Curvilinearly T-Stiffened Panel Optimization Framework under Multiple Load Cases Using Parallel Processing

Abstract

Future aerospace vehicles like 'Hybrid wing/body', 'Truss-braced Wing' and 'DoubleBubble' would be having pressurized non-circular fuselage structures and complex wing geometry. Traditional aircraft designs have led to the confidence and experience of designing such structures using the knowledge-base built over the years and the resulting thumb-rules. However, there is a lack of experience of load-calculations and design of complex, multifunctional, aircraft structural concepts for future aerospace vehicles. Designing such structures will require a physics-based optimization framework, so a new optimization framework, EBF3PanelOpt is being developed. Commercial software, MD-PATRAN(Geometry modeling and mesh generation), MD-NASTRAN (Finite Element Analysis), are integrated in EBF3PanelOpt framework using Python programming environment to design stiffened panels with curvilinear stiffeners. Currently, EBF3PanelOpt is supported with curvilinear blade stiffeners without loads through the stiffeners to optimize the panels for minimum mass subjected to buckling, von Mises stress, and crippling or local failure of the stiffener constraints. EBF3PanelOpt is enhanced to have curvilinear T stiffeners with or without axial loads in addition to loads through plate. The panel/stiffener geometry is defined in a parametric fashion based on design variables that include variables for orientation and shape of the stiffeners, the thicknesses and heights of the webs and flanges of the stiffeners, and the plate pockets thicknesses. This framework is supported with coarse-grained parallelism using Python to analyze multiple designs on the cluster. Using this framework, a vertical stabilizer skin panel of transport aircraft panel having two extreme load-cases, is optimized using with or without stiffener loads. When the equivalent uniform loads are applied through the plate only, plate buckling becomes critical during the optimization as compared to combined buckling of plate and stiffeners when loads applied through the plate and stiffeners. Straight T stiffened panel is optimal than curvilinearly T stiffened panel when the loads are applied through both the plate and stiffeners.

EBF3PanelOpt: A Computational Design Environment for Panels Fabricated by Additive Manufacturing

“…al 35 . Figure 6-a shows best optimal design of T-stiffened panel when the loads are applied through both the plate and stiffeners, obtained using EBF3PanelOpt.…”

“…Using this framework, a vertical stabilizer skin panel of an example transport aircraft panel having two extreme load-cases, is optimized using with or without stiffener loads. [35][36] When the equivalent uniform loads are applied through the plate only, plate buckling becomes critical during the optimization as compared to combined buckling of plate and stiffeners when loads applied through the plate and stiffeners. Straight T-stiffened panel is optimal than curvilinearly 'T' stiffened panel when the loads are applied through both the plate and stiffeners.…”

“…[26][27][28][29][30][31][32][33][34] Currently, EBF3PanelOpt framework allows the user to perform multi-objective design optimization of flat multi-sided panels with straight/curved edges having curvilinear, blade and 'T' stiffeners. In the case of T-stiffened panels [35][36] , the additional option is provided to apply compression directly to the stiffeners. The mass and the vibroacoustic response of the panel are optimized subjected to constraints on buckling, von Mises stress, and crippling or American Institute of Aeronautics and Astronautics 3 local failure of the stiffener using global optimization techniques like PSO or GA or gradient based optimization techniques.…”

Weight trades in the design of a composite wing box: effect of various design choices

“…Recent improvements in computational enabled the study of advanced concepts in stiffened panel design such as the use of curvilinear stiffening members [13][14][15]. Furthermore, the use of parallel processing [13,16] or response surfaces [17] has been used to cope with the optimization aspects of individual stiffened panels [13,14,17] or entire wings [15,16]. Topology optimization has been used to determine the location of wing sub-structure under aeroelastic loads [18,19] or minimizing compliance of a wing modelled as truss structure [20].…”