Design, Optimization, and Evaluation of Integrally Stiffened Al-7050 Panel with Curved Stiffeners

Slemp, Wesley C. H.; Bird, R. Keith; Kapania, Rakesh K.; Havens, David; Norris, Ashley; Olliffe, Robert

doi:10.2514/1.c031118

Cited by 30 publications

(11 citation statements)

References 13 publications

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“…The final layout is shown in Figure 16a,b. Figure 16c shows the optimized stiffener layout under biaxial compression with a relative buckling load object corresponding to Equation (7). The results of both the initial straight and bionic optimized stiffeners under different situations are given in Table 3, and their detailed finite element analysis result are given in Figures 17 and 18, respectively.…”

Section: Results Analysismentioning

confidence: 99%

“…Dan Wang made full use of these streamlined characteristic to design a fiber path, and these non-uniform curved grid-stiffened composite (NCGC) structures have achieved a remarkable increase in their buckling load [5,6]. Kapania engaged in extensive research on the shape optimization of curved stiffeners for composite structures [7], while Mohammad Rouhi proposed a variable stiffness composite cylinder by fiber steering to maximum the buckling load under pure bending [8]. Beyond the shape or size optimization of the stiffeners or varying the path of the stiffeners' distribution, there are several novel features in this paper's surface design.…”

Section: Introductionmentioning

confidence: 99%

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Bionic Stiffener Layout Optimization with a Flexible Plate in Solar-Powered UAV Surface Structure Design

et al. 2019

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A cellular-based evolutionary topology optimization scheme over a small curvature big contour wing surface is proposed for the design of an ultralight surface structure. Using this method, a ground-structure technique is first applied to obtain homogeneous mesh generation with a predefined weight value over the design domain. Secondly, the stiffener path’s description is guided by a modified map L system topology method that simulates the growth of the bionic branch, and the structural components are obtained by the specified searching method according to weights of the previous mesh vertexes. Thirdly, an optimal curved stiffener layout is achieved using an agent-based algorithm to create individual instances of designs based on a small number of input parameters. These parameters can then be controlled by a genetic algorithm to optimize the final design according to goals like minimizing weight and structural weakness. A comparison is implemented for long-span panel stiffener layout generation between an initial straight case and a bionic optimal case via our method, thereby indicating the significant improvement of the buckling loads by steering the stiffener’s path. Finally, this bionic method is applied to the wing box structure design and achieves remarkable weight loss at last.

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Section: Results Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bionic Stiffener Layout Optimization with a Flexible Plate in Solar-Powered UAV Surface Structure Design

et al. 2019

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“…The details of the frame and experimental validation are discussed. [41][42][43] The rectangular panel which is section of the rib, having two holes, was designed for combined in-plane compression and shear loads using four curvilinear stiffeners with damage tolerance constraints; the same panel was tested at NASA Langley. The predicted and experimental results using nonlinear analysis for the rib panel were closely matched.…”

Section: Optimal Designs For 'Loads Through Both the Panel And The mentioning

confidence: 99%

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

Kapania

Mulani

Tamijani

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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We have developed an optimization framework, EBF3PanelOpt to design stiffened panels with curvilinear stiffeners. The curvilinear stiffening tries to utilize the larger design space created by such additive manufacturing techniques like Electron Beam Free Form Fabrication, Friction Stir Welding, and Selective Laser Sintering. Structural loads of future aerospace vehicles may not be well characterized using our knowledge-based databases, so medium-fidelity modeling capabilities of software, Msc.Patran (geometry and meshing), and Msc.Nastran (finite element analysis) are integrated in EBF3PanelOpt. The EBF3PanelOpt minimizes the mass of the stiffened panel with the constraints on buckling, von Mises stress and crippling of the stiffeners. The panel/stiffener geometry is parameterized using design variables that include variables for orientation and shape of the stiffeners, the thicknesses and height of the stiffeners, and the plate thickness. The plate can have uniform thickness or non-uniform thicknesses for the pockets created by the stiffeners. The EBF3PanelOpt is enhanced to have curvilinear T stiffeners with or without axial loads in addition to loads through plate Both the vibro-acoustic and structural optimization are supported using multi-objective optimization in EBF3PanelOpt. To enhance the computational efficiency, an improved surrogate model built using artificial neural network and kriging is utilized. To quantify the uncertainty in the design variables or parameters, reliability analysis is supported in EBF3PanelOpt.

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“…11 In a tensile test, multi-axial behavior was obtained by DIC. [12][13][14][15] Characterization of nonlinear properties for composite materials was obtained by using DIC and finite element analysis. [16][17][18] During mechanical testing of hard and soft tissues, the DIC technique could measure full-field surface strains.…”

Section: Introductionmentioning

confidence: 99%

A method for predicting the blasting pressure of balloons using the surface strain in low pressure

Shen

Lin

Tan

2019

Advances in Mechanical Engineering

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Balloons made by cut fabric pieces are widely used in space research. To predict the blasting pressure of a balloon, we propose a novel method based on the non-contact test strain at a low internal pressure. The three-dimensional digital image correlation technique is introduced to measure the surface strain of the balloon. Representative regions of the balloon are selected as the test regions. A correction factor is proposed that accounts for the relationship between the internal pressure and the surface strain for the actual and the ideal balloon. By combining the maximum surface strain at a given internal pressure and the correction factor, we can predict the blasting pressure of the balloon. A blasting test is carried out to verify the feasibility of the predictive method. When the value of the ratio of the maximum test strain to the limiting strain reaches about a reference value, the absolute value of the deviation percentage between the predicted blasting pressure and the actual blasting pressure is less than 10%. The blasting pressure for balloon can be predicted accurately. This method does not require the balloon to be inflated to a high internal pressure, which improves the practicality of the prediction.

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Design, Optimization, and Evaluation of Integrally Stiffened Al-7050 Panel with Curved Stiffeners

Cited by 30 publications

References 13 publications

Bionic Stiffener Layout Optimization with a Flexible Plate in Solar-Powered UAV Surface Structure Design

Bionic Stiffener Layout Optimization with a Flexible Plate in Solar-Powered UAV Surface Structure Design

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

A method for predicting the blasting pressure of balloons using the surface strain in low pressure

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