M.Sc Thesis

M.Sc StudentRalbag Gilad
SubjectDesign Guidelines for Rapid Prototyping Wind Tunnel Models
DepartmentDepartment of Mechanical Engineering
Supervisor DR. Ehud Kroll
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Rapid manufacturing technology is a common name for many methods that are available today for three-dimensional model printing directly from a computer file. The first rapid manufacturing technology has been around since the late 80's . There are several methods of three-dimensional plastic model printing. In order to print the model we used Eden printers from Objet Company. There are many advantages in producing a wind tunnel model with rapid manufacturing technology. The first benefits are time and cost. The time it takes to print three dimensional models and the cost are a tenth of the time and cost of conventional production. These advantages also allow short-time and low-budget projects to make a wind tunnel experiment. The time and cost advantages also provide flexible execution model design changes even while a series of experiments is in the tunnel. Another advantage is weight lower weight wind tunnel model allows use of a more sensitive balance which will enable better results. In addition, lower weight means higher frequency self-mode, allowing higher angle of attack without structural vibration.

During the wind tunnel test, aerodynamic forces act on the model. The three-dimensional rapid manufacturing parts have inferior mechanical properties than metals. In order to strengthen the printed structure it is necessary to combine pieces of metals. We found that the best wing reinforcement was obtained by adding a steel beam which is threaded throughout the wing.

In order to do a low-speed wind tunnel comparative experiment, we took a metal model of an industrial gliding bomb. We performed design for printed wings reinforced with steel plates. In order to evaluate the stress and deformation of the wing, we performed finite element analysis on the reinforced wing. The tunnel comparative experiment was carried out with the metal model and the same metal model body with reinforced plastic wings. A comparison of the experimental results shows that the printed wing with appropriate reinforcement can generate correct and valuable information.

The last chapter contains the design guidelines for rapid prototyping wind tunnel models. This chapter details a set of principles and recommendations from the general design of printed parts, continues to structure of wind tunnel reinforced model, making the necessary connections, and finishes with the model finite element analysis.