ADDITIVE MANUFACTURING FOR A LOW-COST BIAXIAL TESTING MACHINE

In the last years a lot of effort has been devoted to the understanding of the mechanical behavior of biological tissues, and, in particular, of vascular vessel walls. Nowadays, in fact, the triggering mechanism of pathological lesions (such as aneurysms, dissections, etc..) and, above all, the disease evolution till rupture are still not clear. In this field, the mechanical characterization of pathological specimens can play a crucial role, providing information that, combined with histologic, genetic, and imaging data, can lead to predictive models of disease evolution and rupture. In this context, only planar biaxial testing allows for a two-dimensional stress-state that can be used to fully characterize their (anisotropic) mechanical properties. Biaxial testing machines are usually tailored on a specific class of materials since it is usually complex to adapt the machine and its equipment (i.e., load cells, grips, actuators) to test a large variety of materials. Moreover, the biaxial machines available on the market are quite expansive, with a price in the order of hundred thousand euros. In the present paper, we illustrate the design steps for building a low-cost biaxial testing machine exploiting additive manufacturing. In particular, different design steps are described: from machine concept, to CAD design and additive manufacturing with FDM technology. The machine frame will be also equipped with actuators and properly calibrated sensors. A camera will be positioned over the testing region to capture sample deformation