Shape optimization of high-energy absorbers

In this paper, a new approach to simulate and to optimize the performances of a crash-box, in terms of energy absorption or acceleration peak, is presented. As soon as the maximum size of the crash-box (longitudinal and transversal dimensions) has been fixed, the new approach allows optimizing the shape of the transversal section and the thickness of the structure. Thanks to the proposed procedure, engineers can easily identify the best crash-box depending on the particular working conditions. The new method has been tested with different cases study by considering different objective functions. The obtained results show the procedure works well and also demonstrate that the optimal number …

Study of the performances of a fluidynamic actuator

Aim of this paper is presented a new methodology to study how different geometric parameters affect the performance of a hydraulic actuator. Preliminarily, the real working conditions of a hydraulic machine have been simulated by means of a CFD module. After, to test the reliability of the simulations, the obtained numerical results have been compared with the experimental data of a real prototype. This comparison demonstrates a good level of agreement between numerical and experimental results. Different simulations have been setup by modifying the actuator geometry and evaluating the efficiency of every analysed configuration. The results of this study give useful guidelines for the choic…

Behaviour of a speargun with a novel muzzle

The paper presents the results of a numerical and experimental investigation performed on a barrel of a speargun equipped with two kinds of muzzle. In particular, a standard muzzle for speargun (having an elastic propulsion) has been compared with an innovative one called ‘roller’. This new muzzle is equipped with two rollers and special bands. The rubber bands, fixed at the lower side of the barrel, run through the rollers and are engaged in suitable seats of the shaft. These bands are, therefore, longer than the traditional ones and, consequently, with equal force applied by the diver, the roller speargun has a longer range. Thanks to the particular geometry of the new muzzle, one of the …

Methodical redesign of a semitrailer