Pseudo-Cylindrical Shells: A New Concept for Undersea Structures

Knapp, R.H.

doi:10.1115/1.3439263

Cited by 16 publications

(2 citation statements)

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“…However, imperfection sensitivity still remains (Hutchinson and Frauenthal 1969;Singer et al 1971), and the manufacture of stiffeners is often impractical and costly. Intrinsically stiffened shells, such as pseudocylindrical concave polyhedral shells (Knapp 1977;Yoshimura 1955), 'Aster' shells (Araar et al 1998;Combescure and Jullien 2015) and free-form wavy cylindrical shells (Ning andPellegrino 2015, 2017), have also been developed, with the latter two types having corrugated rather than circular cross-sections and achieving higher strength from their waviness. The potential of corrugated cylindrical shells, in terms of reduced imperfection sensitivity and enhanced load-bearing capacities, can be readily exploited through additive manufacturing.…”

Section: Introductionmentioning

confidence: 99%

Testing and Analysis of Additively Manufactured Stainless Steel Corrugated Cylindrical Shells in Compression

et al. 2023

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Initial geometric imperfections have been identified as the main cause for the large discrepancies between experimental and theoretical buckling loads of thin-walled circular cylindrical shells under axial compression. The extreme sensitivity to imperfections has been previously addressed and mitigated through the introduction of stiffeners; however, sensitivity still remains. Optimized corrugated cylindrical shells are largely insensitive to imperfections and hence exhibit excellent load-bearing capacities, but their complex geometries make their construction difficult and costly using conventional manufacturing techniques. This was overcome in the present study through additive manufacturing (AM). Nine optimized corrugated shells with different diameter-to-thickness ratios, together with one reference circular cylindrical shell, were additively manufactured by means of powder bed fusion (PBF) 2 from austenitic and martensitic precipitation hardening stainless steel. The structural behavior of the AM shells was then investigated experimentally, with the testing program comprising tensile coupon tests, measurements of basic geometric properties and axial compression tests.Numerical analyses were also conducted following completion of the physical experiments.The experimental and numerical results verified the effectiveness of optimized corrugated cylindrical shells in achieving improved local buckling capacity and reduced imperfection sensitivity. Initial recommendations for the structural design of the studied cross-sections are made.

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Section: Introductionmentioning

confidence: 99%

Testing and Analysis of Additively Manufactured Stainless Steel Corrugated Cylindrical Shells in Compression

et al. 2023

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“…As an alternative to reinforcing thin cylindrical shells with stiffeners, intrinsically stiffened shells have been developed, such as pseudocylindrical concave polyhedral shells [6,7], 'Aster' shells [8][9][10] and wavy shells [11][12][13][14][15], with the two latter types having corrugated cross-section shapes rather than circular cross-sections. The use of corrugations effectively reduces the local slenderness of the cross-section due to the reduced local radius of curvature; this results in reduced imperfection sensitivity and improved load-carrying capacity.…”

Section: Introductionmentioning

confidence: 99%

Optimisation and compressive testing of additively manufactured stainless steel corrugated shells

Zhang¹,

Gardner²,

Meng³

et al. 2021

ce papers

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Axially compressed circular cylindrical shells with large diameter‐to‐thickness ratios are known to be highly sensitive to initial geometric imperfections, which can drastically reduce their load‐carrying capacity. Their design typically involves the application of severe knock‐down factors on their theoretical buckling loads, which greatly impair their structural efficiency. In this paper, with the aim of reducing sensitivity to imperfections and enhancing load‐bearing resistance, optimised corrugated cylindrical shells are designed, additively manufactured, tested and analysed. Two corrugated shells with different equivalent diameter‐to‐thickness ratios, along with a reference circular cylindrical shell, were produced by powder bed fusion (PBF) additive manufacturing from martensitic precipitation hardening stainless steel powder. The structural performance of the PBF corrugated and circular shells was experimentally investigated, including tensile coupon tests, initial geometric measurements and compression tests. Numerical analyses were also carried out in parallel with the testing. The experimental and numerical results demonstrate that the optimised corrugated cross‐sections have lower imperfection sensitivity and higher axial resistances compared with their reference circular sections.

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Self‐Reconfiguring and Stiffening Origami Tube

et al. 2022

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Reconfigurable structures have attracted increasing attention in numerous fields, such as aerospace, biomechanical, and civil engineering, owing to their nature to reshape and readjust without altering their original architectures. However, one of the most challenging issues in designing a reconfigurable structure is to ensure a load‐bearing capacity after reconfiguration, while keeping the structural flexibility during the transformation process. Here, an origami tube that can be easily reconfigured into multiple shapes, yet offering a stiffening mechanism for load‐bearing purposes is presented. A complete set of possible configurations that a single design can be reconfigured into is mathematically identified and classified. Significant differences in their axial stiffness for various configurations are analytically and experimentally investigated. Lastly, a self‐reconfiguring and stiffening mechanism of the proposed origami tube structure made with shape memory polymer (SMP), which automatically reinforces its axial stiffness about an order of magnitude through kinematic transitions is demonstrated.

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Pseudo-Cylindrical Shells: A New Concept for Undersea Structures

Cited by 16 publications

References 0 publications

Testing and Analysis of Additively Manufactured Stainless Steel Corrugated Cylindrical Shells in Compression

Testing and Analysis of Additively Manufactured Stainless Steel Corrugated Cylindrical Shells in Compression

Optimisation and compressive testing of additively manufactured stainless steel corrugated shells

Self‐Reconfiguring and Stiffening Origami Tube

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