Development of a Process Simulation Model of a Pultrusion Line

The applications for fiber reinforced plastic (FRP) composite structures have increased tremendously in the automotive and aerospace industries due to their lightweight nature. However, because of their high manufacturing cost, composite structures are typically only used for high-end parts. The reason behind this is the relatively low mass production rate of composite structures. Among the various composite manufacturing methods available, pultrusion is a continuous production process, meaning that the potential for mass production is there, if the process can be made fast enough. The process of pultrusion is defined as extrusion with pulling, in contrast with the conventional ‘extrusion process’, which is used for manufacturing uniform cross section structures such as circular bars, hollow tubes, I section beams etc. [1] [2]. Currently, pultrusion has a wide range of applications in the “architecture, transportation, construction, agriculture, chemical engineering, aircraft, and aerospace industry” [2]. On the basis of the polymer used in the manufacturing process, pultrusion can be divided into two types namely: thermoset and thermoplastic pultrusion. Many studies in the past have been conducted on thermoset pultrusion whose main advantage over thermoplastic pultrusion is the fiber impregnation, or ‘wetting out of the fiber reinforcement’ due to the resin’s low viscosity [3]. On the other hand, thermoplastic pultrusion can create parts which are recyclable, post formable, weldable, have excellent environmental stability and good mechanical properties such as high “fracture toughness, higher damage resistance” [1]. Due to such economic, environmental and mechanical advantages, many researchers have contributed to the development of thermoplastic pultrusion mainly in the field of fiber impregnation with thermoplastic resins [1] [4] [5]. With the advancement in thermoplastic prepreg technologies, pultrusion experiments with pre-consolidated tapes (PCT), powder coated tow-pregs and commingled yarns were performed and studied [1]. Moreover, in the early 1990s, thermoplastic pultrusion models were developed by researchers in order to understand the workings of the process [3] [6]. Most of the current research is focused mainly on investigating the effects of process and material parameters on the mechanical performance of the pultruded part. However, the interrelationship between the materials, process, and product is still not fully understood or has been incorporated into a complete CAE processing chain. The development of analytic, computational, and experimental approaches continues and the need of a fully developed simulation model, which can be used to optimize process parameters, avoid a trial and error approach and to improve productivity still exists.