Optimal Design of Grid-Stiffened Composite Panels

A design strategy for optimal design of composite grid-stiffened panels subjected to global and local buckling constraints is developed using a discrete optimizer. An improved smeared stiffener theory is used for the global buckling analysis. Local buckling of skin segments is assessed using a Rayleigh-Ritz method that accounts for material anisotropy and transverse shear flexibility. The local buckling of stiffener segments is also assessed. Design variables are the axial and transverse stiffener spacing, stiffener height and thickness, skin laminate, and stiffening configuration, where the stiffening configuration is herein defined as a design variable that indicates the combination of axial, transverse, and diagonal stiffeners in the stiffened panel. The design optimization process is adapted to identify the lightest-weight stiffening configuration and stiffener spacing for grid-stiffened composite panels given the overall panel dimensions, in-plane design loads, material properties, and boundary conditions of the grid-stiffened panel.

[1]  Damodar R. Ambur,et al.  Formulation of an improved smeared stiffener theory for buckling analysis of grid-stiffened composite panels , 1996 .

[2]  Damodar R. Ambur,et al.  Buckling analysis of general triangular anisotropic plates using polynomials , 1995 .

[3]  R. Haftka,et al.  Optimization of laminate stacking sequence for buckling load maximization by genetic algorithm , 1993 .

[4]  Damodar R. Ambur,et al.  Optimal Design of Grid-Stiffened Composite Panels Using Global and Local Buckling Analysis , 1996 .

[5]  Zafer Gürdal,et al.  Optimal design of geodesically stiffened composite cylindrical shells , 1992 .

[6]  D. S. Hague,et al.  Application of multivariable search techniques to structural design optimization , 1972 .

[7]  Michael R. Horne,et al.  Minimum weight design , 1979 .

[8]  Navin R. R. Jaunky.  Buckling Analysis and Optimum Design of Multidirectionally Stiffened Composite Curved Panel , 1995 .

[9]  Lawrence W. Rehfield,et al.  Continuous filament wound composite concepts for aircraft fuselage structures , 1985 .

[10]  Zafer Gürdal,et al.  Design of a blade stiffened composite panel by a genetic algorithm , 1993 .

[11]  Damodar R. Ambur,et al.  Optimal design of general stiffened composite circular cylinders for global buckling with strength constraints , 1998 .

[12]  Carlos Alberto Brebbia.  1 – Approximate Methods , 1980 .

[13]  Damodar R. Ambur,et al.  Damage tolerance and failure analysis of a geodesically stiffened structure loaded in axial compression , 1994 .

[14]  Damodar R. Ambur,et al.  Buckling of arbitrary quadrilateral anisotropic plates , 1994 .

[15]  Raphael T. Haftka,et al.  Design of stiffened composite panels by genetic algorithm and response surface approximations , 1995 .

[16]  John A. Nelder,et al.  A Simplex Method for Function Minimization , 1965, Comput. J..

[17]  David Bushnell,et al.  PANDA2: Program for Minimum Weight Design of Stiffened, Composite, Locally Buckled Panels , 1987 .

[18]  R. F. Crawford,et al.  MINIMUM WEIGHT POTENTIALS FOR STIFFENED PLATES AND SHELLS , 1963 .

[19]  A. B. Burns.  Optimum, Axially Compressed, Foam- Core Sandwich Cylinders , 1966 .

[20]  David Bushnell,et al.  Theoretical basis of the PANDA computer program for preliminary design of stiffened panels under combined in-plane loads , 1987 .

[21]  David Bushnell.  Recent enhancements to PANDA2 , 1996 .

[22]  Biswajit Tripathy,et al.  Stiffened composite cylindrical panels—Optimum lay-up for buckling by ranking , 1992 .

[23]  David Bushnell,et al.  Approximate method for the optimum design of ring and stringer stiffened cylindrical panels and shells with local, inter-ring, and general buckling modal imperfections , 1994 .

[24]  T. P. Kicher,et al.  A REPORT ON A STRUCTURAL SYNTHESIS CAPABILITY FOR INTEGRALLY STIFFENED WAFFLE PLATES , 1963 .

[25]  G. J. SlMITSES,et al.  Minimum-Weight Design of Stiffened Cylinders under Axial Compression , 1974 .