Diffraction in Periodic Structures and Optimal Design of Binary Gratings. Part II: Gradient Formulas for TM Polarization

2001 ◽  
pp. 89-108
Author(s):  
Johannes Elschner ◽  
Gunther Schmidt
Keyword(s):  
Optimal Design ◽  
Periodic Structures

Optimal design of waveguiding periodic structures

2003 ◽  
Author(s):  
Roberto Diana ◽  
Agostino Giorgio ◽  
Anna Gina Perri ◽  
Mario Nicola Armenise
Keyword(s):  
Optimal Design ◽  
Periodic Structures

Optimal Design Approach for One-dimensional Rubber-Concrete Periodic Foundations based on Analytical Approximations of Band Gaps

2021 ◽  
Author(s):  
Zhifeng Xu
Keyword(s):  
Optimal Design ◽  
Periodic Structures ◽  
Analytical Approximation ◽  
Band Gaps ◽  
Design Approach ◽  
One Dimensional ◽  
Frequency Responses ◽  
Analytical Approximations ◽  
Resonance Frequencies ◽  
Rubber Concrete

This research investigates band gaps and frequency responses of one-dimensional periodic structures and further presents an optimal design approach for one-dimensional rubber-concrete periodic foundations based on the proposed analytical formulas for approximating the first few band gaps. The presented design approach is optimal for being able of globally searching the best solution which effectively cooperates the band gaps with the superstructure’s resonance frequencies. Firstly, frequency responses of one-dimensional periodic structures and the corresponding approximation method are studied. Furthermore, analytical approximation formulas for the first few band gaps, localization factor, attenuation coefficient, and frequency responses of one-dimensional rubber-concrete periodic foundations are proposed and verified. Lastly, inspired by the proposed analytical approximation for computing band gaps, an optimal design approach for one-dimensional rubber-concrete periodic foundations is presented and applied to a practical example, whose optimality is verified theoretically and numerically.

Design Optimization Toward Alleviating Forced Response Variation in Cyclically Periodic Structure Using Gaussian Process

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
K. Zhou ◽  
A. Hegde ◽  
P. Cao ◽  
J. Tang
Keyword(s):  
Optimal Design ◽  
Gaussian Process ◽  
Design Optimization ◽  
Periodic Structure ◽  
Periodic Structures ◽  
Forced Response ◽  
Design Modification ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Response Variation

Cyclically periodic structures, such as bladed disk assemblies in turbomachinery, are widely used in engineering systems. It is well known that small uncertainties exist among their substructures, which in certain situations may cause drastic change in the dynamic responses, a phenomenon known as vibration localization. Previous studies have suggested that the introduction of small, prespecified design modification, i.e., intentional mistuning, may alleviate vibration localization and reduce response variation. However, there has been no systematic methodology to facilitate the optimal design of intentional mistuning. The most significant challenge is the computational cost involved. The finite-element model of a bladed disk usually requires a very large number of degrees-of-freedom (DOFs). When uncertainties occur in a cyclically periodic structure, the response may no longer be considered as simple perturbation to that of the nominal structure. In this research, a suite of interrelated algorithms is proposed to enable the efficient design optimization of cyclically periodic structures toward alleviating their forced response variation. We first integrate model order reduction with a perturbation scheme to reduce the scale of analysis of a single run. Then, as the core of the new methodology, we incorporate Gaussian process (GP) emulation to conduct the rapid sampling-based evaluation of the design objective, which is a metric of response variation under uncertainties, in the parametric space. The optimal design modification can thus be directly identified to minimize the response variation. The efficiency and effectiveness of the proposed methodology are demonstrated by systematic case studies.

Driven periodic structures in random environment

1999 ◽  
Vol 09 (PR10) ◽  
pp. Pr10-85-Pr10-87
Author(s):  
V. M. Vinokur
Keyword(s):  
Random Environment ◽  
Periodic Structures
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