A simple model for the shock wave induced by high-speed impact.

1972 ◽  
Vol 9 (1) ◽  
pp. 13-18 ◽  
Author(s):  
PETER J. TORVIK ◽  
RONALD J. F. PRATER
Keyword(s):  
Shock Wave ◽  
Simple Model ◽  
High Speed ◽  
High Speed Impact ◽  
Wave Induced

SHADOWGRAPHY OF SHOCK WAVE INDUCED BY DOUBLE PULSE TECHNIQUE

2015 ◽  
Vol 74 (8) ◽  
Author(s):  
Waskito Nugroho ◽  
N. E. Khamsan ◽  
M. Abdullah ◽  
K. Ganesan
Keyword(s):  
Shock Wave ◽  
Nd:Yag Laser ◽  
High Speed ◽  
Laser System ◽  
Optical Breakdown ◽  
Video Camera ◽  
Double Pulse ◽  
Pulse Technique ◽  
Camera Synchronization ◽  
Wave Induced

High-speed videography based on double pulse of Nd:YAG laser to capture dynamic expansion of shock wave is reported. A Q-switched Nd:YAG laser was employed  as an input signal and disturbance source. Nitrodye laser was utilized as a flash. The shock wave generation was recorded via CCD video camera. Synchronization is organized associated with a digital delay generator. Nd:YAG laser was focused to generate an optical breakdown in distilled water. Double pulses were generated within the interval of one second. The first pulse of Nd:YAG laser was used to trigger the dye laser and the second pulse to generate shock wave. Manipulation of delay times allow to freeze the dynamic expansion of shock wave. The double pulse technique is appropriated for laser system with the absence of external trigger unit. Lack of electronic failure is the advantage offer by the double pulse technique.

scholarly journals Breakup and interaction of two droplet columns in a shock wave induced high-speed air flow.

1989 ◽  
Vol 55 (514) ◽  
pp. 1607-1612
Author(s):  
Teruhiko YOSHIDA ◽  
Kazuyoshi TAKAYAMA ◽  
Andrzej Wierzba
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Air Flow ◽  
Wave Induced

scholarly journals Determining the Velocity of Hypersonic Compact Elements in Ground Testing Plants

2019 ◽  
pp. 65-72
Author(s):  
S.I. Gerasimov ◽  
I.A. Odzeriho ◽  
R.V. Gerasimova ◽  
B.A. Yanenko
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Shock Loading ◽  
Experimental Testing ◽  
Complex Structures ◽  
Ground Testing ◽  
High Speed Impact ◽  
Condensed Explosives ◽  
Hypersonic Speeds ◽  
The Impact

Protection of spacecraft from high-speed impact when encountering meteorite particles and man-made debris is currently a pressing issue. This article presents methods for determining the reaction of complex structures to the impact of particles with cosmic velocities. To determine the anti-meteorite resistance of materials and structures and to study the reaction of materials under high-intensity shock loading, schemes are developed for the production and registration of high-speed metal compact elements moving at hypersonic speeds using cumulative explosive throwing devices based on high-power condensed explosives. The use of the ‘hemisphere-cylinder’ shaped lining made it possible to test a shaped charge, consistently forming a steel compact element with a velocity of 6 km/s. The paper presents the results of numerical calculations and experimental testing of such a booster. Using this device, a method for determining the speed of the hypersonic striker pin is developed based on visualization of the head shock wave at the entrance of the striker into water.

scholarly journals Energy Absorption Characteristics of PVC Coarse Aggregate Concrete under Impact Load

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Shi Hu ◽  
Huaming Tang ◽  
Shenyao Han
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
High Speed ◽  
Coarse Aggregate ◽  
Specific Energy Absorption ◽  
Low Speed ◽  
High Speed Impact ◽  
Aggregate Content ◽  
Dynamic Compressive Strength ◽  
Absorption Characteristics

