The effect of simulated hypervelocity space debris on polymers (original) (raw)
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GROUND SIMULATION OF HYPERVELOCITY SPACE DEBRIS IMPACTS ON POLYMERS
Space Technology Proceedings, 2006
Hypervelocity space debris impacts can lead to degradation of satellite performance and, in extreme cases, might cause a total loss of a spacecraft. The increase in space debris population provides the motivation for this study, which focuses mainly on the mechanical behavior of space-qualified polyimide Kapton films impacted by simulated hypervelocity debris. Kapton is used extensively on spacecrafts, especially in thermal control blankets. Kapton films 25, 50 and 125 µm-thick were studied at different impact velocities of up to 2900 m/s generated by a Laser Driven Flyer (LDF) system. The Kapton-impacted sites revealed ductile-type fractures for lowvelocity debris, which changed gradually into mixed ductile-brittle fractures with crack formation when debris impact velocity was increased. High-velocity impacts generated spalls in the Kapton film, with ultrahigh strain rate of above 10 6 1/s. Fractures created by impacts at velocities above 1700 m/s showed central impact regions which experienced the highest strain rate and revealed a ductile-type fracture, while the outer regions which experienced a lower strain rate failed through brittle cracking. A model explaining this phenomenon, based on the temperature profile developed within the impacted region at the time of impact, is presented.
Polymer, 2007
Polyimides are used as the outer layer of thermal control insulation blankets covering most of the external spacecraft surfaces that are exposed to space environment. The combined effect of ground simulated hypervelocity space debris impacts and atomic oxygen (AO) on the fracture of polyimide films was studied. A laser-driven flyer system was used to accelerate aluminum flyers to impact velocities of up to 3 km/s. The impacted films were exposed to an RF plasma source, which was used to simulate the effect of AO in the low Earth orbit. Scanning electron microscopy and atomic force microscopy were used to characterize the fracture and surface morphology. When exposed to oxygen RF plasma, the impacted polyimide film revealed a large increase in the erosion rate, the damage being characterized mainly by the formation of new holes. This effect is explained by the formation of residual stresses due to the impact and enhancement of oxygen diffusivity and accumulation. A complementary experiment, in which a stressed polyimide was exposed to RF plasma, supports this model. This study demonstrates a synergistic effect of the space environment components on polymers' degradation, which is essential for understanding the potential hazards of ultrahigh velocity impacts and AO erosion for completing a successful spacecraft mission.
Simulation of Hypervelocity Debris Impact and Spacecraft Shielding Performance
The objective of the work presented in this paper is the simulation of hypervelocity impact on aluminiumcarbon/epoxy-aluminium shields; such multi-layered arrangement is being used by the European Columbus module of the International Space Station. In addition, thermodynamically consistent material models are introduced for each component of the multilayered array which yields a more accurate physical representation of the material response to high velocity impact loading. Thermodynamically consistent models for aluminium and carbon/epoxy are proposed. In order to describe material behavior under high-intensity loadings a 2-D anisotropic elasto-plastic constitutive model coupled with a damage tensor ij ω , an equation of state, and a failure criterion (based on the critical value of a specific entropy function expressed in terms of the dissipation function) have been developed. The model includes the following key aspects of material response to hypervelocity impact: non-linear anisotropic strength, shock effects and associated energy dependence, compaction, compressive and tensile failure and strain rate effects. The severe deformations occurring in any hypervelocity impact event are best described by meshless methods since they offer clear advantages for modelling large deformations and failure of solids when compared to mesh based methods. The simulations presented here are the result of the application of the Smoothed Particle Hydrodynamics (SPH) method to the impact and penetration problem and the incorporation of thermodynamically consistent material models into the Cranfield University SPH solver.
Numerical investigation of debris impact on spacecraft structure at hyper-high velocity
Numerical investigation of debris impact on spacecraft structure at hyper-high velocity, 2020
In this paper, our analysis concentrated on the mechanical behavior of sandwich panel subjected to impact loading. Thus, to improve the resistance of satellite structures from debris collision consequences; we proceed a performance investigation numerically of different materials based on the evaluation of contact force, total energy and kinetic energy generated from the impact of spherical steel debris on sandwich panel. Furthermore, a comparison of deformations and stresses levels in sandwich panel collide by a projectile at hyper-high velocity using finite element with ANSYS code was made. The difference between our models is the type of skins materials which are aluminum and functionally graded material FGM (alumina/ nickel). The impact results a total perforation of sandwich panel with aluminum facesheets creating a fragments; contrary to FGM which the projectile penetrates only the front facesheet and honeycomb core. However, for an effective protection of sandwich panel against debris perforation, the introduction of FGM skins technique is considered as a candidate solution.
