scholarly journals Fragment velocity distribution in the impact disruption of thin glass plates

2005 ◽  
Vol 72 (4) ◽  
Author(s):  
Toshihiko Kadono ◽  
Masahiko Arakawa ◽  
Noriko K. Mitani
Keyword(s):  
Velocity Distribution ◽  
Thin Glass ◽  
Glass Plates ◽  
The Impact

Simplified Static Analysis for Shock Behavior Evaluation of Thin Glass Plates

2006 ◽  
Vol 110 ◽  
pp. 263-270
Author(s):  
Seong In Moon ◽  
Chang Hoi Kim ◽  
Ja Choon Koo ◽  
Jae Boong Choi ◽  
Young Jin Kim ◽  
...  
Keyword(s):  
Static Analysis ◽  
Impact Loading ◽  
Ad Hoc ◽  
Solid Mechanics ◽  
Static Problem ◽  
Impact Behavior ◽  
Mechanical Shock ◽  
Thin Glass ◽  
Glass Plates ◽  
The Impact

Recently, mechanical shock failures of a flat display unit such as TFT-LCD device have been an important concern of designers. In order to achieve the mechanical shock requirement, it is necessary to perform the detailed FE analyses which could be very expensive either by the lengthy computation or by the complicated geometry modeling. The objective of this study is to propose a simplified analysis methodology to simulate impact behavior of thin glass plates. The static problem equivalent to the impact one is found from the concept of solid mechanics to estimate the maximum deflection and stress under impact loading. To show the plausibility of the proposed approach, it is applied to the idealized problem which is a two dimensional beam subjected to impact loading. Based on explicit FE analyses using the LS-DYNA FE program, it was shown that the impact problem can be solved by the equivalent static analysis which is much easier to solve in practice. Therefore, the proposed approach provides significant advantages in design optimization of a TFT-LCD device against shock failure, and enables the designer to avoid ad hoc modeling of the transient dynamics so that product design cycle could be shortened.

DART and LICIACUBE: Documenting Kinetic Impact

2021 ◽  
Author(s):  
Andrew Cheng ◽  
Elizabetta Dotto ◽  
Eugene Fahnestock ◽  
Vincenzo Della Corte ◽  
Nancy Chabot ◽  
...  
Keyword(s):  
Time Delay ◽  
Velocity Distribution ◽  
Physical Properties ◽  
Optical Depth ◽  
Depth Profiles ◽  
Full Characterization ◽  
Approach Distance ◽  
Impact Ejecta ◽  
The Impact

<p>The NASA Double Asteroid Redirection Test (DART) mission will demonstrate asteroid deflection by a kinetic impactor. DART will impact Dimorphos, the secondary member of the (65803) Didymos system, in late September to early October, 2022 in order to change the binary orbit period. DART will carry a 6U CubeSat called LICIACube, contributed by the Italian Space Agency, to document the DART impact and to observe the impact ejecta. LICIACube will be released by DART 10 days prior to Didymos encounter, and LICIACube will fly by Dimorphos at closest approach distance of about 51 km and with a closest approach time delay of about 167 s after the DART impact. LICIACube will observe the structure and evolution of the DART impact ejecta plume and will obtain images of the surfaces of both bodies at best ground sampling about 1.4 m per pixel. LICIACube imaging importantly includes the non-impact hemisphere of the target body, the side not imaged by DART.</p> <p> </p> <p>The LICIACube flyby trajectory, notably the closest approach distance and the time delay of closest approach, are designed to optimize the study of ejecta plume evolution without exposing the satellite to impact hazard. LICIACube imaging will determine the direction of the ejecta plume and the ejection angles, and will further help to determine the ejecta momentum transfer efficiency <em>β</em>. The ejecta plume structure, as it evolves over time, is determined by the amount of ejecta that has reached a given altitude at a given time. The LICIACube plume images enable characterization of the ejecta mass versus velocity distribution, which is strongly dependent on target properties like strength and porosity and is therefore a powerful diagnostic of the DART impact, complementary to measurements of the DART impact crater by the ESA Hera mission which will arrive at Didymos in 2026. Hera will measure crater radius and crater volume to determine the total volume of ejecta, which together with a ejecta mass-velocity distribution gives a full characterization of the DART impact.</p> <p> </p> <p>Models of the ejecta plume evolution as imaged by LICIACube show how LICIACube images can discriminate between different target physical properties (mainly strength and porosity), thereby allowing inferences of the magnitude of the ejecta momentum. Measured ejecta plume optical depth profiles can distinguish between gravity-controlled and strength-controlled impact cases and help determine target physical properties. LICIACube ejecta plume images further provide information on the direction of the ejecta momentum as well as the magnitude, requiring full 2-D simulations of the plume images. We will present new simulation model optical depth profiles across the plume at arbitrary positions.</p> <p><br />We thank NASA for support of the DART project at JHU/APL, under Contract # NNN06AA01C, Task Order # NNN15AA05T. The Italian LICIACube team acknowledges financial support from Agenzia Spaziale Italiana (ASI, contract No. 2019-31-HH.0 CUP<br />F84I190012600).</p>

scholarly journals IV. Impact with a liquid surface studied by the aid of instantaneous photography. Paper II

1900 ◽  
Vol 194 (252-261) ◽  
pp. 175-199 ◽  
Keyword(s):  
Liquid Surface ◽  
Thin Glass ◽  
Water Line ◽  
Glass Vessel ◽  
Camera Lens ◽  
General Arrangement ◽  
Set Up ◽  
The Impact ◽  
Rough Sphere ◽  
Smooth Sphere

