Design SND Analysis of Two Wheeler Rocker ARM

www.ijatir.org

ISSN 2348–2370

Vol.09,Issue.06,

May-2017,

Pages:0832-0839

Copyright @ 2017 IJATIR. All rights reserved.

Design SND Analysis of Two Wheeler Rocker ARM P. PRASAD

Assistant Professor, Dept of Mechanical Engineering, GIITS Engineering College, Aganampudi, Visakhapatnam (Dt), AP, India,

E-mail: [email protected].

Abstract: Rocker arms are part of the valve actuating

mechanism. A rocker arm is designed to pivot on a pivot pin

or shaft that is secured to a bracket. The bracket is mounted

on the cylinder head. One end of a rocker arm is in contact

with the top of the valve stem, and the other end is actuated

by the camshaft. In installations where the camshaft is

located below the cylinder head, the rocker arms are

actuated by pushrods. The lifters have rollers which are

forced by the valve springs to follow the profiles of the cams

In this thesis, finds the various stresses under extreme load

condition. For this we are modeling the arm using

design software and the stressed regions are found out

using ANSYS software. Here in this thesis we are

observing that by changing different materials(carbon

steel, HMCF UD & Aluminum alloy7075). In this thesis the

static analysis to determine the stress, deformation and strain

at different materials. Modal analysis is determining the

deformations and frequency at different mode shapes.

Fatigue analysis to estimate the life of the component 3D

modeling done in CREO parametric software and analysis

done by the ANSYS software.

Keywords: Finite Element Analysis, Rocker Arm, Static

And Model Analysis.

I. INTRODUCTION

A. Rocker ARM

A rocker arm is an oscillating lever that conveys radial

movement from the cam lobe into linear movement at the

poppet valve to open it. One end is raised and lowered by a

rotating lobe of the camshaft while the other end acts on the

valve. When the camshaft lobe raises the outside of the arm,

the inside presses down on the valve which is used for

opening the valve. When the outside of the arm is permitted

to return due to the camshafts rotation, the inside rises,

allowing the valve spring to close the valve.

B. Working Concept of Rocker ARM

The drive cam is driven by the camshaft. It pushes the

rocker arm up and down about the rocker shaft. Friction may

be reduced at the point of contact with the valve stem by a

roller cam follower. A similar arrangement transfers the

motion via another roller cam follower to a second rocker

arm. This rotates about the rocker shaft, and transfers the

motion via a tappet to the poppet valve For car engines the

rocker arms are generally steel stampings, providing a

reasonable balance of strength, weight and economical cost.

Because the rocker arms are reciprocating weight, excessive

mass especially at the lever ends limits the engine's ability to

reach high operating speeds. Truck engines use stronger and

stiffer rocker arms made of cast iron or forged carbon steel.

Energy is required to move a rocker arm and depress a valve;

their weight can be an important consideration. If a rocker

arm is excessively heavy, it may require too much energy to

move. This may prevent the engine from achieving the

desired speed of rotation.

Fig.1.

C. Variable Valve Actuation

Variable valve actuation (VVA) technologies are used to

flexible the engine’s valve train by introducing variable

valve event timing, duration or lift. The main type of VVA

technologies include valve timing control (VTC), variable

valve lift (VVL) and cam less valve trains. A rocker arm is

used to operate variable valve lift. In variable valve lift

operating system, there is two type of lift will be gotten as a

minimum lift and a maximum lift. Such operating system is

known as 2 step valve train system. This rocker arm which is

used in such system is known as 2 step rocker arm. It’s

named by its working operation. A 2-step Valve train system

is developed that features switchable rocker arms on all

intake valves and solenoid-actuated oil control valves

(OCV). Fig.2 shows a sectional view of the 2-step system. It

is a 2 step valve train system with hydraulic lash adjusters

(HLA).

mailto:[email protected]

P. PRASAD

International Journal of Advanced Technology and Innovative Research

Volume. 09, IssueNo.06, May-2017, Pages: 0832-0839

D. Problem Identification

The rollers and low lift cam lobes are relatively narrow

compared to conventional valve trains for contacting the 24

mm width target. If the spring pre-load reaction force at the

HLA is too large, the HLA cannot expand properly to

recover the fluid displaced by leak down during the lift

event. Therefore, the preload must be limited to an

acceptably low value travel limit feature must be

incorporated in the rocker arm. The mechanical lash

variation in a 2-Step rocker arm only produces valve lift

variation when the rocker arm operates in high mode.

Fig.2.

The Methodology Followed In The Project Is As Follows:

Create a 3D model of the cantilever beam assembly

using parametric software creo.

Convert the surface model into Para solid file and

import the model into ANSYS to do analysis.

Perform static analysis on the cantilever beam.

Perform model analysis on the existing model of

the cantilever beam.

II. INTRODUCTION TO CAD/CAE

Computer-aided design (CAD), also known as computer-

aided design and drafting (CADD), is the use of computer

technology for the process of design and design-

documentation.

A. Introduction To Pro-Engineer

Pro/ENGINEER Wildfire is the standard in 3D product

design, featuring industry-leading productivity tools that

promote best practices in design while ensuring compliance

with your industry and company standards. Integrated

Pro/ENGINEER CAD/CAM/CAE solutions allow you to

design faster than ever, while maximizing innovation and

quality to ultimately create exceptional products.

Different Modules In Pro/Engineer: Part design,

Assembly, Drawing& Sheet metal.

B. Introduction To Finite Element Method

Finite Element Method (FEM) is also called as Finite

Element Analysis (FEA). Finite Element Method is a basic

analysis technique for resolving and substituting complicated

problems by simpler ones, obtaining approximate solutions

Finite element method being a flexible tool is used in various

industries to solve several practical engineering problems. In

finite element method it is feasible to generate the relative

results.

