scholarly journals An Impact Location Algorithm for Spacecraft Stiffened Structure Based on Posterior Possibility Correlation

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 368 ◽  
Author(s):  
Lei Qi ◽  
Zhoumo Zeng ◽  
Lichen Sun ◽  
Xiaobo Rui ◽  
Fan Fan ◽  
...  
Keyword(s):  
Posterior Probability ◽  
Cross Correlation ◽  
Bayesian Posterior Probability ◽  
Probability Method ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Impact Location ◽  
Weight Method ◽  
Location Algorithm ◽  
The Impact

In order to ensure the safety of spacecrafts in orbit, impact location is an important part of structural health monitoring systems. In this paper, an impact location algorithm based on posterior probability correlation is proposed to solve the problem, that is, the impact point in the stiffened structure of a spacecraft is difficult to locate. The algorithm combines the Gaussian cross-correlation possibility weight method and the Bayesian posterior probability method. The cross-correlation possibility weight superposition based on grids was used to reduce the dependence of the accuracy of time difference extraction. Gaussian and normalized fitting were used to compensate the reflection, modal transformation, and amplitude attenuation of a stiffened plate. The location result was further optimized by the posterior probability. The proposed algorithm can be applied to the impact source localization of complex stiffened plate structures. The experiment results showed that the average location error can be 2.57 cm with proper sensor network schemes.

scholarly journals Location, orbit, and energy of a meteoroid impacting the Moon during the lunar eclipse of 2019 January 21

2019 ◽  
Vol 492 (1) ◽  
pp. 1432-1449
Author(s):  
J I Zuluaga ◽  
M Tangmatitham ◽  
P Cuartas-Restrepo ◽  
J Ospina ◽  
F Pichardo ◽  
...  
Keyword(s):  
Posterior Probability ◽  
Light Flash ◽  
Probability Distributions ◽  
Lunar Eclipse ◽  
The Moon ◽  
Impact Location ◽  
Crater Size ◽  
Rgb Images ◽  
The Impact ◽  
Geographical Locations

ABSTRACT During lunar eclipse of 2019 January 21, a meteoroid impacted the Moon producing a visible light flash. The impact was witnessed by casual observers offering an opportunity to study the phenomenon from multiple geographical locations. We use images and videos collected by observers in seven countries to estimate the location, impact parameters (speed and incoming direction), and energy of the meteoroid. Using parallax, we achieve determining the impact location at lat.$-29.43^{+0.30}_{-0.21}$, lon.$-67.89^{+0.07}_{-0.09}$, and geocentric distance as 356 553 km. After devising and applying a photometric procedure for measuring flash standard magnitudes in multiple RGB images having different exposure times, we found that the flash, had an average G-magnitude 〈G〉 = 6.7 ± 0.3. We use gravitational ray tracing (GRT) to estimate the orbital properties and likely radiant of the impactor. We find that the meteoroid impacted the moon with a speed of $14^{+7}_{-6}$ km s−1 (70 per cent C.L.) and at a shallow angle, θ < 38.2 deg. Assuming a normal error for our estimated flash brightness, educated priors for the luminous efficiency and object density, and using the GRT-computed probability distributions of impact speed and incoming directions, we calculate posterior probability distributions for the kinetic energy (median Kmed = 0.8 kton), body mass (Mmed = 27 kg) and diameter (dmed = 29 cm), and crater size (Dmed = 9 m). If our assumptions are correct, the crater left by the impact could be detectable by prospecting lunar probes. These results arose from a timely collaboration between professional and amateur astronomers that highlight the potential importance of citizen science in astronomy.

scholarly journals Numerical Investigation on the Ultimate Strength of Box Beams with Impact Damage

2020 ◽  
Author(s):  
Wei Xu ◽  
C. Guedes Soares
Keyword(s):  
Residual Stress ◽  
Ultimate Strength ◽  
Impact Damage ◽  
Ship Hulls ◽  
Four Point Bending ◽  
Impact Location ◽  
Box Beam ◽  
Box Beams ◽  
Fracture Damage ◽  
The Impact

