M.S. Thesis Presentation by Matt Lebeck
Thursday, September 12, 2002

(Dr. Steven Liang, advisor)

"Predictive Methods Applied to the Vibratory Response of Machining Structural Steel and Weldments"

Abstract

The potential cost and time savings that the construction equipment industry could reap from decreasing machining related forced vibration issues late in the design phase of a new product warranted an evaluation of the current methods of force prediction. A method that provides a closed-form solution for the three dimensional forces in face milling was selected for this study. A physical experiment was conducted in an attempt to correlate the prediction forces with the measured forces. The experiment was designed so as to incorporate the type of variation seen in structural steel and steel weldments. Namely, material property variation, material flatness variation, and residual stresses from plate processing and welding. On the basis of trend correlation, the predicted and measured correlated for several cutting properties, but did not for the majority. This was likely due to the non-incorporation of temperature and strain-rate effects in the predictive model and a continuously changing axial depth of cut due to part vibration. Also, several cases of finite element analysis were conducted to attempt a preliminary correlation. The case that had the highest level of forced vibration did not correlate, most likely because of the changing axial depth of cut. Likely future research could entail expanding the predictive force model to define axial depth of cut as a time dependent variable and possibly incorporating temperature and strain-rate effects.