The increasing destructiveness of explosive-formed penetrators or projectiles (EFPs) in modern warfare has posed significant challenges in developing effective armored solutions incorporating advanced ceramics as crucial components, offering enhanced protection against high-velocity-formed projectiles. [1] In other words, Explosively Formed Penetrators pose a significant threat to military vehicles, necessitating the development of advanced armor solutions to counteract their destructive potential. Thus, Finite Element Analysis (FEA) research is crucial for the armor system against this threat. In addition, since EFP tests are costly and time-demanding, performing these experiments with FEA provides significant cost and performance efficiency. This study analyzes the composite armor system integrating Nurol Teknoloji [2] ceramics against EFP threats utilizing LS-DYNA, a program for nonlinear dynamic analysis of structures in three dimensions.
Military vehicles are exposed to mine and explosive loads in operational conditions and the vehicle must have the appropriate protection level to prevent personnel injuries. Blast mitigation seats represent a critical component in ensuring personnel safety. In this study, we conducted mine blast simulations using the non-linear finite element code LS-DYNA® to examine the structural behavior of blast mitigation seats. The blast simulations were carried out in accordance with the requirements of NATO AEP-55 STANAG 4569 VOL-2. We employed the Structured Arbitrary Lagrangian-Eulerian (ALE) method for these simulations. The model encompassed an ALE domain, including soil, air, explosive definitions, and a Lagrange domain for the 4x4 military vehicle. To assess the impact of the explosive charge on the occupant, we utilized the LSTC Hybrid III 50th dummy. We measured force and acceleration outputs from the dummy and compared them with the allowable limits defined in NATO AEP-55 STANAG 4569 VOL-2.
Aluminum Honeycombs are classified as advanced engineering solution for specific requirements and utilized as composite core material, thermal isolator, optical aligner, floor mat, packaging filler and energy absorber for different industries. Many materials may be mentioned here as cheaper and simpler alternative that can offer similar or maybe higher performance for these purposes even with lower cost, however none of them can come close to the weight advantage of honeycombs thanks to the extensive air space and load path provided by its peculiar shape.
Mapping technique has been developed to allow the decomposition of a calculation in several steps. The transitions are allowed 1D to 2D/3D, 2D to 2D/3D, or 3D to 3D/2D etc [1], that the data from the model’s latest cycle is saved in a binary file and can be mapped into another model using the “map” command in the expression. This technique has a wide range of application since it allows to adjust mesh length or model size, as well as include Lagrangian or Eulerian Parts.
Massively used in aeronautical structures, composites are nowadays essential in the search for a more ecological and successful industry. Their low density enables weight reduction and then decreases airplanes consumption. However, the current composites assembly process represents a limitation in their use. In fact, we do not have any reliable, industrialized and non-destructive technology to control the adhesive quality. Then composites are also riveted which adds weight and a drilling process during which fibres can be locally damaged. For about 10 years, the LASAT (LAser Shock Adhesion Test) technology appears to be a promising alternative as a non-destructive control mean to asses bonding quality. The laser impact creates a plasma that induces shock waves propagation in the structure. The LASAT technology can also be used to generate damage anywhere in the assembly thickness. The experimental technology is mature but is lacking a numerical tool in order to calibrate the input laser parameters depending on the targeted results.
Military vehicles and their occupants in conflict zones face a significant risk from improvised explosive devices (IEDs). Simulating IED risks on armored military vehicles requires employing various modeling approaches. However, to ensure the accuracy and effectiveness of these approaches, it is crucial to accurately transfer the explosive load onto the vehicle structures. This study aims to address this critical point by developing a methodology for selecting the appropriate vehicle components for load transfer and evaluating the proximity of the analysis model to live fire test results.
Pretension in reinforced concrete beams is commonly used within the construction industry to provide sufficient precompression to the tension face of an element, such that static dead and live loads develop low or no tension stress within the concrete components of the element. While this is advantageous for conventional structural design, allowing the element to carry more load over longer spans, beam elements subjected to significant uplift loading, such as those experienced during an accidental explosion, can develop additional tensile stresses on the element's top surface.
It is well known that spalling failure occurs when concrete walls are subjected to impact loading. This is explained by the fact that the compressive stress wave generated by the impact propagates from the front surface to the back surface and is reflected at the back surface as a tensile stress wave that exceeds the tensile strength of the concrete. Spalling failure is one of the most important failure modes in evaluating the response of concrete structures subjected to impact loading. Ansys LS-DYNA has several capabilities to simulate spalling failure, but whether the depth from the surface where spalling occurs is accurately simulated is an important indicator for predicting the actual response of the structure with high accuracy. Therefore, in this study, the accuracy of the simulation of spalling failure using LS-DYNA was investigated based on the wave propagation theory. As a result, it was confirmed that LS-DYNA could reproduce the behavior of spalling failure with high accuracy.
A Numerical Investigation on the Ballistic Performance of Ceramic Composite Armors against EFP Threats