Evaluation of the Applicability of Digital Photogrammetry-Based Initial Imperfections on NLFEM Ultimate Strength Analysis of Ship- Type Stiffened Plates

Year 2023, Issue: 224, 60 - 77, 31.01.2024

Hasan Ölmez

https://doi.org/10.54926/gdt.1386576

Abstract

In this study, the effects of initial imperfections on the ultimate strength values of ship-type stiffened plate structures are discussed and analysed from the point of view of how the initial imperfection forms are obtained. Ship stiffened panels are subjected to complex loading conditions during their operational lifespan. Accurate prediction of their strength and failure modes necessitates a thorough understanding of the effects of various imperfections on their behavior. Two primary sources of initial imperfections are considered: the buckling mode shapes resulting from linear eigenvalue buckling analysis and measurements based on digital photogrammetry. Buckling mode shapes, arising from the manufacturing process are extracted using linear static structural analysis. Digital photogrammetry is employed to capture and quantify imperfections by analysing high-resolution images of the physical structure. Numerical investigation is conducted by incorporating these two types of initial imperfections into non-linear finite element method (NLFEM) calculations. The buckling mode imperfections are applied as geometric perturbations, while the photogrammetry-based imperfections are incorporated as statistically representative deviations from the ideal geometry. Stiffened panel's structural response is analysed under longitudinal uniaxial compression. A new NLFEM project schematic has been utilized instead of the procedure outlined in the technical circular S.P 01/19 by Türk Loydu, which has been discontinued after ANSYS® Workbench™V.2019R2. This is proven by two validation case studies in ANSYS® Workbench™2022R2 version for considering buckling mode initial imperfections. A case study is then conducted using a 3D model of a stiffened plate panel, which is fabricated in a shipyard located in Trabzon, created by Photomodeler V. 2023.3.0.238 employing the digital photogrammetry method.NLFEM analysis is carried out for both initially deflected model after eigenvalue buckling analysis and naturally deflected model after welding operations. The comparative ultimate strength results are quite consistent, and this shows that the digital photogrammetric modelling method can be used in the analysis of ship structural elements.

Keywords

Ship strength, stiffened plate, initial imperfection, ultimate strength, NLFEM, Digital Photogrammetry

Dijital Fotogrametri Tabanlı Başlangıç Kusurlarının Gemi Tipi Desteklenmiş Levhaların NLFEM ile Nihai Mukavemet Analizlerinde Kullanılabilirliğinin İncelenmesi

Abstract

Bu çalışmada, başlangıç sehimlerinin gemi tipi desteklenmiş panel yapılarının nihai mukavemet değerleri üzerindeki etkileri, başlangıç sehim formlarının nasıl elde edildiği açısından ele alınmış ve analiz edilmiştir. Gemilerdeki desteklenmiş paneller, operasyonel ömürleri boyunca karmaşık yükleme koşullarına maruz kalmakta ve yapısal bütünlüklerinin korunmasını kaçınılmaz hale getirmektedir. Mukavemetlerinin ve göçme modlarının doğru bir şekilde tahmin edilmesi, çeşitli kusurların davranışları üzerindeki etkilerinin kapsamlı bir şekilde anlaşılmasını gerektirir. Bu çalışmada, başlangıç kusurlarının iki temel kaynağı ele alınmıştır. Bunlar, doğrusal öz değer burkulma analizi sonuçları ve dijital fotogrametri tabanlı ölçümler sonucunda ortaya çıkan burkulma modu şekilleridir. Üretim sürecinden kaynaklanan burkulma modu şekilleri, doğrusal statik yapısal analiz kullanılarak elde edilmiştir. Öte yandan, fiziksel yapının yüksek çözünürlüklü görüntülerini analiz ederek kusurları yakalamak ve ölçmek için dijital fotogrametri kullanılmıştır. Sayısal hesaplamalar, bu iki tür başlangıç kusurunun doğrusal olmayan sonlu elemanlar yöntemi (NLFEM) analizlerine dahil edilmesiyle gerçekleştirilmiştir. Burkulma modu kusurları geometrik düzensizlikler olarak uygulanırken, fotogrametri tabanlı kusurlar ideal geometriden istatistiksel olarak temsili sapmalar olarak elde edilmiştir. Desteklenmiş panelin yapısal davranışı, boyuna tek eksenli basınç yüklemesi altında analiz edilmiştir. Ansys 2019R2 versiyonundan itibaren artık kullanılmayan Türk Loydu'nun S.P 01/19 teknik genelgesinde verilen prosedür yerine yeni bir NLFEM proje şeması kullanılmıştır. Önerilen bu yöntemin geçerliliği, Ansys 2022R2 versiyonunda, burkulma modu başlangıç kusurlarını dikkate alan iki doğrulama çalışması ile kanıtlanmıştır. Daha sonra, Trabzon'daki bir tersanede imal edilen modelden dijital fotogrametri yöntemi ile Photomodeler V. 2023.3.0.238 programında oluşturulan desteklenmiş panel yapısı için bir uygulama çalışması yapılmıştır. NLFEM analizi, hem öz değer burkulma analizinden sonra elde edilen başlangıç sehimleri modeli ile hem de kaynak montaj işlemlerinden sonra doğal olarak yapısal bozulmalara uğramış model için gerçekleştirilmiştir. Karşılaştırmalı nihai mukavemet sonuçları oldukça tutarlı belirlenmiş ve bu da dijital fotogrametrik modelleme yönteminin gemi yapı elemanlarının mukavemet analizinde kullanılabileceğini göstermiştir.

