Ride Vibrations on a 7·5kW Rotary Power Tiller

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: Introductionmentioning

confidence: 99%

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

Nawayseh

et al. 2019

IJAME

“…For the whole body vibration acceleration, frequency weighting was directly employed through the in-built filters provided in SWAN Pic software, which are in tune with ISO 2631/1, 1997. The spectrum of vibration acceleration was thus obtained for each 1/3 rd octave band in the range of 1-80 Hz [14][15][16]. The measurement procedure of vibration acceleration is presented in the Figure 1.…”

Section: Measurement Of 1/3 Rd Octave Band Vibration Accelerationmentioning

confidence: 99%

Ergonomic Assessment of Self-Propelled Machinery Seats for Agricultural Workers

Singh¹,

Tewari²,

Hota³

et al. 2019

J Ergonomics

Excessive vibrations in self-propelled machinery engaged in agricultural farm operations cause mechanical failures and subject the operators to discomfort. Laboratory tests were carried out in a completely randomized design in a factorial arrangement (type of seat×engine, speeds×subject) with a view to evaluate the self-propelled machinery seat ergonomically. Various performance parameters like 1/3 rd octave band vibration acceleration, Working Heart Rate (WHR), Oxygen Consumption Rate (OCR), Energy Expenditure Rate (EER) were measured during the operation of self-propelled machinery with different types of seats (SM-1 to SM-5) and statistically analyzed. The 1/3 rd octave band vibration acceleration of self-propelled machinery was found to be lowest with SM-5 seat i.e. 0.983, 0.646, 1.019 m/sec 2 and highest with SM-1 seat i.e. 4.21, 2.77 and 9.819 m/sec 2 in X, Y and Z direction, respectively. It was observed that the vibration acceleration in Z direction is higher as compared to X and Y direction and vibration acceleration has a linear correlation with engine speed. The vibration acceleration and physiological parameters viz. working heart rate, oxygen consumption rate and energy expenditure rate of the subjects were found lesser for SM-5 as compared to other four seats at different engine speed for the self-propelled machinery. Different types of seat, engine speed and subject has statistically significant effect on 1/3 rd octave band vibration acceleration, WHR, OCR and EER at 1% level.

“…The hand-transmitted vibration of a single-axle tractor is very strong because the handle grip is a cantilever beam, with the excitation power obtained from the one-cylinder diesel engine (Ying et al, 1998). The low-frequency vibrations to which the operator is subjected result from both linear displacements of the single-axle tractor and rotational oscillations of the pitch and roll modes (Mehta et al, 1997). The four principal effects of ride vibrations are considered to be degraded health, impaired activities, impaired comfort and motion sickness.…”

Section: Introductionmentioning

confidence: 99%

“…Also, he found that the vibration on the handles of the GN-5 walking tractor was very strong and seriously affected the operator"s health. Mehta et al (1997) measured ride vibrations on a single axle tractor with a seating attachment under various operating conditions and compared them with the values specified under ISO-2631ISO- (1985 in relation to working efficiency, health, and safety of the operator. They found that exposure time for the single axle tractor should not exceed 2 to 5 h per day for rototilling operations.…”

Section: Introductionmentioning

confidence: 99%

Physiological responses of operators to handle vibration of diesel-fueled single-axle tractor

Busse¹,

Sinclair²,

Wondimu³

et al. 2019

Afr. J. Agric. Res.

Hand-arm transmitted vibration originating from a 15 horsepower single-axle tractor can be very strong and cause operator fatigue plus various physiological disorders in vascular, neurological, and musculoskeletal systems. The objective of this work was to measure the characteristics of such handtransmitted vibrations and its effect on the health of the single-axle tractor operator, in a research program conducted at the Melkasa Agricultural Research Center of Ethiopia. During the study, the measurement of anthropometric data and the heart rate of the operators and vibration at the handle of single axle tractor were conducted. From measured data, the requirement of expenditure energy, physical workload, and operators' daily vibration exposure was calculated. The average measured resting heart rate, working heart rate and heart rate after the operation was 717, 1624 and 12624 beats/min, respectively. The calculated values of HR reserve (%HRR) or physiological workload and the ratio of working to resting heart rate were 7410% and 2.30.4 (p < 0.0001), respectively. The total energy expenditure of single-axle tractor operators was calculated to be 351.2 kJ/min. The daily exposure m/s 2 A (8) and total exposure points which were calculated indirectly from measured vibrations at the tractor handle and duration of operation were 12.6 m/s 2 and 2520 points, respectively. From measurements of operators' heart rates, it was concluded that the physical workload fell into the category of extremely heavy work, for which the working heart rate more than doubled the resting heart rate (p < 0.0001).