International Journal on Mechanical Engineering and Robotics (IJMER)
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Design and Analysis of Railway Casnub Bogie Using Fem
Zeyaullah Ansari
VIF College of Engg & Tech. Hyderabad 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, fatigue- life/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
4. Minimize generation of track irregularities and rail abrasion Railway CASNUB 22HS-Bogie is a three- piece bogie consists of two side-frames connected by a bolster. The primary suspension connects the side-
frames 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
icons are logically grouped together, based on capability.
Figure 2.1:3-D Solid Model of Bogie Assembly and3-D Solid Model of Side-Frame
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
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
Fig 3.1 Meshing of Bolster
Fig 3.2 Boundary conditions
A model is meshed with triangular shape each triangular 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.
Fig 3.4 Displacement vector sum
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 290.899Mpa is induced. The maximum stress is indicated as MX which is at the corner surface of fixed plate.
SMX = 290.899Mpa (maximum stress) SMN = 2.502Mpa (Minimum stress)
Fig 3.7 Meshed model of side frame
Fig 3.9 Displacement vector sum
A model is meshed with triangular shape each triangular 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 3.10 Von-Mises-Stress of side frame Above figure describes the von-mises-stress which is 314.792Mpa.Maximum stress occurs at the fixed portion
Fig 3.12 Meshing of assemble model
Fig 3.13 Loading conditions
A model is meshed with triangular shape each triangular 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)
deformation is decreasing.The maximum stress is induced value is 397.347Mpa. And the minimum stress is 0.20533Mpa.
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 397.347Mpa. and the minimum stress is 0.20533Mpa.
Displacement and stresses:- S.
No
Description Displacement (mm)
Von-Mises- Stress(Mpa)
1 Side frame 2.108 314.792
2 Bolster 1.81 290
3 Casenub bogie (assembled)
3.992 397.347
CONCLUSIONS:
The Maximum Stresses For Side Frame 314Mpa, Bolster 290mpa & Casenub Bogie 397.347Mpa. 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:
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