Forster, D., Paul, S., Bischoff, M., & Sychterz, A. C. (2024). Structural Assessment of Architected Material Using the Redundancy Matrix and Experimental Testing.
ASME Journal of Applied Mechanics,
91.
https://doi.org/10.1115/1.4065840 Zusammenfassung
This paper presents the integration of a numerical structural model based on the redundancy matrix and experimental results of Multi-Layered Randomized Architected Materials (MLRAM). It presents a combination of the relatively new field of architected materials with a load-independent performance indicator from theoretical structural mechanics. The redundancy matrix by itself provides a measure for structural assessment that is independent of a specific load case. Various layouts of the MLRAM samples and recorded testing allow the analysis of the redundancy distribution within the structure as it undergoes failure. An in-depth analysis of the tested MLRAM samples is provided, as they show a high degree of static indeterminacy and thus, multiple different load paths. A special focus lies on the change of the redundancy distribution as global progressive failure happens. Another focus is set on the investigation of the failure initiation, meaning that the redundancy distribution can help to identify critical elements. A simple introductory example shows the interdependence between the variation of the geometric location of nodes and the redundancy distribution. The study shows, that the distribution of static indeterminacy can be used as a measure to quantify vulnerability to failure and rank the individual element's importance. Furthermore, progressive collapse is identified as a series of local effects in the highly statically indeterminate MLRAM samples, underlining the fact that the spatial distribution of static indeterminacy is of central importance for the assessment of structural safety.BibTeX
Forster, D., von Scheven, M., & Bischoff, M. (2024). Alternative Beurteilung von Tragwerken mit Hilfe der Redundanzmatrix. In B. Oesterle, A. Bögle, W. Weber, & L. Striefler (Hrsg.),
Berichte der Fachtagung Baustatik – Baupraxis 15, 04. und 05. März 2024, Hamburg (S. 67--74).
https://doi.org/10.15480/882.9247 Zusammenfassung
Zur Analyse von Tragwerken ist es in frühen Entwurfsphasen häufig ausreichend, Schnitt- und Verschiebungsgrößen, sowie Spannungen im Rahmen der linearen Elastizitätstheorie zu bestimmen. Eine weitere fundamentale Eigenschaft von Tragwerken ist der Grad der statischen Unbestimmtheit und deren Verteilung innerhalb des Tragwerks. Die Redundanzmatrix liefert diese Information und stellt damit ein lastfallunabhängiges Maß zur Beurteilung von Tragwerken hinsichtlich Robustheit, Assemblierbarkeit und Adaptierbarkeit zur Verfügung.BibTeX
Kannenberg, F., Zechmeister, C., Gil Pérez, M., Guo, Y., Yang, X., Forster, D., Hügle, S., Mindermann, P., Abdelaal, M., Balangé, L., Schwieger, V., Weiskopf, D., Gresser, G. T., Middendorf, P., Bischoff, M., Knippers, J., & Menges, A. (2024). Toward reciprocal feedback between computational design, engineering, and fabrication to co-design coreless filament-wound structures.
Journal of Computational Design and Engineering,
11(3), 374--394.
https://doi.org/10.1093/jcde/qwae048 Zusammenfassung
Fiber-reinforced composites offer innovative solutions for architectural applications with high strength and low weight. Coreless filament winding extends industrial processes, reduces formwork, and allows for tailoring of fiber layups to specific requirements. A previously developed computational co-design framework for coreless filament winding is extended toward the integration of reciprocal design feedback to maximize design flexibility and inform design decisions throughout the process. A multi-scalar design representation is introduced, representing fiber structures at different levels of detail to generate feedback between computational design, engineering, and fabrication. Design methods for global, component, and material systems are outlined and feedback generation is explained. Structural and fabrication feedback are classified, and their integration is described in detail. This paper demonstrates how reciprocal feedback allows for co-evolution of domains of expertise and extends the existing co-design framework toward design problems. The developed methods are shown in two case studies at a global and component scale.BibTeX
Forster, D., Kannenberg, F., von Scheven, M., Menges, A., & Bischoff, M. (2023). Design and Optimization of Beam and Truss Structures Using Alternative Performance Indicators Based on the Redundancy Matrix. In K. Dörfler, J. Knippers, A. Menges, S. Parascho, H. Pottmann, & T. Wortmann (Hrsg.),
Advances in Architectural Geometry 2023 (S. 455--466). De Gruyter.
