Finite element model validation for a 14.5 mm armor piercing bullet impact on a multi-layered add-on armor plate

For armor plates testing and evaluation the use of modeling and simulation tools, together with a validated finite element model is a reliable approach in respect to a firing conducted session. The paper presents the validation of an advanced finite element model on the impact between two 14,5 mm armor piercing bullets with a multilayered add-on armor plate made by aluminum alloy, alumina tiles, aramid fabric woven, ultra-high molecular weight polyethylene fiber composite and a steel plate. An 8 mm thick armor steel witness plate was placed at 2 cm behind the add-on plate. The real tests were conducted in a firing range and a chronograph was used to measure the values of the bullet impact velocities. The test results showed that the first bullet penetrates the witness plate and the second bullet only deforms it. A three-dimensional finite element model of the bullet and armor plates was conceived to perform the impact simulations in LS-DYNA. Tensile and compression tests, as well as other scientific methods were employed to establish the strength and failure model parameters for each material. The results of the finite element model follow the experimental ones regarding the yaw angle assumptions that were applied for a simulation scenario

Determining the influence of dynamic balance in the technical training in football game at U13 level

Background and Study Aim. Technical training in football plays an important part in scoring goals. Precise movements can become the key to victory in a match. Among the principal factors determining the accuracy of shooting or kicking the ball is balance. The study aims to determine the influence of dynamic balance on technical training in U13 football. Material and Methods. A group of 26 football players from Otopeni Sports Club (Romania), aged 12-13 years, in the U13 category, participated in this study. Dynamic balance was assessed using the Sensamove MiniBoard platform with tests including: Lateral bipedal balance (LBB), Vertical bipedal balance (VBB), and Vertical unipedal balance for both right (VBRL) and left (VBLL) legs. Technical training was evaluated using tests recommended by the Romanian Football Federation: instep kick from 9 m (Test 1, points), outside kick in 30 sec. (Test 2, points), and 20 m long pass (Test 3, points). Pearson’s correlation coefficient was used to analyze the relationship between dynamic balance (lateral and vertical bipedal, and vertical unipedal for both legs) and technical training in U13 footballers. Results. The analysis of the comparative results between LBB and VBB variables reveals better performances by 9.2% at VBB. There are lower values of the vertical deviations mean by 2.9 degrees forward at LBB and by -2.8 degrees backward. The mean of lateral deviations is lower by -2.7 degrees to the left at VBB and by 3.3 degrees to the right. The comparative results between VBRL and VBLL variables show better performances by 0.3% at VBRL. The values of the vertical deviations mean are lower by 0.5 degrees forward at VBRL and 0.3 degrees backward. The mean of the lateral deviations (left-right) have equal values. Analyzing the performances obtained in technical tests highlights 22.2% (estimated maximum score) at instep kick, 62.5% (individual maximum value) at outside kick and 34.5% (estimated maximum value) at 20 m long pass. The influence of dynamic balance on technical training shows 60.7% positive connections and 39.3% negative ones between LBB and VBB variables. As for VBRL and VBLL variables, there are 67.9% positive connections and 32.1% negative connections between them. Conclusions. The weighting of values at performance and maintaining in space was highlighted. The mean of front-back and left-right deviations in bipedal and unipedal balance has lower values. The technical performances obtained were compared with the estimated maximum score and the individual maximum value. An increased number of positive connections to balance performance variables and of negative connections to the mean of deviations was noticed. This fact contributed to determining the degree of influence on the investigated variables. The findings can serve as a recommendation for future research

DETAILS OF OPERATIONS PERFORMED BY THE REMOTE CONTROL ROBOT (CONCEPT) TO THE HORIZONTAL FUEL CHANNEL DURING DECOMMISSIONING PHASE OF NUCLEAR REACTOR CALANDRIA STRUCTURE. PART I: OUTSIDE OPERATIONS