III. RESULTS AND DISCUSSIONS

A. Models of cantilever beam using creo parametric

The cantilever beam is modeled using the given

specifications and design formula from data book as shown

in Figs. 3 to 29. The cantilever beam outer casing body

profile is sketched in sketcher and then it is extruded using

extrude option.

Fig.3.

B. Static Analysis Of Multi Plate Clutch

Material Properties:

CARBON STEEL

Young’s modulus = 7.85g/cc

Poisson’s ratio = 200GPa

Density = 0.285

HMCF UD

Young’s modulus = 1.6 g/cc

Poisson’s ratio = 175GPa

Density = 0.3

Aluminum alloy 7075

Young’s modulus = 2.81g/cc

Poisson’s ratio = 71.7 GPa

Density = 0.33

Save Pro-E Model As .Iges Format:

→→Ansys → Workbench→ Select analysis system → static

structural → double click

http://en.wikipedia.org/wiki/Computer

Design SND Analysis of Two Wheeler Rocker ARM



→→Select geometry → right click → import geometry →

select browse →open part → ok

→→ Select mesh on work bench → right click →edit

Double click on geometry → select MSBR → edit material

→

Fig.4.

Select mesh on left side part tree → right click → generate

mesh →

Fig.5.

Select static structural right click → insert → select

rotational velocity and fixed support → Select displacement

→ select required area → click on apply → put X,Y,Z

component zero →

Fig.6.

Select force → select required area → click on apply →

enter rotational velocity

Select solution right click → solve →

Solution right click → insert → deformation → total →

Solution right click → insert → strain → equivalent (von-

mises) →

Solution right click → insert → stress → equivalent (von-

mises) →

Right click on deformation → evaluate all result.

Material – Carbon Steel:

Fig.7. Deformation.

P. PRASAD



Fig.8. Stress.

Fig.9. Strain.

Material – Aluminum Alloy 7075:

Fig.10. Deformation.

Fig.11. Stress.

Fig.12. Strain.

Material – HMCF UD:

Fig.13. Deformation.




Fig.14. Stress.

Fig.15. Strain.

Fatigue Analysis Of Rocker Arm Material – Carbon

Steel:

Fig.16. Life.

Fig.17. Damage.

Fig.18. Safety factor.

Material – Aluminum Alloy 7075:

Fig.19. Life.

P. PRASAD



Fig.20. Damage.


Material – HMCF UD:

Fig.22. Life.

Fig.23. Damage.


Modal Analysis Of Rocker ARM Material – Carbon

Steel:

Fig.25. Mode shape -1.








IV. RESULTS AND DISCUSSIONS ANALYSIS

RESULT TABLE

A. Static Analysis Results

TABLE I: Static Analysis Results

TABLE II: Modal Analysis Results

TABLE III: Fatigue Analysis Results

P. PRASAD



V. CONCLUSION

For this we are modeling the arm using CREO

parametric software and the stressed regions are found

out using ANSYS software. Here in this thesis we are

observing that by changing different materials(carbon

steel, HMCF UD & Aluminum alloy7075). By observing the

static analysis the stress values are less for the carbon steel

compare with aluminum alloy and HMCF UD. By observing

the fatigue analysis the safety factor more for carbon steel

material. So it can be concluded the carbon steel is better

material for rocker arm.

Future Scope: By using composite material the stress values

are reduced by that the life time of the rocker arm increases.

VI. REFERENCES [1]Chin-Sung Chung and Ho-Kyung Kim (2010), “Safety

Evaluation of the Rocker Arm of a Diesel Engine”, Materials

& Design, Vol. 31, No. 2, pp. 940-945.

[2]Christer Spiegelberg and Soren Andersson (2006),

“Simulation of Friction and Wear in the Contact Between the

Valve Bridge and Rocker Arm Pad in a Cam Mechanism”,

Machine Design, Royal Institute of Technology, S-100 44

Stockholm, Sweden.

[3]Dong-Woo Lee, Soo-Jin Lee, Seok-Swoo Cho and Won-

Sik Joo (2005), “Failure of Rocker Arm Shaft for 4-Cylinder

SOHC Engine”, Engineering Failure Analysis, Vol. 12, No.

3, pp. 405-412.

[4]Dong Woo Lee, Seok Swoo Cho and Won Sik Joo

(2008), “An Estimation of Failure Stress Condition in

Rocker Arm Shaft Through FEA and Microscopic

Fractography”.

[5]Giovanni Scire Mammano and Eugenio Dragoni (2013),

“Design and Testing of an Enhanced Shape Memory

Actuator Elastically Compensated by a Bistable Rocker

Arm”, Structures Journal of Intelligent Material Systems and

Structures.

[6]Hendriksma N, Kunz T and Greene C (2007), “Design

and Development of a 2-Step Rocker Arm”, SAE

International, USA.

[7]James M Miller (1980), “Rocker Arm Having

Perpendicular Geometry at Valve Mid Lift”, United States

Patent Appl. No. 211, 638, December 1.

[8]Kano M and Tanimoto I (1991), “Wear Resistance

Properties of Ceramic Rocker Arm Pads”, pp. 6-1, Materials.

Author Profile:

P.PRASAD Received his BTECH Degree

in Mechanical Engineering from Dr. Paul

Raj Engg College, Yatapaka, Khammam

(Dt), A.P and MTECH Degree in Thermal

Engineering From Andhra University,

Visakhapatnam, A.P. His is currently

working as Assistant Professor in Gonna

Institute of Information Technology and

sciences, Aganampudi, Visakhapatnam, A.P, India.

Design SND Analysis of Two Wheeler Rocker ARM

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