Download and Read Free Online Impact Dynamics by Zukas, Jonas A., . books online, book reviews epub, read books online, books to read. Swift, Longin B. Greszczuk, Donald R. Curran [PDF EBOOK EPUB site] Online Impact Dynamics By Jonas A. Zukas, Theodore Nicholas, Hallock F. Swift, . Structures Dynamics. Contents. Introduction to impact phenomena; Material failure at high strain rates; Material characterization at high strain rates; Introduction.

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Results 1 - 15 of 15 Impact Dynamics by Nicholas, Theodore,Zukas, Jonas A. and a great selection of related books, art and collectibles available now at. Authors: Jonas Zukas . Open - download once, receive and download all available eBook formats, including PDF, EPUB, A hydrocode refers to a computer program used for the study of the dynamic response of materials and structures to impulse (primary blast), impact (involving everything from car and aircraft collisions to. impact physics, materials science, mechanics, terminal ballistics, shock waves accounting for strength, and fully resolved explicit dynamics simulations. J. Zukas, High Velocity Impact Dynamics. .. DISCLAIMER: The above article has been published in Epub (ahead of print) on the basis of the materials provided by .

This study proposed an approach to experimentally measure the velocity of the back surface of an A36 steel plate impacted by a projectile. All experiments used a combination of a two-stage light-gas gun and the photonic Doppler velocimetry PDV technique.

The experimental data were used to benchmark and verify computational studies. Two different finite-element methods were used to simulate the experiments: Lagrangian-based smooth particle hydrodynamics SPH and Eulerian-based hydrocode.

Experiments and simulations were compared based on the physical damage area and the back surface velocity.

The results of this study showed that the proposed simulation approaches could be used to reduce the need for expensive experiments. Introduction Hypervelocity impact events are ubiquitous in many areas, including micrometeoroid collision with spacecraft, projectile impacts, and when modeling effects of explosives on structures.

Consequently, researchers have been studying various aspects of this problem for several decades.

A common technique to study hypervelocity impact in laboratory settings is the two-stage light-gas gun [ 1 , 2 ], which can accelerate a projectile to generate shock waves in a target similar to those created by detonating high explosives or meteorite collisions [ 3 ].

Swift [ 4 ] discussed the historical development of this type of gun. On the other hand, thick plates experience several failure modes during impact, such as spalling, petalling, discing, and plugging [ 5 ].

These failure modes depend upon several factors, such as the impact velocity, the properties of the plate material, and the geometry of the projectile. Spalling, which is of a particular interest in this study, occurs when a triangular-shaped stress wave is reflected from the back of the target plate, thereby creating a tensile pressure that is greater than the material strength [ 6 ], which then results in an internal crack that progresses normal to the direction of the wave.

Goldsmith et al. Failure modes for rod penetration experiments under hypervelocity impact conditions have been studied only by a relatively small number of researchers [ 8 ].

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Christman and Gehrig [ 9 ] studied the penetration mechanics and cratering processes in metallic and nonmetallic targets at impact velocities from 0. Sorensen et al. Subsequent studies on spall fracture and dynamic response of materials were reviewed by Oscarson and Graff [ 6 ].

Shockey et al. In addition, they reported microstructural changes and the pressure induced polymorphic transition of the steel plates during impact. The penetration behavior of long rod tungsten-alloy projectiles in high-hard armor steel plates was studied by Anderson et al.

Bond [ 13 ] suggested that spallation damage and phase-transition kinetics were important in damage studies of martensitic steel armor when subjected to hypervelocity impact. An analytical model was developed based on those limits. Analytical models were developed to predict the cratering, depth of penetration, and perforation of semi-infinite target plates by long rod penetrators by Wen et al.

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Recent work on impact dynamics and shock physics of materials has emphasized the use of velocimetry data in flyer plate experiments to characterize the equation of state, spall strength, polymorphic phase transition, and the Hugoniot elastic limit of materials.

Velocimetry data can provide a clear representation of the response of materials under high pressure and high strain rates, which may lead to developing accurate predictive computational models for materials. The following is a brief overview of velocimetry diagnostic techniques. This technique became widely popular within the shock physics community.

However, complexity, cost, and various issues that cannot be easily resolved, such as obtaining velocities from multiple points on a moving surface, prompted the development of an alternative diagnostic tool known as photonic Doppler velocimetry PDV , a displacement interferometer that collects velocity data based on measuring displacement using optical fiber probes [ 29 ]. Advantages of PDV include its relative simplicity, robustness, cost, accuracy, and versatility [ 30 ].

