Research On The Optimization Design And Key Technologies Of Advanced Pultrusion System For Half Lenticular Tube

Composite lenticular tube is a kind of ultra-long thin-walled tubular spatial deployable structure, which is a hotspot recently and has extensive application prospects in the aerospace field. However, the traditional process is not suitable for the preparation of composite lenticular tube due to its ultra-long characteristic. Consequently, Advanced Pultrusion(ADP) technology, a cost-effective automated continuous molding method, has been applied to manufacture composite lenticular tube and the length of lenticular tube is not limited. On the background of automatic forming for composite lenticular tube, the study optimized the traditional ADP technology for half lenticular tube, moreover, the key technologies such as the uniformity of the molding pressure and curing process were investigated in detail.(1) Conducted the optimization design of ADP mechanical systems. Firstly, the guidelines on preforming technology were established, which required three steps to complete preformed curved surface configuration. Afterwards, pretreatment device was designed, the length of the pretreatment mold, the selection of pneumatic executive component, the heating mode and the loading way of solf/hrad mould combination was confirmed. And a traction-tension device design was proposed and on the basis of this, the traction-trimming device was further improved. Moreover, the scheme design of relevant control system was achieved, including the confirmation of action sequence of each unit in ADP system, the programming of PLC and the creation of a touch screen interface.(2) The effects of different shapes and thicknesses of silicone rubber on the contact pressure distribution during ADP processing for half lenticular tube were studied using finite element method, and the dispersion coefficient was used to evaluate the uniformity of the contact pressure. Results on the condition that the contact pressure of 1MPa, temperature of 156? indicated that the dispersion coefficient decreased initially and then increased with the increasing vertical thickness of offset surface silicone rubber or upright thickness of translated surface silicone rubber, which meant the uniformity of the contact pressure improved initially and declined afterwards. Moreover, the dispersion coefficient reached its minimum at 0.79% when the upright thickness of translated surface silicone rubber was 9mm, which implied that the contact pressure was the most uniform at this point.(3) Effect of silicon rubber material systems, molding temperature and molding pressure on the uniformity of molding pressure were investigated by finite element method using single factor experiment. The results showed that the equalizing pressure ability of silicone rubber improved with its decreasing hardness. Furthermore, the uniformity of molding pressure rose and then declined with increasing temperature and the uniformity of contact pressure tended to be improved with increasing applied pressure.(4) The curing process parameters of this prepreg resin system were obtained by DSC experiments. Optimal process was determined with three phases. Initially the prepreg was pretreated at 125? for 7.8min, then hot-pressed at 156? for 30 min and finally post-cured at 176? for 36 min. Eventually, the workpiece was tested according to related specification. The results showed that the curing degree, resin weight percent, crimp radius and surface quality were qualified for the specification.