Three-Dimensional Characterization of Pultruded Fiberglass-Epoxy Composite Materials

Abstract

Computer simulation is helpful for understanding the manufacturing of pultruded advanced composites. This research involves a three-dimensional examination of the temperature and thermochemical aspects for the manufacturing of cartesian fiberglass-epoxy composite materials. Comparison of the computer generated predictions were made with experimentally measured temperature profiles and the degree of cure obtained using a Differential Scanning Calorimeter (DSC). A numerical model employing Patankar's [1] control volume based finite difference technique was employed for solving the governing energy and species equations used to model the entire heating (moving and non-moving) sections of the pultruder. This computer model can be utilized to establish functional relationships between combinations of pull speed, fiber volume, and die temperature profiles and can be employed to refine the pultruder for manufacturing composites, indicating the importance of controlling the processing parameters in producing quality pultruded products. Since this computer simulation is independent of predetermined laboratory values in generating results, it can establish the guidelines in the design of an advanced pultrusion machine itself, and in orchestrating the future development of advanced composite materials.

Optimum design of pultrusion process via evolutionary multi-objective optimization

“…Lumped material properties are used and assumed to be constant throughout the process. The volumetric internal heat generation (q) (W/m 3 ) due to the exothermic reaction of the epoxy resin can be expressed as follows [8,10]:…”

“…where V f is the fiber volume fraction, ρ r is the resin density, α is the degree of cure, H tr is the total heat of reaction during the complete cure of the resin sample which is obtained by using a differential scanning calorimetry (DSC) analysis [7,8]. R r (α, T ) is the rate of degree of cure dα/dt defined by an Arrhenius type of relation and expressed in Eq.…”

“…Generally, dα/dt is linearly correlated with the rate of heat, dH (t)/dt, generated during the curing of the resin sample, as seen in Eq. 4. dH (t)/dt is also obtained from the DSC analysis [8].…”

“…K o , E, and n can be obtained by a curve fitting procedure applied to the experimental data evaluated using the DSC [8].…”

“…For the transient solution, an unconditionally stable alternating direction implicit Douglas-Gunn (ADI-DG) scheme was implemented. An experimental and numerical investigation of the pultrusion were conducted in [7,8]. The process-induced residual stresses and distortions have been predicted in [9][10][11].…”