Effects of projectile parameters on the momentum transfer and projectile melting during hypervelocity impact

The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical simulation.By comparing the computation results with the experimental results,the correctness of the calculation and the statistical method of momentum transfer coefficient is verified.Different shapes of aluminum,copper and heavy tungsten alloy projectiles striking aluminum,basalt,and pumice target for impacts up to 10 km/s are simulated.The influence mechanism of the shape of the projectile and projectile/target density on the momentum transfer was obtained.With an increase in projectile density and length-diameter ratio,the energy transfer time between the projectile and targets is prolonged.The projectile decelerates slowly,resulting in a larger cratering depth.The energy consumed by the projectile in the excavation stage increased,resulting in lower mass-velocity of ejecta and momentum transfer coefficient.The numerical simulation results demonstrated that for different projectile/target combinations,the higher the wave impedance of the projectile,the higher the initial phase transition velocity and the smaller the mass of phase transition.The results can provide theoretical guidance for kinetic impactor design and material selection.

Experimental and numerical study of hypervelocity impact damage on composite overwrapped pressure vessels

Ground-based tests are important for studying hypervelocity impact(HVI)damage to spacecraft pressure vessels in the orbital debris environment.We analyzed the damage to composite overwrapped pressure vessels(COPVs)in the HVI tests and classified the damage into non-catastrophic damage and catastrophic damage.We proposed a numerical simulation method to further study non-catastrophic damage and revealed the characteristics and mechanisms of non-catastrophic damage affected by impact conditions and internal pressures.The fragments of the catastrophically damaged COPVs were collected after the tests.The crack distribution and propagation process of the catastrophic ruptures of the COPVs were analyzed.Our findings contribute to understanding the damage characteristics and mechanisms of COPVs by HVIs.

Satellite breakup behaviors and model under the hypervelocity impact and explosion:A review

The primary causes of satellite breakups are hypervelocity impact and explosion,the research on satellite breakup can be used not only to evaluate the influence of breakup event on the space environment,but also to trace whether the satellite has been deliberately attacked.It is of great significance in both civil and military aspects.The study of satellite breakup behaviors and model is reviewed to summarize the research progress and insufficiency in recent decades,including the satellite breakup experiment,measurement and characterization of fragments,distribution characteristics of breakup fragments,satellite breakup model,etc.The classical studies are introduced in detail,and the limitations of the current research are pointed out.According to the current research results,the contemporary challenges and future directions for satellite breakup study are presented.The research on satellite breakup is developing in two directions:the miniaturization of satellite size and the complexity of satellite component.The study on satellite breakup needs to be explored and deepened on improving the experimental launch speed,expanding the model application range and breakup revealing the results under combined effect of impact and explosion.

Research and development on hypervelocity impact protection using Whipple shield:An overview

Whipple shield,a dual-wall system,as well as its improved structures,is widely applied to defend the hypervelocity impact of space debris(projectile).This paper reviews the studies about the mechanism and process of protection against hypervelocity impacts using Whipple shield.Ground-based experiment and numerical simulation for hypervelocity impact and protection are introduced briefly.Three steps of the Whipple shield protection are discussed in order,including the interaction between the projectile and bumper,the movement and diffusion of the debris cloud,and the interaction between the debris cloud and rear plate.Potential improvements of the protection performance focusing on these three steps are presented.Representative works in the last decade are mentioned specifically.Some prospects and suggestions for future studies are put forward.

Analysis of the stress wave and rarefaction wave produced by hypervelocity impact of sphere onto thin plate

Shock wave is emitted into the plate and sphere when a sphere hypervelocity impacts onto a thin plate.The fragmentation and phase change of the material caused by the propagation and unloading of shock wave could result in the formation of debris cloud eventually.Propagation models are deduced based on one-dimensional shock wave theory and the geometry of sphere,which uses elliptic equations(corresponding to ellipsoid equations in physical space)to describe the propagation of shock wave and the rarefaction wave.The“Effective thickness”is defined as the critical plate thickness that ensures the rarefaction wave overtake the shock wave at the back of the sphere.The“Effective thickness”is directly related to the form of the debris cloud.The relation of the“Effective thickness”and the“Optimum thickness”is also discussed.The impacts of Al spheres onto Al plates are simulated within SPH to verify the propagation models and associated theories.The results show that the wave fronts predicted by the propagation models are closer to the simulation result at higher impact velocity.The curvatures of the wave fronts decrease with the increase of impact velocities.The predicted“Effective thickness”is consistent with the simulation results.The analysis about the shock wave propagation and unloading in this paper can provide a new sight and inspiration for the quantitative study of hypervelocity impact and space debris protection.

