"Delamination is a well-recognized problem associated with drilling in fiber-reinforced composite materials (FRCM). The most noted problems occur as the drill enters and exits the FRCM. Since drilling is often a final operation during assembly, any defects introduced in parts by drilling represent an expensive loss. Studies based on linear elastic fracture mechanics theory have proposed critical thrust forces in the various drilling regions that will prevent crack growth or delamination. Using these critical thrust force curves as a guide, a thrust force controller was developed to minimize the delamination while drilling in graphite epoxy laminates. A neural network control scheme is implemented which requires a neural network identifier to model the drilling dynamics and a neural network controller to learn the relationship between feed rate and the desired thrust force. Experimental results verify the validity of this control approach as well as the robustness of the design. Visual measurements of the delamination zones are used to quantify the benefits of the controlled process versus the "uncontrolled" conventional drilling process in the graphite epoxy laminate"-Abstract p.iii
Lokeswarappa R. Dharani
Roger H. Hering
Mechanical and Aerospace Engineering
M.S. in Mechanical Engineering
University of Missouri--Rolla
viii, 51 pages
© 1995 Robert Boyce Stone, All rights reserved.
Thesis - Open Access
Print OCLC #
Stone, Robert B., "A neural network thrust force controller to minimize delamination during drilling in graphite epoxy laminates" (1995). Masters Theses. 4380.