Experimental Investigations Regarding the Behaviour of Composite Panels Based on Polyurea and Kevlar or Dyneema Layers Under Blast and Fragments

This paper describes the use of video and digital image processing in investigation of the impact between a rigid hemispherical shape impactor and Hybrid Polyurea-Polyurethane-MWCNTs Nanocomposite Coatings. An experimental study was performed for six sample configurations: single aluminum plates (reference test), multilayer plates with 4 types of coatings and double aluminum plates. The impact phenomenon was recorded with a high-speed video camera and the variation of the projectile s velocity during the impact was obtained through digital analysis. Additionally, the test was instrumented using a force sensor specially designed and mounted on the impactor. The video processing was used to draw the velocity curves and to estimate the evolution of the contact forces between the impactor and the multilayer structures, the results obtained being compared with the force sensor data. Some differences between these two types of measurements are observed, so in order to analyze the configurations behavior, a numerical study of the phenomena was performed in LS-DYNA software using a 2D axial symmetric model. The simulations showed that the profile of the force evolution measured with the sensor is affected by the chosen constructive solution and the data obtained based on the video images are more accurate. The deformations were analyzed, the maximum deformation based on image processing and the residual deformation based on 3D Scan post-test. The video technique combined with 3D Scan are precise enough to study the impact at low velocities and the numerical simulations provide results according to reality. The hyperelastic coatings contribute to a better resistance of the aluminum plates.

Section: Introductionmentioning

confidence: 99%

Assessment of Multilayered Plates with Hyperelastic Coatings Subjected to Dynamic Loadings by Impact at Low Velocities

Bucur,

Matache

2024

“…The third material used is ABS (Acrylonitrile-butadiene-styrene). The material is easy to process without the need for a heated bed and does not produce smoke during construction [33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Considerations on the Plastic Structure of a UAV Payload Made by 3D Printing Technology

Grigore¹,

Stefan²,

Orban³

et al. 2021

Self Cite

With the development of unmanned aerial vehicle (UAV) systems for a multitude of real-time applications, 3D printing technologies have been developed to make thermoplastic structures by fusing filament Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF). However, we consider that the realization of new technologies of experimental models / technological demonstrators / prototypes becomes profitable by using 3D printing technologies. The main aim of the paper is to highlight how the use of three types of materials, which are processed differently, influences the Von Mises stresses of the payload used for a UAV, with the mission of photographing and filming from high altitude.

“…All this stipulates that at the mesoscale level the characteristics in the contact area can be reduced, so that the size of the nozzle hole must be reduced, but not randomly. The increase of the contact surfaces [3,5,10,11,38] is considered to give very good results if the vacuum density is between -5% and -27% (1), depending on the direction of the efforts (Figure 3).…”

Section: Introductionmentioning

confidence: 99%

Using PET-G to Design an Underwater Rover Through 3D PrintingTtechnology

Grigore¹,

Stefan²,

Orban³

2020

Self Cite

The development of 3D printing technologies has gained considerable momentum. Almost every technical-scientific field uses this technology. The technology of 3D printing thermoplastic materials (or fusible filaments - FFF), is based on the realization of the parts by depositing successive layers of extruded filament at temperatures corresponding to the viscous aggregation state. One of the research activities of the CERAS research center is the realization of collaborative drone systems, drones capable of moving in each of the three unstructured environments: aerial, terrestrial aquatic / underwater. This paper presents a study on the choice of the type of thermoplastic material, for making the structural elements (chassis) of an underwater Rover. The need for this study arose from the fact that the design and construction of underwater vehicles is generally demanding. The materials must be characterized by resistance to compression / stretching / shearing, as in underwater environments the existence of currents, pressures (with increasing depth of immersion). Also, the materials must be chemically neutral, because in aquatic environments we can find various chemicals spilled in water (intentional or not) and finally salinity.