Evidence in Oman for Mantle Excavating Hypervelocity Impact at the Cenomanian-Turonian Boundary?

Speculation that elliptical to circular segments of surface exposed lithospheric mantle belts might mark rims of large terrestrial impact basins suggests that the ophiolite rimmed Sulu Sea, Loyalty and Yucatan basins may have resulted from middle Miocene, late Eocene and K-Pg boundary mantle excavating hypervelocity impacts on Earth(Olds, 2019). The Semail ophiolite suggests such a circular rim segment with a ~250 km radius of curvature implying an originally ~500 km diameter impact basin before subsequent deformation/destruction at plate boundaries. Presently the Arabian plate is being actively consumed at the Makran subduction zone(Penney et al., 2017) which evidently will result in subduction of the Gulf of Oman and suturing of the adjacent Semail ophiolite in the near geological future. For large impact basins on the rocky planets, O’Keefe and Ahrens(1993) estimate maximum excavation depth to be roughly 5% of final crater diameter. In this case maximum ejecta source depths of ~25 km are implied, a number roughly comparable with observed thicknesses of crust plus mantle sections for the Semail ophiolite(Aldega et al., 2017) and depths of burial due to over-thrusting(obduction) implied by the exhumed metamorphic sole(Cowan et al., 2014). Hacker et al.(1996) and Roberts et al.(2016) place peak metamorphism timing of the Semail metamorphic sole within uncertainty of the C-T Boundary at 94 Ma. Study of possible correlation of peak obduction timing with end-Cenomanian global extinction plus anoxic events(Wan et al., 2003) and C-T boundary impact ejecta plus tsunami deposits(Monteiro et al., 2001) may be warranted.

Experimental and analytical assessment of the hypervelocity impact damage of GLAss fiber REinforced aluminum

This article addresses the response of GLAss fiber REinforced aluminum to hypervelocity impacts of micrometeoroid analogs at impact velocities of 7 km/s and beyond.In relation,the damage modes of different GLAss fiber REinforced aluminum configurations have been exemplified.The GLAss fiber REinforced aluminum configurations comprised six to twelve variably thick aluminum layers and up to four plies of glass fiber reinforced epoxy per composite laminate.Hypervelocity impact experiments have been conducted with the help of a two-stage light-gas gun,wherein aluminum-and stainless steel projectiles were launched at velocities up to 7.15 km/s.Visual inspection of the damage area suggested the dissipation of impact energy in elastic-plastic deformation,petalling,delamination,debonding,tensile failure of fibers,and pyrolysis of epoxy.A prevailing damage mode was not apparent albeit.The quasi-isotropic ply orientation of S2-glass/FM94-epoxy laminates promoted the interference of shockand rarefaction waves and suppressed the damage area of GLAss fiber REinforced aluminum.To discriminate between the impact performance of different GLAss fiber REinforced aluminum configurations,the energy dissipated in different damage modes of GLAss fiber REinforced aluminum has been assessed quantitatively.In terms of normalized energy,the cross-ply GLAss fiber REinforced aluminum dissipated higher energy in petal formation than in other primary damage modes.The normalized petalling energy was found to decline with the increase of impact energy.The outcomes of this study will help to optimize the GLAss fiber REinforced aluminum laminate,which will be employed as a bumper shield to prevent the fatal damage and the unzipping of a spacecraft pressure bulkhead.

