ملخص البحث :

ABSTRACT: Free vibration analysis of the isotropic skew plate with three supporting conditions (CCCC, CFCF and FCFC) were studied. ANSYS APDL version 17.2. with two-dimensional model (SHELL281 element) and three-dimensional model (SOLID186 element) were adopted. The effects of width-thickness ratio (a/t), aspect ratio (a/b), mode number, skew angle and supporting conditions on the first five natural frequencies were investigated. The results showed that the non-dimensional fundamental frequency coefficients (Kf) increases when the skew angle at any aspect ratio (a/b) , mode number and supporting type. Also, the effect of skew angle appears sharply when the skew edges are clamped (i.e. CCCC and CFCF) while in when the skew edge is free , the effect of skew angle is not appear . Finally, the comparison between the two elements (SHELL281 and SOLID186) shows that there is a good agreement between them when the skew angle is smaller than 60o and the mode number is smaller than fourth mode.