Experimental investigation of structural system capacity with multiple fatigue cracks. (July 2021)

• Record Type: Journal Article
• Authors: Zhang, Kaihua; Collette, Matthew
• Is Part Of: Marine structures. Volume 78(2021)
• Publication Date: 2021-07
• Subjects: Fatigue test -- Laboratory scale -- Multi-degradation -- Marine structures -- Crack length measurement; Naval architecture -- Periodicals; Offshore structures -- Periodicals; Architecture navale -- Périodiques; Structures offshore -- Périodiques; Naval architecture; Offshore structures; Periodicals; 620.4162
• DOI: 10.1016/j.marstruc.2021.102943
• Languages: English
• ISSNs: 0951-8339

Abstract

Abstract: Few experimental data sets exist in the literature to support the development and evaluation of digital twins predicting structural degradation. The literature is especially sparse for system tests where multiple failures occur and interact. In this work, a laboratory-level experiment is conducted to mimic many of the properties of larger and more complex marine structures with redundant load paths, failure interaction, and component-to-system level integration. In the experiment, such properties are reflected by a hexagon tension specimen with four propagating fatigue cracks tested under displacement-controlled loading. The applied loading cycles and corresponding crack lengths are recorded as the major time-varying data of degradation, with the resisting force at maximum extension used as the system capacity. A novel computer vision method is used to measure the crack length. Strain gauges are also used to monitor the structure's status. The experimental data is presented and analyzed in this paper. The resulting data sets can be used to evaluate the performance of different digital twin updating approaches. Highlights: A laboratory-scale structural system model is presented to create data for evaluating digital twins. The model consists of four interacting cracks growing on a hollow hexagon specimen. Crack sizes, strains, and system-level resisting forces are measured. A new computer-vision based crack measurement system is described.