Venation-inspired Growth Technique For Stiffener Layout Design Of Plate Structures

With the development of bionics, bionic design method has been widely applied to the stiffener layout design of plate structures. By adopting the morphogenesis or function mechanism of biological system to direct the stiffener design, distinct and effective stiffener layouts can be obtained. However, the existing researches commonly focus on specific structures and can only solve limited engineering problems. Thus the range of application is very limited. Inspired by the morphogenesis mechanism of dicotyledonous venation, a universally applicable bionic design method for stiffener layout is proposed in this paper. The method is applied to the stiffness and frequency optimization of stiffeners for some typical structures. And different layouts are compared by experiments.Firstly, through the similarity analysis between irregular stiffeners and leaf veins, the bionic principle of stiffener layout design is explained. Based on the morphogenesis mechanism of dicotyledonous venation, the venation-inspired growth technique for stiffener layout is proposed. The concepts, growth/degeneration rules and implementation process are clarified. During the design process, the growth and degeneration of the stiffeners are determined by the elemental sensitivity numbers. The sensitivity numbers of solid and void elements are derived, respectively. And a sensitivity filter scheme is proposed. The algorithm is programmed in Python and integrated with Abaqus software. An Abaqus/CAE plug-in program is designed.Secondly, the proposed method is applied to the stiffness optimization of stiffener layouts. Using the adjoint method, the elemental stiffness sensitivity numbers are derived.Then the setting principles of design parameters in the stiffness optimization are discussed.With the objective of maximizing the overall stiffness, the stiffener layouts of some typical structures are designed.Thirdly, the venation-inspired growth technique is extended to the frequency optimization problem. Based on the FEA equilibrium equation of undamped free vibration,the elemental frequency sensitivity numbers are derived. By studying the cantilever square plate, the setting principles of design parameters in the frequency optimization are discussed.With the objectives of maximizing the natural frequency and the distance between two natural frequencies, the proposed method is applied to some typical stiffener layout design problems.Finally, the results obtained in this paper are compared with those in existing literatures and traditional orthogonal layout by experiments. In the static experiment, influences of different layouts on the structural stiffness are evaluated by measuring the displacements of plates under static loads. In the modal experiment, the first five natural frequencies of plates with different stiffener layouts are obtained by using the hammering method. The experiment results demonstrate that the stiffener layouts obtained by using the proposed method can effectively improve the structural static and dynamic mechanical properties.Numerical examples and experiment results indicate that the proposed venation-inspired growth technique is efficient and can be applied to the stiffener design of arbitrary structures with different objective functions. Distinct stiffener layouts, which can significantly improve the the structural properties, are achieved. Besides, the Abaqus plug-in program is easy to implement.