In a previous paper (‘Philosophical Transactions,’ A, 1897, vol. 189, p. 137) we have drawn attention to the fact that the disturbance set up in a liquid by the impact of a rough sphere falling into it, differs in a very remarkable manner from that which follows the entry of a smooth sphere. In the present paper we describe further experiments, made with the object of ascertaining the reason of this difference, and give the conclusions reached. It appeared desirable, in the first place, to take instantaneous photographs of the disturbed liquid below the water-line. These were easily obtained by letting the splash take place in an approximately parallel-sided thin glass vessel (an inverted clock-shade) illuminated from behind. The liquid surface when undisturbed was about level with the middle of the camera-lens, which was focussed for the sphere when under water. The general arrangement of the optical apparatus will be suffi­ciently understood from the accompanying cut (fig. 1). The method of timing the illumination was that already described ( loc. cit. ).

Dynamic Analysis of Thin Glass Under Ball Drop Impact With New Metrics

2013 ◽  
Author(s):  
Liang Xue ◽  
Claire R. Coble ◽  
Hohyung Lee ◽  
Da Yu ◽  
Satish Chaparala ◽  
...  
Keyword(s):  
High Speed ◽  
Impact Testing ◽  
Image Correlation ◽  
Thin Glass ◽  
Fea Model ◽  
Wear And Tear ◽  
Local Measurements ◽  
Drop Impacts ◽  
Global And Local ◽  
The Impact

Response of brittle plate to impact loads has been the subject of many research studies [1–7]. Specifically, glass presents a wide variety of applications in daily life, and helps to protect the displays of smartphones, tablets, PCs, and TVs from everyday wear and tear. Therefore, the necessity of glass to resist scratches, drop impacts, and bumps from everyday use leads to the importance of investigation of the glass response under dynamic impact loading. The ball drop test has been applied in the past, specifying an energy threshold as a prediction metric. Use of energy as the key parameter in impact testing is limited, since it does not account for the time spent in contact during the impact event. This study attempts to establish a reliable metric for impact testing based on a momentum change threshold. The deformation and the strain of the glass will be obtained by the Digital Image Correlation (DIC) system, while the rebound velocity will be measured with the high speed cameras. The global and local measurements are conducted to verify the accuracy of the experimental results. Finally, the FEA model is developed using ANSYS/LS-DYNA to provide a comprehensive understanding of the dynamic response of the glass. Excellent correlation in deflection is obtained between the measurements and predictions.

The theory of the extraction of electrons from metals by metastable atoms, II

1931 ◽  
Vol 27 (3) ◽  
pp. 460-468 ◽  
Author(s):  
H. S. W. Massey
Keyword(s):  
Hydrogen Atom ◽  
Velocity Distribution ◽  
Spherical Cavity ◽  
Metal Surfaces ◽  
Excited Atoms ◽  
Positive Ions ◽  
Order Of Magnitude ◽  
The Impact

In a previous paper the nature of the phenomena occurring when electrons are ejected from metal surfaces by the impact of metastable atoms and positive ions was discussed. It was shown that electrons may be ejected by excited atoms at considerable distances from the surface, and by considering the case of an excited hydrogen atom at the centre of a spherical cavity in the metal the order of magnitude of the effects to be expected and the velocity distribution of the ejected electrons was determined. In this paper the theory will be extended in two directions.

scholarly journals Effects of Support and Heat Dissipation in Thermal Stress Cleaving of Thin Glass Plates

2009 ◽  
Vol 3 (3) ◽  
pp. 529-540 ◽  
Author(s):  
Fumitaka MOTOMURA ◽  
Yasufumi IMAI ◽  
Akihide SAIMOTO
Keyword(s):  
Thermal Stress ◽  
Heat Dissipation ◽  
Thin Glass ◽  
Glass Plates

Stress-optimal loading of thin glass plates in conditions of radiant heat transfer

1986 ◽  
Vol 22 (9) ◽  
pp. 898-902 ◽  
Author(s):  
S. F. Budz ◽  
Ya. I. B�rak ◽  
E. M. Irza
Keyword(s):  
Heat Transfer ◽  
Radiant Heat ◽  
Radiant Heat Transfer ◽  
Thin Glass ◽  
Optimal Loading ◽  
Glass Plates

Mechanical Characterization of Sandwich Composite Structure using a New Experimental Approach

2016 ◽  
Vol 25 (5) ◽  
pp. 096369351602500 ◽  
Author(s):  
F. Alila ◽  
J. Fajoui ◽  
M. Kchaou ◽  
P. Casari ◽  
N. Wali ◽  
...  
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Life Time ◽  
Test Method ◽  
Core Material ◽  
Sandwich Composite ◽  
Foam Core ◽  
Current Standard ◽  
Thin Glass ◽  
The Impact

In marine construction, ship hulls are subjected to high fatigue stresses due to the impact of waves and their cyclic solicitations. However, fatigue behaviour evaluation of the constitutive materials of hull is based on standard tests. The objective of this study is to take a critical view on the current standard test method set to investigate the fatigue life of cellular foam core material as used in high performance sandwich materials. The highlight of this study is to develop a new geometry of specimen in order to achieve coherence between the actual fatigue life time of the real structure and the one of specimens tested in a controlled laboratory environment. The tested specimen is made out of a high-density foam core and thin glass fabric faces. Moreover, a new test rig of different flexure types, in quasi-static or fatigue loadings on sandwich specimens, was developed and validated.

Sign in / Sign up

Export Citation Format

Share Document