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Stresses and vibrations in bandsaw blades

University of British Columbia

Due to rising lumber costs it has become more and more important to optimize the cutting performance of bandsaws as they are used in the forest products industry. One important aim is to reduce the lateral and torsional deflections of the blade to minimize the thickness of the cut. This study tries to assess the influence of various typical bandsaw parameters on the stress distribution in the bandsaw blade and on the vibrational behaviour of the stationary and the running sawblade. Experiments were performed with a fullsize industrial production bandsaw. The experimental results for the stress-strain measurements of the stationary sawblade are compared with results from theoretical solutions. Vibration measurements of the stationary and of the running blade are compared to values derived from MOTE'S [9] flexible band solution and KANAUCHI'S solution [21] for lateral deflection and with ALSPAUGH'S [2] solution for torsional vibrations. The results presented show that the static stress measurements agree very well with the analytically predicted results. Major factors influencing the stress distribution in the blade: the axial prestress, stresses due to bending of the blade over the bandsaw wheels, and stresses due to tilting of the top bandsaw wheel were examined. A comparison of the experimental and analytical results of the vibration measurements for the stationary sawblade showed very good agreement for the lateral natural frequencies, while the torsional natural frequencies were considerably higher than the analytically predicted values. Similar results could be observed for the natural frequencies of the running blade. The mode shapes of the stationary sawblade at the natural frequencies were measured. It was found that the modeshapes consisted of coupled modes for most tiltstress differences.

Text

2010-04-22

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http://hdl.handle.net/2429/24073

Mechanical Engineering

University of British Columbia

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