Thermoplastic composites consolidation

It is clear from the description of the commonly used fabrication techniques that thermoplastic composite consolidation is a nonisothermal manufacturing process that involves continuous heating, compacting, and solidification. The major mechanisms,... 

The final step of thermoplastic composite consolidation is to cool and solidify the consolidated parts. It is well known that the physical and mechanical properties of composites are determined by the microstructure of the matrix in addition to the reinforcement, whereas the morphology of the thermoplastics is determined by its thermal history [14-17]. 

The mechanism by which a thermoplastic matrix composite consolidates to form a laminate was attributed to autohesive bond formation between plies [13,18]. Autohesion, however, can... 

In the preceding section, a brief review of efforts to model the intimate contact process during consolidation of thermoplastic composites was given. Models based on the original work of... 

The degree of bonding analysis has been verified for both compression molding and online consolidation of thermoplastic composites. In these studies, composite test specimens were consolidated under controlled processing conditions. The most common types of tests performed to measure the interply bond strength were the interlaminar (short beam) shear test [21,25] or the lap shear test [12,21,26]. 

The process by which a thermoplastic matrix composite consolidates to form a laminated structure has been attributed to autohesive bond formation at the ply interfaces. Autohesive bond formation is controlled by two mechanisms (1) intimate contact at the ply interfaces, and (2) diffusion of the polymer chains across the interface (healing). The rate of autohesive bond formation and hence the speed of the composite consolidation process is directly related to the temperature-pressure-time processing cycle. 

Liu, K.S., Ph.D. Thesis, A Mathematical Model for In-Situ Consolidation of Thermoplastic Composites, (1995) Stanford University, Stanford, CA... 

Flow charts with relevant inputs and outputs for each submodel are shown in Figures 13.7 and 13.8 for winding of thermosetting and thermoplastic composite cylinders, respectively. The primary differences between process models for thermosetting and thermoplastic cylinders arise in (1) the method of heating, and (2) the mechanics of consolidation/ fiber motion. 

Agarawal, V. The Role of Molecular Mobility in the Consolidation and Bonding of Thermoplastic Composite Materials (1991) Center for Composite Materials, University of Delaware, Newark, Delaware... 

L Ye, V KlinkmuUer, K Friedrich. Impregnation and consolidation in composites made of GF/PP powder impregnated bundles. J Thermoplastic Composite Materials 5 32-48, 1992. 

This process has been developed specifically for thermoplastic composite plate materials. But it is also well suited for commingled fabrics, especially when they are pre-consolidated by the use of a double belt press into continuous organic sheets [8]. Further details about the thermoforming procedure are described in the chapter Thermoforming of fiber reinforced composite sheets. 

Flat laminates can be produced using the processes described in other chapters of this handbook. For example, a double belt press or compression moulding can produce the precursor laminate. Figure 5.3a shows thermoplastic composites with unidirectional fibres in each layer consolidated into a laminate with a picture frame mould. A picture frame mould goes into a hot press or autoclave and turns composite lamina into a fused precursor. To some extent, sheet forming adds cost to a final structure because a manufacturer creates two components the flat precursor and the formed structure. 

Detailed information about the thermal transport and consolidation in thermoplastic composites appears in Raju Dave and Alfred Loos Processing of composites published by Hanser in 2000. 

Beyler, E. P. and Gii9eri, S. L, Experimental investigation of laser assisted thermoplastic tape consolidation . Journal of Thermoplastic Composite Materials, 1988,1, 107. 

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