scholarly journals Design optimization of hatch cover opening and closing mechanism of ships. Application of minimax non-linear optimization method.

1985 ◽  
Vol 51 (462) ◽  
pp. 460-468
Author(s):  
Koichi ITO ◽  
Tadashi KUROIWA ◽  
Shinsuke AKAGI
Author(s):  
J. G. Michopoulos

Design optimization in the context of finite element modeling (FEM) and analysis (FEA) has been traditionally used to help designers determine optimal structural geometry and/or material property parameters according to objective functions of interest and necessary constraints. In the present paper it is attempted to generalize the design optimization methodology into a program synthesis technique for determining the code necessary to encapsulate the constitutive behavior of the material system required for generalized FEA applications. The core concept behind the methodology followed by our group in the past, has been the experimental identification of a dissipated energy density (DED) function for polymer matrix composites (PMCs) through a non-linear optimization scheme for determining the free coefficients of the sum of the basis functions that are used to construct the DED function and is based on the energy balance of the specimen under testing. The utilized testing generated massive amounts of experimental data that would be produced by exposing PMC specimens to multidimensional loading paths with the help of custom made multi-axial computer-controlled testing machines. The variety of custom environments utilized to implement the analytical and numerical details has often created difficulties in transferring our technology to end users in the design and material communities. The present implementation was greatly enabled by recent advances in finite element techniques and “of the shelf” design optimization integration technologies along with the parallel hardware and software evolution. The program synthesis lies on a process that automatically generates the code of a user material subroutine through minimization of the error between measured and simulated specimen behavior. The generated code can be subsequently used with any geometry and loading specification definable within the limits of the non-linear element library in commercial codes such as ANSYS and ABAQUS.


Mathematics ◽  
2021 ◽  
Vol 9 (14) ◽  
pp. 1680
Author(s):  
Hui Chen ◽  
Kunpeng Xu ◽  
Lifei Chen ◽  
Qingshan Jiang

Kernel clustering of categorical data is a useful tool to process the separable datasets and has been employed in many disciplines. Despite recent efforts, existing methods for kernel clustering remain a significant challenge due to the assumption of feature independence and equal weights. In this study, we propose a self-expressive kernel subspace clustering algorithm for categorical data (SKSCC) using the self-expressive kernel density estimation (SKDE) scheme, as well as a new feature-weighted non-linear similarity measurement. In the SKSCC algorithm, we propose an effective non-linear optimization method to solve the clustering algorithm’s objective function, which not only considers the relationship between attributes in a non-linear space but also assigns a weight to each attribute in the algorithm to measure the degree of correlation. A series of experiments on some widely used synthetic and real-world datasets demonstrated the better effectiveness and efficiency of the proposed algorithm compared with other state-of-the-art methods, in terms of non-linear relationship exploration among attributes.


2001 ◽  
Vol 700 ◽  
Author(s):  
Anders G. Froseth ◽  
Peter Derlet ◽  
Ragnvald Hoier

AbstractEmpirical Total Energy Tight Binding (TETB) has proven to be a fast and accurate method for calculating materials properties for various system, including bulk, surface and amorphous structures. The determination of the tight binding parameters from first-principles results is a multivariate, non-linear optimization problem with multiple local minima. Simulated annealing is an optimization method which is flexible and “guaranteed” to find a global minimum, opposed to classical methods like non-linear least squares algorithms. As an example results are presented for a nonorthogonal s,p parameterization for Silicon based on the NRL tight binding formalism.


2000 ◽  
Author(s):  
Jules R. Muñoz ◽  
Michael R. von Spakovsky

Abstract An application of the Iterative Local-Global Optimization (ILGO) decomposition approach developed in an accompanying paper (Muñoz and von Spakovsky, 2000b) is presented. The synthesis / design optimization of a turbofan engine coupled to an environmental control system for a military aircraft was carried out. The problem was solved for a given mission (i.e. the load / environmental profile) composed of fifteen segments. The number of decision (independent) variables used for this highly non-linear optimization problem is one hundred fifty-three, some of which are integer. Both thermodynamic and physical (weight and volume) simulations use state-of-the art tools. Two objective functions were investigated: take-off gross weight and mission fuel consumption, and no observable differences were found in the final results. In addition to the mathematical foundations for global convergence of the proposed decomposition approach presented in Muñoz and von Spakovsky (2000b), numerical support for this convergence was found by solving the entire mixed-integer non-linear programming (MINLP) problem without decomposition using a subset of the independent variables. The constant value of the marginal costs (or linear behavior of the Optimum Response Surface — OSR) played a major role in the global convergence of the ILGO.


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