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

Experimental and Computing Methods to Determine the External Surface Temperature of the Gun Barrel

The need to determine the small arms weapon system barrel temperature under a variety of conditions makes modelling and simulation a good alternative to the expensive real tests. Therefore, in a unique way, this paper includes three alternatives to assess the external surface temperature in order to better understand the balance between the chosen calculation method accuracy and the computed time. For numerical simulations, the initial conditions were established based on STANREC 4367 thermodynamic interior ballistic model. The heat transfer was solved for One-Dimensional and Two-Dimensional model using the finite difference discretisation method, with code written in Matlab. The Three-Dimensional model was resolved by finite element analysis method in Ansys. The simulations results are validated by means of the results obtained in case of two real firing scenarios. During the field testing, a new detection method based on shockwaves microphones was used in order to exactly establish the moment of each shoot and to precisely observe the temperature evolution on barrel surface

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