The authors contribution to this paper is to present a concept solution of a remote control robot (RCR) used for the horizontal fuel channels pressure tube decommissioning in the CANDU nuclear reactor. The authors highlight in this paper, few details of geometry, operations, constraints by kinematics and dynamics of the robot movement outside of the reactor fuel channel. Outside operations performed has as the main steps of dismantling process the followings: positioning front of Calandria structure at the fuel channel to be decommissioned, coupling and locking to the End Fitting (EF), sorting and storage extracted items in the safe container. All steps are performed in automatic mode. The remote control robot (RCR) represents a safety system controlled by sensors and has the capability to analyze any error registered and decide next activities or abort the outside decommissioning procedure in case of any risk rise in order to ensure the environmental and workers protection

Some aspects of cycle variability at the Diesel engine fuelled with animal fats

The progressive diminution of the oil reserves all over the world highlights the necessity of using alternative fuels derived from durable renewable resource. The use of the alternative fuels represents a viable solution to reduce the pollutant emissions and to replace fossil fuels. Thus, a viable solution is the use of the animal fats in mixture with the diesel fuel at the diesel engines. A D2156 MTN8 diesel engine was firstly fuelled with diesel fuel and then with different blends of diesel fuel-animal fats (5% and 10% animal fats content). In the paper are presented some results of the experimental investigations of engine fuelled with preheated animal fats. The raw animal fats effects on the combustion process and on the pollutant emissions at different engine loads and 1450 rev/min engine speed are showed. The engine cycle variability increases at the animal fats content increase. The cycle variability for maximum pressure, maximum pressure angle and indicated mean effective pressure is analysed. The cycle variability coefficients values don’t exceed the recommended values of the standard diesel engine

The study of the spark ignition engine operation at fuelling with n-butanol-gasoline blends

For conventional internal combustion engines alternative fuels such alcohols (ethanol, methanol and butanol) have attracted more attention. This aspect is due to the fact that alcohols have good combustion properties and high oxygen content. Butanol is a viable fuel for blending with conventional fuels such as gasoline or diesel because of its high miscibility with these conventional fuels. The high combustion speed of butanol compared to that of gasoline ensures a shorter burning process thus the engine thermal efficiency can potentially be improved. Moreover, the additional oxygen content of the alcohol n-butanol can potentially improve the combustion process and can lead to a reduction of carbon monoxide and unburnt hydrocarbons emissions level. Utilizing butanol-gasoline blends can provide a good solution for the reduction of greenhouse gases level (CO2) and pollutants level (CO, HC, and NOx). An experimental study was carried out in a spark ignition engine which was fueled with a blend of n-butanol-gasoline at different volume percentages. The objective of this paper is to determine the effects of butanol on the engine energetic performances and on the emissions (HC, CO and NOx). At first the engine fueled with pure gasoline to set up a reference at the engine load χ=55%, engine speed of n=2500 min-1 and different excess air coefficients (λ). After setting the reference the engine was fueled with butanol-gasoline blend (10% vol. butanol 90% vol. gasoline) with the same engine adjustments. At butanol use the CO, HC and CO2 emissions level decreased, but the NOx emission level increased. The butanol can be considered a good alternative fuel for the spark ignition engines without modifications

Experimental and Numerical Study on Perforated Plate Mitigation Capacity to Near-Field Blasts

Based on the analysis of existing collective shockwave protection methods worldwide, this paper addresses the mitigation of shock waves by means of passive methods, namely the use of perforated plates. Employing specialized software for numerical analysis, such as ANSYS-AUTODYN 2022R1®, the interaction of shock waves with a protection structure has been studied. By using this cost-free approach, several configurations with different opening ratios were investigated, pointing out the peculiarities of the real phenomenon. The FEM-based numerical model was calibrated by employing live explosive tests. The experimental assessments were performed for two configurations, with and without a perforated plate. The numerical results were expressed in terms of force acting on an armor plate placed behind a perforated plate at a relevant distance for ballistic protection in engineering applications. By investigating the force/impulse acting on a witness plate instead of the pressure measured at a single point, a realistic scenario can be considered. For the total impulse attenuation factor, the numerical results suggest a power law dependence, with the opening ratio as a variable