Effects of the DART (NASA) mission collision on the structure and spin state of the secondary of the Near-Earth asteroid (65803) Didymos binary system.

2020 ◽  
Author(s):  
Paula Benavidez ◽  
Adriano Campo Bagatin ◽  
Manuel Perez-Molina ◽  
Derek C. Richardson ◽  
Antonio Santana-Ros ◽  
...  
Keyword(s):  
Binary System ◽  
Kinetic Energy ◽  
Orbital Plane ◽  
Impact Angle ◽  
Numerical Code ◽  
Asteroid Impact ◽  
Earth Asteroid ◽  
Post Impact ◽  
Impact Kinetic Energy ◽  
The Impact

<p>AIDA (Asteroid Impact & Deflection Assessment) is an international collaboration between NASA and ESA which involves both DART (Double Asteroid Redirection Test, NASA) and Hera (ESA) missions. The target is an asteroid of approximately 160 m in size, namely the secondary of the binary Near-Earth Asteroid (65803) Didymos. Little is known about the shape of the satellite, with a moderately elongated shape (b/a<1.2) compatible with available ground-based estimations. In this work we investigate the possible reaction of the target to the DART collision to be performed in 2022, under the assumption that it is a gravitational aggregate produced in the formation of the binary system. The very structure of the target is unknown, therefore we model it by (1) mono- and multi-dispersed distributions of spherical basic elements and by (2) considering irregular components. We perform numerical simulations of the collision event by using a discrete-element N-body numerical code (PKDGRAV-SSDEM). We do not perform simulations of the shattering phase, we instead concentrate on the effect of the collision on the target, after the shattering phase implying material damage (melting, vaporization, heating and deformation), is over. Therefore, our synthetic projectile carries the same nominal momentum as the DART mission does, but it delivers to the target only the kinetic energy expected to survive once the shattering (non-elastic) phase has dissipated most of the impact kinetic energy. We account for different centre- and off-centre- possible impact geometry compatible with DART nominal impact angle with respect to the target orbital plane.</p> <p>Here we report on results obtained so far on the effects of the DART impact on the structure of the Didymos satellite, including changes in its spin period and direction of the direction of the spin axis, as well as change of shape.</p> <p>Moreover, we look at the velocity field of surface particles to infer if any motion is expected away from the impact point and regolith particles can be ejected from locations far from it.</p> <p>Such predictions may be of interest in the study of the post-impact dynamics of the system –that will be determined by the Hera mission measurements. This, in turn will help in the interpretation of the results of the outcome of the DART impact mission, including the determination of the momentum multiplication (beta) factor.</p> <p> </p>

Motion Situation and Kinetic Energy Analysis for Ore Pass of Underground Mine

2011 ◽  
Vol 90-93 ◽  
pp. 383-386
Author(s):  
Yong Heng Huang ◽  
Ping Cao ◽  
Yi Xian Wang
Keyword(s):  
Kinetic Energy ◽  
High Speed ◽  
Impact Damage ◽  
Critical Value ◽  
Impact Angle ◽  
Underground Mine ◽  
Damaged Zone ◽  
Impact Kinetic Energy ◽  
The Impact ◽  
Ore Pass

The fragmentation of ore pass under loading belongs to one of the typical disaster in underground mine. This paper is concerned with the description and explanation of this phenomenon and presents brittle fragmentation for impact damage of rock block based on impact test, high-speed camera was used to study the relation between fragmentation and damage and the effect of the kinetic energy of projectile on them, the experimental results demonstrate that the damaged zone, invasion depth increase with the increase of the kinetic energy of projectile, but are influenced by the impact angle; the results show that prior to the impact kinetic energy reaches the critical value, the energy dissipation is mainly for damaged zone, when the impact kinetic energy increases to the critical value.

scholarly journals Pendulum-based measurements reveal impact dynamics at the scale of a trap-jaw ant

2021 ◽  
pp. jeb.232157
Author(s):  
J. F. Jorge ◽  
S. Bergbreiter ◽  
S. N. Patek
Keyword(s):  
Kinetic Energy ◽  
Target Material ◽  
Contact Duration ◽  
Pendulum Motion ◽  
High Acceleration ◽  
Post Impact ◽  
Biological Impacts ◽  
Impact Kinetic Energy ◽  
Odontomachus Brunneus ◽  
The Impact

