NOISE REDUCTION ON AGRICULTURAL TRACTOR BY SHEET METAL OPTIMIZATION TAFE LIMITED SK MD ASIF BASHA (SENIOR MEMBER COE NVH) M SUNDARAVADIVEL (SENIOR MEMBER NVH) Date (22 nd July 2016)
Tractors and Farm Equipment Limited Tractors and Farm Equipment Limited (TAFE), is a unit company of the Amalgamations Group Consists of 43 Companies, 37 Manufacturing Plants and a work-force of a little over 15, 000. Has grown under the leadership of Shri.A.Sivasailam, its Chairman, 1964-2011. Ms Mallika Srinivasan, Chairman & CEO of TAFE was conferred with Padma Shri in 2014. TAFE STRENGTH IN INDIA Strong Domestic presence Second largest in the country Reputed for quality products and after sales support Low cost of ownership & Highest resale value Consistently pursuing excellence
NOISE REDUCTION ON AGRICULTURAL TRACTOR BY SHEET METAL OPTIMIZATION Objective of case study The Objective of this study is noise and vibration reduction on an agricultural tractor by optimizing sheet metal components. To Perform Simulation for Complete Fender and Platform Assembly and correlation of the same with the Test results. Statement of problem This paper outlines the systematic approach for Sheet Metal Optimization through CAE simulations. The baseline FE model is developed with standard FE modelling methods and correlated with the test results. FE modeling techniques were reviewed and optimized based on development tests and the structural modifications were carried on the Complete Fender and Platform Assembly. here 3
Sources of Noise & Vibration in Tractor Exhaust Noise Transmission Noise Gear Rattle & Whine Structure Borne Noise Sheet Metal Components Housings, etc. here 4
Process Methodology Baseline CAE evaluation of the Fender Assembly Baseline Testing and Measurements on Tractor Physical test and Simulation correlation Improvements in FE model based on test correlation CAE based design modification iterations Certification test and correlation here 5
Noise db(a) Baseline Testing and Measurements Driver ear noise measurement Using microphones Vibration measurement on fender using accelerometer Vibration measurement on platform using accelerometer here 6
FE Model and Loading Foot rest Fender Assembly here 7 Mounting Bracket Reinforcements FE Model Major structural parts considered for FE model Cad data is converted to FEA model. Mesh type is taken as Mixed (quad & tria) elements and mesh Size is Considered as 3~ 5mm. All are connected with Rigid Elements (Seam Welds, Spot Welds and Bolts). Constant damping assumed based on previous experience. Load & BC ~25 load collectors (Eigrl, Spc,Tabled,Spcd,Freq1,Rload, Tabdamp1,etc..) are used to carry out vibration response analysis. Acceleration is given as input in the Mounting location of Fender and Platform. Frequency range Considered is from 20-250 Hz.
Frequency (Hz) Frequency (Hz) Baseline Simulation Modal Analysis Fender Modes Mode 1 Mode 2 Mode 7 Physical Test and Simulation Correlation Platform Modes Fender Modes Mode Number here 8 Mode Number
Vibration Correlation Fender- Vibration Response Constrained and Acceleration is applied at mounting locations. TEST DATA Response @ Fender Back here 9 Correlating Test and CAE Data. The Peak coming at 49 Hz is in Vertical Direction in Test Data. The Peak coming at 48 Hz is in Vertical Direction in CAE Data.
Vibration Correlation Platform - Vibration Response TEST DATA Response @ Platform Rear here 10 Correlating Test and CAE Data. The Peak coming at 180 Hz is in Vertical Direction in Test Data. The Peak coming at 182 Hz is in Vertical Direction in CAE Data.
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CAE Based Final Design Structural Modifications Fender Platform Many iterations (>~30) have been performed in an effort to reduce Fender & Platform vibration. Final Iteration Structural Modifications are shown in the above Figures. Top Reinforcement, Side Reinforcement are the Major Modifications in the Fender. Bottom Reinforcements are added on both sides in Platform. Simulation helps to reduce development time and cost. here 12
Vibration Vibration Correlation Simulation- Base vs Improved y-axis Response @ Platform Rear z-axis Response @ Fender Front Reduction in vibration compare to baseline is observed. Improved model is giving 40-45% reduction compared to base model. here 13
Vibration Vibration Proposal / Optimization for Improvement Vibration comparison on fender Vibration comparison on platform here 14