Chau et al. Accurate predictive modeling of impact events under hypervelocity conditions can provide a less expensive alternative to conducting actual experiments. However, these numerical simulations require the identification of a large number of parameters that are needed to describe the nonlinearities of the problem.

In many cases, hypervelocity impact simulation models are based on many simplifications that affect the accuracy of these simulations. One feature of hypervelocity impacts is that solid materials behave somewhat like fluids after the initial elastic-plastic transition.

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Therefore, it is appropriate to model plate penetration using hydrodynamic techniques having a separately defined strength model. Recently, a considerable effort has gone into developing models that deal with perforation and penetration problems.

For example, it was shown that an accurate computational model of impact depends on the selection of the proper physics models and input parameters [ 32 ]. Several constitutive models were developed over the years to simulate hypervelocity impact events.

Johnson and Cook [ 33 ] developed a constitutive model for materials subjected to large strains, high strain rates, and high temperatures. Two other flow stress models were developed for plastic deformation of ductile materials: Zerilli-Armstrong [ 34 ] and Steinberg-Cochran-Guinan-Lund model [ 35 ].

A comparative study of all these models was performed by Banerjee [ 36 ].

Beside all of these constitutive relations, equation of state EOS models were developed to understand the dynamic behavior of materials under shock loading and were often used in this type of simulations. Additionally, plate perforation with various nose shapes for projectiles was simulated [ 40 — 42 ] using the viscoplastic relationship described in [ 39 ]. Eftis and Nemes simulated ductile spall fracture and postspall behavior of a circular plate, using the PRONTO finite element code where a viscoplastic constitutive relationship was implemented that included the microvoid volume fraction as a scalar material damage variable [ 43 ].


Recently, several computational packages based on hydrocode methods that simulate events are associated with extreme high-pressure dynamics [ 44 ]. This technique has been used for penetration modeling of different steel plates such as Eulerian-based CTH hydrocode [ 12 , 45 — 47 ]. Another simulation approach is to use the Lagrangian-based method of smooth particle hydrodynamics SPH technique [ 48 ], a meshless Lagrangian numerical method that can address the problems associated with the large geometric distortions where typical grid-based mesh techniques have difficulties.

The SPH technique has recently gained popularity in simulating impact-penetration problems [ 49 — 53 ]. Although numerous studies describe the perforation and penetration mechanics of plates during hypervelocity impact, only a few discussed the plastic deformation of plates that do not experience complete penetration under such conditions [ 13 ].

This study presents velocimetry data captured by a PDV system in experiments using a two-stage light-gas gun to understand the plastic-deformation behavior of A36 steel plates that have not had full penetration. Two computational approaches were developed to simulate the experiments.

Results were compared with each other and to the experimental data. Materials and Methods 2. Materials All gas gun experiments in this study used Lexan projectiles, cylinders 5.

Depending on the fill pressure of the gas used, the projectile velocity varied from about 4. The thickness of the target plates was chosen to prevent their complete penetration due to projectile impacts at these velocities. Advances in Applied Ceramics. Effect of stress state and microstructural parameters on impact damage of alumina-based ceramics. Journal of Materials Science.

Fractographic analysis of composites based on ultra high molecular weight polyethylene.

Composites Part B: Engineering. Ballistics: Theory and Design of Guns and Ammunition. Boca Raton: CRC; Rio de Janeiro; Analytical models for penetration mechanics: A review. International Journal of Impact Engineering.

Penetration analysis of a projectile in ceramic composite armor. Composite Structures. The mechanics of penetration of projectiles into targets. International Journal of Engineering Science. Mechanics of penetration: Analysis and experiment.

An apparent viscosity function for shear thickening fluids. Journal of Non-Newtonian Fluid Mechanics. Review on shear thickening fluids and applications.Gayden: Deformation and fracture of miniature tensile bars with resistance-spot-weld microstructures, Metallurg. Mol Cancer Therapeutics , Chang: Wave separation in viscoelastic pressure bars using single-point measurements of strain and velocity, Polymer Testing 22, — Google Scholar Chhabildas, R.

Davison, M. Although numerous studies describe the perforation and penetration mechanics of plates during hypervelocity impact, only a few discussed the plastic deformation of plates that do not experience complete penetration under such conditions [ 13 ]. On the other hand, thick plates experience several failure modes during impact, such as spalling, petalling, discing, and plugging [ 5 ].

Nicholas, A. Bentur, M.

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