Vibration Characteristics of Walking and Riding Type Power Tillers

Nawayseh

et al. 2019

IJAME

The aim of this study is to investigate the compressive stress on lumbar spine due to whole body vibration (WBV) exposure in real field rotary soil tillage operation. The spinal stress was evaluated in terms of daily equivalent static compression dose (Sed) with respect to various ride conditions (i.e. forward speed, pulling force and tilling depth). Taguchi's L9 orthogonal array was used to form a systematic set of experiments by varying each ride condition over three levels. Signal-to-noise (S/N) ratios were computed to analyse the holistic effect of ride conditions among all the experimental conditions. In addition, the power spectral density (PSD) of the acceleration at the seat pan was measured along the dominant axis for each experiment. A second order regression model was developed to predict the real experimental Sed response. Further, the ride conditions were optimised by using desirability technique with the aim of minimizing Sed response. The magnitude of daily equivalent static compression dose was found between 0.38 and 0.76 MPa which shows a moderate probability of an adverse health effects as per ISO2631-5: 2004. Statistically, forward speed and pulling force are found to significantly affect the Sed response with a contribution of 64.43% and 24.73%, respectively. The PSD indicated that the vibration energy of the acceleration measured on the seat pan depend on the ride conditions. The predicted response of regression model showed 4.56% error in obtaining the actual experimental values. The optimised forward speed, pulling force and tilling depth levels were found to be 0.6 m/s, 2 kN, and 0.10 m, respectively.

Section: Signal-to-noise (S/n) Ratiomentioning

confidence: 99%

Investigation of Compressive Stress on Lumbar Spine due to Whole Body Vibration Exposure in Rotary Tillage Operation

Nawayseh

et al. 2019

IJAME

“…Using the gear 2 and 3, the combine driver is permitted to drive for 4 h and 2.5 h per day. Based on these results, it can be noted that the effect of reducing engine revolution to increase the allowable exposure time is more than that of shifting gear [24].…”

Section: Allowable Exposure Timementioning

confidence: 90%

Vibrations analysis of combine harvester seat in time and frequency domain

Jahanbakhshi¹,

Ghamari²,

Heidarbeigi³

2020

JMES

Agricultural machineries as one of the main inputs in producing agricultural materials are associated with some problems on occupational health such as vibrations. At the lowest level, vibrations cause different diseases such as those affecting blood vessels, nerves, muscles, etc. The aim of this study was to determine and investigate the seat vibrations in John Deere 1055I combine harvester at different conditions. The experiments were carried out based on ISO 2631 and the Iranian standard number 14133. The tests were done at different engine revolutions and gear ratios with three replications. The collected data were analyzed considering factorial experiments based on completely randomized design. The results of variance analysis related to the effect of the main factors on combine seat vibrations showed a significant difference at the probability level of 1%. Effect of engine revolutions on vibration of the combine seat was higher than that of shifting gears. By calculating the allowable exposure time, there was concluded that for the first and second gears at the engine revolution of 1800 rpm and the first gear at the revolution of 2500 rpm, operators can easily drive the combine harvester for eight hours every day without any problems. The results of this study can be used to optimize the components affecting the vibration of the combine seat.

“…In addition, the rise in acceleration magnitudes could be the result of uneven terrain condition. These increasing acceleration levels should be monitored and controlled as it may affect the ride behavior and lower the work capacity of tractor operator [27]. Moreover, the overall daily vibration exposure found to decrease with the increase in draft and tillage depth levels as per SNRs.…”

Section: Signal-to-noise Ratiomentioning

confidence: 99%

Whole Body Vibration Exposure during Rotary Soil Tillage Operation:

Singh¹,

Nawayseh²,

Singh³

et al. 2018

IJAME

The present investigation attempted to study the overall daily vibration exposure A(8) in actual field rotary tillage operation at various ride conditions (i.e. average velocity, draft and average soil tillage depth). Three different levels of each ride condition were chosen to formulate an organised design of experiments by using Taguchi’s approach. The concurrent root mean square (RMS) acceleration values were measured at the tractor platform, seat pan and seat backrest along the three translation axes to determine the A(8). Signal-to-noise ratios (SNRs) were computed and analysed concerning the conducted experiments. Further, the dominant frequencies at each set of experiment were determined by fast fourier transform (FFT) analysis. A linear regression model was developed to predict the output response and further, the ride conditions were optimised by using desirability approach. The overall daily vibration exposure was found between fairly uncomfortable to uncomfortable category (i.e. 0.64 and 0.84 m/s2) as per ISO 2631-1 (1997). Moreover, the exposure levels are beyond the exposure action limit recommended by Directive2002/44/EU. The average velocity and draft effects on the A(8) response were found significant (p≤0.05) with a contribution of 78.38% and 18.54%, respectively. The FFT analysis depicted a range of dominant peaks in the frequency range of 0.8 to 3.7 Hz. However, the exact frequency of the peaks was found to depend on the experimental condition. The prediction model indicates a good correlation between predicted and actual experimental response with an average error of 1.02%. Desirability and Taguchi’s approaches gave identical optimised ride conditions (i.e. 0.6 m/s, 6 kN, and 0.14 m) with the aim of reducing the A(8) value.