https://doi.org/10.1515/9783111162683-034 Zusammenfassung
In structural optimization processes, a common goal is to limit deflectionsor stresses through topological changes, shape adaption or cross-sectional adjust-ments. Beyond these well-established performance indicators, alternative measuresfor the assessment of structures based on the redundancy matrix can be used in thedesign and optimization process. This contribution shows the extension of the redun-dancy calculation to three-dimensional beam structures in detail. Using the conceptof redundancy for the design of structures, one goal is to homogeneously distributeredundancy within a structure in order to make an overall collapse due to failure ofindividual elements less likely. Furthermore, the sensitivity towards imperfections isquantified by the redundancy matrix, offering the opportunity to design connectionsof substructures, such that no constraint forces are introduced during the assemblyprocess. Those two concepts are showcased exemplarily within this contribution. Themethod is embedded into a computational co-design framework, which allows forquick, interactive feedback on design changes to strengthen the interplay between thedesign and engineering process.BibTeX
Gil Pérez, M., Mindermann, P., Zechmeister, C., Forster, D., Guo, Y., Hügle, S., Kannenberg, F., Balangé, L., Schwieger, V., Middendorf, P., Bischoff, M., Menges, A., Gresser, G. T., & Knippers, J. (2023). Data processing, analysis, and evaluation methods for co-design of coreless filament-wound building systems.
Journal of Computational Design and Engineering,
10(4), 1460–1478.
https://doi.org/10.1093/jcde/qwad064 Zusammenfassung
The linear design workflow for structural systems, involving a multitude of iterative loops and specialists, obstructs disruptive innovations. During design iterations, vast amounts of data in different reference systems, origins, and significance are generated. This data is often not directly comparable or is not collected at all, which implies a great unused potential for advancements in the process. In this paper, a novel workflow to process and analyze the data sets in a unified reference frame is proposed. From this, differently sophisticated iteration loops can be derived. The developed methods are presented within a case study using coreless filament winding as an exemplary fabrication process within an architectural context. This additive manufacturing process, using fiber-reinforced plastics, exhibits great potential for efficient structures when its intrinsic parameter variations can be minimized. The presented method aims to make data sets comparable by identifying the steps each data set needs to undergo (acquisition, pre-processing, mapping, post-processing, analysis, and evaluation). These processes are imperative to provide the means to find domain interrelations, which in the future can provide quantitative results that will help to inform the design process, making it more reliable, and allowing for the reduction of safety factors. The results of the case study demonstrate the data set processes, proving the necessity of these methods for the comprehensive inter-domain data comparison.BibTeX
Gil Pérez, M., Zechmeister, C., Kannenberg, F., Mindermann, P., Balangé, L., Guo, Y., Hügle, S., Gienger, A., Forster, D., Bischoff, M., Tarín, C., Middendorf, P., Schwieger, V., Gresser, G. T., Menges, A., & Knippers, J. (2022). Computational co-design framework for coreless wound fibre–polymer composite structures.
Journal of Computational Design and Engineering,
9(2), 310--329.
https://doi.org/10.1093/jcde/qwab081 Zusammenfassung
In coreless filament winding, resin-impregnated fibre filaments are wound around anchor points without an additional mould. The final geometry of the produced part results from the interaction of fibres in space and is initially undetermined. Therefore, the success of large-scale coreless wound fibre composite structures for architectural applications relies on the reciprocal collaboration of simulation, fabrication, quality evaluation, and data integration domains. The correlation of data from those domains enables the optimization of the design towards ideal performance and material efficiency. This paper elaborates on a computational co-design framework to enable new modes of collaboration for coreless wound fibre–polymer composite structures. It introduces the use of a shared object model acting as a central data repository that facilitates interdisciplinary data exchange and the investigation of correlations between domains. The application of the developed computational co-design framework is demonstrated in a case study in which the data are successfully mapped, linked, and analysed across the different fields of expertise. The results showcase the framework’s potential to gain a deeper understanding of large-scale coreless wound filament structures and their fabrication and geometrical implications for design optimization.BibTeX
Oesterle, B., Geiger, F., Forster, D., Fröhlich, M., & Bischoff, M. (2022). A study on the approximation power of NURBS and the significance of exact geometry in isogeometric pre-buckling analyses of shells.
Computer Methods in Applied Mechanics and Engineering,
397(115144), Article 115144.
https://doi.org/10.1016/j.cma.2022.115144 Zusammenfassung
We present a comprehensive study on the approximation power of NURBS and the significance of exact geometry in stability analyses of shells. Pre-buckling analyses are carried out to estimate the critical load levels and the initial buckling patterns. Various finite element solutions obtained with the commercial code ANSYS are compared with solutions from the isogeometric version of the finite element method, using our in-house code NumPro. In some problem setups, the isogeometric shell elements provide superior accuracy compared to standard (as opposed to isogeometric) shell finite elements, requiring only a fractional amount of degrees of freedom for the same level of accuracy. The present study systematically investigates the sources of this superior accuracy of the isogeometric approach. In particular, hypotheses are tested concerning the influence of exact geometry and smoothness of splines.BibTeX
