Composite fabrication processes

In summary an FDEMS sensor system can be used to monitor the processing properties in situ during the fabrication process of a composite part. A smart sensor control system can be used to monitor resin properties for reproducability-quality assurance, to ensure fabric impregnation, and to control and optimize the composite fabrication process intelligently through in situ sensor feedback. 

Transport of mass, energy, and momentum in porous media is a key aspect of a large number of fiber-reinforced plastic composite fabrication processes. In design and optimization of such processes, computer simulation plays an important role. Recent studies [1-14] have... 

The majority of composite fabrication processes are carried out with thermosetting resins. One must therefore keep track of both the cured and uncured resin. In what follows, first the overall mass balance equation for the resin phase will be developed, then a balance equation for the cured portion of the resin will be presented. 

Fabrication methods have overwhelmingly focused on improving nanotube dispersion because better nanotube dispersion in polyurethane matrix has been found to improve the properties of the nanocomposites. The dispersion extent of CNTs in the polyurethane matrix plays an important role in the properties of the polymer nanocomposites. Similar to the case of nanotube/solvent suspensions, pristine nanotubes have not yet been shown to be soluble in polymers, illustrating the extreme difficulty of overcoming the inherent thermodynamic drive of nanotubes to bundle. Therefore, CNTs need to be surface modified before the composite fabrication process to improve the load transfer from the polyurethane matrix to the nanotubes. Usually, the polyurethane/CNT nanocomposites can be fabricated by using four techniques melt-mixing (15), solution casting (16-18), in-situ polymerization (19-21), and sol gel process (22). 

Segregant-weakened interfaces are an attractive concept based on the possibility of eliminating the coating phase from the composite fabrication process. This concept has only been demonstrated, however, on model composite systems. A major technical issue is whether the matrix or fiber, or both, would have to be doped to control the fiber-matrix interfacial energy. If polycrystalline fibers require doping, then the effects of dopants on creep performance must be considered. Therefore, additional basic research of this interface concept, utilizing available polycrystalline fibers and candidate oxide matrices, is recommended. 

Blackglas Ceramic Fiber Composite Fabrication Process... 

FIGURE 2. Schematic of Composite Fabrication Process Using Blackglas Resin and Ceramic Fibers... 

Composite Fabrication. Orthotropic composites were fabricated using the PP/VB (50/50 wt.%) woven preforms. Four fabric preform layers were placed between layers of polypropylene sheet as shown in Figure 2. In order to produce orthotropic composites, the fabric layers were alternately oriented 90° because the woven preforms possessed different fiber counts in the warp and weft directions. The composites were consolidated at 200°C and 3500 kPa using a model 2696 Carver Laboratory Press with heated plates. The thickness of the PP sheets used in the composite fabrication process was varied in order to achieve the desired final composite composition and to control the distribution of the four fabric layers across the composite cross section. 

In an attempt to maximize flexural properties, PP/VB composites were fabricated with the reinforcing preform layers selectively placed near the composite surfaces where the greatest tension / compression occurs during flexural loading. During the composite fabrication process, PP sheets of varied thickness were used in order to situate two preform layers just inside both composite surfaces. The tensile and flexural mechanical properties for a -<10 VB wt.% composite with such uneven fabric distribution are provided in Table II along with the properties for its... 

Prepreg Common term to describe a fiber material that has been previously impregnated with a matrix resin for use in structural composite fabrication processes. 

Krolewski, S. and Gutowski, T. (1986), Effect of the automation of advanced composite fabrication process on part cost , Sampe Quarterly, 18(1), 43-51. 

Composite fabrication processes and equipment that incorporate reinforcement impregnation as part of the process, just before the raw material die entry or mold contact... 

The composite fabrication process begins once the trees have been processed into a dried furnish and the furnish is transported to a device such as rotating drum (as is the case for flakes, particles, and fibers). Here, the adhesive and other... 

Figure 2. Unidirectional silk fiber reinforced composite fabrication process.

The composite fabrication process inherently produces microresidual stresses at the interface. Both experimental and analytical methods have been advanced to investigate the microresidual stress state at the interface and to obtain an estimate of its effects on available interfacial bond strength. 

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