Some computational and experimental aspects of optimal design process of composite structures

The article discusses methods for optimizing the design of the Neutron Converter research plant design with parameters that are most suitable for a particular consumer. 38 similar plant structures with different materials and sources were calculated, on the basis of which the most optimal options were found. As part of the interaction between OKBM Afrikantov JSC and the Nizhny Novgorod State Technical University named after R. E. Alekseev, the Neutron Converter research plant was designed and assembled. The universal neutron converter is a device for converting a stream of fast neutrons emitted by isotopic sources into a "standardized" value of flux density with known parameters in the volume of the central part of the product, which is the working part of the universal neutron converter. To supply neutron converters to other customer organizations (universities, research organizations and collective centers), it is necessary to take into account the experience of operating an existing facility, as well as rationalize the design process of each specific instance in accordance with the requirements of the customer.

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Development of Optimal Design Method for Steel Double-Beam Floor System Considering Rotational Constraints

Applied Sciences ◽

10.3390/app11073266 ◽

2021 ◽

Vol 11 (7) ◽

pp. 3266

Author(s):

Insub Choi ◽

Dongwon Kim ◽

Junhee Kim

Keyword(s):

Optimal Design ◽

Design Process ◽

Design Method ◽

Steel Beams ◽

High Gravity ◽

Double Beam ◽

Iterative Analysis ◽

Floor Systems ◽

Optimal Design Method ◽

Floor System

Under high gravity loads, steel double-beam floor systems need to be reinforced by beam-end concrete panels to reduce the material quantity since rotational constraints from the concrete panel can decrease the moment demand by inducing a negative moment at the ends of the beams. However, the optimal design process for the material quantity of steel beams requires a time-consuming iterative analysis for the entire floor system while especially keeping in consideration the rotational constraints in composite connections between the concrete panel and steel beams. This study aimed to develop an optimal design method with the LM (Length-Moment) index for the steel double-beam floor system to minimize material quantity without the iterative design process. The LM index is an indicator that can select a minimum cross-section of the steel beams in consideration of the flexural strength by lateral-torsional buckling. To verify the proposed design method, the material quantities between the proposed and code-based design methods were compared at various gravity loads. The proposed design method successfully optimized the material quantity of the steel double-beam floor systems without the iterative analysis by simply choosing the LM index of the steel beams that can minimize objective function while satisfying the safety-related constraint conditions. In particular, under the high gravity loads, the proposed design method was superb at providing a quantity-optimized design option. Thus, the proposed optimal design method can be an alternative for designing the steel double-beam floor system.

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Multi-Objective Optimal Design of Sandwich Composite Laminates Using Simulated Annealing and FEM

Volume 3: Design and Analysis ◽

10.1115/pvp2008-61606 ◽

2008 ◽

Cited By ~ 1

Author(s):

A. Sarhadi ◽

M. Tahani ◽

F. Kolahan ◽

M. Sarhadi

Keyword(s):

Simulated Annealing ◽

Optimal Design ◽

Composite Laminates ◽

Composite Structures ◽

Simulated Annealing Algorithm ◽

Core Layer ◽

Sandwich Composite ◽

Surface Layers ◽

Multi Objective ◽

Aspect Ratios

Multi-objective optimal design of sandwich composite laminates consisting of high stiffness and expensive surface layers and low-stiffness and inexpensive core layer is addressed in this paper. The object is to determine ply angles and number of surface layers and core thickness in such way that natural frequency is maximized with minimal material cost and weight. A simulated annealing algorithm with finite element method is used for simultaneous cost and weight minimization and frequency maximization. The proposed procedure is applied to Graphite-Epoxy/Glass-Epoxy and Graphite-epoxy/Aluminum sandwich laminates and results are obtained for various boundary conditions and aspect ratios. Results show that this technique is useful in designing of effective, competitive and light composite structures.

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Vibroacoustic design optimization of curved composite shells

Polymers and Polymer Composites ◽

10.1177/09673911211060654 ◽

2021 ◽

Vol 29 (9_suppl) ◽

pp. S1520-S1531

Author(s):

Rilwan K Apalowo ◽

Dimitrios Chronopoulos

Keyword(s):

Optimal Design ◽

Structural Design ◽

Composite Structures ◽

Sensitivity Analyses ◽

Computational Time ◽

Design Parameters ◽

Sandwich Shell ◽

Acoustic Transmission ◽

Composite Shells ◽

Model Composite

The need to simultaneously optimize the structural design properties, and attain a satisfactory vibroacoustic performance for composite structures, has been a challenging task for modern structural engineers. This work is aimed at developing a statistical energy analysis (SEA) based numerical scheme for computing the optimal design parameters of each individual layer of layered curved shells having arbitrary complexities and layering. The main novelty of the work focuses on the computation of SEA properties for curved composite shells and derive the sensitivities of the acoustic transmission coefficient, expressed through the computed SEA properties, with respect to the structural design characteristics to be optimized. A wave finite element approach is employed to calculate the wave propagation constants of the curved shell. The calculated wave constants are then applied to compute the vibroacoustic properties for the curved shell using a SEA approach. Sensitivity analyses are conducted on the vibroacoustic properties to estimate their response to changes in the structural properties. Gradient vector is then formulated and hence the Hessian matrix, which is employed to formulate a Newton-like optimisation algorithm for optimizing the properties of the layered composite shell. The developed scheme is applied to a sandwich shell; optimal design parameters of [Formula: see text] and [Formula: see text] are obtained for the facesheet and the core of the shell whose base parameters are [Formula: see text] and [Formula: see text], respectively. This simultaneously optimizes the structure with maximum stiffness and minimum mass and attains a satisfactory dynamic performance for acoustic transmission through the sandwich shell. The principal advantage of the scheme is the ability to accurately model composite panels of arbitrary curvature at a rational computational time.

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