Buckling load prediction of grid-stiffened composite cylindrical shells using the vibration correlation technique

Shahgholian‐Ghahfarokhi, Davoud; Rahimi, G. H.

doi:10.1016/j.compscitech.2018.08.046

Cited by 55 publications

(16 citation statements)

References 56 publications

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“…The prediction accuracy was also found to generally improve when experimental data of f m vs. P for greater P / P b ratios were used, as expected. The VCT-predicted and experimental KDFs for the highest load levels used in each of the studies [ 21 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] are presented in a parity plot in Figure 1 a. Specifically, for CFRP shells, the maximum loads in these VCT studies amounted to P / P b = 0.81…0.98 [ 21 , 25 , 26 , 27 , 28 ], whereas for metal shells, they were P / P b = 0.54…0.99 [ 26 , 30 , 31 ].…”

Section: Empirical Vct Techniquesmentioning

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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Section: Empirical Vct Techniquesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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“…Natural frequency vs. hydrostatic pressure characteristic is useful for predicting critical buckling pressure of shells using vibration correlation technique 21,22 . It is a non-destructive technique for predicting the critical buckling pressure.…”

Section: Modal Testing Under Hydrostatic Pressurementioning

confidence: 99%

Study of Vibration Behaviour of Stiffened Polymer Composite Shells for Underwater Structural Applications

Patil¹,

Murthy²,

Srivatsa³

et al. 2020

Def. Sc. Jl.

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This paper presents vibration behavior of ring stiffened polymer composite thick shells used for underwater structures. Filament wound shells stiffened with internal and external rings and with hemispherical ends were tested for vibration in air and water in free-free boundary condition using roving hammer and fixed response method. Modal testing of the shells was performed under hydrostatic loading in a custom designed buckling tester for determining natural frequency at higher sea depths. Accelerometer was mounted on the inner surface of the shell. It was excited using a plumbob, rope and pulley arrangement. Experimental results were validated by modal analysis using Hyperworks and ANSYS. Vibration behavior in water was simulated by Fluid structure interaction approach. Experimental first natural frequency in water was lesser than that in air. With increase in hydrostatic pressure, the shell showed moderate variation in natural frequency. The experimental and numerical results of natural frequency and mode shapes were in good agreement with each other. Natural frequencies were lower in long and thick shells.

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“…Skukis et al [ 14 ] verified this method experimentally with a good result. Recent papers confirmed effectiveness of the modified VCT by conducting experimental and numerical analyses on cylindrical shells stiffened with lozenge grid cores [ 15 ], pressurised orthotropic shells with rectangular stiffeners [ 16 ], sandwich plates with iso-grid cores [ 17 ], composite unstiffened shells [ 18 ] and variable angle tow composite cylindrical shells [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

Impact of Geometrical Imperfections on Estimation of Buckling and Limit Loads in a Silo Segment Using the Vibration Correlation Technique

Żmuda-Trzebiatowski

Iwicki

2021

Materials

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The paper examines effectiveness of the vibration correlation technique which allows determining the buckling or limit loads by means of measured natural frequencies of structures. A steel silo segment with a corrugated wall, stiffened with cold-formed channel section columns was analysed. The investigations included numerical analyses of: linear buckling, dynamic eigenvalue and geometrically static non-linear problems. Both perfect and imperfect geometries were considered. Initial geometrical imperfections included first and second buckling and vibration mode shapes with three amplitudes. The vibration correlation technique proved to be useful in estimating limit or buckling loads. It was very efficient in the case of small and medium imperfection magnitudes. The significant deviations between the predicted and calculated buckling and limit loads occurred when large imperfections were considered.

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Buckling load prediction of grid-stiffened composite cylindrical shells using the vibration correlation technique

Cited by 55 publications

References 56 publications

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

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

Study of Vibration Behaviour of Stiffened Polymer Composite Shells for Underwater Structural Applications

Impact of Geometrical Imperfections on Estimation of Buckling and Limit Loads in a Silo Segment Using the Vibration Correlation Technique

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