Effects of DART impact on Dimorphos’ spin state and surface motion away from the impact point

2021 ◽  
Author(s):  
Po-Yen Liu ◽  
Paula Gabriela Benavidez ◽  
Adriano Campo Bagatin ◽  
Derek Charles Richardson ◽  
Laura Parro
Keyword(s):  
Spin State ◽  
Impact Point ◽  
Surface Motion ◽  
The Impact

scholarly journals Analysis of Errors in the Estimation of Impact Positions in Plate-Like Structure through the Triangulation Formula by Piezoelectric Sensors Monitoring

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3426 ◽  
Author(s):  
Eugenio Marino-Merlo ◽  
Andrea Bulletti ◽  
Pietro Giannelli ◽  
Marco Calzolai ◽  
Lorenzo Capineri
Keyword(s):  
Propagation Velocity ◽  
Lamb Waves ◽  
Correlation Method ◽  
Time Of Arrival ◽  
Impact Point ◽  
Laboratory Procedure ◽  
Impact Position ◽  
Set Up ◽  
Two Parameters ◽  
The Impact

The structural health monitoring (SHM) of critical structures is a complex task that involves the use of different sensors that are also aimed at the identification of the location of the impact point using ultrasonic sensors. For the evaluation of the impact position, reference is often made to the well-known triangulation method. This method requires the estimation of the differential time of arrival (DToA) and the group velocity of the Lamb waves propagating into a plate-like structure: the uncertainty of these two parameters is taken into consideration as main cause of localization error. The work proposes a simple laboratory procedure based on a set-up with a pair of sensors that are symmetrically placed with respect to the impact point, to estimate the uncertainty of the DToA and the propagation velocity estimates. According to a theoretical analysis of the error for the impact position, the experimental uncertainties of DToA and the propagation velocity are used to estimate the overall limit of the SHM system for the impact positioning. Because the error for the DToA estimate depends also on the adopted signal processing, three common methods are selected and compared: the threshold, the correlation method, and a likelihood algorithm. Finally, the analysis of the positioning error using multisensory configuration is reported as useful for the design of the SHM system.

scholarly journals Geomagnetic field disturbances from the fall of the Lipetsk (june 21, 2018) and Chelyabinsk (february 15, 2013) meteorites

2019 ◽  
Vol 485 (3) ◽  
pp. 361-365
Author(s):  
A. A. Spivak ◽  
S. A. Riabova
Keyword(s):  
Delay Time ◽  
Geomagnetic Field ◽  
Maximum Effect ◽  
Impact Point ◽  
Cosmic Body ◽  
Meteorite Impact ◽  
Geomagnetic Disturbances ◽  
Geophysical Observatory ◽  
Earth’S Atmosphere ◽  
The Impact

Based on the Chelyabinsk (February 13, 2013) and Lipetsk (June 21, 2018) events, disturbances in the Earth's geomagnetic field, which were induced by the fall of these meteorites, were studied. Based on the data provided by geomagnetic observatories of the INTERMAGNET network and the mid-latitude Mikhnevo geophysical observatory (IDG RAS), it was established that the fall of meteorites through the Earth's atmosphere, in general, induces geomagnetic disturbances of up to 5 nT at distances up to 2700 km from the impact point of a cosmic body; the maximum effect is reached with a delay time ranging from ~5 to ~10 min, and the duration of the period of the induced geomagnetic field disturbances varies from ~5 to ~20 min. The estimation dependencies of the amplitude and duration of induced geomagnetic disturbances from a distance from the meteorite impact points are proposed.

scholarly journals STUDY ON IMPACT FORCES OF THE UNDERWATER CAVITY PROJECTILE

2016 ◽  
Vol 54 (6) ◽  
pp. 797
Author(s):  
Nguyen Thai Dung ◽  
Nguyen Duc Thuyen
Keyword(s):  
Drag Force ◽  
Impact Force ◽  
Center Of Mass ◽  
Forward Direction ◽  
Cavity Wall ◽  
Impact Point ◽  
Impact Forces ◽  
Underwater Projectile ◽  
The Impact ◽  
Cavity Effect

The motion of the underwater projectile with cavity effect including two motions: the projectile moves in the forward direction, center of mass of the projectile rotation around its nose makes tail of the projectile impacts on the cavity wall. According to, the impact forces occur, they include the drag force at its none, the impact force at impact point. The paper studies the forces occur on during motion of the underwater cavity projectile. Added, this paper considers the effect of the length and distributive projectile to the magnitude of impact force and the drag force of the underwater cavity projectile.

Design and Simulation of Guidance Law for a Kind of Flight Test Missile

2012 ◽  
Vol 538-541 ◽  
pp. 2887-2891
Author(s):  
Yu Qian ◽  
Xiao Jun Xiang ◽  
Jun Li Yang
Keyword(s):  
Flight Test ◽  
Target Point ◽  
Impact Point ◽  
Integral Term ◽  
Guidance Law ◽  
Velocity Information ◽  
The Difference ◽  
Miss Distance ◽  
Midcourse Guidance ◽  
The Impact

To reduce the miss distance of flight test missile, the midcourse guidance law is studied in this paper. The nonlinear projectile dynamic model is developed at first, and then designed the midcourse guidance law with the impact point prediction information. The guidance law was designed using the difference between predicting impact point and target point. To improve the guidance law’s performance, this research inducted the predicted impact point’s velocity information and integral term into guidance law command. At the end, the simulation was developed. The results of simulation show that the guidance law designed in this study is successful and it can satisfy the test missile’s flight mission requirements.

