CompositesWorld
Issue link: https://cw.epubxp.com/i/742140
NOVEMBER 2016 46 CompositesWorld FOCUS ON DESIGN the simulation engineering firm contracted by TRI-UHN to develop the DriverLab's tech- nical specifications. ose requirements drove PEI to design the dome in a toroidal shape, with an upper cap (see drawing, p. 45) to allow sufficient surface area for the multiple projec- tion scenarios. Laminate finish requirements were strict in terms of smoothness to ensure quality of the projected graphics on the composite surface (Fig. 3, p. 47, above right), so manufacturability and tool quality needed careful consideration during the design phase. Lastly, driving simulations would include water sprayed onto the car inside the dome to simulate rain, so the floor element had to be designed to capture and drain the water. Keeping weight and costs low e dome structure's FE model was created using Femap software for pre- and post-processing, together with NX Nastran (both supplied by Siemens PLM Software, Plano, TX, US). e modeling software enabled static, quasi-static and modal (natural frequency) analyses, and determination of maximum dynamic loads and stresses due to the motion platform and lifting scenarios, so that design factors of safety could be applied. e software's buckling eigenvalue solution module and classical engineering equations helped PEI ensure buckling factors of safety were met, says DiEdwardo, and ultimately resulted in the dome's laminate architecture, which would consist of cored fiber- glass sandwich segments bolted together with metallic fasteners. "Our solution to get the strength and stiffness that we needed was to construct the segments with [out-]turned flanges bolted together, to act as stiffening structure and provide a smooth inner surface," explains DiEdwardo. "e thick, uncored flanges are very effective in providing an efficient load path for inertial loads from the projectors, and from the motion-control platform, and allowed us to keep the cored field regions of the dome and cap very light in weight, while keeping construction simple." He adds that flanges were reinforced with aluminum brackets where they connected to the floor frame and to the projector mount in the dome cap. Trade studies were conducted to optimize the FRP laminate thickness and number of skin plies, ply orientations, and core density and thickness for the segments. e trade studies also helped optimize the metal floor frame-member sections for strength and stiffness, as well as ease of shipping and installation. e final design of the frame comprised three sections that bolt together. Fig. 2 Emphasis on frequent portability The dome is "swappable" with other simulator payloads, so it must not only be lightweight but also able to withstand lifting stresses when moved, via CEAL's overhead lift (pictured here) onto or off of the common hydraulic motion platform. Read this article online | short.compositesworld.com/DrvierLab