Characteristics of Polyimide Debris Clouds Produced by Hypervelocity Impact

Polyimide is a typical complex high-molecular polymer of imide monomers,which is widely used in the manufacture of parts for aerospace engineering.The hypervelocity impacts between the spacecraft and orbital debris can induce great damage to the spacecraft.In order to improve the safety of spacecraft,the characteristics of polyimide debris clouds produced by hypervelocity impact should be studied.Firstly,a Mie-Grüneisen equation of state based on the shock adiabat for polyimide,which describes the mechanical behavior in the numerical simulation,was obtained from hypervelocity impact experiments,then a 3-dimentional smoothed particle hydrodynamics program was compiled to numerically simulate the hypervelocity impact between aluminum projectiles(orbital debris)and polyimide targets with different impact velocities(3.km/s,5.km/s,8.km/s)and angles(0°,30°,45°,60°),finally typical shapes of debris clouds produced in different impact velocities and angles were collected from simulation results,the characteristics of which were systemically discussed.

Debris cloud structure and hazardous fragments distribution under hypervelocity yaw impact

This study investigates how the debris cloud structure and hazardous fragment distribution vary with attack angle by simulating a circular cylinder projectile hypervelocity impinging on a thin plate using the finite element-smoothed particle hydrodynamics(FE-SPH)adaptive method.Based on the comparison and analysis of the experimental and simulation results,the FE-SPH adaptive method was applied to address the hypervelocity yaw impact problem,and the variation law of the debris cloud structure with the attack angle was obtained.The screening criterion of the hazardous fragment at yaw impact is given by analyzing the debris formation obtained by the FE-SPH adaptive method,and the distribution characteristics of hazardous fragments and their relationship with the attack angle are given.Moreover,the velocity space was used to evaluate the distribution range and damage capability of asymmetric hazardous fragments.The maximum velocity angle was extended from fully symmetrical working conditions to asymmetrical cases to describe the asymmetrical debris cloud distribution range.In this range,the energy density was calculated to quantitatively analyze how much damage hazardous fragments inflict on the rear plate.The results showed that the number of hazardous fragments generated by the case near the 35°attack angle was the largest,the distribution range was the smallest,and the energy density was the largest.These results suggest that in this case,debris cloud generated by the impact had the strongest damage to the rear plate.

Insights into microstructural evolution and deformation behaviors of a gradient textured AZ31B Mg alloy plate under hypervelocity impact

We have for the first time elucidated the microstructural evolution and deformation behaviors of a gradient textured AZ31 B Mg alloy plate under the ultrahigh strain rate of ~10~6 s^(-1) that is generated by a two-stage light gas gun with the hypervelocities of 1.6-4.4 km s^(-1). The hypervelocity impact cratering behaviors indicate that the cratering deformation of AZ31 B Mg alloy is mainly affected by the inertia and strength of the target material. The crater prediction equation of AZ31 B Mg alloy target under impact velocity of 5 km s^(-1) is given. The 2017 Al projectile completely melts in the Mg alloy target plate at the impact velocities of 3.8 km s^(-1) and 4.4 km s^(-1), and the microstructural evolution around the crater is: dynamic recrystallization zone, high-density twinning zone, low-density twinning zone, and Mg alloy matrix. It is found that the dynamic recrystallization, twinning and cracking are the main deformation behaviors for the AZ31 B Mg alloy to absorb the shock wave energy and release the stress generated by the hypervelocity impact. The main plastic deformation mechanisms of the Mg alloy target during hypervelocity impact are twinning and dislocation slip. Microstructure analysis shows the interactions of twins-twins, dislocations-dislocations, and twins-dislocations determine the strain hardening during the hypervelocity impact process, which eventually contributes the dynamic mechanical properties. The evolution of microhardness around the crater further demonstrates the microstructural evolutions and their interactions under the hypervelocity impacts.

