Sandwich Design of a Platform Lift Floor

Sammanfattning: Mobility is a symbol of dignity. A platform lift enables everyone of different physical abilities to move vertically with ease. Currently, the platform lift by Aritco Lift is made of steel sheet metal. It is heavy, thus difficult to handle. Sandwich design is researched to see whether and, if possible,how much dead load reduction. A simulation model is produced in SolidWorks to facilitate the material selection and the sandwich design. Sandwiches of aluminium face sheets are investigated, although steel face sheet works as well. No recommendation on core material can be made. Connection methods are investigated in SolidWorks to join the 35mm-thick sandwich-based floor to the lift body without creating a large deflection. Several general directions are investigated. None yielded results sufficiently satisfactory, although two directions have provided results that are very close to the requirements. Simulations are conducted on a 40mm-thick sandwich using one of the optimal joint options, yielding better weight savings and deflection results. Certain honeycomb properties are approximated using formulae rather than measured or simulated directly. To quantify how significant is the deviation of the approximated model, simulations are conducted by changing the length, width, and height of the sandwiches modelled using both the approximation and exact geometry. Fatigue life analyses are conducted on two of the candidate floors. Both are comfortably within the limit imposed by the standards. The success of a design in this thesis hinged on the validity of the honeycomb model. The test results reject the honeycomb model as the deflection is significantly higher than simulated. Plastic deformation has also occurred, though more probably due to the deformation local at the weld. Even though honeycomb is demonstrated not to be able to meet the requirements on its own, sandwich as a category of structure should not be discounted as a whole. Environmental factor is a drawback for using large quantities of aluminium even considering the weight difference between the design and the original steel structure.