Research On The Mechanism Of Fiber Placement On Conical Mandrel And Computer Simulation

Due to epoxy composite's high specific strength and stiffness, high specific modulus, excellent fatigue and resistance to corrosion, they were successfully introduced and now widely used for military industry, aerospace, chemical industry, etc.Fiber reinforcement plastics have some other exceptional performance except for above, for example the higher reliability and efficiency, the lower cost for material. Despite this and other advantages, a number of problems or limitations are presented by current filament winding techniques. For example, in the formation of coniform shaped objects, the continuous fibers traverse the tool longitudinally from end to end to form the individual layers of the wall of the part. This produces a buildup of fibers at the small end of the part, which wastes fiber material at the small end of the part if it is not needed there. Another problem is fibers will span the concave surface. This is because no means are provided to press or compact the fibers directly into the concave area. The lack of direct compaction pressure also creates new problems in the winding of box-shaped parts. The fibers are laid down on the flat sides of the box with little or no compaction whereas the corners of the box are highly compacted. The box-shaped part is thus unevenly compacted by filament winding machines, and has a thinner wall thickness around the corners than the sides.These problem or limitations in filament winding techniques make people invent the placements techniques. Placement techniques is place the fibers or tape on the surface of tool in accordance with some regulations, through directly compaction pressure provided by compaction roller or shoe. Generally, the placement head has apparatus for individually cutting and restarting one or more of the tows. The ability to selectively cut or restart individual tows within the fiber band, can not only lay down the tows in an arcuate path, but save a lot of material.The paper designed a fiber placement machine for coniform shaped objects. It include 8 movement axis. There are 6 in the machine(3 linear axis and 3 rotatable axis) and the other 2 axis in the placement head. All 8-axis movements are CNC. Therefore, the placement machine can control placement head to place fiber in any position. There is a set of cut/restart mechanism in the placement head. It can place 4 tows on the coniform shaped model at the same time, and individually cut and restart one or more of the tows. Also, the fiber tows are heated in placement head.Additionally, it study the basical placement regulations for coniform shaped objects, and design a simulation program to simulate the course of placement to verify those regulations.