Design and Analysis of Railway Casnub Bogie Using Fem

Transcription

1 Design and Analysis of Railway Casnub Bogie Using Fem Abstract : Indian Railways is a vital sector for the economic development in our country. Wherein, freight movement is the major activity of revenue generation. Cast Steel CASNUB 22HS-bogie is a type of railway bogie commonly used in freight stock. Due to the need of faster turnaround time and higher Pay load carrying capacity, weight reduction of components and systems is of utmost importance in railway industry. Reducing weight translates into higher performance and lower fuel/power consumption. This requires modification of existing components or introduction of new design. This work is an effort in the direction of modifying the design of critical components in order to optimize the total weight of CASNUB-22HS Bogie. The weight optimization needed to be performed in such a way that the overall dimensions of the bogie remain unchanged. For this, finite element approach by ANSYS is used. In the first stage, given geometry models are simulated with the specified load cases to establish a baseline performance in terms of Maximum Von-Mises stress induced, stiffness, fatiguelife/strength, eigen-behavior and vehicle running behavior while running on the track with irregularities. Later, design of the Bogie components are optimized keeping weight as upper limit constraint and minimum strain energy as objective function. Same load cases were applied to the proposed optimized models. I. INTRODUCTION: The railway train running along a track is one of the most complicated dynamical Systems in engineering. Many bodies comprise the system and so it has many degrees of freedom. The principal difference between a railway vehicle and other types of wheeled transport is the guidance provided by the track. The surface of the rails not only supports the wheels, but also guides them in both lateral and longitudinal direction. The Railcar Bogies perform following functions: 1. Support railcar body firmly 2. Run stably on both straight and curved track 3. Ensure good ride comfort by absorbing vibration generated by track irregularities and minimizing Impact of centrifugal forces when train runs on curves at higher speeds Zeyaullah Ansari VIF College of Engg & Tech. Hyderabad 4. Minimize generation of track irregularities and rail abrasion Railway CASNUB 22HS-Bogie is a threepiece bogie consists of two side-frames connected by a bolster. The primary suspension connects the sideframes to the axle and wheel assembly. Each side frame is connected to the bolster by a central coil spring (load coil) and a friction wedge suspension system supported by smaller coil springs. The secondary suspension provides damping in both the vertical and lateral directions. Figures 1.1 provides the 3-dimensional view of the bogie. 2.1 PRO/E DESIGN: Pro/ENGINEER is a parametric, integrated 3D CAD/CAM/CAE solution created by Parametric Technology Corporation (PTC). It was the first to market with parametric, feature-based, associative modeling software. The application runs on Microsoft-Windows platform, and provides modeling, assembly and drafting, finite element analysis, and NC and tooling functionality for mechanical engineers. When we want to create any solid model, you have to create it using number of features hence it is known as feature base. Pro/ENGINEER is feature-based. Geometry is composed of a series of easy to understand features. A feature is the smallest building block in a part model. Things to remember: Pro/ENGINEER allows building a model incrementally, adding individual features one at a time. This means, as you construct your model feature by feature you choose your building blocks as well as the order you create them in, thus capturing your design intent. Design intent is the motive, the all-driving force, behind every feature creation. Simple features make your individual parts as well as the overall model flexible and reliable. The fly-out icons will appears automatically on the right side screen when you enter the sketcher mode. These 68

2 icons are logically grouped together, based on capability. directions at the locations where the wedge liners and bolster land surface liners are attached. Also, bolster is constrained in Z direction at both ends on the surface where secondary Suspension springs are placed. The loading and boundary conditions are shown in Figure Load varies linearly from 0 to its final value along with the time step duration of 1 second. Pressure calculations : M = mass on the casenub bogie = 2500Kg, F = Mg, F = 2500 * 9.81 = 24525Mpa P = F A = 24525/1000 = 25 Mpa Figure 2.1:3-D Solid Model of Bogie Assembly and3-d Solid Model of Side-Frame Fig 3.1 Meshing of Bolster Figure 2.3: 3-D Solid Model of Bolster CASNUB BOGIE ANALYSIS: Railway Bogie generally consists of shells, plates and beams. Behavior of these members directly affects static and dynamic structural behaviors of these vehicles. In this chapter, finite element method is used to assess the static and dynamic structural behavior of Railway Bogie. The material chosen for these parts is alloy cast iron (E= 52GPa; density= 7850 x 10-9 kg/mm3) and the section used is solid homogeneous type. Analysis step used in this analysis is of Static, Description Value (Mpa) Youngs modulus 52.2E3 Passion`s ratio 0.27 Yield stress 435Mpa Loading and Boundary Conditions: In this case, a transverse load of magnitude 2500 kg was applied at the center pivot through a load block with a loading area in line with the center plate of the bolster. The bolster was constrained on both side from translating in X and Y Fig 3.2 Boundary conditions element is connected with 3 nodes. There are 1560 elements and 1040 nodes in bolster. Fine quality of meshing gives much accurate results, if the occupying area of model is more than errors will be reduced. The pressure is applied at the pivoted circle of bolster. The pressure value is 25Mpa and bottom two surfaces are fixed in all DOF. 69

