The Effect of Operation and Engine Speed on Chainsaw Vibration

ماشین های کشاورزی

Article 3, Volume 8, Issue 2 - Serial Number 16, 2018, Pages 263-277   

Document Type: Research Article

DOI: 10.22067/jam.v8i2.60794

Authors

M. Feyzi^{* 1}; A. Jafari²; H. Ahmadi²

¹Ph.D. Student of Biosystems Engineering, University of Tabriz, Tabriz, Iran

²Department of Mechanical Engineering of Agricultural Machinery, University of Tehran, Karaj, Iran

Abstract

Introduction
Tree felling is an important part of forest exploitation. According to the condition of Iranian forests, mechanization in these forests has not been grown as it should be. Therefore, a main part of tree felling operations are performed by chainsaw. This machine can cause high level hand-arm vibration which is one of the main reasons of white finger syndrome. This syndrome affects the nerves, blood vessels, muscles, and joints of the hand, wrist, and arm. Reducing and controlling chainsaw vibrations are unlikely to be achievable without awareness of effective factors of it. So, the effects of various factors should be studied. It seems that, single cylinder engine and the interaction of the chain with wood can be the main reasons of chainsaw vibration. Therefore, in the current study the effects of engine rotary speed and wood type on the vibration acceleration of a common chainsaw have been investigated. In contrast to the previous studies, no-cutting condition as a control sample was added to experiments and the effects of cutting itself were evaluated. Experiments were also conducted in three different engine speeds to investigate the effects of interaction between wood species and engine speed.

Materials and Methods
The vibration acceleration was measured on three orthogonal axes on the front handle of Stihl-070 chainsaw. The measurements were conducted at three levels of engine speed (6000, 7720, and 8630 RPM) during four operations. The operations include cutting three types of Iranian woods (Beech, Hornbeam, and Alder) and no-cutting as a control sample. The experiments were conducted in split-factorial design where the operation was taken as main plot and different speeds and directions as factors. A single-axis piezoelectric accelerometer (VMI-192) was used to sense the vibration. Vibration signals were received and analyzed by a portable data acquisition system (Easy Viber). The RMS vibration acceleration at one-third octave frequency bands in the center frequency range between 6.3Hz to 1250Hz were calculated from acceleration-frequency vibration spectra. Then, the amounts of frequency-weighted vibration acceleration (ahw) were computed based on international standards. SAS software was used to analyze the data statistically.

Results and Discussion
The results of ANOVA showed that the effect of operation on frequency-weighted acceleration was insignificant, but the effects of engine speed and vibration axis were significant at the 1% level. When the chainsaw was free of cutting, the vibration acceleration values were lower in lower frequencies and higher in higher frequencies compared to cutting wood operations. There was a significant difference between the vibration acceleration in 6000 RPM engine speed and other two speeds, but the differences between 7720 RPM and 8630 RPM engine speeds was insignificant. However, an increase in engine rotary speed increased the value of frequency-weighted vibration acceleration. The acceleration-frequency vibration spectra had peaks at frequencies in accordance with the engine combustion frequencies (100 Hz in 6000, 125 Hz in 7720, and 160 Hz in 8630). Maximum value of unweighted vibration acceleration was observed during no-cutting operations in 6000, 7720, and 8630 RPM engine speeds to be 77.2, 138.6, and 139.0 m s^-2, respectively. Vibration acceleration was highest along the Xh (perpendicular to the palm area) equal to 12.05 m.s^-2 followed by Yh axis (along the third metacarpal bone) with the value of 9.12 m s^-2. Altogether, the results of these tests indicated that the vibration level of employed chainsaw in this study is very higher than other machines has been investigated by other researchers.

Conclusion
The effects of wood species and engine speed on the hand-transmitted vibration of chainsaw were evaluated. The operation has not significantly affected the frequency-weighted vibration acceleration. However, cutting operations, increase and decrease the vibration acceleration values in lower and higher frequencies, respectively. The frequency-weighted vibration acceleration had higher values in higher engine speeds. Also, it is concluded that the risk of white finger syndrome among the operators of this type of chainsaw is very high.

Keywords

Chainsaw; Combustion; Frequency-weighted vibration acceleration; One-tired octave bands

References

1. Ahmadian, H. 2012. Measurement, analysis and evaluation of a power tiller vibration on transportation mode. University of Tehran. (In Farsi).

2. Ahmadian, H., S. R. Hassan-beygi, and B. Ghobadian. 2014. Investigating a power tiller handle and seat vibration on transportation mode. CIGR journal 16: 164-206.

3. Arastoo, S. 2007. Economical and practical foundations of forest management. University of Tehran press. Tehran. (In Farsi).

4. Broyde, M., P. Donati, and L. Bitsch. 1989. Subjective assessment of the vibration discomfort produced by different hand held machines. Journal of Low Frequency Noise and Vibration 8: 50-61.

5. Burdorf, A., and P. Swuste. 1993. the effect of seat suspension on exposure to whole body vibration of professional drivers. The Annals of Occupational Hygiene 37: 45-55.

6. Dewangan, K. N., and V. K. Tewari. 2009a. Vibration energy absorption in the hand–arm system of hand tractor operator. Biosystems Engineering 103: 445-454.

7. Dewangan, K. N., and V. K. Tewari. 2009b. Characteristics of hand-transmitted vibration of a hand tractor used in three operational modes. International Journal of Industrial Ergonomics 39: 239-245.

8. Feyzi, M., A. Jafari, and H. Ahmadi. 2016a. Investigation of vibration transmissibility from chainsaw handle to wrist and arm of operator. Iranian Journal of Biosystem Engineering 47: 345-351. (In Farsi).

