Session: 04-04-01: (04-04: Advances in Aerospace Structures and Materials & 04-11: Advances in Mechanics, Multiscale Models and Experimental Techniques for Composites)

Paper Number: 95843

95843 - A Topology Optimization Methodology With Vibration Constraint for an Aerospace Bracket Design 

The most important need in the aviation industry is the realization of high-strength and lightweight designs. For this reason, topology optimization methods for designing lightweight parts with maximized stiffness have become widespread recently. Complex geometry designs resulting from the topology optimization can be fabricated with the help of additive manufacturing technology. Besides, meeting the natural frequency requirements is one of the important design elements. However, topology optimization with stiffness maximization requires a static finite element analysis evaluation while the natural frequency calculation requires a modal analysis evaluation. Using these two different analysis procedures at the same time in the topology optimization process, on the other hand, is a challenging task.

To address this challenge, a topology optimization methodology that account for the natural frequency constraints in a stiffness maximization process is presented in this study. In particular, the fact that the resulting design has maximized stiffness under static loads and can provide the desired vibration frequencies, i.e., optimizing these two different requirements together stands out as an innovative aspect.  Since the commercial software for topology optimization can only perform one of these at the same time, the presented methodology may also have an accelerating effect in the sector.

Optimization studies aim to find the lowest value of an objective. In this study, the geometry with the lowest compliance value is tried to be found so that the stiffness of the part can be maximized under a given volume ratio and natural frequency constraint. The topology optimization process is coded in MATLAB with Solid Isotropic Material Penalization (SIMP) to update the density variables of each element. OptiStruct program is called in the background for the static and vibration analysis results required at each iteration. A density-based filtering technique is used in the topology optimization. Thus, problems such as mesh dependency and the checkboard effect are prevented. In addition to these, the final geometry obtained by using this filter has also provided convenience in terms of production with additive manufacturing.

There are many optimization methods and choosing the appropriate one is important in terms of speeding up the processes and the accuracy of the results. While choosing the appropriate method, some simple benchmark examples are studied. Optimization studies were also conducted by increasing the number of elements in the selected algorithms. As a result of the comparison studies, the Method of Moving Asymptotes (MMA) is determined to be the optimization method for the proposed topology optimization. The developed algorithm is used for a real-world aerospace bracket design with vibration and mass constraints. A prototype of the design is fabricated using the additive manufacturing technique.

Presenting Author: Recep M. Gorguluarslan TOBB University of Economics and Technology

Presenting Author Biography: Recep M Gorguluarslan received his B.S. degree in Mechanical Engineering from the TOBB<br/>University of Economics and Technology, Ankara, Turkey, in 2010. He was awarded a Fulbright<br/>scholarship for his doctoral studies in the U.S. in 2011. He received his Ph.D. in December 2016<br/>in Mechanical Engineering from Georgia Institute of Technology. He worked as a post<br/>doctoral researcher at Georgia Institute of Technology in 2017. He currently works as an assistant<br/>professor in the Mechanical Engineering Department of TOBB University of Economics and<br/>Technology. His research interests include, among the others, design optimization, probabilistic<br/>modeling, multiscale modeling, cellular structures, additive manufacturing and surrogate<br/>modeling.

Authors:

Hüseyin Karabiyik TOBB University of Economics and Technology
Osman Eroglu TOBB University of Economics and Technology
Muhammed Metin Eskimez TOBB University of Economics and Technology
Berk Oncu Oncul TOBB University of Economics and Technology
Muhammet Tayyip Yilmaz TOBB University of Economics and Technology
İstemihan Gökdağ Turkish Aerospace Industry
Recep M. Gorguluarslan TOBB University of Economics and Technology