Modeling of Conventional Autoclave Curing of Unsaturated Polyester Based Composite Materials as Production Process Guide

Abstract

Abstract:Modeling of composite curing process is required prior to composite production as this would help in establishing correct production parameters thereby eliminating costly trial and error runs. Determining curing profile temperatures from experiment is a huge challenge which in itself is like re-inventing the wheel of trial and error, when mathematical models of physical, chemical and kinetic properties of the constituent materials could be used in modeling the cure situation to some degree of trust. This work has modeled two types of polymer based composite materials (Aluminum filled polyester and carbon-black filled polyester) representing polymer-metal and polymer-organic composites in order to predict the possible trends during conventional autoclave heating with regards to effect of heating rate on degree of cure of the composites. The numerical models were constructed by taking into account the heat transferred by conduction through the resin/filler mixture, as well as kinetic heat generated by cure reaction. The numerical solution of the mathematical models presented were discretized using forward finite differences of the Runge Kuta Method and finally solved using MATLAB® C programming language. It was observed that Aluminum filled polyester composite responded faster to heat input-induced curing and as such was able to cure faster than polyester -carbon black composite which had much slower cure -heat input response. This implies that in the production process of polymer-organic composites, faster heating rate was necessary to input heat into the process as there was no heat of reaction released during the cure process whereas, polymer-metal composites release heat of reaction contributing to the quick transfer of heat into the metal components causing the metal components to behave as points of adhesion to the polymer matrix thereby necessitating a slower heating rate.

Effect of Microwave and Conventional Heating on the Cure Cycles of Particulate Reinforced Polymer Matrix Composites

“…This is due to the fact that there were more cross linking reactions with higher percentage weight fraction of particulate reinforcement. The high rate of heat transferred through the material was therefore as a result of aggregate of volumetric heating from the microwave system and total exothermic heat of reaction due to cross-linking reaction [14]. Figure 4.2a&b show that there were serious overlapping in temperature in between the samples and gradual increase in temperature as a function of time for conventional curing in respective of variation in the percentage weight fraction of the reinforcement.…”

Comparism of Cure Modeling of Unsaturated Polyester Based Composites Using Microwave and Autoclave Assisted Hand Lay-Up Process in Cylinderical Mould

“…Cure refers to an irreversible exothermic chemical reaction by which the composite lay is transformed from a soft, multi-layered mixture of fillers and resin, to a hard structural component [6] exothermicity of the curing reaction associated with the low conductivity of the material is a feature of fundamental importance. As a result, the curing reaction gives rise to high temperature within the resin especially at the center, and high temperature gradients are developed through the sample [1] [7] [8]. These facts lead to cracking [9][10].…”

“…Several numerical modeling and experimental investigations have been performed on different problems related to the hand lay-up process particularly, on the analyses of the rate of heat transfer and degree of cure [1] The importance of the analyses of the rate of heat transfer and degree of cure in hand lay-up process is highly recognized to obtain a final product character desired mechanical properties or to realize defects free end products. Numerical modeling and simulation of the process of cure is of great importance from a theoretical point of view in order to gain a fuller insight into the nature of the process, and from an experimental point of view, to optimize the operational conditions.…”

“…The high exothermicity of the curing reaction associated with the low conductivity of the material is a feature of fundamental importance. As a result, the curing reaction gives rise to high ially at the center, and high eveloped through the sample [1] [7] Several numerical modeling and experimental investigations have been performed on different problems particularly, on the at transfer and degree of cure [1]. The importance of the analyses of the rate of heat transfer up process is highly recognized to obtain a final product characterized by the desired mechanical properties or to realize defects free endNumerical modeling and simulation of the process of cure is of great importance from a theoretical point of view in order to gain a fuller insight into the nature of the cess, and from an experimental point of view, to optimize…”

“…Composites have found many wide spread applications in modern industries [1]. This increased demand for composites has led researchers in pursuit of better and faster methods of manufacturing composites.…”