Variational Bayesian multi-sparse component extraction for damage reconstruction of space debris hypervelocity impact

To improve the survivability of orbiting spacecraft against space debris impacts,we propose an impact damage assessment method.First,a multi-area damage mining model,which can describe damages in different spatial layers,is built based on an infrared thermal image sequence.Subsequently,to identify different impact damage types from infrared image data effectively,the variational Bayesian inference is used to solve for the parameters in the model.Then,an image-processing framework is proposed to eliminate variational Bayesian errors and compare locations of different damage types.It includes an image segmentation algorithm with an energy function and an image fusion method with sparse representation.In the experiment,the proposed method is used to evaluate the complex damages caused by the impact of the secondary debris cloud on the rear wall of the typical Whipple shield configuration.Experimental results show that it can effectively identify and evaluate the complex damage caused by hypervelocity impact,including surface and internal defects.

Dynamic modeling and damage analysis of debris cloud fragments produced by hypervelocity impacts viaimage processing

It is always a challenging task to model the trajectory and make an efficient damage estimation of debris clouds produced by hypervelocity impact(HVI)on thin-plates due to the difficulty in obtaining high-quality fragment images from experiments.To improve the damage estimation accuracy of HVIs on a typical double-plate Whipple shield configuration,we investigate the distributive characteristic of debris clouds in successive shadowgraphs using image processing techniques and traditional numerical methods.The aim is to extract the target movement parameters of a debris cloud from the acquired shadowgraphs using image processing techniques and construct a trajectory model to estimate the damage with desirable performance.In HVI experiments,eight successive frames of fragment shadowgraphs are derived from a hypervelocity sequence laser shadowgraph imager,and four representative frames are selected to facilitate the subsequent feature analysis.Then,using image processing techniques,such as denoising and segmentation techniques,special fragment features are extracted from successive images.Based on the extracted information,image matching of debris is conducted and the trajectory of debris clouds is modeled according to the matched debris.A comparison of the results obtained using our method and traditional numerical methods shows that the method of obtaining hypervelocity impact experimental data through image processing will provide critical information for improving numerical simulations.Finally,an improved estimation of damage to the rear wall is presented based on the constructed model.The proposed model is validated by comparing the estimated damage to the actual damage to the rear wall.

Spacecraft damage infrared detection algorithm for hypervelocity impact based on double-layer multi-target segmentation

To detect spacecraft damage caused by hypervelocity impact,we propose an advanced spacecraft defect extraction algorithm based on infrared imaging detection.The Gaussian mixture model(GMM)is used to classify the temperature change characteristics in the sampled data of the infrared video stream and reconstruct the image to obtain the infrared reconstructed image(IRRI)reflecting the defect characteristics.The designed segmentation objective function is used to ensure the effectiveness of image segmentation results for noise removal and detail preservation,while taking into account the complexity of IRRI(that is,the required trade-offs are different).A multi-objective optimization algorithm is introduced to achieve balance between detail preservation and noise removal,and a multi-objective evolutionary algorithm based on decomposition(MOEA/D)is used for optimization to ensure damage segmentation accuracy.Experimental results verify the effectiveness of the proposed algorithm.

Survivability assessment of spacecraft impacted by orbit debris

To help optimize the spacecraft design and reduce the risk of spacecraft mission failure, a new approach to assess the survivability of spacecraft in orbit is presented here, including the following three steps: 1)Sensitivity Analysis of spacecraft. A new sensitivity analysis method, a ray method based on virtual outer wall, is presented here. Using rays to simulate the debris cloud can effectively address the component shadowing issues. 2) Component Vulnerability analysis of spacecraft. A function "Component functional reduction degree-Component physical damage degree" is provided here to clearly describe the component functional reduction. 3) System-level Survivability Assessment of spacecraft. A new method based on expert knowledge reasoning, instead of traditional artificial failure tree method, is presented here to greatly improve the efficiency and accuracy of calculation.

