Agile Product Testing with Constrained Prototypes

The means to acquire reliable functional information is a critical factor that differentiates product development time and cost. Thanks to advances in solid freeform fabrication techniques, industries can produce geometrically complex parts within dramatically reduced time and cost. Even though industries can save significant efforts by performing functional tests rapid prototypes, they still prefer full-scale product tests, especially in later design phases, due to inherent limitations in traditional similarity methods (TSM). This paper describes a new method to perform reliable functional tests with rapid prototypes that cannot be properly handled by the TSM.Mechanical Engineerin

Empirical Similitude Method for the Functional Test with Rapid Prototypes

Rapid prototyping has the potential to improve the performance of the design process both in cycle time and resources. Such improvements may be realized through the timely visual, ergonomic, and functional information provided by solid freeform fabrication (SFF) parts. Of these information classes, functional information is perhaps the least realized with current technology. A number of technical issues have limited functional testing of SFF parts, including sensor fusion, range of prototyping materials, part size etc. Our focus here concerns the material issues of functional testing, especially the potential differences in prototyping material choices to actual production materials. For example, to derive accurate functional information of non-polymeric products from polymeric rapid prototypes, an improved similitude method that can overcome the distortion of material characteristics is necessary. In this paper, a new similitude method that utilizes specimen test data is introduced. This method develops a mathematical transformation between prototype and product behavior through specimen testing. This transformation replaces the role ofthe scale factor of the traditional similitude method, and provides a basis for relating prototypes to proposed production parts, even under dependent loading and material conditions. Computational and experimental results of a structural design provide verification ofthe new method.Mechanical Engineerin