Cure Cycle for Thick Glass/Epoxy Composite Laminates

Abstract

Duringthe curingprocess of thick glass/epoxy composite laminates, substantial amounts of temperature lagand overshoot at the center of the laminates is usually experienced due to the large thickness and low thermal conductivity of the glass/epoxy composites, which require a long time for full and uniform consolidation. In this work, the temperature profiles of a 20mm thick unidirectional glass/epoxy laminate duringan autoclave vacuum bag process were measured and compared with the numerically calculated results. For the calculation of distributions of the temperature, degree of cure, resin pressure, exothermic heat and required time for full consolidation by three-dimensional finite element analyses, the effects of convective heat transfer coefficient and geometry of mold and bagging assembly on the temperature profiles were taken into consideration. Based on the numerical results, an optimized cure cycle with the coolingand reheatingsteps was developed by minimizingthe objective function to reduce the temperature overshoot in the composite. From the experimental and numerical results, it was found that the measured temperature profiles were in good agreement with the numerical ones, and conventional cure cycles recommended by prepregmanufacturers for thin laminates should be modified to prevent temperature overshoot and to obtain full consolidation.

A fiber optic temperature sensor based on the combination of epoxy and glass particles with different thermo-optic coefficients

“…temperature during curing, and therefore, the curing properties [30,31]. Figure 5 shows the temperature and the voltage U M (for a wavelength of 460 nm and 650 nm) with respect to the time for sensor elements with different lengths and a particle size of d 50.3 =43 m.…”

Mechanical and thermal properties of MWCNT-reinforced epoxy nanocomposites by vacuum assisted resin transfer molding

“…Composite forming methods include press molding, hand lay-up, extruding, and resin transfer molding. Vacuum assisted resin transfer molding (VARTM) provides advantages of low cost, easy forming, continuous production, the possibility of manufacture of various forms, and mass production of composites such as flat shapes is possible [18][19][20][21][22]. For example, thin film composites made via the VARTM method have various application fields ranging from potable supplies to electrode industries.…”

Effect of cure cycle on curing process and hardness for epoxy resin

“…They calculated through-the-thickness temperature distributions of arbitrary shape composite structures including the mandrel. Oh and Lee [21] studied the cure cycle for glass/epoxy composite laminate by 3-dimensional finite element model based on commercial finite element software ANSYS. An optimized cure cycle with the cooling and reheating steps was developed by minimizing the objective function to reduce the temperature overshoot in the composite.…”

“…Only a few literatures studied the temperature and degree of cure fields by finite element analysis. Although several special-purpose numerical softwares have been developed to study the curing process, few analyses made by general-purpose numerical software [21,23] were published. Because general-purpose finite element software has well developed pre-and post-processors, researchers can be released from the tedious programming work, and devote their most efforts to the explanation and employment of the simulation results.…”

“…Because general-purpose finite element software has well developed pre-and post-processors, researchers can be released from the tedious programming work, and devote their most efforts to the explanation and employment of the simulation results. In the previous studies [5,21,23], general finite element software ANSYS were used for predicting curing of resin matrix composites and also for casting resins. But large amount of code was still needed, and programmed by APDL (ANSYS parametric design language).…”