Papers by Keyword: Impact Velocity

Abstract: The work is devoted to a study of the probable causes of a decrease in joint strength during explosion welding of metals with sharply differing physical and mechanical properties. The influence of kinematic and energy parameters on the structure and strength of the steel-aluminum composite under various conditions of explosive loading is shown.

Abstract: The paper discusses the results of the numerical simulation of high-speed impact effect of compact projectiles made of steel and tungsten alloy with steel obstacles of equal mass. The obstacles have different initial porosity of the material. Conducted the final evaluation of the penetration speed of the projectile depending on the porosity of the obstacle and the initial speed of the shock interaction. The initial impact velocity range from 1 to 16 [km/s]. The destruction, melting and evaporation of the interacting bodies are taken into account. The analysis of porosity influence evaluation of obstacles material revealed that the protective advantage of porous obstacles disclose at the higher impact velocities, greater than 1.5 [km/s] for steel strikers and 2 [km/s] for projectiles of tungsten alloy. The more impact velocity the more protective effect of porous obstacles.

Abstract: The paper presents the results of research on the creation of heat-resistant composite A5-Cr-St3 with diffusion barrier. It considers the influence of the thickness of the chromium layer and the kinematic parameters of the structure and thermal steel-aluminum composite.

Abstract: This paper discusses the structure and regularities of formation of compounds during explosive welding plate steel-aluminum composite. The influence of thickness of the welded element on the structure and the shear deformation of the metal in the heat-affected zone under different conditions of explosive loading was investigated.

Abstract: The paper discusses the results of the numerical simulation of high-speed impact effect of compact projectiles made of steel and tungsten alloy with steel obstacles of equal mass. The obstacles have different initial porosity of the material. Conducted the final evaluation of the penetration speed of the projectile depending on the porosity of the obstacle and the initial speed of the shock interaction. The initial impact velocity range from 1 to 16 [km/s]. The destruction, melting and evaporation of the interacting bodies are taken into account. The analysis of porosity influence evaluation of obstacles material revealed that the protective advantage of porous obstacles disclose at the higher impact velocities, greater than 1.5 [km/s] for steel strikers and 2 [km/s] for projectiles of tungsten alloy. The more impact velocity the more protective effect of porous obstacles.

Abstract: Magnetic pulse welding (MPW) is a promising technology to join dissimilar metals and to produce multi-material structures, e.g. to fulfill lightweight requirements. During this impact welding process, proper collision conditions between both joining partners are essential for a sound weld formation. Controlling these conditions is difficult due to a huge number of influencing and interacting factors. Many of them are related to the pulse welding setup and the material properties of the moving part, the so-called flyer. In this paper, a new measurement system is applied that takes advantage of the high velocity impact flash. The flash is a side effect of the MPW process and its intensity depends on the impact velocity of the flyer. Thus, the intensity level can be used as a welding criterion. A procedure is described that enables the user to realize a fast parameter development with only a few experiments. The minimum energy level and the optimum distance between the parts to be joined can be identified. This is of importance since a low energy input decreases the thermal and mechanical shock loading on the tool coil and thus increases its lifetime. In a second step, the axial position of the flyer in the tool coil is adjusted to ensure a proper collision angle and a circumferential weld seam.

Abstract: The developments of the high power proton accelerators become a worldwide interest to provide various applications, where the targets are demanded to efficiently produce secondary beams and to survive intensive MW class proton beam power supplied by the accelerators. Solid metal targets might be melted by very high heat flux that is caused by the intensive proton beam bombardment. In fact, the incident occurred at J-PARC (Japan Proton Accelerator Research Complex), in which the gold solid target was locally melted to explosively jet molten gold. The molten gold jet collided with a structural beryllium flange plate that has a function of vacuum boundary. Some parts of molten gold were splashed and the other stuck on the flange plate. The relationship between the impact velocity and the morphology of the sticking pattern on the plate was quantitatively evaluated by introducing fractal analysis. It was found that the fractal dimension is correlated with the impact velocity and might be a useful factor to indicate the localized impact force and behavior.

Abstract: Erosive wear is defined as material loss from surface due to impact of liquid and solid particles. This mechanism can be seen widely in the industry such in mining, valves, pipe and pump systems. Characteristics and wear amount of erosive wear is affected by different parameters like geometry, impact speed, impingement angle of the hard particles, solid-liquid rate, material hardness and toughness. To determine the effect of these parameters on erosive wear, a wear slurry tank is designed. Before the prototype design of the test tank, different geometrical parameters of the tank are analyzed using simulation software. By computational investigations, the 3-D flow in a liquid/solid (slurry) tank is established and analyzed. Aim of the mathematical analysis was to detect the effect of the tank design parameters on liquid impact velocity and distribution on the test specimen surface. According to the results, geometrical parameters of the tank such as; baffle width, propeller length, assembly position of the specimens in the slurry tank, the distance between the propeller and specimens are defined.

Abstract: The behavior of thin plate subjected to impact loading is still an interesting field to study. This paper studies about Aluminum thin plate perforation. It focused on the experimental result of thin plate perforation. The thin plates are tested using blunt and conical strikers on a instrumented impact testing machine. Two different thicknesses of was used to observed the maximum work done with four impact velocities. The result indicated that the maximum work done increased proportionally with impact velocities. In addition, an elastic FEM analysis is carried out to confirm the experimental result by using ANSYS software. Both experimental and numerical results showed a close agreement.

Abstract: Investigation of impact damage on advanced composite materials of Carbon Fiber Reinforced Epoxy (CFRE) composites and Glass Fiber Reinforced Epoxy (GFRE) composites under high strain rate impact load have been conducted in the present study. Four types of GFRE plates were studied after being impacted with various thicknesses and fixed impact parameters. Results of the present experiments were characterized by the comparison of damage zone among CFRE/GFRE, GFRE with honeycomb core and GFRE without honeycomb core. The result suggests that CFRE is the better structure than GFRE under low velocity impact loads. Higher energy needed to damage the surface of GFRE with core compared to GFRE without core plates.