross Sectional ◽  
Elliptic Cross

The purpose of the present investigation is to determine numerical results in respect of the heat transfer to the wall of a duct which has an elliptic cross section and through which a hot viscous fluid flows with a steady established laminar motion. The wall of the channel is at a constant temperature which is less than that of the entering fluid. Results for several cross-sectional eccentricities are presented and correlated.

First Observation of Elastic Plowing in Nanofriction

2005 ◽  
Author(s):  
Z. Charles Ying ◽  
Stephen M. Hsu
Keyword(s):  
Friction Force ◽  
Coefficient Of Friction ◽  
Cross Sectional Area ◽  
Elastic Contact ◽  
Sectional Area ◽  
Device Design ◽  
Friction Measurement ◽  
Cross Sectional ◽  
Elastic Regime ◽  
Series Of Experiments

Accurate friction measurement at nanoscale is critical in reliable micro- and nano-device design. Different values of coefficient of friction (COF) have been reported in the literature for the same material when different instruments and tip sizes were used [1–3]. We have conducted a series of experiments to delineate the effects of different tip sizes and shapes on friction as a function of load and found that friction force values under the elastic contact regime for various tips can be unified when plotted against the tip cross-sectional area in the direction of sliding. This observation implies a volumetric dependence of friction that has not been reported before in the elastic regime.

Numerical Investigation of Stainless Steel Welded I-Sections Subjected to Lateral-Torsional Buckling

2016 ◽  
Vol 853 ◽  
pp. 317-321
Author(s):  
Mohammad Anwar-Us-Saadat ◽  
Mahmud Ashraf ◽  
Shameem Ahmed
Keyword(s):  
Stainless Steel ◽  
Rational Design ◽  
Slenderness Ratio ◽  
Numerical Results ◽  
Maintenance Cost ◽  
Test Results ◽  
Structural Members ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Cross Sectional

Stainless steel is now widely used in construction as structural members in recognition to its unique beneficial properties such as corrosion resistance, higher strength and ductility, andnegligible maintenance cost. Recent research on stainless steel has seen development of rational design rules to predict cross-sectional resistances but still lacks in appropriate knowledge at the member level. The current paper investigates the lateral-torsional buckling (LTB) behaviour of welded stainless steel I sections. Available test results were used to develop and validate nonlinear finite element (FE) models. Limited experimental evidences were supplemented by a large number of reliable numerical results covering wider range of member slenderness ratio. All test and numerical results were used to investigate the performance of Eurocode EN-1993-1-4 and Australian code AS/NZS 4673 in predicting member resistances against lateral-torsional buckling.

On the Contact Problem of Thin Circular Rings

1965 ◽  
Vol 32 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Chien-Heng Wu ◽  
Robert Plunkett
Keyword(s):  
Contact Problem ◽  
Closed Form ◽  
Constant Curvature ◽  
Complete Solution ◽  
Elliptic Functions ◽  
Numerical Results ◽  
Elastic Contact ◽  
Flat Plates ◽  
Circular Rings

It is well known that the solution of an elastica subjected to end loads can be obtained in terms of elliptic functions. In the present paper, the combined problem of elastic contact between uniform circular rings or cylinders is reduced to a set of end-loaded elasticas. The approach is demonstrated by finding the complete solution in closed form for two unequal rings pressed between rigid anvils of constant curvature. Numerical results are obtained for the set of problems of two rings with equal stiffness but unequal radii compressed between two rigid flat plates.

Analysis of Steady Motions on Curved Tracks Using Multibody Models

2007 ◽  
Author(s):  
Jose´ L. Escalona ◽  
Rosario Chamorro
Keyword(s):  
Periodic Orbit ◽  
Equations Of Motion ◽  
Steady Motion ◽  
Contact Method ◽  
Elastic Contact ◽  
Coordinate Transformations ◽  
Railroad Vehicles ◽  
Curving Performance ◽  
The Stability ◽  
Steady Motions

In this paper a systematic procedure for evaluating the steady curving of railroad vehicles is developed. The equations of motion obtained using multibody dynamics and the elastic contact method are used to this end. The method proposed can deal with flange contact of the wheels. Two coordinate transformations are needed to evaluate the steady curving as an equilibrium position of the system instead of a periodic orbit. The stability of the motions is also evaluated by using a special eigenvalue analysis of the equations of motion. The procedure developed simplifies significantly the analysis of the curving performance of railroad vehicles without loosing accuracy or generality. The paper includes as a numerical example the steady motion of an unsuspended wheelset. The comparison of the numerical results with classical theories shows the accuracy of the method proposed.

Sign in / Sign up

Export Citation Format

Share Document