In‐situ monitoring of the resin transfer molding impregnation and cure process

Abstract

Resin transfer molding (RTM) of advanced fiber architecture materials promises to be a cost effective process for obtaining composite parts with exceptional strength. However there are a larger number of material processing parameters that must be observed, known, and/or controlled during the resin transfer molding process. These include the viscosity both during impregnation and cure. In-situ sensors which can observe these processing properties within the RTM tool during the fabrication process are essential. This paper will discuss recent work on the use of frequency dependent electromagnetic sensing (FDMS) techniques to monitor these properties in the RTM tool. Our objective is to use these sensing techniques to address problems of RTM scaleup for large complex parts and to develop a closed loop, intelligent, sensor controlled RTM fabrication process.

Complexation of Silver Ions with Poly(butyl methacrylate) and Propylene Toward Facilitated Propylene Transport

“…For polymer systems containing ionic species, the dielectric loss factor (e99) is composed of two parts according to Equation (2) e99 = e99 ion + e99 dipole (2) where and are the contributions of dipolar groups and ionic species, respectively. [19,20] is not significant at low temperature due to the low mobility of ion species but becomes more significant with increasing temperature. Thus, it is suggested that the c-peak is related to the motion of the pendant ester groups under these experimental conditions.…”

In situ sensor monitoring and intelligent control of the resin transfer molding process

“…In studies of epoxies, polyimides, phenolics, and unsaturated polyesters, frequency-dependent electromagnetic sensing (FDEMS) has been shown to be a convenient automated instrumental technique for monitoring in situ the processing properties of thermoset resins continuously throughout the cure process. FDEMS is able to monitor the progress of cure including reaction onset, point and magnitude of maximum flow, fluidity, solvent evolution, buildup in modulus, approach to Tg, reaction completion and degradation (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). FDEMS measurements are particularly useful as they can be conveniently made both in a laboratory and in situ in the tool during processing in the fabrication environment.…”

Flow enhancement in liquid composite molding processes by online microwave resin preheating

“…[5][6][7][8] Preforms are usually realized from woven fibers (conventionally glass, carbon, or Kevlar), stitched mats, multiaxial orientated textiles, or three-dimensional weaves. [1,9] After the cutting operation, the preform is placed in a rigid or semirigid mold and is saturated promoting the resin flow. Afterward, the workpiece is cured, demolded, and finally postprocessed.…”