AbstractIn this paper, polyvinyl chloride (PVC) coarse aggregate with different mixing contents is used to solve the problems of plastic pollution, low energy absorption capacity and poor damage integrity, which provides an important reference for PVC plastic concrete used in the initial support structures of highway tunnels and coal mine roadway. At the same time, the energy absorption characteristics and their relationship under different impact loads are studied, which provides an important reference for predicting the energy absorption characteristics of concrete under other PVC aggregate content or higher impact speed. This study replaced natural coarse aggregate in concrete with different contents and equal volume of well-graded flaky PVC particles obtained by crushing PVC soft board. Also, slump, compression, and splitting strength tests, a free falling low-speed impact test of steel balls and a high-speed impact compression test of split Hopkinson pressure bar (SHPB) were carried out. Results demonstrate that the static and dynamic compressive strength decreases substantially, and the elastic modulus and slump decrease slowly with the increase of the mixing amount of PVC aggregate (0–30%). However, the energy absorption rate under low-speed impact and the specific energy absorption per MPa under high-speed impact increase obviously, indicating that the energy absorption capacity is significantly enhanced. Regardless of the mixing amount of PVC aggregate, greater strain rate can significantly enhance the dynamic compressive strength and the specific energy absorption per MPa. After the uniaxial compression test or the SHPB impact test, the relative integrity of the specimen is positively correlated with the mixing amount of PVC aggregate. In addition, the specimens are seriously damaged with the increase of the impact strain rate. When the PVC aggregate content is 20%, the compressive strength and splitting strength of concrete are 33.8 MPa and 3.26 MPa, respectively, the slump is 165 mm, the energy absorption rate under low-speed impact is 89.5%, the dynamic compressive strength under 0.65 Mpa impact air pressure is 58.77 mpa, and the specific energy absorption value per MPa is 13.33, which meets the requirements of shotcrete used in tunnel, roadway support and other impact loads. There is a linear relationship between the energy absorption characteristics under low-speed impact and high-speed impact. The greater the impact pressure, the larger the slope of the fitting straight line. The slope and intercept of the fitting line also show a good linear relationship with the increase of impact pressure. The conclusions can be used to predict the energy absorption characteristics under different PVC aggregate content or higher-speed impact pressure, which can provide important reference for safer, more economical, and environmental protection engineering structure design.

Investigation on the mechanical properties of press-hardened boron steel sheets using the conductive heating technique

2020 ◽  
Vol 234 (8) ◽  
pp. 1084-1098
Author(s):  
O Kocar ◽  
H Livatyalı
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Boron Steel ◽  
Fast Heating ◽  
Heating Method ◽  
Conductive Heating ◽  
Press Hardening ◽  
High Speed Impact ◽  
Significant Difference ◽  
Structural Parts

An aluminized 22MnB5 (Boron) steel sheet, used for structural parts in the automotive industry, was subjected to press-hardening followed by austenitizing, both in a conventional furnace and via the conductive (electric resistance) heating method, an innovative technique based on the Joule’s principle for fast heating of the sheet metal. Conductive heating presents a number of advantages over the in-furnace heating method. These include a more efficient use of energy, as well as the requirement of less time and space for heating, thus lowering costs. After press-hardening was performed using both methods, the microstructural and mechanical characterizations of both specimens were examined for optical microscopy, hardness, tensile strength, and high-speed impact tests. The results showed that the press-hardening process transformed the ferritic–pearlitic microstructure in the as-received state into martensite after die quenching and caused a substantial increase in hardness and strength at the expense of ductility and impact toughness. On the other hand, no significant difference was observed in either the microstructure or mechanical properties with respect to the heating method used. The results obtained in the present investigation concur with the findings of current literature.

High Speed Impact Behaviour of Thermo-Mechanically Processed AA 6082-T6 Thin Plates

2018 ◽  
Vol 5 (9) ◽  
pp. 17203-17212 ◽  
Author(s):  
Rahul Dubey ◽  
Srinivasa Rakesh ◽  
R Velmurugan ◽  
R Jayaganthan
Keyword(s):  
High Speed ◽  
Thin Plates ◽  
Impact Behaviour ◽  
High Speed Impact

A study of the collapse of arrays of cavities

1988 ◽  
Vol 190 ◽  
pp. 409-425 ◽  
Author(s):  
J. P. Dear ◽  
J. E. Field
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
High Speed Photography ◽  
Cavitation Damage ◽  
Major Mechanism ◽  
Collapse Mechanisms ◽  
Multiple Jets ◽  
Circular Holes ◽  
Schlieren Photography ◽  
Thick Glass

This paper describes a method for examining the collapse of arrays of cavities using high-speed photography and the results show a variety of different collapse mechanisms. A two-dimensional impact geometry is used to enable processes occurring inside the cavities such as jet motion, as well as the movement of the liquid around the cavities, to be observed. The cavity arrangements are produced by first casting water/gelatine sheets and then forming circular holes, or other desired shapes, in the gelatine layer. The gelatine layer is placed between two thick glass blocks and the array of cavities is then collapsed by a shock wave, visualized using schlieren photography and produced from an impacting projectile. A major advantage of the technique is that cavity size, shape, spacing and number can be accurately controlled. Furthermore, the shape of the shock wave and also its orientation relative to the cavities can be varied. The results are compared with proposed interaction mechanisms for the collapse of pairs of cavities, rows of cavities and clusters of cavities. Shocks of kbar (0.1 GPa) strength produced jets of c. 400 m s−1 velocity in millimetre-sized cavities. In closely-spaced cavities multiple jets were observed. With cavity clusters, the collapse proceeded step by step with pressure waves from one collapsed row then collapsing the next row of cavities. With some geometries this leads to pressure amplification. Jet production by the shock collapse of cavities is suggested as a major mechanism for cavitation damage.

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