This project is for Princeton's Mechanical and Aerospace Engineering Engineering Design class (MAE 321). This is a two-part project to design, simulate, and build a wingbox and rotation mechanism. The first part of the project is to develop and test the wingbox alone. The wingbox must weigh less than 3lbs and must support a load of at minimum 220lbs. Once this milestone is accomplished, a mechanized joint between the wingbox and the test rig must be developed to rotate the wingbox 20°, lock it in place, and lift 130lbs. This design accomplished all the requirements on first attempts without permanent deformation or signs of weakening. The design was not tested to failure.
CAD
The entire design workflow of this project was carried out using PTC CREO 3.0. The wingbox was designed and simulated using PTC CREO's shell functionality and was then converted to a solid model. The rotation mechanism was also designed and developed in PTC CREO. The simulation analyses on the wingbox focused on buckling analyses to ensure the structural soundness of the design. The simulation incorporated complex finite element analyses aspects such as fasteners. The visual simulation toolbox in PTC CREO greatly helped develop and troubleshoot the locking mechanism. All parts were fabricated using technical drawings produced in PTC CREO and specific parts were machined using CNC mills and lathes, incorporating the PTC CREO manufacturing toolbox.
Simulations
The simulation aspect of this project proved to be the pivotal section of the design process. The initial wingbox design was modeled using a shell model, allowing for more efficient simulations in PTC CREO. PTC CREO's Finite Element Analysis toolbox was used for all simulations ranging from Von Mises stress analyses to buckling analyses. These simulations identified various problems throughout the design iterations and lead to the final design with the necessary bulkheads, ribs, and weight-saving cutouts. The simulations also calculated safety margins to evaluate the risk of the proposed design. The loading and deformation of the wingbox validated the simulation results.
Construction
All aspects of the crane design and construction were executed in Princeton University Mechanical and Aerospance Engineering Machine Shop. The wingbox was designed, built, and tested first. This included using tools such as the bandsaw, mills, and lathes. Given the lightweight nature and optimized design of the wingbox, the exact manufacturing was important to avoid any compromising weaknesses do to manufacturing defects. All components of the wingbox were riveted together to provide simple fasteners. The rotation mechanism was designed and built in a similar fashion, this time employing advanced tools such as CNCs for complex components. Again, due to the loads on the entire mechanism, tolerances were a critical aspect of the construction of the design.
