Fundamental Research On Path Generation Algorithm Of Composite Components In Automatic Fiber Placement

With the development of aviation industry, one of the certain trends is the extensive use ofcomposite materials on aircraft, and the automatic fiber placement (AFP) is one of the determinationsto acechieve this transition. In developed countries, many large components are manufactured on AFPmachines, and the correlative technology is in the initial stage in China. The fundamental elements ofAFP are CAD/CAM technology, material and processing equipment. And as the importanttechmology in CAD/CAM, predetermined path planning and design is deeply researched in thisthesis.Basd on differential geometry theory and vector algebra, the mathematic models and path equationsare induced under various placement conditions. So path trajectory is solved by iterative calculation ofordinary differential equations, and the rule of path generation and varity is revealed at the same time.Achievements on this thesis are described as follows.[1] The constraint is analzed among fiber placement rules, surface shape and path planning.First, the general principle of composite structure design is analyzed. Then thegeometric change of mould surface with continuous multi-layer placement is studied,and the curvature extremum is proposed first time correspond to fiber placement rules.Finally, mathematical expression method is studied and determined for mould surfaceand path trajectory.[2] Based on preliminary work, the initial path generation methods are developed. Aim tovarious typical components, several methods are proposed such as section, intersectionof straight line and surface, line projection, fitting and mapping, and so on. Everyalgorithm is verfied with experiment.[3] It is researched that the path trajectories are continuously offset and covered on mouldsurface. The exact and approximate path offset methods are both proposed for differentplacement conditions. And another different equidistant path generation method isproposed for explicit stress distribution. In addition, path extension on surfaceboundary and path filling on fiber gap are solved with uniform treatments.[4] The path generation method for multi-layer fiber placement is developped andextended. Since the finished components are manufactured by multi-layer fiberplacement, the path algorithm ought to comprise offset surfaces. First, curves on theoffset surfaces are analyzed, then the corresponding algorithms of initial path andoffset path generation for multi-layer placement are developped according to thelaminated plate.[5] Algorithms are applied to several typical components. The various simulations areproposed to verify the path generation algorithms.