Noise db(a) Prototype Testing Base Vs Improved DPNL (Base vs Improved) Measurement location LHS Fender Top front - X axis LHS Fender Top rear - X axis LHS Platform front - Z axis LHS Platform rear - Z axis RHS Fender Top front - X axis RHS Fender Top rear - X axis RHS Platform front - Z axis Test condition Baseline With improvement Changes happened Peak vibration Peak vibration Overall Overall Operating Operating vibration Vibration Operating vibration Vibration Overall speed Frequency speed Frequency level level condition level level value (rpm) (Hz) (rpm) (Hz) (m/s2) (m/s2) (m/s2) (m/s2) m/s2 Operating condition Vibration level change Percentage Percentage Peak change in change in value overall peak m/s2 (%) (%) Idling speed 750 8.38 4.25 96 Idling speed 750 3.13 0.53 77 5.25 3.72 62.6 87.5 1400 9.1 4.45 140 1400 9.27 3.04 22-0.17 1.41-1.9 31.7 Max torque 1700 13.1 4.31 121 Max torque 1700 10.6 1.23 86 2.5 3.08 19.1 71.5 Flyup speed 2400 33.1 17.6 56 Flyup speed 2400 20.8 2.13 40 12.3 15.47 37.2 87.9 Peak value 2272 27.2 19.3 75 Peak value 897.6 12.1 10.3 22 15.1 9 55.5 46.6 Idling speed 750 5.76 2.5 20 Idling speed 750 3.32 1.06 19 2.44 1.44 42.4 57.6 1400 8 2.75 70 1400 7.03 1.04 69 0.97 1.71 12.1 62.2 Max torque 1700 10.9 2.1 57 Max torque 1700 9.63 1.2 85 1.27 0.9 11.7 42.9 Flyup speed 2400 26 13 40 Flyup speed 2400 15.3 3.15 80 10.7 9.85 41.2 75.8 Peak value 1989 24.7 17.9 49 Peak value 2409 15.3 3.15 80 9.4 14.75 38.1 82.4 Idling speed 750 10.4 4.27 115 Idling speed 750 7.9 1.91 96 2.5 2.36 24.0 55.3 1400 60.6 41.5 105 1400 22.6 4.34 177 38 37.16 62.7 89.5 Max torque 1700 40.6 16.3 161 Max torque 1700 31.7 8.47 180 8.9 7.83 21.9 48.0 Flyup speed 2400 52.5 33.9 100 Flyup speed 2400 47.2 25.1 181 5.3 8.8 10.1 26.0 Peak value 1816 124 91.6 105 Peak value 1171 46 31.3 87 78 60.3 62.9 65.8 Idling speed 750 6.15 1.4 175 Idling speed 750 4.77 0.586 179 1.38 0.814 22.4 58.1 1400 15.9 6.89 176 1400 14.5 3.98 176 1.4 2.91 8.8 42.2 Max torque 1700 27.3 16.2 178 Max torque 1700 18.8 4.54 181 8.5 11.66 31.1 72.0 Flyup speed 2400 37 16.3 182 Flyup speed 2400 32.2 16.3 181 4.8 0 13.0 0.0 Peak value 2376 72.1 50 177 Peak value 1186 11.6 2.8 178 60.5 47.2 83.9 94.4 Idling speed 750 4.08 3.04 73 Idling speed 750 4.67 1.52 501-0.59 1.52-14.5 50.0 1400 11 5.23 66 1400 9.55 1.68 483 1.45 3.55 13.2 67.9 Max torque 1700 14.9 8.09 113 Max torque 1700 12.5 1.99 523 2.4 6.1 16.1 75.4 Flyup speed 2400 21 11.9 303 Flyup speed 2400 23.9 10.6 502-2.9 1.3-13.8 10.9 Peak value 1330 20.1 15.6 66 Peak value 1036 19.5 15.2 25 0.6 0.4 3.0 2.6 Idling speed 750 4.26 1.45 45 Idling speed 750 3.24 2.05 19 1.02-0.6 23.9-41.4 1400 10.1 2.77 46 1400 5.13 0.566 35 4.97 2.204 49.2 79.6 Max torque 1700 12.8 2.62 391 Max torque 1700 6.99 0.901 98 5.81 1.719 45.4 65.6 Flyup speed 2400 27.8 11.1 304 Flyup speed 2400 11.5 1.92 60 16.3 9.18 58.6 82.7 Peak value 2430 27.8 11.1 304 Peak value 824.9 4.56 3.17 20 23.24 7.93 83.6 71.4 Idling speed 750 9.51 7.02 78 Idling speed 750 6.34 1.23 96 3.17 5.79 33.3 82.5 1400 16.7 6.2 79 1400 15.7 4 92 1 2.2 6.0 35.5 Max torque 1700 19.9 6.74 165 Max torque 1700 20.6 3.73 99-0.7 3.01-3.5 44.7 Flyup speed 2400 33.1 18.2 81 Flyup speed 2400 29.4 5.65 241 3.7 12.55 11.2 69.0 Peak value 2400 33.1 18.2 81 Peak value 1232 20 13.1 92 13.1 5.1 39.6 28.0 Total 38 % 61 % Vibration (Base vs Improved) LHS 33 % 60 % RHS 43 % 61 % Significant reduction (about 0.5 db(a)) is observed in the driver ear noise level. The improved sheet panels shows about 38% reduction in the vibration level. here 15
Benefits Summary 1. Vibration at fender and platform of tractor is predicted with good correlation. 2. Correlated model was used for design optimization to reduce vibration. 3. Approximately 30 design concepts were simulated and studied. 4. Nearly 3 Months of time and proto costs were saved by avoiding physical testing. here 16
Conclusion A good correlation in terms of vibration was observed in physical test and simulation for baseline model. The correlated FE model was used for structural optimization using simulation and was implemented in final design. Prototype based upon final selected design was tested and vibration levels were measured. The results show vibration reduction by 38%. The above study and the process developed will help in refining FE modelling techniques and to reduce number of physical tests in future. The major structural resonances can be identified and will be addressed through structural optimization for vibration reduction at early design stage. here 17