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In this paper we present results that extend the sequential quadratic programming (SQP) algorithm with an additional feasibility refinement based on parametric sensitivity derivatives. The refinement is applicable without restriction on the problem dimensions in sparse SQP solvers. Parametric sensitivity analysis is a tool for post optimality analysis of the solution of a nonlinear optimization problem. For the refinement approach we apply this technique on the quadratic subproblems in order to improve the overall algorithm. The sensitivity derivatives required for this approach can be computed without noticeable computational effort as the system of linear equations to be solved coincides with the system already solved for the search direction computation. For similar algorithms in the context of post optimality analysis a linear rate of convergence has been proven and therefore an extrapolation method is applied to speed up the process. The presented algorithm has been integrated into the nonlinear program (NLP) solver WORHP and we perform a numerical study to evaluate different termination criteria for the proposed algorithm. Furthermore, numerical results on the CUTEst test set are shown. 相似文献
55.
Impervious areas change hydrological processes, reducing infiltration and evapotranspiration, and increasing direct runoff. Stormwater practices using green infrastructure are implemented locally to control runoff and preserve the hydrological cycle. Applying these techniques in semiarid and Mediterranean regions requires accounting for aspects related to the maintenance of green areas. This study develops the Integrated Hydrological Model at Residential Scale, a continuous model for representing the performance and irrigation of green stormwater facilities at residential scales. Among other relevant process, the model simulates evaporation from bare soil and redistribution between soil layers. Different components of the model were tested using laboratory and numerical experiments, and then an application to a case study and a sensitivity analysis were carried out. The model identifies significant differences in the performance of a rain garden with different vegetation, climate and irrigation practices and provides good insight for the maintenance needs of green infrastructure for runoff control. 相似文献
56.
57.
This paper presents an integrated approach that supports the topology optimization and CAD-based shape optimization. The main
contribution of the paper is using the geometric reconstruction technique that is mathematically sound and error bounded for
creating solid models of the topologically optimized structures with smooth geometric boundary. This geometric reconstruction
method extends the integration to 3-D applications. In addition, commercial Computer-Aided Design (CAD), finite element analysis
(FEA), optimization, and application software tools are incorporated to support the integrated optimization process. The integration
is carried out by first converting the geometry of the topologically optimized structure into smooth and parametric B-spline
curves and surfaces. The B-spline curves and surfaces are then imported into a parametric CAD environment to build solid models
of the structure. The control point movements of the B-spline curves or surfaces are defined as design variables for shape
optimization, in which CAD-based design velocity field computations, design sensitivity analysis (DSA), and nonlinear programming
are performed. