The external curing method is usually adopted as the traditional molding process of thermoset fiber composite shell, which places the wound shell into the thermal compression reactor or the oven to cure. This kind of process greatly limits the molding efficiency because winding and curing proceed respectively and separately. The internal curing can be adopted because of the hollow structure of the cylinder-shaped shell, which heats the mandrel with high pressure steam to realize the in-situ curing of the wound shell. This paper researches the new fiber composite molding process named heated mandrel winding. Not only does the heated mandrel winding inherit the advantages of internal curing process, it also greatly improves molding efficiency and quality. This paper introduces the process principle of heated mandrel winding and uses the finite element analysis software FLUENT to carry out the numerical simulation of steam flow and heat transfer during the mandrel heating process, and the simulation results are verified by experiment. According to the simulation results, the distribution and changing course of the flow field and temperature field of the system are obtained, and the relationships between the physical quantities including pressure, temperature and velocity and the parameters of the steam control and channel structure are analyzed.

Multicoil inside solidification combined winding machine, which can wind, solidify inside and extract high-pressure glass reinforced plastic (GRP) tubes, combines three conventional working procedures. The machine tool has four spindles of two groups working coordinately, improving machining efficiency greatly. This paper presents the realization of its control system, including the hardware and software architecture of the winding, inside solidification and extraction subsystems, and the mutual communication among them. Several key technologies such as the realization of openness, multicoil winding for heavy caliber tubes and remote control are also introduced.

Multi-axis winding machine can realize automatic winding of composite elbow, but its mechanical structure and control system is complex, which restricts its industrial application. In this paper, two-axis FRP elbow winding machine applied teaching and playback method is designed, which accomplish the winding of elbow by controlling the rotation motion of the mandrel and the reciprocating motion of the carriage along a semicircular track. In teaching mode, the positions of spindle and carriage are collected and stored as teaching document when the spindle rotates a certain angle, while in playback mode the control method of electronic cam is applied to realize the playback winding. The mechanical structure and the working principle of elbow winding machine are introduced, and the control system of winding machine is analyzed. It is proved that the system is stable, and it can wind certain type of composite elbows.

At present, only the temperature of external surface of the filament wound composite and the core mode can be detected in the curing process which is developed by experiencing many times, and the change of the internal parameters is not available. Based on the glass fiber pipe production line as the experimental platform, the paper suggests that the fiber grating sensors be embedded fiber composite materials at different levels when winding and the multipoint detection be performed in the internal curing process. The comparison analysis of the plotted curves for data collected from different points shows that the method is reliable to improve production efficiency and promote the automation of intelligent control.

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