Modellierung des Fügewickelprozesses zur Herstellung von leichten Fachwerkstrukturen
Creators: name: Dackweiler, Marius
Publisher: name: Karlsruhe
Year: 2020
Subjects: Leichtbau
Faserwickeln
Modellierung
Fachwerk
Faserverbund

description: Changing ecological awareness and legal conditions lead to an increased use of light- weight components made of fibre composites in industrial applications. Therefore, this thesis focuses on a novel process for joining profiles made of such composite materials. First, fundamental investigations on the process with a winding ring, guided by a vertical articulated robot, were conducted in (Schädel 2014). Based on this study, the aim of this thesis is to model the wound joint and its associated kinematics to increase the flexibility and reproducibility of the process. According to the state of the art, winding for joining hollow profiles differs from existing joining techniques due to its high lightweight potential and design freedom. To fully uti- lize this potential, however, a complete modeling of winding paths as well as the move- ments in the process is necessary. Approaches for this have already been presented, though they mainly refer to the fiber winding with a rotating mandrel and to simple, rotationally symmetrical geometries. In order to compensate the existing deficits and to achieve the goal of modeling the joining process, a modular approach is presented. This consists of single modules for modelling the windings, the methodology for the simulation of mechanical load capacity, the kinematic modelling as well as model validation. First, the variables relevant for the model are identified, with the variance of winding patterns determined by manual wind- ing tests. The friction of the fibers when deposited on the profile surface is investigated as it is an important parameter in the modelling process. Modelling the winding paths requires first a mathematical description of the surfaces for both profiles. On this basis, the winding paths on the longitudinal profile are generated using a stepwise algorithm for non-geodetic curves. These curves are continued tangentially in the transition area between both profiles and modelled on the longitudinal profile using a cubic function. An iterative algorithm optimizes the curve with respect to the maximum slip angle in order to avoid fiber slippage. In addition, the methodology developed for the structure of a FEM simulation allows qualitative statements with material parameters to be deter- mined in the future about the load-bearing capacity of the joint. Modeling the move- ments during the process is based on the geometries of the robot and winding ring. Together with the points of the modelled winding pattern and the geometry parameters of the profiles, the individual joint positions and the rotor position of the winding ring can be determined for each step using inverse kinematics. An iterative algorithm for collision avoidance of the winding ring with the profiles is applied in each calculation step. The winding unit is redesigned and assembled in a prototype with a new drive and bearing concept for the rotor and a self-regulating roving pre-tensioning module. The control commands required for the movements are automatically derived from existing models. Model validation is carried out by experimental winding tests with different pro- files (DoE). The joints are evaluated by a comparison of the position of the individual windings and the nominal positions from the modelling.