scholarly journals Mesoscale modeling and debris generation in hypervelocity impacts

2019 ◽  
Author(s):  
Stephanie N. Q. Bouchey ◽  
Jeromy T. Hollenshead
Keyword(s):  
Experimental Data ◽  
Fragment Size ◽  
Infinite Plate ◽  
Hypervelocity Impact ◽  
Mesoscale Modeling ◽  
Strain Rates ◽  
Hypervelocity Impacts ◽  
Modeling Approach ◽  
Grain Properties ◽  
Material Temperature

Abstract Material fragmentation after a hypervelocity impact is of interest to predictive electro-optical and infrared (EO/IR) modeling. Successful comparisons with data require that submicron fragments are generated in such impacts; however, experimental data has so far been unable to produce fragments of this scale [e.g., 1-3]. This effort investigated the generation of predicted debris from hypervelocity impact of a sphere on a flat, semi-infinite plate. It is hypothesized that explicit modeling of grains, especially in the presence of void and varying grain properties, may lead to differences in predicted strain rates (locally higher) associated with the grain boundaries. Such an effect may lead to smaller predicted fragments sizes than when using the traditional bulk modeling approach and may provide improved understanding of fragmentation modeling in hypervelocity impacts. Comparisons of predicted strain rates at failure (a proxy for fragment size) and material temperature were made between simulations run using a bulk modeling approach and a mesoscale grain modeling approach.

Unlocking the Physics of Hypervelocity Impact

2013 ◽  
Author(s):  
Andrew Thurber ◽  
Javid Bayandor
Keyword(s):  
Fluid Dynamics ◽  
Finite Element Analysis ◽  
Failure Modes ◽  
Structural Response ◽  
Hypervelocity Impact ◽  
Extreme Conditions ◽  
Strain Rates ◽  
Element Analysis ◽  
Standard Material ◽  
Hypervelocity Impacts

Satellites and spacecraft in orbit can impact micrometeorites and other debris at velocities exceeding thousands of meters per second. The shock pressures and temperatures created by these hypervelocity impacts greatly surpass standard material strengths, and deform structures in unconventional failure modes. Under these extreme conditions and strain rates, plastic deformation of a solid can resemble viscous fluidic motion. Using meshless finite element analysis methods, the present research attempts to quantify this fluidic structural response and identify analogous interactions in fluid dynamics.

scholarly journals Survival of fossils under extreme shocks induced by hypervelocity impacts

2014 ◽  
Vol 372 (2023) ◽  
pp. 20130190 ◽  
Author(s):  
M. J. Burchell ◽  
K. H. McDermott ◽  
M. C. Price ◽  
L. J. Yolland
Keyword(s):  
Peak Pressure ◽  
Fragment Size ◽  
Hypervelocity Impact ◽  
The Moon ◽  
Hypervelocity Impacts ◽  
The Earth ◽  
Giant Impacts ◽  
The Mean ◽  
Peak Pressures ◽  
Impact Experiments

Experimental data are shown for survival of fossilized diatoms undergoing shocks in the GPa range. The results were obtained from hypervelocity impact experiments which fired fossilized diatoms frozen in ice into water targets. After the shots, the material recovered from the target water was inspected for diatom fossils. Nine shots were carried out, at speeds from 0.388 to 5.34 km s −1 , corresponding to mean peak pressures of 0.2–19 GPa. In all cases, fragmented fossilized diatoms were recovered, but both the mean and the maximum fragment size decreased with increasing impact speed and hence peak pressure. Examples of intact diatoms were found after the impacts, even in some of the higher speed shots, but their frequency and size decreased significantly at the higher speeds. This is the first demonstration that fossils can survive and be transferred from projectile to target in hypervelocity impacts, implying that it is possible that, as suggested by other authors, terrestrial rocks ejected from the Earth by giant impacts from space, and which then strike the Moon, may successfully transfer terrestrial fossils to the Moon.