Small organisms can produce powerful, sub-millisecond impacts by moving tiny structures at high accelerations. We developed and validated a pendulum device to measure the impact energetics of microgram-sized trap-jaw ant mandibles accelerated against targets at 105 m s−2. Trap-jaw ants (Odontomachus brunneus; 19 individuals; 212 strikes) were suspended on one pendulum and struck swappable targets that were either attached to an opposing pendulum or fixed in place. Mean post-impact kinetic energy (energy from strike converted to pendulum motion) was higher with a stiff target (21.0-21.5 µJ) than a compliant target (6.4-6.5 µJ). Target mobility had relatively little influence on energy transfer. Mean contact duration of strikes against stiff targets was shorter (3.9-4.5 ms) than against compliant targets (6.2-7.9 ms). Shorter contact duration was correlated with higher post-impact kinetic energy. These findings contextualize and provide an energetic explanation for the diverse, natural uses of trap-jaw ant strikes such as impaling prey, launching away threats, and performing mandible-powered jumps. The strong effect of target material on energetic exchange suggests material interactions as an avenue for tuning performance of small, high acceleration impacts. Our device offers a foundation for novel research into the ecomechanics and evolution of tiny biological impacts and their application in synthetic systems.

scholarly journals Particle Impact and Breakup in Aircraft Measurement

2009 ◽  
Vol 26 (5) ◽  
pp. 972-983 ◽  
Author(s):  
German Vidaurre ◽  
John Hallett
Keyword(s):  
Kinetic Energy ◽  
Surface Energy ◽  
Cloud Particle ◽  
Aircraft Measurement ◽  
University Of North Dakota ◽  
Particle Properties ◽  
Imaging Probes ◽  
Impact Kinetic Energy ◽  
The Impact ◽  
Particle Approach

Abstract Measurements of cloud particle properties from aircraft by optical and impact techniques are subject to artifacts following particle breakup prior to detection. The impact kinetic energy to surface energy ratio (ℒ) provides a breakup criterion at ℒ ≥ 7 for water and ice with major fragmentation for ℒ > 100. This applies to optical imaging probes for particle concentration, size, and projected area spectra measurement. Uncertainty arises should impacting particles shatter and disperse, defeating the intent of the original measurements. Particle shatter is demonstrated in Formvar replicas (University of North Dakota Citation) and video records of particle approach and impact on the Cloudscope (NCAR C-130, NASA DC-8) at airspeeds of 130 and 200 m s−1. Sufficient impact kinetic energy results in drop splash and ice shatter, with conversion to surface energy and ultimately thermal energy through viscous dissipation and ice defect production occurring down to the molecular scale. The problem is minimized in design by reducing the regions responsible for particle breakup to a minimum and locating sensors in regions inaccessible to shatter fragments.

Research of Performance about Ceramic Coating on Aluminum Bumper to Resist Hypervelocity Impact

2013 ◽  
Vol 577-578 ◽  
pp. 629-632
Author(s):  
Gong Shun Guan ◽  
Qiang Bi ◽  
Yu Zhang
Keyword(s):  
Kinetic Energy ◽  
Optimum Design ◽  
Critical Thickness ◽  
Ceramic Coating ◽  
Impact Angle ◽  
Hypervelocity Impact ◽  
Front Side ◽  
Gas Gun ◽  
Whipple Shield ◽  
The Impact

Shield structure based on ceramic coating on aluminum bumper was designed, and a series of hypervelocity impact tests were practiced with a two-stage light gas gun facility. Impact velocities were varied between1.5km/s and 5.0km/s. The diameter of projectiles were 3.97mm and 6.35mm respectively. The impact angle was 0°. The damage of the ceramic coating on aluminum bumper under hypervelocity impact was studied. It was found that the ceramic coating on aluminum bumper could help enhancing the protection performance of shield to resist hypervelocity impact. The results indicated when the ceramic coating is on the front side of aluminum bumper, it was good for comminuting projectile and weakening the kinetic energy of projectile. For a certain aluminum bumper, existing a critical thickness of ceramic coating in which capability of Whipple shield to resist hypervelocity impact is the best. On this basis, the proposal of the optimum design for ceramic coating on aluminum bumper was made.

