Lobachevsky State University of Nizhni Novgorod NATIONAL RESEARCH UNIVERSITY ABOUT APPLICABILITY OF LOCAL INTERACTION MODELS FOR DEFINITION OF FORCES OF RESISTANCE TO INTRODUCTION OF THE BLUNTED BODIES OF REVOLUTION IN THE NONLINEARCOMPRESSIBLE SOIL Linnik E. Yu.
Relevance: The ideas of the task used in the study of penetration depth of the water and ice, the structure and composition of cosmic objects, radioactive waste disposal, the impact of wells in the ground on an active volcano, the study of small cosmic bodies. In this regard, the calculation of the penetration process, optimization of body shape and stability analysis of motion are fundamentally important and relevant in the present [1 -4]. Purpose: definition of common patterns in the study process, impact and penetration of the bodies of various shapes, taking into account changes in environmental parameters, shape and material impactors. Objective: Verification of local interaction techniques as applied to the study of the impact of the shock-penetrating projectiles of various shapes on the ground environment. 1. Bogdanov A. V. et al. A method for the study of terrestrial planets // Cosmic Research . 1988. V 24, N 4. P. 591 -603 2. Zaitsev A. V. et. al. Possibilities of the hypervelocity impact experiment in frames of demonstration project “Space patrol”//Intern. J. Impact Engng. 1997. V 20. P. 849 -860 3. Simonov I. V. et. Al. Before catastrophic state of geophysical objects, triggering effects and penetration //reports of the Russian Academy of Sciences. 1996 V. 347, № 6. P. 811 -813 4. Veldanov V. A. et. al. The use of technologies based on the interaction of shock-penetrating // Dual technology, 1998, № 2. P. 1 -14
Deformation model of ground environment Grigoryan
Model of deformable media
The problem of expanding spherical cavity in the ground
The problem of expanding spherical cavity in the ground Error in determining the speed of the wave front and the tension on the border of the cavity * Kotov V. L. , Linnik E. Yu. , Makarova A. A. , Tarasova A. A. Analysis of approximate solutions to the problem of expanding spherical cavity in the soil environment//Problems of Strength and Plasticity: Interuniversity Collection. V. . 73. N. Novgorod: publishing house UNN. 2011
The parameters of local interaction The parameters of models the Estimate of convergence of the method* Parameters of LIM * - Bazhenov V. G. The software package "Dynamics 2" for the solution of plane and axisymmetric nonlinear problems of unsteady interaction of structures with compressible media// ММ. - 2000. V. 12. № 6. - P. 67 -72.
The use of LIM for spherical projectiles
The use of LIM for spherical projectiles
Evaluation of applicability of LIM for spherical projectiles Modification of LIM - angle separation; - adjustable parameter
The use of LIM, taking into account Coulomb account Evaluation of applicability of LIM, taking into account the friction
Criterion of applicability of LIM 1 -Fmax/Fst ≈0 The ratio of the maximum and quasi-steady force of resistance -without the friction force - taking into account friction force
The use of LIM for conical projectiles
Evaluation of applicability of LIM for conical projectiles Error estimate Validity criterion
Range of applicability of LIM
Conclusion 1. A new analytical solution to the problem of expanding spherical cavity in the assumption of incompressibility of the impact front (as opposed to the exact numerical solution is less than 5%). 2. A comparison with the results of axisymmetric calculations of the introduction of spherical and conical projectiles into the ground. It is shown that the error derived LIM-based solution to expand a spherical cavity in the determination of the maximum resistance force is 10 - 15%. It is shown that the rate of fall of stress is proportional to the coefficient of lateral pressure in the soil and reaches a maximum at K = 1 (k = 0). As a consequence, the ratio of the maximum resistance force to the quasi-stationary value also increases with a decrease in the coefficient of internal friction (the highest for K = 1). 3. 1. It is noted that the criterion of applicability of LIM in the case of the penetration of spherical and conical projectiles into the soil can serve as a quasi-stationary and the ratio of the maximum values of resistance force.
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