Experimental and Numerical Study on the Mesh Bumper by Hypervelocity Impact

2012 ◽  
Vol 457-458 ◽  
pp. 108-112
Author(s):  
Min Lin ◽  
Bao Jun Pang ◽  
Jin Cheng

In order to systematically explore the properties of the mesh bumper under hypervelocity impact, the quantitative research of protect characteristics was carried out with the numerical simulation. The experiments, in which the projectile impacted the multi-layers mesh bumper at hypervelocity, were simulated using the Ls-Dyna hydro-codes. The results for simulations and experiments were compared and analyzed. The effectiveness and accuracy of the simulation model is proved. It is shown that the morphologies of debris cloud were obviously varied with the change of impact position.

2012 ◽  
Vol 525-526 ◽  
pp. 401-404
Author(s):  
Gong Shun Guan ◽  
Rui Tao Niu

In order to study the fragmentation of projectile and ejection of debris clouds caused by hypervelocity impacting mesh bumper, simulation of aluminum sphere projectile hypervelocity normal impacting aluminum mesh bumper was practiced with SPH arithmetic of LS-DYNA soft. The diameter of projectile was 4mm. Impact velocities of aluminum spheres were varied between 2.2km/s and 6.2km/s. The impact angle was 0°. The relationship between the debris clouds characteristic of projectile and the impact position on aluminum mesh bumper was studied. The effect on fragmentation of projectile from different combination mode of aluminum mesh bumper was analyzed. The results showed that the morphologies of the debris cloud varied with the impact position when a projectile impacted the mesh bumper. The debris clouds as palpus was found, and some local kinetic energy concentrated appeared in the debris clouds. Debris clouds distribution was more uniform when projectile impacted wire across point on the mesh bumper. Debris clouds had more diffuse area and less residual kinetic energy when mesh bumper was combined with interleaving mode. Mesh bumper combined with interleaving mode was helpful in enhancing the protection performance of shields.


2013 ◽  
Vol 405-408 ◽  
pp. 57-62
Author(s):  
Wei Zhou Li

Numerical simulation model was established with FLAC3D to calculate the bearing capacity and the settlement of composite foundation with different pile-soil shear modulus. Then the rules of the effect of pile-soil shear modulus upon mixed pile composite foundation have been obtained. The results show that there is a great relationship between the pile-soil shear modulus and the bearing capacity of mixed pile composite foundation. Along with the increase of pile-soil shear modulus, the bearing capacity increase. Also, this paper suggest that the right value of pile-soil shear modulus of mixed pile composite foundation solidified by HEC or HAS consolidator dosing 12%, which can be used for the design of mixed pile composite foundation.


2017 ◽  
Vol 21 (2) ◽  
pp. 532-551 ◽  
Author(s):  
Hao Zhou ◽  
Rui Guo ◽  
Rongzhong Liu

The stuffed corrugated sandwich structure was proposed for the application in the protection of the spacecraft against orbital debris. In order to investigate the protection properties of the stuffed corrugated sandwich structure under hypervelocity impact, numerical simulations were carried out to analyze the impact characteristics. The hypervelocity impact process was presented and the properties such as shock waves propagation, energy absorption, and expansion of the debris cloud were discussed; corresponding properties of mass equal Whipple structure under impact were analyzed for comparison. The results illustrate the protection mechanism of the stuffed corrugated sandwich subject to hypervelocity impact and show that it has superior protection performance to monolithic plate, which prove that the stuffed corrugated sandwich structure has potentially broad application prospect in the field of spacecraft protection against the orbital debris. The research can provide reference for the design of protection shield of the spacecraft.


