BULGARIAN ACADEMY OF SCIENCES
NATIONAL COMMITTEE OF THEORETICAL AND APPLIED MECHANICS
JOURNAL OF THEORETICAL AND APPLIED MECHANICS

Editor-in-Chief: MARIA DATCHEVA
Institute of Mechanics, Bulgarian Academy of Science
Akad. G. Bonchev St., Bl. 4, 1113 Sofia, Bulgaria
Phone: (3592) 979 6751; E-mail: datcheva@imbm.bas.bg
Honorary Editor: STEFAN RADEV
Institute of Mechanics, Bulgarian Academy of Science
Akad. G. Bonchev St., Bl. 4, 1113 Sofia, Bulgaria

Responsible Editors:
SOLID MECHANICS:FLUID MECHANICS:
Prof. Emil Manoach, Prof. Maria DatchevaProf. Stefan Radev, Prof. Sonya Tabakova
GENERAL MECHANICS:INTERDISCIPLINARY TOPICS:
Prof. Nikolay Vitanov, Prof. Petia DinevaProf. Vasil Kavardzhikov, Assoc. Prof. Sergey Ranchev

Editorial Board

Advisory Editorial Board

A. BALTOVA. GUZ
Institute of Mechanics, BAS, SofiaInstitute of Mechanics, UAS, Kiev, Ukraine
D. KARAGIOZOVAA. LIOLIOS
Institute of Mechanics, BAS, SofiaDemocritus-University of Thrace, Greecee
P. DJONDJOROVD. GROSS
Institute of Mechanics, BAS, SofiaTU Darmstadt, Germany
E. KUSTOVAG. MANOLIS
Saint Petersburg University, RussiaAristotle University, Thessaloniki, Greece
M. DATCHEVAG. PANZA
Institute of Mechanics, BAS, Sofia University of Trieste, Italy, Head of SAND group at
the Abdus Salam International Centre for Theoretical Physics
M. MEDALEL. LILOV
Aix-Marseille University, FranceUniversity of Sofia, Bulgaria
N. VITANOVM. ALVES
Institute of Mechanics, BAS, SofiaUniversity of Sao Paulo, Brazil
P. DINEVA S. GROZDEV
Institute of Mechanics, BAS, Sofia Institute of Mechanics, BAS, Sofia
S. TABAKOVA V. KOVTUN
Institute of Mechanics, BAS, Sofia Gomelski Injenernij Institut, Byelorussia
Ts. RANGELOV V. GUSHCHIN
Institute of Mathematics and Informatics, BAS, SofiaInstitute of Computer Aided Design, RAS, Russia
V. KAVARDJIKOVW. SCHIEHLEN
Institute of Mechanics, BAS, Sofia University of Stuttgart, Germany
Y. IVANOV Z. MROZ
Institute of Mechanics, BAS, SofiaIPPT-PAS, Poland
MAOSEN CAO
Hohai University, Nanjing, Jiangsu, P. R. China
E. MANOACH
Institute of Mechanics, BAS, Sofia
S. RANCHEV
Institute of Mechanics, BAS, Sofia

Founding Editor: G. BRANKOV