Starting with the last century, a lot of enthusiastic researchers have invested significant time and energy in proposing various drives capable to generate linear propulsion force. Regrettably, only a few of these devices passed the patent phase and have been practically materialized. The aim of this paper was to simulate the dynamic behavior of an inertial propulsion drive (IPD) developed by the authors, to demonstrate its functionality. The core of the IPD consists of two symmetric drivers that each performs rotation of eight steel balls on an eccentric path. We propose three solutions for the element which maintain the off-center trajectory of the balls. For the simulation, we used the multibody system approach and determine the evolution of the displacement, velocity, and power consumption. Further, we analyze the collisions between the elements of the system and the influence of this phenomenon on the dynamic behavior of the IPD. We found that collisions generate impact forces which affect the ball acceleration values achieved by simulation. We have concluded that the developed system is capable to generate linear movement. In addition, in terms of velocity and power consumption, the best constructive version of the retaining disk is that which has a cylindrical inner bore placed eccentric relative to the rotation center of the balls.

The Reverse Engineering is a reliable technique to convert a real geometry of a part into 3D computer file. One reason for scanning a part may be the lack of the drawings to manufacture a new one that will replace the old part. The paper illustrates the Reverse Engineering of a Francis runner geometry with a diameter of 1160 mm and 19 blades, which, after 50 years of operation, has pronounced wear marks, high porosity surfaces and cracked areas. The geometry will be scanned through Photogrammetry technique and processed with the following software packages: Agisoft Photoscan and Geomagic Design X (formerly Rapidform XOR); finally, the solid geometry and the drawing of the runner were generating using the SolidWorks software.

The paper presents ample researches on cavitation erosion of two charges of stainless steel type X3CrNi13-4 on a cavitation stand, through the stationary specimen method. The results of the experimental trials are highlighted in tables and in graphics regarding the reproduction of mass losses and the cavitation erosion rate according to time. The images of the microstructures before the cavitation test and the macrostructures after the cavitation test of the two charges of stainless steel type X3CrNi13-4 are also presented in this paper.

The paper illustrates the reverse engineering process of a blade, from a Kaplan runner with a diameter of 5400 mm, using the following software packages: Agisoft Photoscan and Geomagic Design X (formerly Rapidform XOR); the next step was to generate the solid geometry of the blade using the SolidWorks software. The last step was to compare, using GOM Inspect software, the geometry of the designed blade with the corresponding geometry obtained using Photogrammetry and finally answer the question if this technique can be used in the mechanical field to get a precise 3D reconstruction of large objects with complex geometries.

The paper presents the cavitation stand used, the work methodology, the trials realized on specimens of gray cast irons, with flake graphite and spheroidal-graphite, which were tested for cavitation erosion during different periods of time of the cavitation attack. Finally, the conclusions were interpreted on the basis of comparative graphics realized at the macro and microstructures level obtained for these two types of cast iron. Of the two types of gray cast iron, the nodular cast iron presents a better cavitation erosion resistance.