Modeling Hypervelocity Impacts Using Smoothed Particle Hydrodynamics

2018 ◽  
Author(s):  
M. Ganser ◽  
B. van der Linden ◽  
C. G. Giannopapa
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Large Deformations ◽  
Hypervelocity Impact ◽  
Density Fluctuations ◽  
Computational Domain ◽  
Simulation Tool ◽  
Hypervelocity Impacts ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

Hypervelocity impacts occur in outer space where debris and micrometeorites with a velocity of 2 km/s endanger spacecraft and satellites. A proper shield design, e.g. a laminated structure, is necessary to increase the protection capabilities. High velocities result in massive damages. The resulting large deformations can hardly be tackled with mesh based discretization methods. Smoothed Particle Hydrodynamics (SPH), a Lagrangian meshless scheme, can resolve large topological changes whereas it still follows the continuous formulation. Derived by variational principles, SPH is able to capture large density fluctuations associated with hypervelocity impacts correctly. Although the impact region is locally limited, a much bigger domain has to be discretized because of strong outgoing pressure waves. A truncation of the computational domain is preferable to save computational power, but this leads to artificial reflections which influence the real physics. In this paper, hypervelocity impact (HVI) is modelled by means of basic conservation assumptions leading to the Euler equations of fluid dynamics accompanied by the Mie-Grueneisen equation of state. The newly developed simulation tool SPHlab presented in this work utilizes the discretization method smoothed particle hydrodynamics (SPH) to capture large deformations. The model is validated through a number of test cases. Different approaches are presented for non-reflecting boundaries in order to tackle artificial reflections on a computational truncated domain. To simulate an HVI, the leading continuous equations are derived and the simulation tool SPHlab is developed. The method of characteristics allows to define proper boundary fluxes by removing the inwards travelling information. One- and two-dimensional model problems are examined which show excellent absorption behaviour. An hypervelocity impact into a laminated shield is simulated and analysed and a simple damage model is introduced to model a spallation failure mode.

scholarly journals A Comparative Study on Johnson Cook, Modified Zerilli–Armstrong, and Arrhenius-Type Constitutive Models to Predict Compression Flow Behavior of SnSbCu Alloy

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1726 ◽  
Author(s):  
Tongyang Li ◽  
Bin Zhao ◽  
Xiqun Lu ◽  
Hanzhang Xu ◽  
Dequan Zou
Keyword(s):  
Experimental Data ◽  
Flow Behavior ◽  
Constitutive Models ◽  
Strain Range ◽  
Type Model ◽  
Strain Rates ◽  
Compression Tests ◽  
Predictive Values ◽  
Specific Strain ◽  
Optimum Model

The flow behavior of the SnSbCu alloy is studied experimentally by the compression tests in the range of the strain rates from 0.0001 to 0.1 s−1 and temperature from 293 to 413 K. Based on the experimental data, three constitutive models including the Johnson–Cook (J–C), modified Zerilli–Armstrong (Z–A), and Arrhenius-type (A-type) models are compared to find out an optimum model to describe the flow behavior of the SnSbCu alloy. The results show that the J–C model could predict the flow behavior of the SnSbCu alloy accurately only at some specific strain rates and temperature near the reference values. The modified Z–A and A-type constitutive models can give better fitting results than the J–C model. While, at high strains, the predictive values of the modified Z–A model have larger errors than those at low strains, which means this model has limitations at high strains. By comparison, the A-type model could predict the experimental results accurately at the whole strain range, which indicates that it is a more suitable choice to describe the flow behavior of the SnSbCu alloy in the focused range of strain rates and temperatures. The work is beneficial to solve the tribological problem of the bearing of the marine engine by integrating the accurate constitutive model into the corresponding numerical model.

Evolution of Anand Parameters With Elevated Temperature Aging for SAC Leadfree Alloys

2020 ◽  
Author(s):  
Pradeep Lall ◽  
Vikas Yadav ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
Experimental Data ◽  
High Strain ◽  
Constitutive Models ◽  
Tensile Tests ◽  
Model Parameters ◽  
Strain Rates ◽  
Automotive Electronics ◽  
High Strain Rates ◽  
Operating Temperatures ◽  
Electronic Assemblies

Abstract Electronic equipment in automotive, agricultural and avionics applications may be subjected to temperatures in the range of −55 to 200°C during storage, operation and handling in addition to high strain-rates. Strain rates in owing to vibration and shock may range from 1–100 per sec. Temperature in electronic assemblies depends typically on location, energy dissipation and thermal architecture. Some investigators have indicated that the required operating temperature is between −40 to 200°C for automotive electronics located underhood, on engine, on transmission. Prior data indicates the evolution of mechanical properties under extended exposures to high temperatures. However, the constitutive models are often only available for pristine materials only. In this paper, effect of low operating temperatures (−65°C to 0°C) on Anand-model parameters at high strain rates (10–75 per sec) for aged SAC (SAC105 and SAC-Q) solder alloys has been studied. Stress-Strain curves have been obtained at low operating temperatures using tensile tests. The SAC leadfree solder samples were subjected to isothermal-aged up to 4-months at 50°C before testing. Anand Viscoplastic model has been used to describe the material constitutive behavior. Evolution of Anand Model parameters for SAC solder has been investigated. The computed parameters of the experimental data were used to simulate the tensile test and verified the accuracy of the model. A good correlation was found between experimental data and Anand predicted data.

