DESIGN CHALLENGE – FLOATING STRUCTURES
The KOers design challenge is an activity were students are not only challenged by designing a structure, but also challenged by building and testing their design. The exercise was to build a floating structure that could span 5 meters. The total width of the structure was limited to 1.2 meter. Each end of the structure floated in a swimming pool. At midspan space had to be created for the application of a load. The materials each group had at their disposal were: timber purlins 28 x 28 square millimeters; nylon rope; screw eyes; turnbuckles; and tie-wraps. The main criterion the groups were judged on was the stiffness of the structure. Subsequently, the jury judged each group on the level of innovation and effective use of materials. Before the event started only the theme was released by the organization. All participants got the description of the challenge at the start of this one day event.
Considering the boundary conditions and the location of the applied load we came up with the idea to design a triangular shaped structure. With this shape the elements are only loaded in tension or compression. In contrary to bending active elements this results in increase of the stiffness of the structure. We used rope for the structural elements that were loaded in tension to reduce the weight of the structure. We optimized the four structural elements that were loaded in compression by designing this elements as polygons. Due to this shape we increased the buckling resistance of these elements. The jury judged our structure best on both ‘level of innovation’ and ‘effective use of material’.