Simultaneous topology, shape, and layer optimization of jointed isotropic components and fiber composite laminates considering material damage and fail-safety

• Applicant: Professor Dr.-Ing. Benedikt Kriegesmann
• Subject Area: Lightweight Construction, Textile Technology ; Mechanics
• Term: from 2019 to 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 406315228

• Final Report Year: 2025

Final Report Abstract

In structural mechanics (particularly in aviation), certain components are required to be failsafe, which means that the structure must be able to withstand a certain proportion of the intended load despite the absence of a primary load path. Furthermore, optimization methods are increasingly being used in the design process of load-bearing structures, for example to save as much weight as possible. In conventional design optimization, it is possible to take failure safety into account as a secondary condition within the optimization. For this purpose, structural elements are removed during the optimization and the reliability is checked. In topology optimization, on the other hand, a structure is only created during the optimization process. As a result, failure safety could previously only be taken into account during optimization at extremely high computing costs. During the first phase of the project, a method was initially developed to identify load paths during optimization and thus specifically take their failures into account and reduce computing times. However, it turned out that the resulting continuous change of the optimization problem usually prevents convergence. Therefore, an approach was developed in which a cost-efficient topology optimization generates a redundant design, which is then shape-optimized. Since load paths do not change during the shape optimization, a reduced set of damage scenarios can be considered. Furthermore, it was investigated how the consideration of stresses affects the topology optimization considering fail safety. It was found that the shape of the assumed damage has a surprisingly small influence on the optimization result. In addition, fail safety was taken into account in the simultaneous optimization of two components and their connecting elements. This work formed the basis for the second project funding phase. In this phase, the connection of an isotropic component and a fiber composite shell was considered. An approach was developed in which the isotropic component is topologically optimized, while at the same time the locations of the connecting elements and the fiber composite laminate are optimized. It was shown that the consideration of a damage criterion in the fiber composite shell alone has a significant influence on the topology of the isotropic component. These results underline the importance of a holistic approach when optimizing assemblies of components.

Publications

• Adaptive Strategies for Fail-Safe Topology Optimization. EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization, 200-211. Springer International Publishing.
  Ambrozkiewicz, Olaf & Kriegesmann, Benedikt
  
• Fail-safe optimization of beam structures. Journal of Computational Design and Engineering, 6(3), 260-268.
  Lüdeker, Julian Kajo & Kriegesmann, Benedikt
  
• „Fail-safe design of topology optimized structures using density-based member shaping“, in 5th ECCOMAS Young Investigators Conference, Krakow, Poland, Sep. 2019
  O. Ambrozkiewicz & B. Kriegesmann
  
• Density-based shape optimization for fail-safe design. Journal of Computational Design and Engineering, 7(5), 615-629.
  Ambrozkiewicz, Olaf & Kriegesmann, Benedikt
  
• Simultaneous topology and fastener layout optimization of assemblies considering joint failure. International Journal for Numerical Methods in Engineering, 122(1), 294-319.
  Ambrozkiewicz, Olaf & Kriegesmann, Benedikt
  
• An empirical study on stress-based fail-safe topology optimization and multiple load path design. Structural and Multidisciplinary Optimization, 64(4), 2113-2134.
  Kranz, Micah; Lüdeker, Julian K. & Kriegesmann, Benedikt
  
• Fail-safe topology optimization, gehalten auf dem 16th TOP Webinar, Online, 28. Oktober 2021. [Online]
  M. Kranz, O. Ambrozkiewicz, J.K. Lüdeker & B. Kriegesmann
  
• „Simultaneous topology and fastener layout optimization of assemblies“, gehalten auf dem 12th TOP Webinar, Online, 29. April 2021. [Online]
  O. Ambrozkiewicz & B. Kriegesmann
  
• „Data-fitted constraint aggregation schemes“, gehalten auf dem 8th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2022), Oslo, Norway, 09.06 2022
  O. Ambrozkiewicz & B. Kriegesmann
  
• „Structural optimization of components and joints in assemblies considering fail-safety“, Dissertation, Technische Universität Hamburg
  O. Ambrozkiewicz
  
• „Simultaneous Optimization of Composite Plates, Metallic Components and Their Joints“, gehalten auf dem 9th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2024), 4. Juni 2024
  B. Kriegesmann, O. Ambrozkiewicz & K. Schneider