| The purpose of the work described in this dissertation is to increase the understanding of injection-pultrusion process. Three major sub-studies related to injection-pultrusion have been completed: measurement of the compressibility of fiber reinforcements, measurement of in-plane and transverse resin flow through fiber reinforcements, and development of a resin flow model. Advancements in each of these topics should prove valuable not only to pultruders, but also to all those working with "wet" composite material processing technologies.; Compressibility experiments were performed by compressing stacks of various fiber reinforcing materials under carefully controlled loading conditions, and observing the change of fiber volume with load. Effects of parameters such as testing speed, repeated loading and unloading, material lubrication, material type, fiber orientation, multi-material combinations, stacking sequence and hysteresis during loading and unloading are presented. Applications of a new type of pressure sensing device designed specifically for measurement of locally applied pressures in composite material processes are also described.; This dissertation also presents results of an experimental and analytical investigation of in-plane and transverse resin flow through fiber reinforcements. Experimental results show that the flow behavior is mainly dependent on the fiber structures and fiber volume fraction. Other parameters such as resin saturation, flow rate, and number of testing layers are discussed. This study also presents flow behavior in combined layers of two different fiber orientations and presents analytical flow models to understand flow behavior in multilayer fiber reinforcements. Experimental results of measured maximum possible injection pressure without resin leakage at the die entrance are presented as a function of fiber volume and pulling speed, and compared with theoretical predictions. The experimental data showed that leakage occurred at injection pressures lower than predicted values. However, as fiber volume fraction increased, experimental results fit predictions better. |