AbstractThe objective of this paper is to study the residual ultimate strength of box beams with impact-induced damage, as a model of what may occur in ship hulls. The bottom and side plates of ship hulls can suffer denting or fracture damage due to grounding, collision and other contacts during the ship’s service life and these impact-induced damages could result in considerable strength degradation. Box beams are firstly subjected to impact loading and then four-point bending loading is imposed on the damaged structures to assess the residual strength using ANSYS/LS_DYNA. The ultimate moment and collapse modes are discussed considering the effect of impact location. The impact-induced deformation is introduced in the four-point bending simulation, and the impact-induced stress is included or not to determine the effect of residual stress and distortion after impact. It is shown that impact location has significant influence on the residual ultimate bending moment of the damaged box beam providing that the impact energy is kept constant. The collapse modes also change when the impactor strikes on different locations. Damaged hard corner and inclined neutral axes might explain the reduction of ultimate strength and diverse collapse modes. The residual stress in the box beam after impact may increase or decrease the ultimate strength depending on impact location.

Integrated design optimization of stiffened plate structures

1999 ◽  
Vol 16 (8) ◽  
pp. 934-952 ◽  
Author(s):  
F. Belblidia ◽  
S.M.B. Afonso ◽  
E. Hinton ◽  
G.C.R. Antonino
Keyword(s):  
Design Optimization ◽  
Integrated Design ◽  
Stiffened Plate ◽  
Plate Structures

An Equivalent 3-D Method for Analyzing Orthogonally Stiffened Plate Structures

1987 ◽  
Vol 31 (02) ◽  
pp. 101-106
Author(s):  
Kyu Nam Cho ◽  
William S. Vorus
Keyword(s):  
Bridge Decks ◽  
Three Dimensional ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Work Related ◽  
Beam Elements ◽  
Proposed Model ◽  
The Relationship

A new three-dimensional method is proposed for analyzing orthogonally stiffened grillage structures. The method is based on earlier work related to bridge decks. The relationship between system displacement and loads is described mathematically, and matrices are developed to examine the shear compatibility between plate and beam elements. The paper concludes with a comparison between deflections obtained by several different procedures and the proposed model.

Idealized Structural Unit Method for Collapse Analyses of Stiffened Plate Structures

2003 ◽  
Vol 50 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Patrick Kaeding ◽  
Masahiko Fujikubo ◽  
◽  
Keyword(s):  
Structural Unit ◽  
Stiffened Plate ◽  
Plate Structures

scholarly journals THE IMPACT OF TAXATION AS AN AID TO ECONOMIC DEVELOPMENT (APPLIED STUDY IN KURDISTAN REGIONAL GOVERNMENT)

2020 ◽  
Author(s):  
Amanj Mohamed Ahmed ◽  
Muhammad Nawzad Ali
Keyword(s):  
Economic Development ◽  
Primary Source ◽  
Educational Systems ◽  
Secondary Source ◽  
Probability Method ◽  
Regional Government ◽  
Chi Square ◽  
The Government ◽  
Taxation System ◽  
The Impact

<p><em>This research was carried out to determine the weight of taxation in economic development, the main purpose is to discover the level of impact of taxation on economic development or if it has any impact. Another key objective is to improve the level of understandability and find probable solutions toward issues in taxation within the Kurdistan region, as well as unveiling the Kurdistan Regional Government’s taxation system in compliance with the up to date old Iraqi tax laws. KRG is barely surviving this crisis, with the increase of unemployment and poverty could taxation work as an aid to support the piles of the region. The current corruption in the government that does not use tax money efficiently and lack of transparency has been evaluated. Primary and secondary research methods were used to be able to gather information in order to reach an understanding. The primary source of data includes personal interviews and questionnaires, meanwhile, the secondary source of data includes the use of textbooks, social media, internet, and newspapers. Non-probability method of sampling was used in selecting the respondents. The study used the standard deviation, chi-square formula, and tables for the method of the examination. The results clearly illustrates that the government should</em> <em>commence the critical pursuit of broadening regional economy in order to improve economic growth and expansion and to become meticulous to fight with real corruption. The limitation and resources should be expanded by the government and bring taxation back to life through educational systems and social awareness.</em></p>

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