Fluidic Deformation Under Hypervelocity Impacts

2014 ◽  
Author(s):  
Andrew Thurber ◽  
Javid Bayandor
Keyword(s):  
Hypervelocity Impact ◽  
Orbital Debris ◽  
Inertial Forces ◽  
Impact Event ◽  
Aerospace Materials ◽  
Computational Framework ◽  
Hypervelocity Impacts ◽  
Dramatic Rise ◽  
Impact Risk

The increased frequency of exploration into space has caused a dramatic rise in the density of debris in orbit. Orbital debris, both natural and man-made, poses an extreme impact risk to satellites and spacecraft. The relative velocities between orbital components and debris can exceed thousands of meters per second, giving rise to immense kinetic energies even for small objects. In such a hypervelocity impact event, the shock pressures exceed the strength of common aerospace materials, and brief shock-induced temperature rises cause melting and vaporization of most structural bodies. Under these extreme conditions, the failure and deformation of solids can resemble fluid flow. By using meshless Lagrangian models in an explicit computational framework, this work identifies analogous fluidic interactions and further quantifies the role of shear and inertial forces in hypervelocity impacts (HVI).

Investigation into Damage of Aluminum Multi-Wall Shield under Hypervelocity Projectiles Impact

2008 ◽  
Vol 385-387 ◽  
pp. 201-204
Author(s):  
Gong Shun Guan ◽  
Bao Jun Pang ◽  
Run Qiang Chi ◽  
Nai Gang Cui
Keyword(s):  
Aluminum Alloy ◽  
Space Debris ◽  
Hypervelocity Impact ◽  
Wall Structure ◽  
First Wall ◽  
Experiment Data ◽  
Normal Impact ◽  
Advanced Method ◽  
Hypervelocity Impacts ◽  
Gas Gun

In order to study the hypervelocity impact of space debris on spacecraft through hypervelocity impact on aluminum alloy multi-wall structure, a two-stage light gas gun was used to launch 2017-T4 aluminum alloy sphere projectiles. The projectile diameters ranged from 2.74mm to 6.35mm and impact velocities ranged from 1.91km/s to 5.58km/s. Firstly, the advanced method of multi-wall shield resisting hypervelocity impacts from space debris was investigated, and the effect of amount and thickness of wall on shield performance was discussed. Finally, by regression analyzing of experiment data, the experience equations for forecasting the diameter of the penetration hole on the first wall and the diameter of the damaged area on the second wall of aluminum multi-wall shield under hypervelocity normal impact of Al-spheres were obtained. The results indicated that the performance of multi-wall shield with more amount of wall is excellent when area density is constant. At the same time, intensity of the first wall and protecting space play the important roles.

scholarly journals Hypervelocity impacts on thin brittle targets: Experimental data and SPH simulations

2006 ◽  
Vol 33 (1-12) ◽  
pp. 441-451 ◽  
Author(s):  
Y. Michel ◽  
J.-M. Chevalier ◽  
C. Durin ◽  
C. Espinosa ◽  
F. Malaise ◽  
...  
Keyword(s):  
Experimental Data ◽  
Hypervelocity Impacts

The Rate (Time)-Dependent Mechanical Behavior of the PMR-15 Thermoset Polymer at 316°C: Experiments and Modeling

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
M. B. Ruggles-Wrenn ◽  
O. Ozmen
Keyword(s):  
Experimental Data ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Inelastic Deformation ◽  
Rate Sensitivity ◽  
Experimental Program ◽  
Strain Rates ◽  
Neat Resin ◽  
Strain Behavior ◽  
Thermoset Polymer

The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at 316°C. The experimental program was designed to explore the influence of strain rate on tensile loading, unloading, and strain recovery behaviors. In addition, the effect of the prior strain rate on the relaxation response of the material, as well as on the creep behavior following strain-controlled loading were examined. Positive, nonlinear strain rate sensitivity is observed in monotonic loading. The material exhibits nonlinear, “curved” stress-strain behavior during unloading at all strain rates. The recovery of strain at zero stress is strongly influenced by the prior strain rate. The prior strain rate also has a profound effect on relaxation behavior. Likewise, creep response is significantly influenced by the prior strain rate. The experimental data are modeled with the viscoplasticity theory based on overstress (VBO). The comparison with experimental data demonstrates that the VBO successfully predicts the inelastic deformation behavior of the PMR-15 polymer under various test histories at 316°C.

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