Keywords

Gemi mukavemeti, başlangıç kusurları, nihai mukavemet, NLFEM, Dijital Fotogrametri, desteklenmiş levha

References

• Xu, MC., Yanagihara, D., Fujikubo, M. and Soares, CG. (2013). Influence of boundary conditions on the collapse behaviour of stiffened panels under combined loads. Marine Structures, 34, 205-225.
• Kim, DK., Lima, HL. and Yua, SY. (2018). A technical review on ultimate strength prediction of stiffened panels in axial compression. Ocean Engineering, 170, 392–406.
• Li, S., Kim, DK. and Benson, S. (2021). The influence of residual stress on the ultimate strength of longitudinally compressed stiffened panels. Ocean Engineering, 231, 1-15.
• Khan, I. and Zhang, S. (2011). Effects of welding-induced residual stress on ultimate strength of plates and stiffened panels. Ships and Offshore Structures, 6(4), 297–309.
• Yao, T. and Fujikubo, M. (2016). Buckling and ultimate strength of ship and ship-like floating structures. First edition. Butterworth-Heinemann, Elsevier.
• Tanaka, S., Yanagihara, D., Yasuoka, A., Harada, M., Okazawa, S., Fujikubo, M., et al. (2014). Evaluation of ultimate strength of stiffened panels under longitudinal thrust. Marine Structures, 36, 21–50.
• Paik, JK. And Seo, JK. (2009). Nonlinear finite element method models for ultimate strength analysis of steel stiffened-plate structures under combined biaxial compression and lateral pressure actions–Part II: stiffened panels. Thin-Walled Structures, 47, 998–1007.
• Ozdemira, M., Ergin, A., Yanagihara, D., Satoyuki Tanaka, S. and Yao, T. (2018). A new method to estimate ultimate strength of stiffened panels under longitudinal thrust based on analytical formulas. Marine Structures, 59, 510–535.
• Tekgoz, M. and Garbatov, Y. (2021). Collapse strength of intact ship structures. Journal of Marine Science and Engineering, 9, 1-20.
• Kim, DK., Lima, HL., Kim, MS., Hwanga, OJ. and Park, KS. (2017). An empirical formulation for predicting
• the ultimate strength of stiffened panels subjected to longitudinal compression. Ocean Engineering, 140, 270–280.
• Kim, DK., Poh, BY., Lee, JR. and Paik, JK. (2018). Ultimate strength of initially deflected plate under longitudinal compression: Part I = An advanced empirical formulation. Structural Engineering and Mechanics, 68(2), 247-259.
• Li, S., Georgiadis, DG., Kim, DK. and Samuelides, MS. (2022). A comparison of geometric imperfection models for collapse analysis of ship-type stiffened plated grillages. Engineering Structures, 250, 1-13. Georgiadis, DG., Samuelides, MS., Li, S., Kim, DK., Benson, S., Amdahl, J. and Guedes Soares, C. (2021).
• Influence of stochastic geometric imperfection on the ultimate strength of stiffened panel in compression. Developments in the Analysis and Design of Marine Structures. Taylor & Francis.
• Yi, MS., Lee, DH., Lee, HH. and Paik, JK. (2020). Direct measurements and numerical predictions of welding-induced initial deformations in a full-scale steel stiffened plate structure. Thin-Walled Structures, 153, 1-17.
• Ringsberg, JW., Darie, I., Nahshon, K., Shilling, G., Vaz, MA., Benson, S., et al. (2021). The ISSC-2022 Committee III.1-Ultimate strength benchmark study on the ultimate limit state analysis of a stiffened plate structure subjected to uniaxial compressive loads. Marine Structures, 79, 1-26.
• Paik, JK. and Kim, BJ. (2002). Ultimate strength formulations for stiffened panels under combined axial load, in-plane bending and lateral pressure: a benchmark study. Thin-Walled Structures, 40(1), 45–83.
• Georgiou, D. (2019). Buckling and Ultimate Strength of Stiffened Panels. Master Thesis. Norwegian University of Science and Technology, Norway.
