Thermomechanical modeling and analysis of a redesigned pultrusion cavity die using experimental and finite element methods
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Date
2024-04
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University of New Brunswick
Abstract
Pultrusion enjoys one of the most versatile composite manufacturing methods. Pultrusion die (or mould) plays a central role in creating the condition for thermomechanical transformation of incoming fibers (mostly glass or carbon) impregnated with polymer matrix to obtain profiles of desired shape and size. In the process, the die material undergoes considerable wear/erosion due to sustained temperature, pressure, and friction at the contact point between fiber rovings and die cavity surface and, as well as from the leftover residue from previous runs. As a result, die maintenance is a common practice requiring opening and cleaning up of die compartments, made up of top and bottom segments, which often takes hours by skilled workforce. This is a dilemma; in one hand, pultrusion when automated can serve as a mass manufacturing method, and, on the other, when left unattended causes long downtime and process inefficiency.
The primary objective of this research was to redesign the pultrusion die with a novel ‘bi-material’ concept. The new design incorporated a hard chromed P20 steel tube inside a lighter Al6061 alloy rectangular two-segment cavity die. The goal is to interchange the worn-off tube periodically, at minimum process interruption. Concurrently, the project integrated a thermoplastic polymer in the pultrusion manufacturing, thus replacing traditional thermoset resin with a goal to develop greener, structurally-flexible, long-lasting pultruded profiles in the redesigned die.
To achieve the dual objectives, the research adopted a combined experimental/numerical research methodology on the utilization of a suite of tools and techniques. These included a bi-material design philosophy, die thermomechanical profile modeling using ABAQUS/Explicit® finite element method, material machining and surface finish, pultrusion design of experiments (DoE), material testing/characterization, and statistical analysis. The project addresses the exacerbating coastal erosion problems in the Acadian Peninsula of northern New Brunswick.