[1] Clermont Univ, CNRS, Inst Pascal, UBP,IFMA, BP 20265, F-63175 Aubiere, France
[2] Dnepropetrovsk Natl Univ, Dept Theoret & Appl Mech, Dnepropetrovsk, Ukraine
[3] Clermont Univ, French Inst Adv Mech, Inst Pascal, UBP,IFMA,CNRS, F-63175 Aubiere, France