INFLUENCE OF THE IMPACT ANGLE OF A SOLID PARTICLE JET ON THE EROSION WEAR OF 38GSA AND HARDOX 500 STEEL

Tribologia ◽  
2017 ◽  
Vol 273 (3) ◽  
pp. 85-90 ◽  
Author(s):  
Bazyli KRUPICZ ◽  
Wojciech TARASIUK ◽  
Jerzy NAPIÓRKOWSKI ◽  
Krzysztof LIGIER
Keyword(s):  
Mechanical Properties ◽  
Kinetic Energy ◽  
Solid Particle ◽  
Quartz Sand ◽  
Impact Angle ◽  
Erosion Wear ◽  
Sand Particles ◽  
Work Of Deformation ◽  
The Impact

The paper investigated the influence of the impact angle of a solid particle jet on the erosion wear of 38GSA and Hardox 500 steel. The basis of the analysis was the assumption of the existence of a correlation between mechanical properties of the material, represented by the work of deformation (P) determined from the stressstrain diagram (U). The impact angle of quartz sand particles (30, 60, and 90 °) was considered through the separation of kinetic energy of particles impacting the eroded surface perpendicularly and tangentially.

Initial response mechanism and local contact stiffness analysis of the floating two-stage buffer collision-prevention system under ship colliding

2021 ◽  
pp. 136943322098610
Author(s):  
Kai Lu ◽  
Xu-Jun Chen ◽  
Zhen Gao ◽  
Liang-Yu Cheng ◽  
Guang-Huai Wu
Keyword(s):  
Kinetic Energy ◽  
Impact Force ◽  
Contact Stiffness ◽  
Impact Angle ◽  
Bridge Pier ◽  
Two Stage ◽  
Collision Prevention ◽  
Prevention System ◽  
The Impact ◽  
Depth Curves

A floating two-stage buffer collision-prevention system (FTBCPS) has been proposed to reduce the impact loads on the bridge pier in this paper. The anti-collision process can be mainly divided into two stages. First, reduce the ship velocity and change the ship initial moving direction with the stretching and fracture of the polyester ropes. Second, consume the ship kinetic energy with the huge damage and deformation of the FTBCPS and the ship. The main feature of the FTBCPS lies in the first stage and most of the ship kinetic energy can be dissipated before the ship directly impacts on the bridge pier. The contact stiffness value between the ship and the FTBCPS can be a significant factor in the first stage and the calculation method of it is the focus of this paper. The contact force, the internal force and the general equation of motion have been given in the first part. The structure model of the ship and the FTBCPS are then established in the ANSYS Workbench. After that, 38 typical load cases of the ship impacting on the FTBCPS are conducted in LS-DYNA. The reduction processes of the ship kinetic energy and the ship velocity in different load cases have been investigated. It can be summarized that the impact angle and the ship initial velocity are the main factors in the energy and velocity dissipation process. Moreover, the local impact force-depth curves have also been studied and the impact angle is found to be the only significant factor on the ship impact process. Next, the impact force-depth curves with different impact angles are fitted and the contact stiffness values are accordingly calculated. Finally, the impact depth range, the validity of the local simulation results and the consistency of the fitted stiffness value are verified respectively, demonstrating that the fitted stiffness values are applicable in the global analysis.

scholarly journals Apsidal motion in the massive binary HD 152248

2020 ◽  
Vol 642 ◽  
pp. A221
Author(s):  
S. Rosu ◽  
A. Noels ◽  
M.-A. Dupret ◽  
G. Rauw ◽  
M. Farnir ◽  
...  
Keyword(s):  
Binary System ◽  
Internal Structure ◽  
Turbulent Diffusion ◽  
Structure Constant ◽  
Orbital Plane ◽  
Apsidal Motion ◽  
Stellar Rotation ◽  
Single Star ◽  
Internal Mixing ◽  
The Impact

