Free-form optimization of CFRP plate/shell structures in natural vibration problem

This work investigates the natural vibration characteristics of free-form shells when considering the influence of uncertainties, including initial geometric imperfection, shell thickness deviation, and elastic modulus deviation. Herein, free-form shell models are generated while using a self-coded optimization algorithm. The Latin hypercube sampling (LHS) method is used to draw the samplings of uncertainties with respect to their stochastic probability models. ANSYS finite element (FE) software is adopted to analyze the natural vibration characteristics and compute the natural frequencies. The mean values, standard deviations, and cumulative distributions functions (CDFs) of the first three natural frequencies are obtained. The partial correlation coefficient is adopted to rank the significances of uncertainty factors. The study reveals that, for the free-form shells that were investigated in this study, the natural frequencies is a random quantity with a normal distribution; elastic modulus deviation imposes the greatest effect on natural frequencies; shell thickness ranks the second; geometrical imperfection ranks the last, with a much lower weight than the other two factors, which illustrates that the shape of the studied free-form shells is robust in term of natural vibration characteristics; when the supported edges are fixed during the shape optimization, the stochastic characteristics do not significantly change during the shape optimization process.

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Shape and Structural Design Optimization of Graphene Sheets in Natural Vibration Problem

Advances in Structural and Multidisciplinary Optimization ◽

10.1007/978-3-319-67988-4_129 ◽

2017 ◽

pp. 1719-1725

Author(s):

Jin-Xing Shi ◽

Keiichiro Ohmura ◽

Masatoshi Shimoda

Keyword(s):

Design Optimization ◽

Structural Design ◽

Natural Vibration ◽

Graphene Sheets ◽

Vibration Problem ◽

Structural Design Optimization

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Development of finite-element models of human skeleton bones and their application to the natural vibration problem

Computational Continuum Mechanics ◽

10.7242/1999-6691/2012.5.3.36 ◽

2012 ◽

Vol 5 (2) ◽

pp. 308-312 ◽

Cited By ~ 1

Author(s):

V.P. Matveenko ◽

I.N. Shardakov ◽

A.P. Shestakov

Keyword(s):

Finite Element ◽

Natural Vibration ◽

Finite Element Models ◽

Human Skeleton ◽

Vibration Problem

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Isogeometric analysis of laminated smart shell structures covered with piezoelectric sensors and actuators using degenerated shell formulation

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x19849264 ◽

2019 ◽

Vol 30 (13) ◽

pp. 1913-1931 ◽

Cited By ~ 3

Author(s):

Sajjad Nikoei ◽

Behrooz Hassani

Keyword(s):

Single Layer ◽

Laminated Composite ◽

Piezoelectric Sensor ◽

Basis Functions ◽

Shell Structures ◽

Free Form ◽

Control Analysis ◽

Sensors And Actuators ◽

Spline Basis ◽

Shell Formulation

An isogeometric approach to the analysis of laminated composite smart shell structures based on the degenerated formulation and Mindlin–Reissner assumptions using non-uniform rational B-spline basis functions is the subject of this article. To model the laminated orthotropic smart free-form shells, the equivalent single layer theory is adopted, and an accurate approach to construct the local basis systems is used. To consider the electric potential in the piezoelectric layers, a sub-layer approach is employed that assumes linear variation over the thickness of the sub-layer. To investigate the performance of the approach, static, free vibration, and static control analysis of laminated composite shells covered with piezoelectric sensor and actuator layers with different degrees of basis functions is performed. Also, the effect of mechanical loading, various input voltages, and different boundary conditions on the static response and natural frequencies have been investigated. Several numerical examples are presented to demonstrate the efficiency and accuracy of the approach and validated with the existing results from the literature.

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