DESIGN AND ANALYSIS OF HARMONIC ANALYSIS OF THREE WHEELER AUTO CHASSIS USING ANSYS

Transcription

1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 12, December 218, pp , Article ID: IJMET_9_12_11 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed DESIGN AND ANALYSIS OF HARMONIC ANALYSIS OF THREE WHEELER AUTO CHASSIS USING ANSYS K. Ashok Reddy Professor, Dept of Mechanical Engineering, St Peters Engineering College, Massimaaguda, Hyderabad -1 Teleganna State, India. P. Sunil Kumar Assistant Professor, Department of Mechanical Engineering, Brilliant Group of Intuitions, Hyderabad A. Nagendra Associate Professor, Dept of Mechanical Engineering, St Peters Engineering College, Massimaaguda, Hyderabad -1 Teleganna State, India. ABSRACT The objective of the present work is to reduce the amount of prototyping and experimental testing for manufacturer s by performing harmonic using FEM. Keywords: harmonic,chassis,wheeler etc. Cite this Article: K. Ashok Reddy, P. Sunil Kumar and A. Nagendra, Design and Analysis of Harmonic Analysis of Three Wheeler Auto Chassis Using Ansys, International Journal of Mechanical Engineering and Technology, 9(12), 218, pp INTRODUCTION Any sustained cyclic load will produce a sustained cyclic response (a harmonic response) in a structural system. Harmonic response analysis gives you the ability to predict the sustained dynamic behavior of structures, thus enabling to verify whether or not the designs will successfully overcome resonance, fatigue and other harmful effects of forced vibrations. Harmonic response analysis is a technique used to determine the steady-state response of a linear structure to loads that vary sinusoidally (harmonically) with time. The idea is to calculate the structure's response at several frequencies and obtain a graph of some response quantity (usually displacements) versus frequency. "Peak" responses are then identified. This analysis technique calculates only the steady state, forced vibrations of a structure. The transient vibrations, which occur at the beginning of the excitation, are not accounted for in a harmonic response analysis editor@iaeme.com

2 K. Ashok Reddy, P. Sunil Kumar and A. Nagendra Three harmonic response analysis methods are available: full, reduced, and mode superposition. A fourth relatively expensive method is to do a transient dynamic analysis with the harmonic loads specified as time-history loading functions. The full method is the easiest of the three methods. It uses the full system matrices to calculate the harmonic response (no matrix reduction). A disadvantage is that this method usually is more expensive than either of the other methods like frontal solver. However, use the JCG (Jacobi Conjugate Gradient) solver or the ICCG (Incomplete Cholesky Conjugate Gradient) solver, the full method can be very efficient. K. Santa Rao, G. Musalaiah and K. Mohana Krishna Chowdary [1] presented in their technical paper design analysis of four wheeler chassis using finite element method. The main observations are noted as maximum stressed regions, deflections, reactions and natural frequencies of a four wheeler automobile chassis. It has been notified that Nickel-Molybdenum (Ni-Mo steel) was found to be suitable. Santosh Hiremath, Naresh Kumar, Nagareddy.G, Lakhan Rathod [2] the frame is an important part in a Two Wheeler and it carries the load acting on the vehicle. So it must be strong enough to resist the shock, twist, vibration and other stresses. In vehicle frame different types of failure occur due to static and dynamic loading conditions. Natural frequency, damping and mode shapes are the inherent structural properties and can be found out by experimental modal analysis. Experimental Modal analysis (EMA) is the process of determining the modal parameters of a structure for all modes in the frequency range of interest.the objective of this study is to determine the natural frequencies, damping and mode shapes of the both chassis of two wheeler namely as Pulsar 15cc and Passion by using experimental modal analysis. Our goal is to minimize the effect of these vibrations, because while it is undesirable, vibration is unavoidable. The dynamic characteristics of the two wheeler chassis such as the natural frequency and mode shape will determine by using finite element (FEM) method. Analysis has been completed for doing modal analysis of the two-two wheeler chassis of pulsar 15cc and passion meeting all international standards of safety. The chassis with alternate material is performing better with a satisfying amount of weight reduction. The weight reduction will hence lead to better fuel of vehicle. Also the new chassis will have reduced vibration as compared to conventional model.hence we concluded that the in comparison between the both two wheeler chassis of pulsar 15cc and passion out of them the better and safe design is pulsar 15cc chassis because of the deformation of the pulsar is less than that of the passion chassis as shown in above result. Archit Tomar & Dheer Singh [3] In Automobile the word chassis Frame means the part of automobile that hold all the important part of vehicle like Engine, Steering Systems, Suspension System etc and all the components constitute together to form a chassis. The conventional chassis is very heavy and bulky in nature due to that it contributes in higher emission and less efficiency of vehicle. In this paper firstly the chassis frame of Eicher truck 11. is modeled in CAD software and the further analysis is done in ANSYS by using the composite material like carbon fiber and E-Glass Epoxy. Modal analysis is done to study the vibration characteristics of the chassis frame also to know the natural frequency of the chassis frame and further Harmonic analysis is done to know the von misses stress in the chassis frame at that natural frequency which incurs maximum deformation in chassis frame after that the results of all the thee materials compare to know which is suitable material for the chassis frame. 2. THREE-WHEELED AUTO CHASSIS MODEL DESCRIPTION Bajaj Rear engine (Diesel) is selected for analysis purpose. The overall length of the chassis is 265mm and the wheelbase is 2mm. The specifications of the vehicle are shown in Table editor@iaeme.com