Context. Apsidal motion in massive eccentric binaries offers precious information about the internal structure of the stars. This is especially true for twin binaries consisting of two nearly identical stars. Aims. We make use of the tidally induced apsidal motion in the twin binary HD 152248 to infer constraints on the internal structure of the O7.5 III-II stars composing this system. Methods. We build stellar evolution models with the code Clés assuming different prescriptions for the internal mixing occurring inside the stars. We identify the models that best reproduce the observationally determined present-day properties of the components of HD 152248, as well as their internal structure constants, and the apsidal motion rate of the system. We analyse the impact on the results of some poorly constrained input parameters in the models, including overshooting, turbulent diffusion, and metallicity. We further build “single” and “binary” GENEC models that account for stellar rotation to investigate the impacts of binarity and rotation. We discuss some effects that could bias our interpretation of the apsidal motion in terms of the internal structure constant. Results. The analysis of the Clés models reveals that reproducing the observed k2 value and rate of apsidal motion simultaneously with the other stellar parameters requires a significant amount of internal mixing (either turbulent diffusion, overshooting, or rotational mixing) or enhanced mass-loss. The results obtained with the GENEC models suggest that a single-star evolution model is sufficient to describe the physics inside this binary system. We suggest that, qualitatively, the high turbulent diffusion required to reproduce the observations could be partly attributed to stellar rotation. We show that higher-order terms in the apsidal motion are negligible. Only a very severe misalignment of the rotation axes with respect to the normal to the orbital plane could significantly impact the rate of apsidal motion, but such a high misalignment is highly unlikely in such a binary system. Conclusions. We infer an age estimate of 5.15 ± 0.13 Myr for the binary system and initial masses of 32.8 ± 0.6 M⊙ for both stars.

scholarly journals Impact of a Multiple Pendulum with a Non-Linear Contact Force

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1202
Author(s):  
Dan B. Marghitu ◽  
Jing Zhao
Keyword(s):  
Kinetic Energy ◽  
Contact Force ◽  
Equations Of Motion ◽  
Linear Equations ◽  
Kinematic Chain ◽  
Double Pendulum ◽  
Lagrange Equations ◽  
Non Linear ◽  
Impact Kinetic Energy ◽  
The Impact

This article presents a method to solve the impact of a kinematic chain in terms of a non-linear contact force. The nonlinear contact force has different expressions for elastic compression, elasto-plastic compression, and elastic restitution. Lagrange equations of motion are used to obtain the non-linear equations of motion with friction for the collision period. The kinetic energy during the impact is compared with the pre-impact kinetic energy. During the impact of a double pendulum the kinetic energy of the non-impacting link is increasing and the total kinetic energy of the impacting link is decreasing.

scholarly journals Microbial life in the nascent Chicxulub crater

Geology ◽  
2020 ◽  
Vol 48 (4) ◽  
pp. 328-332 ◽  
Author(s):  
Bettina Schaefer ◽  
Kliti Grice ◽  
Marco J.L. Coolen ◽  
Roger E. Summons ◽  
Xingqian Cui ◽  
...  
Keyword(s):  
Microbial Mats ◽  
Nutrient Supply ◽  
Core Material ◽  
Asteroid Impact ◽  
Microbial Life ◽  
Sulfur Bacteria ◽  
Post Impact ◽  
Photosynthetic Sulfur Bacteria ◽  
Chicxulub Crater ◽  
The Impact

Abstract The Chicxulub crater was formed by an asteroid impact at ca. 66 Ma. The impact is considered to have contributed to the end-Cretaceous mass extinction and reduced productivity in the world’s oceans due to a transient cessation of photosynthesis. Here, biomarker profiles extracted from crater core material reveal exceptional insights into the post-impact upheaval and rapid recovery of microbial life. In the immediate hours to days after the impact, ocean resurge flooded the crater and a subsequent tsunami delivered debris from the surrounding carbonate ramp. Deposited material, including biomarkers diagnostic for land plants, cyanobacteria, and photosynthetic sulfur bacteria, appears to have been mobilized by wave energy from coastal microbial mats. As that energy subsided, days to months later, blooms of unicellular cyanobacteria were fueled by terrigenous nutrients. Approximately 200 k.y. later, the nutrient supply waned and the basin returned to oligotrophic conditions, as evident from N2-fixing cyanobacteria biomarkers. At 1 m.y. after impact, the abundance of photosynthetic sulfur bacteria supported the development of water-column photic zone euxinia within the crater.

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