Investigation of normal,lateral,and oblique impact of microscale projectiles into unidirectional glass/epoxy composites

Spacesuits and spacecraft must endure high velocity impacts from micrometeoroids. This work considers the impact of 100 μm diameter projectiles into composite targets at velocities from 0.5 km/s to 2 km/s.This work begins by presenting an energy-based theoretical model relating depth of penetration(Do P)and impact force to impact velocity, characteristic time, and threshold velocity and force. Next, this work compares numerical simulations of normal impact on composites to the theoretical model. Numerical simulations are conducted with LS-DYNA and the well-known composite model, MAT-162. The numerical models consider unidirectional S2-glass fiber reinforced SC-15 epoxy composite laminates. The numerical model shows good correlation with the theoretical model. The numerical model also investigates lateral impact, parallel to the fiber direction, and oblique impact at angles from 30°to 82.5°.This work decomposes oblique impact into normal and lateral components, and compares them with normal and lateral impact results. The results show good correlation of the normal component of oblique results with the theoretical model. This numerical and theoretical study focuses on Do P, velocity, and penetration resistance force as functions of time. The theoretical model and numerical simulations are used to determine new Do P parameters: characteristic time of depth of penetration and threshold impact velocity. These models are a first step in developing the capability to predict Do P for oblique,microscale, high-speed impact on composite materials.

Detecting the meteoroid by measuring the electromagnetic waves excited by the collision between the hypervelocity meteoroid and spacecraft

The electromagnetic pulse excited by the collision between a hypervelocity meteoroid and a spacecraft is studied both numerically and theoretically.It is found that there are two kinds of electromagnetic pulse.The high-frequency electromagnetic pulse may be excited by the sum of all the electric dipoles.Each electron can be considered as an electric dipole.The low-frequency electromagnetic pulse is produced by the Langmuir oscillation of electrons.The energy flux density and the duration time of the excited low-frequency electromagnetic pulse by the meteoroid are also studied in the present paper.It is shown that the energy flux density increases as either the impact speed or the mass of the meteoroid increases.It is also shown that the duration time decreases as both the impact speed and the mass of the meteoroid increase.By measuring the strength and the duration time of the electromagnetic pulse excited by the collision between the hypervelocity meteoroid and spacecraft,we can estimate the speed and the mass of the hypervelocity meteoroid,which will be helpful in space flight and space exploration.

Study on damage mechanism and damage distribution of the rear plate under impact of debris cloud

The debris cloud generated by the hypervelocity impact(HVI)of orbiting space debris directly threatens the spacecraft.A full understanding of the damage mechanism of rear plate is useful for the optimal design of protective structures.In this study,the hypervelocity yaw impact of a cylindrical aluminum projectile on a double-layer aluminum plate is simulated by the FE-SPH adaptive method,and the damage process of the rear plate under the impact of the debris cloud is analyzed based on the debris cloud structure.The damage process can be divided into the main impact stage of the debris cloud and the structural response of the rear plate.The main impact stage lasts a short time and is the basis of the rear plate damage.In the stage of structure response,the continuous deformation and inertial motion of the rear plate dominate the perforation of the rear plate.We further analyze the damage mechanism and damage distribution characteristics of the rear plate in detail.Moreover,the connection between velocity space and position space of the debris cloud is established,which promotes the general analysis of the damage law of debris cloud.Based on the relationship,the features of typical damage areas are identified by the localized fine analysis.Both the cumulative effect and structural response cause the perforation of rear plate;in the non-perforated area,cratering by the impact of hazardous fragments is the main damage mode of the rear plate.

Damage quantitative assessment of spacecraft in a large-size inspection

To ensure the safety and reliability of spacecraft during multiple space missions,it is necessary to conduct in-situ nondestructive detection of the spacecraft to judge the damage caused by the hypervelocity impact of micrometeoroids and orbital debris(MMOD).In this paper,we propose an innovative quantitative assessment method based on damage reconstructed image mosaic technology.First,a Gaussian mixture model clustering algorithm is applied to extract images that highlight damage characteristics.Then,a mosaicking scheme based on the ORB feature extraction algorithm and an improved M-estimator SAmple Consensus(MSAC)algorithm with an adaptive threshold selection method is proposed which can create large-scale mosaicked images for damage detection.Eventually,to create the mosaicked images,the damage characteristic regions are segmented and extracted.The location of the damage area is determined and the degree of damage is judged by calculating the centroid position and the perimeter quantitative parameters.The efficiency and applicability of the proposed method are verified by the experimental results.