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Pawan SinghManager, CAE

Javed QuershiJunior Manager, CAE

Rohit LilhareJunior Manager, CAE

Vibration Analysis of Tractor fender Assembly and T est Correlation Using Optistruct

Eicher Tractors, Mandideep

Date: 13/06/2014

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Company Profile

TAFE Motors and Tractors Limited ( TMTL ) is a who lly owned subsidiary of

TAFE, set up in 2006 when TAFE acquired Eicher trac tors. The Eicher brand of

tractors has a distinguished heritage of 50 years i n India. Known for its unique

distinction of offering a range of both air and wat er cooled tractors, its tractors

span the 24 to 60 HP range and have been well recei ved in the segment. Eicher’s

less than 30 HP range has commanded market pre-emin ence in the segment.

TAFE today is recognized as a high quality mass man ufacturer with a extensive

product range to meet every farming need.

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Vibration Analysis of Tractor fender Assembly and T est Correlation

Objective of case study:-

Tractor fenders are prone to failures because It i s subjected to heavy dynamic

loads during various field Operation with implement such as Ploughing, Puddling,

Haulage etc. as well as in static condition (at idl e RPM). To evaluate the structural

performance of tractor fender, it is necessary to determine "g ‟ levels of

acceleration at fender mounting location. Also, onc e the test data is available, it

can be used for correlating it with the FEA results and then load history can be

used for reliable analysis to develop the product. The methodology helps in

moving towards virtual testing and to avoid/reduce physical testing of the sub-

systems to adhere to the constraints on time and co st.

Statement of problem:-

� 1. To carryout Static and dynamic analysis of Fende r for structural strength

� 2. To correlate the test results ( shaker ) with FE A results.

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ACTUAL FIELD USAGES ANF RIG SIMULATION

Rough Road

Puddling

Haulage

Shaker

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Methodology

Experimental test measurements with Various application

FEM Modal Analysis

Modal Superposition

Frequency Response Analysis

Test Correlation

Design IterationFinal Design Validation

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The fender assembly components such as stiffener , brackets, canopy are made

of Structural steel of various grades. FE model has been developed by using pre-

processing software HyperMesh. Metal parts are mode lled with shell elements

CQUAD and CTRIA by extracting mid surfaces . Bolted connections between two

components are modelled with CBEAM elements. The we ld between each

component is modelled with shell elements of averag e of thickness. The masses

of individual parts and whole assembly were careful ly cross checked for good

accuracy of frequency results.

FE Modeling

Fender Assembly

Fender

Back-rest

Stiffner

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Loadcases

Static Analysis 1. Vertical downward direction : Weight of 3 or 4 people 2. Braking load at back rest & Mudguard3. Cornering load at back rest & Mudguard 4. Mudguard with Canopy

Dynamic analysis 1.Modal analysis – Natural Frequencies 2.Frequency Response Analysis to find effect of engine

vibration

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Frequency Response Analysis

This particular analysis was carried out to predict and reduce the road

induced vibration. The fender assembly where it is mounted was

considered for simulation. These boundary condition s were used for

both Modal as well as Frequency response analysis H ere acceleration

derived from road load data is used to excite the a ssembly over an

operational frequency range as dynamic load. Stress and displacement

peaks are determined for the considered frequency r ange. This method

can be used to simulate and predict the actual resp onse.

Frequencies below 10 Hz are not usually considered. The reason is that,

lowest idling rpm is usually above 600 rpm.

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Field Failure Simulation

Stress =144 Mpa

Actual field failure

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Test Correlation

The simulation results are also well correlated by the experimental results in which failure location and pattern is ex actly matched. Further modifications have been incorporated in design to m eet the strength requirement .

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Design Improvements

Different design iterations were analyzed as per the methodology, so as

to shift the natural frequency.

The 1st design proposal, weld location to be changed and i ncreased to

50 mm from 30mm. It has natural frequency of 22 Hz, which results

same vibration levels as base design in frequency r esponse analysis.

In case of 2 nd design proposal, vertical Stiffener height to be in creased

and welding location to be changed than the base de sign resulting in

significant reduction in vibration levels using fre quency response

analysis.

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Analysis and Test Methodology

Initially modal analysis was carried out to estimat e the natural

frequencies of the system. First 10 modes were extr acted in this

analysis.

Acceleration were measured at different locations . Sensor locations on

were chosen such that maximum sensitivity was obser ved.

The measured acceleration Peak value on the fender at base locations

were in turn used for the Frequency Response analys is in Optistruct.

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Loads and Boundary Conditions

Constrained in all directionTest Rig Set up

FE Modeling as Per testing shaker setup

•Measured Acceleration data used for Resonance test at shaker table, Which simulate the same field failure Zone.

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Design Improvements

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Experimental Test Set-up

The fender assembly is tested on shaker table test rig by mounting on

fixture at the bottom plate , with acceleration val ue generated from road

load data, over the operational frequency range.

Tri Axial accelerometer

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Benefits summary

Using FEA based Eigen frequency and frequency respo nse analysis

techniques, the vibration characteristic of fender can be faithfully

replicated as observed in the physical test.

Multiple design proposals could be evaluated in vir tual environment to

arrive at best and optimum design solution. The bes t design proposal

showed reduction in vibration level by 55.2%. Physical test on final

design reconfirmed simulation results and satisfact ory performance of

the final design.

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Conclusion

Optistruct has been used to model and simulate the b ehavior of the

Fender Assembly for Vibrations. The results are mat ching closely with

the experimental test and required design modificat ions have been done

from analysis and iterations.

The work presented in this paper is in the early ph ases of ongoing work

and it is important to note these promising results will strongly demand

more detailed analysis for future projects.

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Acknowledgements/Credits

The authors would like to acknowledge our Design, P rototype and

testing teams for extending their kind support. The authors would also

like to thank the R&D Chief Mr. Hemant Shrikhande , and Testing Head

Mr. Suresh Gopal , Divisional Manager Design Mr. R. S. Kaushik Eicher

tractors for providing this opportunity for publish ing the work.