The teaching of structural stiffness is one of the keystones of the undergraduate curriculum in mechanics and the strength of materials. Standard linear theory, going back to Hooke's law, has proven to be very successful in predicting the performance of elastic structures under load. Many courses in basic mechanics have a conventional laboratory component often involving a universal testing machine and extensometer. However, the advent of 3D printing presents an appealing pedagogical opportunity mid-way between theory and a formal lab experience. The material contained in this paper focuses on using the 3D printing of relatively simple, flexible cantilever structures. The relatively high resolution of modern 3D printers facilitates the production of slender (elastically deformable) structures, and thus provides an opportunity to exploit geometric parametric variations to enhance a practical understanding of fundamental mechanics concepts such as stiffness. This approach has proved successful in initial inclusion in both the classroom via demonstration models, as well as in the lab in which elementary facilities can be utilized to acquire data. The boundary conditions associated with a cantilever, and the application of a point force are especially simple to produce in practice, and provide an effective tactile demonstration of the influence of geometrical changes on the relation between force and deflection, i.e., stiffness.

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