3 Design and Analysis of Harmonic Analysis of Three Wheeler Auto Chassis Using Ansys Components Engine Type Power Dimensions Weights: Table 4.6 Model discription summary Specification Single cylinder 4-stroke Diesel Engine 3 rpm Length: 265 mm Width: 13 mm Height: 171 mm Wheel base: 2 mm Ground clearance: 17 mm Kerb weight: 353 kg Gross Vehicle Weight: 68 kg Max. payload: 33 kg 3. ANSYS MODEL FOR THREE WHEELED CHASSIS The ultimate purpose of a finite element analysis is to re-create mathematically the behavior of an actual engineering system. Model comprises all the nodes, elements, material properties, real constants, boundary conditions and other features that are used to represent the physical system. The model consists of chassis elements, suspension and tyres and the specifications values are listed in the Table4.7. The chassis discretized by taking into account 3D- space frame idealization and it was done by using 4-node quadrilateral shell element with each node having 6 DOF with a thickness of 2mm and combination element is used for suspensions and tyres. 3D-beam element for linkages of rear suspension, pipe element for middle portion of the linkage, structural mass element for various components like engine, gearbox, total sheet metal body have been used lumped at the appropriate node locations. Total number of elements and nodes of the model are 2696 and 2399 respectively. Table 4.7 Stiffness and Damping values Description Stiffness (K)(N/m) Damping Coefficient (C)(N-s/m) Front Suspension 32,7 3,5 Rear Right Suspension 49,8 2,27.5 Rear Left Suspension 5,4 2,27.5 Front Tyre 2,38, Rear Right Tyre 2,5, Rear Left Tyre 2,5, editor@iaeme.com

4 K. Ashok Reddy, P. Sunil Kumar and A. Nagendra 4. PROCEDURE FOR HARMONIC ANALYSIS 1. Build the model by selecting a suitable linear element, which resembles the original vehicle. 2. Define the material properties of the linear isotropic such as young s modulus and density. 3. For laden condition apply the loads such as weights of engine gearbox, propeller shafts, passengers and driver at appropriate nodes using lumped mass system. 4. Apply the constraints to arrest D.O.F at the bottom nodes of the tyre except in vertical direction to allow the displacement in that direction. 5. Enter the ANSYS solution processor in which new analysis is chosen, as harmonic response and solution method is full method. 6. For this analysis the solution technique used is frontal solver. 7. By defining the frequency range as -5Hz with 5 sub-steps and displacement of.5m is given at bottom point of tyres. 8. Solve the problem using current LS command and obtain the result. 5. RESULTS AND DISCUSSION For this analysis the entire frequency range of -5Hz and with amplitude of.5m given input to the tyres contact at base node in the vertical direction. Obtained results are presented in the form of nodal displacements over the entire chassis. The displacements of various nodes were plotted against frequency and are shown in the Fig 6.14 to Fig 6.14 shows the variation of displacement with frequency at the right and left ends of the passenger s seat location. The maximum displacement was obtained at the frequency of 2Hz that closely coincides with bounce frequency. The variation in displacement at the right and left portion of the engine shown in the Fig 6.15 and it is observed that the maximum displacements editor@iaeme.com

5 Design and Analysis of Harmonic Analysis of Three Wheeler Auto Chassis Using Ansys were obtained at bounce and pitch mode frequencies, at bounce mode frequency rear portion of chassis more displaced when compared with the pitch mode frequency. Fig 6.16 depicts the variation in displacement at right and left portion of the driver, the maximum displacements were observed at bounce and pitch mode frequencies, at pitch mode frequency driver seat location of chassis more displaced compared to the bounce mode frequency. The displacement of the front and rear suspensions locations are plotted in Fig 6.17 and it is observed that the displacement in the rear suspension increases suddenly at bounce mode and decreases gradually over the frequency range -5Hz. The maximum values of displacements were obtained at front suspension at frequencies of 19Hz and 26Hz and these frequencies were very close value to the front hop mode and rear tramp mode frequencies obtained by using modal analysis. The front suspension with a displacement was more than that of the rear suspension. Fig 6.18 shows the variation of displacement with frequency at top and bottom of steering column. It can be quoted that maximum displacement was obtained at bottom of the steering column at the front hop mode. The maximum level of the displacement at front hop mode in vertical direction is.25m. From the above results front portion of the chassis getting more displacement when compared to other portion of the chassis because less mass distributed at front portion. Figure 6.14 Variation in displacement at the left and right ends of the passenger seat location reareng-right reareng-left Figure 6.15 Variation in displacement at the left and right ends of the engine editor@iaeme.com

6 K. Ashok Reddy, P. Sunil Kumar and A. Nagendra driver-right driver-left Figure 6.16 Variation in displacement at right and left ends of the driver portion rear suspension front suspension Figure 6.17 Variation of displacement at rear and front suspensions 11 editor@iaeme.com

7 Design and Analysis of Harmonic Analysis of Three Wheeler Auto Chassis Using Ansys.3 steering-top.25 steering-bottom REFERENCES Figure 6.18 variation in displacement at steering-top and bottom portion [1] K. Santa Rao, G. Musalaiah and K. Mohana Krishna Chowdary Finite Element Analysis of a Four Wheeler Automobile Car CHASSIS INDIAN Journal of Science and Technology, Vol 9(2), DOI: /ijst/216/v9i2/83339, January 216 [2] Santosh Hiremath, Naresh Kumar, Nagareddy.G, Lakhan Rathod Modal Analysis Of Two Wheeler Chasis International Journal Of Engineering Sciences & Research Echnology [3] Archit Tomar & Dheer Singh Modelling and Analysis of a Chassis Frame by Using Carbon Fiber and E-Glass Epoxy as Composite Material: A Comparative Study International Research Journal of Engineering and Technology 3(4), 216, editor@iaeme.com