International Journal of Impact Engineering, 2006
A representative carbon fiber reinforced plastic/aluminum honeycomb sandwich panel (CFRP/Al HC SP) spacecraft structure has been modeled in the hydrocode AUTODYN using the state-of-the-art ADAMMO material model [Riedel W, Harwick W, White D, Clegg R. Advanced material damage models for numerical simulation codes. ESA CR(P) 4397, 2003] to study the performance of the structure during impact events that cause perforation and fragment ejection. A new procedure combining a series of existing theoretical methods has been developed and applied to derive a full set of coarse material data. The data set has been implemented in AUTODYN, and the results of the numerical simulation have been compared to experimental impact test data. For impact tests performed near the structural ballistic limit, quantitatively accurate results were obtained over a range of impact velocities and angles. A further increase in the projectile size resulted in significant destruction of the sandwich panel front face-sheet and diversion from the experimental damage measurements. Inspection of the numerical model has shown non-localized propagation of inter-laminar delaminations, possibly caused by an under-prediction of the laminate dynamic inter-laminar tensile strength. The effects of the delamination propagation occur over an extended time scale and were not found to affect the state and trends of the fragment cloud ejected into the satellite interior. Accordingly, experimental trends of fragment cloud dispersion have been qualitatively reproduced.
Peculiarity of polymeric materials destruction on the low Earth orbits
2008
The paper reports on the research of two polymer film sets after in-flight exposure on the orbital space station “Mir” for 28 and 42 months. The investigated films include the samples of polyimide (grades PM-1E, Kapton 100 HN, polyimide coated with fluoroplast, one-side aluminised film PM-1UE-OA), copolymers of tetrafluoroethylene with hexafluoropropylene (grades F4-MB, FEP-100A). During exposure a part of the polymeric films was open to the space environment, while the other part was protected by polymeric ...
Space Debris, 2000
Lagrangian finite element methods have been used extensively in the past to study the non-linear transient behaviour of materials, ranging from crash tests of cars to simulating bird strikes on planes. However, as this type of space discretisation does not allow for motion of the material through the mesh when modelling extremely large deformations, the mesh becomes highly distorted. This paper describes some limitations and applicability of this type of analysis for high velocity impacts. A method for dealing with this problem by the erosion of elements is proposed, where the main driver is the definition of element failure strains. Results were compared with empirical perforation results and were found to be in good agreement. The results were then used to simulate high velocity impacts upon a multi-layered aluminium target in order to predict a ballistic limit curve. LS-DYNA3D was used as the FE solver for all simulations. Meshes were generated using Truegrid.
POSS-Polyimide Nanocomposite Films: Simulated Hypervelocity Space Debris and Atomic Oxygen Effects
High Performance Polymers, 2008
The combined effect of hypervelocity space debris impact and atomic oxygen (AO) attack on the degradation of reinforced polyhedral oligomeric silsesquioxanes (POSS)-polyimide films was studied. A laser-driven flyer (LDF) system was used to accelerate aluminum flyers to impact velocities of up to 3 km s 11 . The impacted films were exposed to an RF-plasma source, which was used to simulate the effect of AO in the low Earth orbit. Scanning electron microscopy (SEM) was used to characterize the fracture morphology. The extent of damage in POSS-polyimide impacted films was found to be much smaller compared to POSS-free films, insinuating on a toughening mechanism developed due to POSS incorporation. When exposed to air RF-plasma, the impacted POSS-free film revealed a synergistic effect associated with a large increase in the erosion rate while impacted POSS-containing samples showed improved erosion resistance. The increased erosion rate of the impacted POSS-free film is explained by formation of residual stresses that affect the oxidation mainly by increasing the diffusivity of oxygen. Downloaded from 476 R. VERKER ET AL.
Hypervelocity impacts on thin brittle targets: Experimental data and SPH simulations
International Journal of Impact Engineering, 2006
The meteoroids and debris environment play an important role in the reduction of spacecraft life time. Ejecta or secondary debris, are produced when a debris or a meteoroid impact a spacecraft surface. These ejecta can contribute to a modification of the debris environment: either locally by the occurrence of secondary impacts on the component of complex and large space structures, or at long distance by formation of small orbital debris. This double characteristic underlines the necessity to model the damages caused by an HVI as well as the material ejection caused by the impact. Brittle materials are particularly sensitive to hypervelocity impacts because they produce features larger than those observed on ductile targets and the ejected fragments total mass including ejectas and spalls is in the order of 100 times bigger than the impacting mass. The French atomic energy commission (CEA) faces to the same problem in the Laser MégaJoule project (LMJ). The various instruments used in the experiment chamber will undergo many aggressions resulting from target disassembly. Thus the lasers optics will be bombarded as hypervelocity debris and shrapnel. In this study, the authors only focus on potential impacts of debris and shrapnel on fused silica optical debris shields. These Main Debris Shields called MDS are 20mm thick fused silica plates placed in front of each lasers way out. 2 mm thick Disposable Debris Shields, DDS, located in front of the MDS might be used to stop vapour, particulate, droplets and substantially reduce very small shrapnel cratering on the main debris shields. But ejecta from the rear surface of the DDS and penetration through the DDS are likely to damage the MDS and seed new laser damage sites. The MDS lifetime is limited by the laser damage growth of those damage sites.