Alternative Approach for the Simulation of Handling Processes for Large Textile Cuttings Used for High Volume Composite Production
High performance composites become an important material for lightweight design and sustainable applications with the main driver automotive, aircraft and wind energy. As a result of the increasing number of units and the demand for consistent quality in connection with falling costs, the industrialization of the composite manufacturing is absolutely necessary. In respect to the complexity of the production steps, serial production of high performance structural composites is still a challenge. The market is dominated by the requirements of aircraft and automotive production because of the high numbers. In contrast rotor blade manufacturing has its unique challenges of high mass throughput. A 65m blade with 20 tons is produced within 48hours. A main challenge in the manufacturing of these three different applications is the handling and lay-up of textile blanks in a mold. The textile blanks, mainly basing on non-crimp fabrics, show high sensitivity against mechanical loads. Though manual handling of large cuttings or high numbers of cuttings in short cycle times will provoke failures in the lay-up. Lay-up failures in a composite structure will reduce mechanical properties significant. In recent years there have been developed many different solutions for mechanization or automation of this process. These solutions are aimed primarily at high quality through careful handling technologies, but less with the goal of high productivity. Fraunhofer IWES has investigated the process of textile handling especially for typical wind turbine rotor blades and is developing processes to new industrialized production concepts. The aim is reducing blade manufacturing costs and reaching higher level of quality at once. Fraunhofer IWES develops methods to achieve cost-effective and high volume production. A rotor blade consists of different substructures, preforming of the dry textiles blanks for this substructures has a huge impact on the productivity and main mold occupation time. Additional the high risk of occuring failures in main textile structures can be monitored or avoided more easily. The development and the planning of this preform process as the design of handling equipment is complex due to the highly non-linear and extremely varying properties of these textiles. An integrated simulation tool developed by IWES basing on a standardized FE-Model in addition to a superposition approach for stretch and bending effects will ease the design of handling equipment and process. In comparison to many other approaches, only a few and easily measureable characteristic mechanical properties are required for this. This model is very practical in terms of both handling and simulation.
Author: Christian Dörsch, Oliver Bagemiel, Pavan Josyula, and Tummala Harsha
Conference: SAMPE Seattle 2017