Dynamic analysis of doubly curved composite panels using lamination parameters and spectral-Tchebychev method

Serhat, Gokhan; Anamagh, Mirmeysam Rafiei; Bediz, Bekir; Basdogan, Ipek

doi:10.1016/j.compstruc.2020.106294

Cited by 17 publications

(5 citation statements)

References 26 publications

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“…This finding also shows that searching only the boundary of the lamination parameters' feasible domain is not always sufficient to obtain the optimal design points for the cylinders, although such an approach has been proposed to improve efficiency in the design of composite plates [39]. Sharp changes in certain regions of the fundamental frequency contours indicate the mode switching phenomenon, which has also been shown in the previous studies concerning composite panels [19,20,40]. Another noteworthy result is the nonconvex response surface of the second natural frequency, which shows multiple local maxima for l/r = 2.0 and h/r = 0.01, 0.02.…”

Section: Eigenfrequency Optimization For Simply Supported Cylinderssupporting

confidence: 51%

“…In many cases, the maximum fundamental frequency points occurred at the interior region of the lamination parameter domain, thus requiring layer angles of multiple absolute values in the stacking sequence retrieval. This finding demonstrates that the stiffness tailoring required to obtain optimal dynamic properties can be remarkably different for cylindrical shells compared to singly curved panels, which have been reported to possess maxima on the boundary of the feasible domain [19,20]. In addition, the response surface for the second natural frequency appeared to be nonconvex for certain combinations of geometrical parameters.…”

Section: Introductionmentioning

confidence: 82%

“…Such inner points require layer angles of multiple absolute values in the stacking-sequence retrieval process [38]. Therefore, stiffness tailoring required to obtain optimal dynamic properties can be remarkably different for cylindrical shells compared to singly curved panels, which have been reported to possess maxima on the boundary of the feasible domain [19,20]. This finding also shows that searching only the boundary of the lamination parameters' feasible domain is not always sufficient to obtain the optimal design points for the cylinders, although such an approach has been proposed to improve efficiency in the design of composite plates [39].…”

Section: Eigenfrequency Optimization For Simply Supported Cylindersmentioning

confidence: 99%

“…This technique was also shown to provide convex solutions for certain responses such as the fundamental frequency of plates [13][14][15]. Lamination parameters have been widely used for maximizing the fundamental frequency of flat [16][17][18] and curved [19,20] laminated panels, as well as their eigenfrequency separation [10,21]. In one study regarding composite cylinders, Trias et al [22] used lamination parameters to maximize the fundamental frequency.…”

Section: Introductionmentioning

confidence: 99%

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Design of Circular Composite Cylinders for Optimal Natural Frequencies

Serhat

2021

Materials

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This study concerns optimizing the eigenfrequencies of circular cylindrical laminates. The stiffness properties are described by lamination parameters to avoid potential solution dependency on the initial assumptions of the laminate configurations. In the lamination parameter plane, novel response contours are obtained for the first and second natural frequencies as well as their difference. The influence of cylinder length, radius, thickness, and boundary conditions on the responses is investigated. The lamination parameters yielding the maximum response values are determined, and the first two mode shapes are shown for the optimum points. The results demonstrate that the maximum fundamental frequency points of the laminated cylinders mostly lie at the inner lamination parameter domain, unlike the singly curved composite panels. In addition, the second eigenfrequency shows a nonconvex response surface containing multiple local maxima for several cases. Moreover, the frequency difference contours appear as highly irregular, which is unconventional for free vibration responses.

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Section: Eigenfrequency Optimization For Simply Supported Cylinderssupporting

confidence: 51%

Section: Introductionmentioning

confidence: 82%

Section: Eigenfrequency Optimization For Simply Supported Cylindersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design of Circular Composite Cylinders for Optimal Natural Frequencies

Serhat

2021

Materials

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“…The material properties of the graphite/epoxy laminae used in the present study are given in Table 1 [ 40 ]. The values are given as relations since the results are normalized and presented in non-dimensional form.…”

Section: Methodsmentioning

confidence: 99%

Concurrent Lamination and Tapering Optimization of Cantilever Composite Plates under Shear

Serhat

2021

Materials

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The operational performance of cantilever composite structures can benefit from both stiffness tailoring and geometric design, yet, this potential has not been fully utilized in existing studies. The present study addresses this problem by simultaneously optimizing layer and taper angles of cantilever laminates. The design objective is selected as minimizing the average deflection of the tip edge subjected to shear loads while keeping the length and total volume constant. The plate stiffness properties are described by lamination parameters to eliminate the possible solution dependency on the initial assumptions regarding laminate configuration. The responses are computed via finite element analyses, while optimal design variables are determined using genetic algorithms. The results demonstrate that the plate aspect ratio significantly influences the effectiveness of stiffness tailoring and tapering as well as the optimal layer and taper angles. In addition, concurrent exploitation of the lamination characteristics and plate geometry is shown to be essential for achieving maximum performance. Moreover, individual and simultaneous optimization of layer and taper angles produce different optimal results, indicating the possible drawback of using sequential approaches in similar composite design problems.

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