9. Feyzi, M., A. Jafari, and H. Ahmadi. 2016b. Investigation and analysis the vibration of handles of chainsaw without cutting. Journal of Agricultural Machinery 6 (1): 90-101. (In Farsi).

10. Giacomin, J., M. S. Shayaa, E. Dormegnie, and L. Richard. 2004. Frequency weighting for the evaluation of steering wheel rotational vibration. International Journal of Industrial Ergonomics 33: 527-541.

11. Goglia, V., Z. Gospodaric, D. Filipovic, and I. Djukic. 2006. Influence on operator’s health of hand-transmitted vibrations from handles of a single-axle tractor. Annals of Agricultural and Environmental Medicine 13: 33-38.

12. Hostens, I., and H. Ramon. 2003. Descriptive analysis of combine cabin vibrations and their effect on the human body. Journal of Sound and Vibration 266: 453-464.

13. Hutton, S. G., N. Paris, and R. Brubaker. 1993. The vibration characteristics of chain saws and their influence on vibration white finger disease. Ergonomics 36: 911-926.

14. ISO 5349. 2001. Mechanical vibration-measurement and evaluation of human exposure to hand transmitted vibration. Pages 32.

15. Jourgholami, M., B. Majnounian, and N. Zargham. 2012. Production and costs of motor-manual tree felling in hyrcanian forest. Journal of Forest and Wood Products 65: 285-297. (In Farsi).

16. Jourgholami, M., V. Rizvandi, and B. Majnounian. 2013. Environmental impact assessment of forest harvesting to residual stand (case study: kheyroud forest). Environmental Researches 4: 115-124. (In Farsi).

17. Ko, Y. H., O. L. Ean, and Z. M. Ripin. 2011. The design and development of suspended handles for reducing hand-arm vibration in petrol driven grass trimmer. International Journal of Industrial Ergonomics 41: 459-470.

18. Kumlin, T., M. Wiikeri, and P. Sumari. 1973. Radiological changes in carpal and metacarpal bones and phalanges caused by chain saw vibration. British Journal of Industrial Medicine 30: 71-73.

19. Laroche, G. P. 1976. Traumatic vasospastic disease in chain-saw operators. Canadian Medical Association Journal 115: 1217-1221.

20. Latibari, A. 2007. Wood cutting technology. Institute of Applied Science. Tehran. (In Farsi).

21. Letz, R., M. Cherniack, F. Gerr, D. Hershman, and P. Pace. 1992. A cross sectional epidemiological survey of shipyard workers exposed to hand-arm vibration. Journal of Industrial Medicine 49: 53-62.

22. Mehta, C. R., M. Shyam, P. Singh, and R. N. Verma. 2000. Ride vibration on tractor-implement system. Applied Ergonomics 31: 323-328.

23. Morioka, M., and M. J. Griffin. 2006. Magnitude-dependence of equivalent comfort contours for fore-and-aft, lateral and vertical hand-transmitted vibration. Journal of Sound and Vibration 295: 633-648.

24. Paddan, G. S., and M. J. Griffin. 2002. Evaluation of whole-body vibration in vehicles. Journal of Sound and Vibration 253: 195-213.

25. Pourabdian, S., E. Habibi, M. Sadegi, and M. Rismanchian. 2010. Effect of anti vibration handle use on hand grinding machine vibration. Journal of Health System Research 6: 124-133. (In Farsi).

26. Rottensteiner, C., and P. Tsioras, and K. Stampfer. 2012. Wood Density Impact on Hand-Arm Vibration. Croatian Journal of Forest Engineering 33: 303-312.

27. Sarikhani, N. 2009. Forest exploitation. University of Tehran Press. Tehran. (In Farsi).

28. Sauni, R., P. Virtema, R. Pääkkönen, E. Toppila, I. Pyykkö, and J. Uitti. 2010. Quality of life (EQ-5D) and hand-arm vibration syndrome. International Archives of Occupational and Environmental Health 83: 209-216.

29. Selim, A. A., K. Sobh, and S. M. Fathy. 2012. Hand-arm vibration syndrome clinical and neuro-physiological studies. Australian Journal of Basic and Applied Sciences 6: 292-299.

30. Sorayaei, M., M. Lotfalian, M. T. Mir Mohammadi, and Y. Gorji Mahlebani. 2014. The study of sound intensity of chain saw during tree felling (case study: gardeshi forest). in First Iranian congress of biology and natural science. Tehran, Iran. (In Farsi).

31. Taghizadeh Ali Saraei, A., T. Tavakoli, and B. Ghobadian. 2007. An investigation of seat vibration in universal 650m tractor. Iranian Journal of Agricultural Science 38: 571-580. (In Farsi).

32. Taghizadeh Ali Saraei, A., T. Tavakoli, and B. Ghobadian. 2010. Vibration analysis of two-wheeled tractors at station. Iranian Journal of Biosystem Engineering 41: 27-35. (In Farsi).

33. Taylor, L. J. 2009. The vibration analysis handbook: Ipp Books.

34. Theriault, G., L. D. Guire, S. Gingras, and G. Laroche. 1982. Raynaud's phenomenon in forestry workers in quebec. Canadian Medical Association Journal 126: 1404-1408.

35. Wakeling, J. M., B. M. Nigg, and A. I. Rozitis. 2002. Muscle activity damps the soft tissue resonance that occurs in response to pulsed and continuous vibrations. Journal of Applied Physiology 93: 1093-1103.

36. Yadama, S., and H. Sakakibara. 1994. Research into hand-arm vibration syndrome and its prevention in japan. Nagoya Journal of Medical Science 57: 3-17.

37. Yue, Z., and J. Mester. 2002. A model analysis of internal loads, energetics, and effects of wobbli mass duringthe whole-body vibration. Journal of Biomechanics 35: 639-647.