An Advanced Method to Correlate Scale Models With Distorted Configurations

Functional testing of prototypes is a critical step in the development of many of today’s products. Results of functional tests allow for verification of proper performance before a product is introduced into the market. The advent of rapid prototyping technologies offers engineers the potential to dramatically reduce the prototype-test-verify cycle and get products to market quickly. However, dimensional and material property limitations of rapid prototypes often prevent them from being used for functional testing without the use of similitude methods to correlate measured prototype behavior with predicted product behavior. The traditional similarity method (TSM), which is based on the Buckingham Π theorem, requires that the dimensionless parameters of the prototype and product systems be identical in order to correlate their states and accurately predict product performance. The requirement of identical dimensionless parameters which is inherent in the TSM is often impossible to realize with the limited properties available from rapid prototyping technologies. In order to overcome this limitation, an empirical similarity method (ESM) has been developed. The general concept of the ESM is introduced along with an implementation procedure. Numerical and experimental examples are presented which demonstrate the feasibility and industrial impact of the ESM in the context of product design.