During the manufacture of polymer-matrix composite components the cure degree must be uniform to have a good quality of the product. For thick composite components this condition is not often respected in fact the cure degree trend between the core and the external surface is different causing structural and geometrical/dimensional unconformities. In most cases, these problems are caused by a wrong design of cure process in terms of thermal cycle and tooling, therefore the cure cycle must be designed and optimized. The optimization of cure thermal cycle should include several performance criteria for the production system such as the targeted cure degree, the targeted maximum temperature of the part and the duration of the cure cycle as well as the production system limitations such as the maximum allowable heating rate, the maximum allowable cooling rate etc. This work aims to define by thermochemical phenomena a first step toward the definition of a method to optimize the cure degree of a thick composite components by focusing particular attention to the aspects of thermal degradations and residual stress.

Until today, there are only automated processes able to manufacture composite components with a constant thickness. This work focuses on the need to find a system able to manufacture composite structural parts characterized by a variable thickness. An innovative tape placement robotic cell composed of a deposition integrated system and an anthropomorphic robot with 6DOF is shown in this work. The main characteristics of the designed deposition integrated system are (i) alternate deposition movement, (ii) tape compaction system, and (iii) tape tension control system by proportional-integral-derivative (PID) controllers. With these systems, it is possible to obtain a high flexibility robotic cell that allows to manufacture variable thickness components with good mechanical volumetric properties. After the design phase, the system has been realized and afterwards it has been validated by analyzing the experimental tests with the quality of some benchmark manufactured by the innovative cell.

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Filament-wound pressure vessels represent the proper choice to obtain good mechanical properties and lightweight. The pressure vessel geometry is generally cylindrical and the wall is composed of a 'liner' and a 'shell.' The liner holds the gas and guards the shell from chemical attacks. The filament-wound shell aims to withstand the hydrostatic load of pressure gas. The shell design has to be defined in observance of both fibers stratification methodology and design structural criteria. For years, pressure vessel design primarily focused on mass; space saving features during pressure vessel design was usually a secondary concern unless specifically required by the customer. Now, more emphasis have being assigned to design light weight pressure vessels that also maximizes use of available space for industry finding such as space on a spacecraft, as well as mass, is at premium. For this reason, it is very important to optimize together the index of performance and packaging of gas storage system. This work aims to develop a parametric method to optimize the index of performance as a function of one or more pressure vessels; in this way, it is possible to optimize also the packaging of the gas storage system.