Ballistic Performance of TiC-TiB2 Composite Armour under the Impact of Long-Rod Tungsten Alloy Projectiles of 1.4 km · s-1

2013 ◽  
Vol 544 ◽  
pp. 310-315
Author(s):  
Xue Gang Huang ◽  
Zhong Min Zhao ◽  
Long Zhang
Keyword(s):  
Layered Composite ◽  
Tungsten Alloy ◽  
Ti Alloy ◽  
Impact Point ◽  
Layered Composites ◽  
Micro Hardness ◽  
Ballistic Performance ◽  
Long Rod ◽  
High Gravity Field ◽  
The Impact

Based on using combustion synthesis in high-gravity field to prepare the solidified TiC-TiB2 composites, the layered composites of the ceramic to Ti-6Al-4V at graded composition were achieved by fusion joint and atomic inter-diffusion between liquid TiC-TiB2 and Ti-6Al-4V substrate. The mechanical properties showed that the relative density, micro-hardness and fracture toughness of TiC-TiB2 ceramic layer measured 98.5%, 21.5 GPa and 13.5 ± 2.5 MPa • m0.5, respectively, and the shear strength at joint of TiC-TiB2 to Ti-6Al-4V measured 450 ± 25 MPa. By conducting DOP test to evaluate ballistic performance of the ceramic and layered-composite targets against long-rod KE projectiles at impact velocity of 1.4 km • s-1, it was obtained the mass efficiency 3.28 of the solidified TiC-TiB2 was achieved as the impact point of the projectile was nearby the centre of the target, whereas the mass efficiency 3.18 of the layered composite with the solidified ceramic to Ti-6Al-4V was also achieved even if the impact point of the projectile was at the edge of the target. By combining penetration damage of the targets with the dynamic behavior of the ceramic, it was obtained that the layered composite achieved by the joint of the solidified ceramic to Ti-6Al-4V not only improve ballistic performance of the ceramic, but also weaken the sensitivity of the ceramic target against the impact point of KE projectile by tearing the joint of the ceramic with Ti alloy to restrain formation and propagation of conical crack and fracture cone in the ceramic.

Modeling and Simulation of Impact Point Prediction Algorithm

2013 ◽  
Vol 347-350 ◽  
pp. 438-442 ◽  
Author(s):  
Zai Ke Tian ◽  
Suo Chang Yang ◽  
De Long Feng ◽  
Yun Zhi Yao
Keyword(s):  
Perturbation Theory ◽  
Degrees Of Freedom ◽  
Prediction Algorithm ◽  
Impact Point ◽  
Guidance Law ◽  
Trajectory Simulation ◽  
Correction Scheme ◽  
Trajectory Correction ◽  
6 Degrees Of Freedom ◽  
The Impact

Trajectory correction projectiles significantly improved shooting accuracy of conventional ammunition.This paper designed an impact point prediction algorithm based on perturbation theory, and proposed trajectory correction scheme based on the impact point prediction algorithm. Based on perturbation theory, getting samples by solving ideal trajectory and typical disturbed trajectory, and solving the coefficients of the prediction model by regression.The 6-degrees of freedom trajectory simulation shows that adopting this correction guidance law, the standard error of the longitudinal falling points of projectiles reduced significantly.

The location of the impact point of the Deep Impact Impactor on Comet 9P/Tempel 1

Icarus ◽  
2013 ◽  
Vol 222 (2) ◽  
pp. 487-491 ◽  
Author(s):  
Dennis D. Wellnitz ◽  
Steven M. Collins ◽  
Michael F. A’Hearn
Keyword(s):  
Impact Point ◽  
Deep Impact ◽  
The Impact

Dispersion reduction of artillery rockets guided by flight path steering method

2016 ◽  
Vol 120 (1225) ◽  
pp. 435-456 ◽  
Author(s):  
S. Mandić
Keyword(s):  
Measurement Errors ◽  
Flight Path ◽  
Guidance System ◽  
Lateral Acceleration ◽  
Dominant Factor ◽  
Measurement Unit ◽  
Impact Point ◽  
Angle Correction ◽  
Flight Path Angle ◽  
The Impact

ABSTRACTArtillery rockets are sensitive to disturbances (total impulse variation, wind, thrust misalignment, etc.). As the range of ground-to-ground rockets increases, the accuracy of free flight rockets decreases. Requirements for the increase of the range and minimisation of the impact point dispersions can be solved by adding guidance and control systems to rockets. Based on the differences between the measured flight parameters and the calculated parameters for the nominal trajectory, the flight path angle correction algorithm is obtained by adding the correction to the nominal value. The flight path steering guidance system with lateral acceleration autopilot in the inner loop, is used for the guidance of hypothetical artillery rockets. The guidance algorithm given in this paper eliminates the time correction due to rocket velocity variations. Efficiency of the proposed algorithm is illustrated by numerical simulation. There is no practical influence of the external disturbances on impact point dispersion. It is also shown that the measurement errors of the inertial measurement unit are the dominant factor affecting impact point dispersion of artillery rockets modified by adding a guidance system based on the flight path steering method.

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