*Article* **Agustín de Betancourt's Double-Acting Steam Engine: Analysis through Computer-Aided Engineering**

**José Ignacio Rojas-Sola 1,\* and Eduardo De la Morena-De la Fuente <sup>2</sup>**


Received: 2 October 2018; Accepted: 16 November 2018; Published: 20 November 2018

**Abstract:** This article analyses the double-acting steam engine designed by Agustín de Betancourt in 1789 and based on the steam engine of James Watt. Its novelty and scientific interest lies in the fact that from the point of view of industrial archaeology and the study of technical historical heritage there is no worldwide study on this invention, which marked a historic milestone in the design of the steam engines of the Industrial Revolution (1760–1840). This underscores the utility and originality of this research. To this end, a study of computer-aided engineering (CAE) was carried out using the parametric software Autodesk Inventor Professional, consisting of a static analysis using the finite-element method of the 3D CAD model of the invention under real operating conditions. The results have shown that the double-acting steam engine was correctly designed considering that the values of the maximum von Mises stress (188.4 MPa) obtained were taken away from the elastic limit of the material it was made of (cast iron), as well as to the maximum deformations (0.14% with respect to its length) obtained in the same element that presents the maximum stress (opening axle of the high pressure steam valve). Similarly, the maximum displacements (18.74 mm) are located in the mobile counterweights that transmit certain inertia to facilitate the opening and closing of the valves. Finally, if we look at the results of the safety coefficient, whose lowest value was 4.02, we could say that the invention was oversized, following constructive criteria of the time, as there were no resistance tests on materials that would help in the optimization of the design of the invention.

**Keywords:** Agustín de Betancourt; double-acting steam engine; Autodesk Inventor Professional; computer-aided engineering; mechanical engineering; finite-element analysis; von Mises stresses; displacements; equivalent deformations; safety coefficient
