Evangelos Tyflopoulos

Dr. Evangelos Tyflopoulos

Norwegian University of Science and Technology (NTNU)
orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 January 2022 in Applied Sciences
Verified
Journal Article
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Evangelos TyflopoulosEvangelos Tyflopoulos
Evangelos Tyflopoulos
MSMartin Steinert
Martin Steinert
Topology optimization (TO) has been a popular design method among CAD designers in the last decades. This method optimizes the given design domain by minimizing/maximizing one or more objective functions, such as the structure’s stiffness, and at the same time, respecting the given constraints like the volume or the weight reduction. For this reason, the companies providing the commercial CAD/FEM platforms have taken this design trend into account and, thus, have included TO in their products over the last years. However, it is not clear which features, algorithms, or, in other words, possibilities the CAD designers do have using these software platforms. A comparative study among the most applied topology optimization software was conducted for this research paper. First, the authors developed an online database of the identified TO software in the form of a table. Interested CAD designers can access and edit its content, contributing in this way to the creation of an updated library of the available TO software. In addition, a deeper comparison among three commercial software platforms—SolidWorks, ANSYS Mechanical, and ABAQUS—was implemented using three common case studies—(1) a bell crank lever, (2) a pillow bracket, and (3) a small bridge. These models were designed, optimized, and validated numerically, as well as compared for their strength. Finally, the above software was evaluated with respect to optimization time, optimized designs, and TO possibilities and features.

5 February 2021 in Applied Sciences
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Journal Article
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Evangelos TyflopoulosEvangelos Tyflopoulos
Evangelos Tyflopoulos
Mathias LienMathias Lien
Mathias Lien
MSMartin Steinert
Martin Steinert
The weight optimization of a structure can be conducted by using fewer and downsized components, applying lighter materials in production, and removing unwanted material. Topology optimization (TO) is one of the most implemented material removal processes. In addition, when it is oriented towards additive manufacturing (AM), it increases design flexibility. The traditional optimization approach is the compliance optimization, where the material layout of a structure is optimized by minimizing its overall compliance. However, TO, in its current state of the art, is mainly used for design inspiration and not for manufacturing due to design complexities and lack of accuracy of its design solutions. The authors, in this research paper, explore the benefits and the limitations of the TO using as a case study the housings of a front and a rear brake caliper. The calipers were optimized for weight reduction by implementing the aforementioned optimization procedure. Their housings were topologically optimized, partially redesigned, prepared for 3D printing, validated, and 3D printed in titanium using selective laser melting (SLM). The weight of the optimized calipers reduced by 41.6% compared to commercial calipers. Designers interested in either TO or in automotive engineering can exploit the findings in this paper.

29 June 2020 in Applied Sciences
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Journal Article
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Evangelos TyflopoulosEvangelos Tyflopoulos
Evangelos Tyflopoulos
MSMartin Steinert
Martin Steinert
Topology and Parametric Optimization are two of the most implemented material optimization approaches. However, it is not clear in the literature which optimization procedure, or possible combination of them, can lead to the best results based on material reduction and optimization time. In this paper, a quantitative comparison of different topology and parametric optimization design processes is conducted using three benchmark examples: A Hollow Plate, an L-Bracket, and a Messerschmitt–Bölkow–Blohm Beam (MBB-Beam). Ten different design processes that were developed in each case study resulted in 30 simulations in total. The design processes were clustered in three main design workflows: The Topology Optimization, the Parametric Optimization, and the Simultaneous Parametric and Topology Optimization. Their results were compared with respect to mass, stress, and time. The Simultaneous Parametric and Topology Optimization approach gave the lightest design solutions without compromising their initial strength but also increased the optimization time. The findings of this paper will help the designers in the pursuit of lightweight structures and will create the basis for the identification of the ideal material optimization procedure.

1 January 2019 in Procedia CIRP
Verified
Journal Article
Open access
Evangelos TyflopoulosEvangelos Tyflopoulos
Evangelos Tyflopoulos
MSMartin Steinert
Martin Steinert

2 December 2021 in Designs
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Journal Article
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Evangelos TyflopoulosEvangelos Tyflopoulos
Evangelos Tyflopoulos
MSMartin Steinert
Martin Steinert
Topology optimization (TO) is a mathematical method that optimizes the material layout in a pre-defined design domain. Its theoretical background is widely known for macro-, meso-, and microscale levels of a structure. The macroscale TO is now available in the majority of commercial TO software, while only a few software packages offer a mesoscale TO with the design and optimization of lattice structures. However, they still lack a practical simultaneous macro–mesoscale TO. It is not clear to the designers how they can combine and apply TO at different levels. In this paper, a two-scale TO is conducted using the homogenization theory at both the macro- and mesoscale structural levels. In this way, the benefits of the existence and optimization of mesoscale structures were researched. For this reason, as a case study, a commercial example of the known jet engine bracket from General Electric (GE bracket) was used. Different optimization workflows were implemented in order to develop alternative design concepts of the same mass. The design concepts were compared with respect to their weight, strength, and simulation time for the given load cases. In addition, the lightest design concept among them was identified.

19 December 2019 in Material Design & Processing Communications
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Evangelos TyflopoulosEvangelos Tyflopoulos
Evangelos Tyflopoulos
MSMartin Steinert
Martin Steinert
Topology optimization (TO) aids designers to come up with new ideas that would be impossible to be designed without this technology. However, the optimized results are usually characterized by high geometric complexity, which makes almost impossible their manufacturing by conventional methods. Additive manufacturing (AM) overcomes this problem and increases the design flexibility. In addition, lattice structures with their porous infill combine the design flexibility with good material properties, such as high strength compared with relatively low mass. In this paper, the authors compare designs derived from traditional TO lattice optimization with respect to their tensile strength. A case study of a custom cylindrical model is used to support the theory and collect empirical data. The simulation data as well as the implemented methodology in this work can be used as a guidance for the designers looking for new lightweight design ideas for AM.