Experimental validation of the vibration correlation technique robustness to predict buckling of unstiffened composite cylindrical shells

Franzoni, Felipe; Odermann, Falk; Lanbans, Edgars; Bisagni, Chiara; Arbelo, Mariano A.; Degenhardt, Richard

doi:10.1016/j.compstruct.2019.111107

Cited by 30 publications

(25 citation statements)

References 20 publications

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“…The number of data sets m of the random vectors X is in this case smaller than the number of vectors elements n; the covariance matrix is therefore singular. The special Mahalanobis transformation has to be used instead which is given by equation (18).…”

Section: Analysis With Vector-valued Imperfectionsmentioning

confidence: 99%

“…The corresponding data collection is given by Takano [15]. [15], [16], [17] and [18] A main cause for the large discrepancy between buckling theory and experiment are shape deviations from the ideal cylinder geometry, namely geometric imperfections [19], [20]. The geometric imperfections have been at first described by expansions in terms of buckling eigenmodes and the corresponding amplitudes were regarded as random variables [21].…”

Section: Introductionmentioning

confidence: 99%

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Probabilistic and deterministic lower-bound design benchmarks for cylindrical shells under axial compression

Wagner

Hühne

Elishakoff

2020

Thin-Walled Structures

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This article contains examples to demonstrate the use of different design concepts for cylindrical shells under axial compression. The examples are based on shells which were manufactured according to electroplating, machining, welding (isotropic cylinders) and prepreg hand layup on a mandrel (composite cylinders). Three of the four shell series are characterized by pure elastic buckling and one shell series buckled in the elastic-plastic region. All relevant data for the numerical analysis are described in the article and summarized in the Elsevier repository of this article (geometry, material, measured imperfection data and Python-ABAQUS scripts). The design concepts are based on the geometric imperfection signatures, probabilistic and deterministic lower-bound methods. The design concepts are representative for the development of design approaches for imperfection sensitive shells from the early 1980 to the late 2010 and are validated with experimental data. Recently developed design lower-bound curves for axially loaded cylinders are presented and compared with currently used design criteria like the Eurocode EN 1993-1-6 and the NASA SP-8007. The results of this article show that the design of imperfection sensitive cylinders has been significantly improved in the last 30 years.

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Section: Analysis With Vector-valued Imperfectionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Probabilistic and deterministic lower-bound design benchmarks for cylindrical shells under axial compression

Wagner

Hühne

Elishakoff

2020

Thin-Walled Structures

View full text Add to dashboard Cite

show abstract

“…A number of empirical and semi-empirical modified VCTs have been proposed to reflect the effect of imperfections on the load–natural frequency relation of shells, as recently reviewed in, e.g., [ 20 , 21 , 22 ]. The most accurate and extensively studied VCT method for unstiffened cylindrical shells, proposed in [ 23 ], departs from the common approach of relating the onset of buckling to fading of the natural frequency of the shell.…”

Section: Introductionmentioning

confidence: 99%

“…This VCT method has been applied for estimation of the buckling load in axial compression of CFRP shells of various lay-ups [ 21 , 23 , 25 , 26 , 27 , 28 ], including a variable-angle tow CFRP shell [ 28 ], as well as grid-stiffened glass/epoxy [ 29 ], composite lattice sandwich [ 22 ], stainless steel [ 26 ] and aluminum alloy [ 30 , 31 ] shells. Apart from a pure axial loading, the critical load for pressurized aluminum alloy shells [ 31 ] has also been studied.…”

Section: Introductionmentioning

confidence: 99%

“…However, a sufficiently detailed characterization of shell imperfections may be overly complicated in industrial applications. The advantage of VCT is that only a relatively uncomplicated nondestructive mechanical test of a shell is required [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] instead of a detailed inspection of different imperfections of the shell. However, the boundary conditions of the structural element have to be accurately recreated in the shell test.…”

Section: Introductionmentioning

confidence: 99%

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Robustness of Empirical Vibration Correlation Techniques for Predicting the Instability of Unstiffened Cylindrical Composite Shells in Axial Compression

et al. 2020

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Thin-walled carbon fiber reinforced plastic (CFRP) shells are increasingly used in aerospace industry. Such shells are prone to the loss of stability under compressive loads. Furthermore, the instability onset of monocoque shells exhibits a pronounced imperfection sensitivity. The vibration correlation technique (VCT) is being developed as a nondestructive test method for evaluation of the buckling load of the shells. In this study, accuracy and robustness of an existing and a modified VCT method are evaluated. With this aim, more than 20 thin-walled unstiffened CFRP shells have been produced and tested. The results obtained suggest that the vibration response under loads exceeding 0.25 of the linear buckling load needs to be characterized for a successful application of the VCT. Then the largest unconservative discrepancy of prediction by the modified VCT method amounted to ca. 22% of the critical load. Applying loads exceeding 0.9 of the buckling load reduced the average relative discrepancy to 6.4%.

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Knockdown factor of buckling load for axially compressed cylindrical shells: state of the art and new perspectives

Wang

Hao

et al. 2022

Acta Mech. Sin.

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Experimental validation of the vibration correlation technique robustness to predict buckling of unstiffened composite cylindrical shells

Cited by 30 publications

References 20 publications

Probabilistic and deterministic lower-bound design benchmarks for cylindrical shells under axial compression

Probabilistic and deterministic lower-bound design benchmarks for cylindrical shells under axial compression

Robustness of Empirical Vibration Correlation Techniques for Predicting the Instability of Unstiffened Cylindrical Composite Shells in Axial Compression

Knockdown factor of buckling load for axially compressed cylindrical shells: state of the art and new perspectives

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