Multiscale Mechanics of Shock Wave Processes

This book presents theoretical and experimental investigations of mechanical behavior of solids under shock loading and highlights a multi-scale exchange process of energy and momentum between meso and macroscopic hierarchy. It also widely covers experimental approaches for the multi-scale response of solids to impacts including uniaxial strain conditions and high-velocity penetration processes.The content comprises two parts. The first part overviews modeling and theory of dynamically deformed solids from the multi-scale point of view. The second part describes experimental characterization of shock-induced solids and experimental probing of mesostructured and mesoscale dynamic processes in solids. The theory presented in the first part is then verified as it is compared with i) experiments of shock loading into different kinds of solids and ii) probed microstructure of post-shocked specimens by scanning electron microscopy, transmission electron microscopy and optical microscopy.

The text is written on the basis of author's lectures at universities and thus is concisely described for postgraduate students. It is also useful for researchers who work on the theory of multi-scale mechanics of solids and engineers who work on testing materials under dynamic loading.

Auteur

Yurii Meshcheryakov is a professor and a laboratory head at the Institute of Problems of Mechanical Engineering, Russian Academy of Science. His work is widely concerned with investigation and characterization of materials under shock loading and shock wave propagation in condensed matter. He received his Ph.D. degree in solid physics from the State Institute of Special Devices Granit, Saint Petersburg, in 1967, and his Doctor of Science degree in physicsmathematical sciences, mechanics, and physics of solids from Saint Petersburg State University in 1984. He moved to his current affiliation as a laboratory head in 1986 and has been a professor there since 1994. He was given an Honored Scientist of the Russian Federation Award in 2000 and the Medal In Commemoration of the 300th Anniversary of Saint Petersburg in 2003.

Contenu

Part 1. Multiscale Mechanics of Dynamically Deformed Solids

Chapter 1. Multiscale Modeling of Steady Shock wave Propagation 1.1.Coupling between strain rate and mesoparticle velocity variation.
1.2.Dislocation dynamics and steady shock-wave propagation.
1.3.Account for the mesoscale effects .
Chapter 2. Kinetic Theory of Continuously Distributed Dislocations. Mesoscale Formation. 2.1. Kinetic approach to dislocation medium.
2.2. Diffusion coefficients of Fokker-Plank equation.
2.3. Transport equations.
2.4. Shock-induced mesostructure formation. Chapter 3. Kinetics of Dislocations and Decay of Sub-Microsecond Stress Pulses. 3.1. Governing equation.
3.2.Comparison with the experiments.
3.3. Conclusions. Chapter 4. Kinetic Theory of Continuously Distributed Mesoparticles. 4.1. Physics of mesoscale.
4.2 The mesoparticle velocity distribution function and its statistical moments. Chapter 5. The Meso-Macro momentum Exchange in Dynamically Deformed Solid. 5.1. Propagation of shock wave in mesoscale medium.
5.2. Criterion for change of the regime of meso-macro exchange.
5.3. On the control of structure under dynamic deformation.

Chapter 6. Mesoscale criteria for dynamic plasticity and fracture. 6.1. Mesoscale criterion for spallation.
6.2. Mesoscale criterion for high-velocity penetration.

Chapter 7. Molecular dynamic simulation of shock wave propagation. 7.1. Method of investigation.
7.2. Results of simulation and discussion.

7.1. Methods for shock loading by using gas gun and explosives.
7.2. Determination of dynamic characteristics of plasticity within strain rates of 103-105 c-1 by using the direct and reverse Taylor techniques. 7.3. Experiments on shock loading the plane targets by using the high-energetic pulse electron beam. Chapter 8. Experimental Methods for Registering both the Mean Particle Velocity and Particle Velocity Variation in Real Time. 8.1. Registering the shock waves by using gauges.
8.2. Registering the shock waves by using interferometers. Chapter 9. Transition into Structure-Unstable State. 9.1. Experiments on checking the mesoscale criterion for transition into structure unstable state.
9.2. Post-shocked meso-structures of dynamically deformed heterogeneous materials.
9.3. Mesoscale rotational structures in dynamically deformed solid. Chapter 10. Role of Mesostructural Effects in Dynamic Plasticity and Strength of Materials. 10.1. Analysis of strength behavior of constructional steels from the position of mesoscale characteristics.
10.2. Mesoscale rotational structures in dynamically deformed solid.
10.3. Correlation between density of mesoscale rotations and spall strength.
10.4. Shock-induced mesoscale structures in copper. Chapter 11. Shock-induced localized structural instabilities and dynamic strength of brittle materials. 11.1. Results of tests: Gabbro-Diabase, Beryllium, Fused Quartz, Gray Iron.
11.2. Analysis of results on dynamic fracture of brittle materials from the mesoscale position. Chapter 12. Mesoscale formation during the high-velocity penetration. 12.1. The threshold regimes of dynamic deformation of aluminum alloys.
12.2. On the correlation between multiscale mechanisms of deformation in uniaxial dynamic straining and high-velocity penetration. Chapter 13. Mesoscale and Shock-Induced Dynamic Recrystallization. 13.1. Role of mesoscale velocity non-uniformity in dynamic recrystallization processes.
13.2. Dynamic recrystallization in aluminum alloys.
13.3. Dynamic recrystallization in 38CrNi3MoFA steel.
13.4. SEM-metallography and X-ray investigations.
13.5. Mesoscale analysis of results. Chapter 14. Comparative analysis tests of aluminum alloys in coarse-grained and microcrystalline state. 14.1. Dynamic yield limit and spall strength.
14.2. Threshold for transition from meso-1 to meso-2 scales.
14.3. Microstructural investigations.