Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Modeling of in-situ laser curing of thermoset -matrix composites in filament winding
Abstract
To manufacture thermoset-matrix composite structures using the filament winding method, the thermal curing process plays a vital role. Traditionally, the curing is done, after the winding process of tow is completed, by placing the whole fiber-wound composite structure in an autoclave or oven at elevated temperature. The curing process is time consuming, especially for fiberwound structures with thick cross section. To shorten the production time and increase productivity, a new method—in-situ laser curing is proposed. With this method, laser illuminates on the surface of tow when it is being wound onto the mandrel so that the thermal curing process is accomplished during the winding of tow. This method may also offer many advantages over the traditional one: reduced residual stresses, easier production of composite structures with thick cross section, significant energy savings due to local heating, design flexibility, etc. In this study, the thermal modeling of in-situ laser curing of thermoset composites in filament winding is conducted numerically. The tow of interest, on which laser illuminates, is that portion of the tow just before and after the contact point between the incoming tow and the mandrel or fiberwound composite structure. A simplified physical model in which tow is considered to be a straight cylinder by neglecting the curvature of mandrel is constructed first. A three-dimensional mathematical model in cylindrical coordinates with orthotropic thermal conductivities is employed. Improvements to this model are made with the two-region tow model and further consideration on interactions between the laser and the resin. Finally, in order to make the simulation of in-situ laser curing process more realistic, a complicated physical model for a spacially helical tow is presented. Boundary-fitted method is applied to this model of complicated geometry. Transformed three-dimensional energy equations with anisotropic thermal conductivities are derived and solved. The profiles of temperature and degree of cure are numerically calculated. The results show that in-situ laser curing can be accomplished within a short period of time during the winding of tow. The relationships among the processing parameters are formulated and discussed.
Subject Area
Mechanical engineering
Recommended Citation
Wang, Xuefeng, "Modeling of in-situ laser curing of thermoset -matrix composites in filament winding" (2001). ETD collection for University of Nebraska-Lincoln. AAI9997022.
https://digitalcommons.unl.edu/dissertations/AAI9997022