3 Fig 3.4 Displacement vector sum Fig 3.9 Displacement vector sum element is connected with 3 nodes. There are 860 elements and 702 nodes in bolster. The maximum deformation takes place the top surface of the side frame because the bogie weight is acting in downward direction. At the both corners are fixed in all DOF. The maximum deformation is 2.108mm which takes place at the centre of the side frame. Redcolor or MX indicating the maximum deformation area. Fig 3.5 Von-Mises Stresses of Bolster Displacement vector sum is indicated as Usum. The maximum deformation at that loading condition is 1.81mm which takes place at the center of the bolster. Above figure 3.5 discribes the Von-Mises-Stress is also called as yield stress. The value of stress is Mpa is induced. The maximum stress is indicated as MX which is at the corner surface of fixed plate. SMX = Mpa (maximum stress) SMN = 2.502Mpa (Minimum stress) Fig 3.10 Von-Mises-Stress of side frame Above figure describes the von-mises-stress which is Mpa.Maximum stress occurs at the fixed portion Fig 3.7 Meshed model of side frame Fig 3.12 Meshing of assemble model 70

4 Fig 3.13 Loading conditions element is connected with 3 nodes. There are 2750 elements and 1950 nodes in casenub bogie. A combination of loads applied at the assemble components of casenub bogie Both side frames are fixed in all dof. So there is no motion. Similarly the pressure is applied at the top surface Of the casenub bogie. The red colour indicating the pressure is applied on the surfaces The maximum deformation takes place at the center of the casenub bogie because at the centre the pressure is concentrated Fig 3.15 Displacement vector sum (Usum) Fig 3.16 Von-Mises-Stress Above figure the maximum deformation is 3.992mm at the center of the casenub bogie. Then gradually the deformation is decreasing.the maximum stress is induced value is Mpa. And the minimum stress is Mpa. RESULTS AND DISCUSSIONS: 1. The maximum deformation is 3.992mm at the center of the casenub bogie 2. The maximum stress is induced value is Mpa. and the minimum stress is Mpa. Displacement and stresses:- S. Description Displacement Von-Mises- No (mm) Stress(Mpa) 1 Side frame Bolster Casenub bogie (assembled) CONCLUSIONS: The Maximum Stresses For Side Frame 314Mpa, Bolster 290mpa & Casenub Bogie Mpa. But the yield stress for cast iron material is 415mpa. so the rsulted von-mises-stress is less than the ultimate tensile strength of the material. so the proposal design as per the boundary conditions this casenub can with stand for human useful purpose. REFERENCES: [1] Indian railways Specification Wd-17-casnub- 22hs-bogie-92 (revision 3) For CASNUB 22 HS cast steel bogies with friction damping arrangement for Broad gauge, Research Designs And Standards Organization, Ministry of Railways. [2] Ankit Agarwal, et al., Modeling, Simulation and Weight optimization of Railway Bogies, Indian Institute of Technology, Roorkee, 2012 [3] Iwnicki, Simon, Handbook of Railway Vehicle Dynamics. Taylor & Francis group, New-York, [4] Karlos Chlus, Wieslaw Krason, Dynamic Analysis of Railway platform Chassis model,journal of KONES Powertrain and Transport, Vol. 18, No [5] C. Baykasoglu, E. Sunbuloglu, S. E. Bozdag, et al, Numerical Static And Dynamic Stress Analysis on Railway passenger and freight car models, International Iron & Steel Symposium, 2012, Karabuk, Turky [6] Richard G. Budynas and J.Keith Nisbett, Shigley smechanical Engineering Design, 9th ed.(mcgraw-hill series in mechanical engineering) 71

5 [8] ANSYS INC., ANSYS Mechanical APDL User Manual, (2013) 138 [9] Ahmet T. Becene Ph.D., Topology Optimization of Nacelle Components with ATOM, Goodrich Corporation [10] Draft 2010 Afcen RCC-MRx Code (Dec), Section III-Tome1-Subsection Z-Appendix A16: Guide for prevention of fast fracture, Leak Before analysis and defect assessment,2010 [11] Brent S. Ballew, Advanced Multi-body Dynamics Modeling of the freight train truck System, Blacksburg, Virginia, 2008 [12] Manish Thaplyal and Amitabh Sinha, Freight bogie for heavy haul operations over Indian Railways, Research Designs and Standards Organization, Ministry of Railways, Lucknow [13] Saeed Hossein, Dynamic Modeling of Frieght Wagons, Blekinge Institute of Technology, Karlskrona, Sweden, 2011 [14] Anderson, T.L. Fracture Mechanics - Fundamentals and Applications. 3rd ed. (2005) 72