Issue 50

O. Mouhat et alii, Frattura ed Integrità Strutturale, 50 (2019) 126-140; DOI: 10.3221/IGF-ESIS.50.12 133 longitudinal (uniform axial compression) edges are simply supported, with 0 w  and 0 x y r r   . The transverse (loaded) edges are simply supported; so 0 w  and 0 x r  , I-shape stiffeners are represented as Fig. 3. Figure 3 : Layup sequence used in the state is 8 layers with total thickness is 1 mm In the current study, the mechanical properties of the composite materials panels made of different laminas are clearly given in table below: Table 1 : Mechanical properties of the CFC, the E-glass and Kevlar used in the analysis [20]. Steps for Nonlinear buckling analysis In post-buckling analysis nonlinear load-deflection curve is produced based on the modified Riks algorithm [21]. The shape of nonlinear buckling is induced with an initial defect based on the modes of buckling extracted. The buckling analysis is modified to perform a nonlinear load deflection analysis to predict post-buckling behavior. The following steps were followed in performing the static nonlinear buckling analysis in Abaqus FEA software. 1. Defined for the composite stiffened panel properties module using a composite layup. 2. The mechanical properties of each lamina are listed in Tab. 1. 3. For nonlinear buckling analysis, the eigenvalue buckling step is a static Riks step. 4. The axial force is defined along with the boundary conditions. 5. The history output query is added to define the displacement history for the loads applied. 6. The boundary conditions are applied and the job is submitted for the static nonlinear buckling analysis, the progress of the solution is monitored. 7. The results of the static nonlinear analysis buckling analysis can be processed. Quantity Symbol Units Material CFC E-glass Kevlar Young’s modulus 0  11 E GPa 164 38 195 Young’s modulus 90  22 33 E E  GPa Shear modulus in planes 12 13 G G  GPa Shear modulus in planes 23 G GPa 12.8 4.5 2.5 8.27 4.14 4 14.6 7.5 5 Poisson’s ratio in planes 12 13    None 0.32 0.25 0.3 Poisson’s ratio in planes 23  None 0.45 0.27 0.45 Density  3 / Kg m 1800 1900 1400