Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

PDF

2006

Mechanical Engineering

Theses and Dissertations

Torque

Articles 1 - 2 of 2

Full-Text Articles in Entire DC Network

A Torque Based Power Input Model For Friction Stir Welding, Jefferson W. Pew Dec 2006

A Torque Based Power Input Model For Friction Stir Welding, Jefferson W. Pew

Theses and Dissertations

For decades models have been developed for predicting the size of the weld nugget and heat affected zones in fusion welded structures. The basis for these models is the welding heat input, which is fairly well understood for most arc welding processes. However, this traditional approach is not as straightforward for Friction Stir Welding (FSW). To date, there is no definitive relationship to quantify the heat input for FSW. An important step to establish a heat input model is to identify how FSW process parameters affect weld power. This study details the relationship between FSW process parameters and torque for ...


Settling-Time Improvements In Positioning Machines Subject To Nonlinear Friction Using Adaptive Impulse Control, Tim Hakala Jan 2006

Settling-Time Improvements In Positioning Machines Subject To Nonlinear Friction Using Adaptive Impulse Control, Tim Hakala

Theses and Dissertations

A new method of adaptive impulse control is developed to precisely and quickly control the position of machine components subject to friction. Friction dominates the forces affecting fine positioning dynamics. Friction can depend on payload, velocity, step size, path, initial position, temperature, and other variables. Control problems such as steady-state error and limit cycles often arise when applying conventional control techniques to the position control problem. Studies in the last few decades have shown that impulsive control can produce repeatable displacements as small as ten nanometers without limit cycles or steady-state error in machines subject to dry sliding friction. These ...