• Kolyvas, E., Drikos, L., Diamanti, E. and A. El Saer, AE. (2015). Application of photogrammetry techniques for the visual assessment of vessels’ cargo hold. Towards Green Marine Technology and Transport, CRC Press, London.
• Koelman, HJ. (2010). Application of a photogrammetry-based system to measure and re-engineer ship hulls and ship parts: An industrial practices-based report. Computer-Aided Design, 42, 731-743.
• Tepegöz, A. (2019). Fotogrametrik yöntemle üç boyutlu gemi modelleme ve proje verileri ile karşılaştırma. Master Thesis, Karadeniz Technical Üniversity, Trabzon, Türkiye.
• Lloyd Register. (2016). ShipRight design and construction. Additional design procedures non-linear structural collapse analysis for plates and stiffened panels, 1-25.
• Türk Loydu. (2019). Procedure for the determination of the ultimate strength of stiffened panels by using Non-Linear Finite Element Analysis. Technical Circular, İstanbul, Türkiye.
• Chen, BQ., Garbatov, Y. and Soares, C.G. (2011). Automatic approach for measuring deformations in complex structures using photogrammetry technique. Proceedings of the 22nd Pan American Conference of Naval Engineering, Maritime Transportation & Ports Engineering, 1-18, Buenos Aires, Argentina.
• Mouhat, O., Khamlichp, A. and Limam, A. (2013). Assessing buckling strength of stiffened plates as affected by localized initial geometric imperfections. International Review of Applied Sciences and Engineering 4(2).
• Cubells, A., Garbatov, Y. and Soares, C.G. (2014). Photogrammetry measurements of initial imperfections for the ultimate strength assessment of plates. Trans RINA, International Journal of Maritime Engineering, Part A4, 156.
• Zhang, S. (2015). A review and study on ultimate strength of steel plates and stiffened panels in axial compression. Ships and Offshore Structures. 11(1), 1-11.
• Woloszyk, K., Bielski, PM., Garbatov, Y., Mikulski, T. (2021). Photogrammetry image-based approach for imperfect structure modelling and FE analysis. Ocean Engineering, 223, 1-14.
• Woloszyk, K., Garbatov, Y., Kowalski, J. and Samson, L. (2020). Experimental and numerical investigations of ultimate strength of imperfect stiffened plates of different slenderness. Polish Maritime Research, 27(108), 120-129.
• Graves, W., Nahshon, K., Aminfar, K. and Lattanzi D. (2023). Finite element model updating with quantified uncertainties using point cloud data. Data-Centric Engineering, 4(16), 1-19.
• Barceló, AC. (2012). Structural assessment based on photogrammetry measurements and Finite Element Method. Master Thesis, Lisbon Technical University, Lisbon, Portugal.
• Quinn, D., Murphy, A., McEwan, W. and Lemaitre, F. (2009). Stiffened panel stability behaviour and performance gains with plate prismatic sub-stiffening. Thin-WalledStructures, 47, 1457–1468.
• ISSC (2012), Ultimate Strength (Committee III.1), Proceedings of the 18th International Ship and Offshore Structures Congress, Rostock, Germany, September.
• Sekban, DM., Ölmez, H., Akterer, SM., Kose, E. and Pürçek, G. (2018). Effect of Friction Stir Processing on Ultimate Strength of Ship Hull Girder Plates Estimated by Finite Element Analysis, Proceedıngs of the 3rd International Naval Architecture and Maritime Symposium, Yıldız Technical University, Istanbul, Turkey, April 24-25, 2018.
• ANSYS® Workbench™ R2022, User’s Manual. https://ansyshelp.ansys.com [Online] [01-25.10.2023]
• Photomodeler V.2023.3.0.238, User’s Manual. https://www.photomodeler.com/downloads/OnlineHelp/index.html [Online] [01-25.10.2023]