Author(s):  
Erkai Watson ◽  
Martin O. Steinhauser

In this paper we introduce a computational model for the simulation of hypervelocity impact (HVI) phenomena which is based on the Discrete Element Method (DEM). Our paper constitutes the first application of DEM to the modeling and simulating of impact events for velocities beyond 5 kms−1. We present here the results of a systematic numerical study on HVI of solids. For modeling the solids, we use discrete spherical particles that interact with each other via potentials. In our numerical investigations we are particularly interested in the dynamics of material fragmentation upon impact. We model a typical HVI experiment configuration where a sphere strikes a thin plate and investigate the properties of the resulting debris cloud. We provide a quantitative computational analysis of the resulting debris cloud caused by impact and a comprehensive parameter study by varying key parameters of our model. We compare our findings from the simulations with recent HVI experiments performed at our institute. Our findings are that the DEM method leads to very stable, energy–conserving simulations of HVI scenarios that map the experimental setup where a sphere strikes a thin plate at hypervelocity speed. Our chosen interaction model works particularly well in the velocity range where the local stresses caused by impact shock waves markedly exceed the ultimate material strength.


2014 ◽  
Vol 134 (7) ◽  
pp. 604-613 ◽  
Author(s):  
Toshiya Ohtaka ◽  
Tomo Tadokoro ◽  
Masashi Kotari ◽  
Tadashi Amakawa

1997 ◽  
Vol 36 (8-9) ◽  
pp. 397-402
Author(s):  
Yasuhiko Wada ◽  
Hiroyuki Miura ◽  
Rituo Tada ◽  
Yasuo Kodaka

We examined the possibility of improved runoff control in a porous asphalt pavement by installing beneath it an infiltration pipe with a numerical simulation model that can simulate rainfall infiltration and runoff at the porous asphalt pavement. From the results of simulations about runoff and infiltration at the porous asphalt pavement, it became clear that putting a pipe under the porous asphalt pavement had considerable effect, especially during the latter part of the rainfall.


2020 ◽  
pp. 014459872098361
Author(s):  
Zhongbao Wu ◽  
Qingjun Du ◽  
Bei Wei ◽  
Jian Hou

Foam flooding is an effective method for enhancing oil recovery in high water-cut reservoirs and unconventional reservoirs. It is a dynamic process that includes foam generation and coalescence when foam flows through porous media. In this study, a foam flooding simulation model was established based on the population balance model. The stabilizing effect of the polymer and the coalescence characteristics when foam encounters oil were considered. The numerical simulation model was fitted and verified through a one-dimensional displacement experiment. The pressure difference across the sand pack in single foam flooding and polymer-enhanced foam flooding both agree well with the simulation results. Based on the numerical simulation, the foam distribution characteristics in different cases were studied. The results show that there are three zones during foam flooding: the foam growth zone, stable zone, and decay zone. These characteristics are mainly influenced by the adsorption of surfactant, the gas–liquid ratio, the injection rate, and the injection scheme. The oil recovery of polymer-enhanced foam flooding is estimated to be 5.85% more than that of single foam flooding. Moreover, the growth zone and decay zone in three dimensions are considerably wider than in the one-dimensional model. In addition, the slug volume influences the oil recovery the most in the foam enhanced foam flooding, followed by the oil viscosity and gas-liquid ratio. The established model can describe the dynamic change process of foam, and can thus track the foam distribution underground and aid in optimization of the injection strategies during foam flooding.


2020 ◽  
Vol 9 (1) ◽  
pp. 27
Author(s):  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Xiping Yu ◽  
Guangwei Liu

A theoretical and numerical study is carried out to investigate the transformation of the wave boundary layer from non-depth-limited (wave-like boundary layer) to depth-limited one (current-like boundary layer) over a smooth bottom. A long period of wave motion is not sufficient to induce depth-limited properties, although it has simply been assumed in various situations under long waves, such as tsunami and tidal currents. Four criteria are obtained theoretically for recognizing the inception of the depth-limited condition under waves. To validate the theoretical criteria, numerical simulation results using a turbulence model as well as laboratory experiment data are employed. In addition, typical field situations induced by tidal motion and tsunami are discussed to show the usefulness of the proposed criteria.


2005 ◽  
Vol 45 (4) ◽  
pp. 500-505 ◽  
Author(s):  
Junya KANO ◽  
Eiki KASAI ◽  
Fumio SAITO ◽  
Takazo KAWAGUCHI

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