Little research has been done to determine the stress states developed in an industrial sawblade for various operating conditions. The stresses are developed from the forces generated during the cutting of materials, and also from the vibration of the sawblade. The difficulty of analyzing these stresses and vibrations results from the sawblade’s high speed of rotation, which make it difficult to instrument the sawblade for analysis. Stress and vibration can ruin the sawblade from loss of material properties due to heat build-up and fatigue failure. The sawblade industry raised natural frequencies away from the operating frequencies to overcome the vibrations.
To raise the natural frequencies of the sawblades away from the operating frequencies, residual stresses have been intentionally induced in the sawbody. The residual stresses come from plastically deforming the sawbody with one or more concentric rings. Experts who determine the location, depth, and number of residual stress rings are called “saw doctors”. This thesis quantifies the residual stresses induced by saw doctors.
Developing and evaluating finite element models of an industrial sawblade while undergoing the effects from rotating and cutting are also included in the thesis. In addition, the effects on the sawblades performance due to various numbers and lengths of expansion slots and sawblade tensioning are explored. Models of the sawblade are plastically deformed leaving residual stresses which are analyzed to determine the natural frequencies of the sawblade. The thesis quantifies the above mechanisms for a sawblade under the loads developed from rotation and a load case representing the cutting process. The work developed in this thesis is a first step toward characterizing the effects of specific mechanisms which can be used to design better, longer lasting sawblades.
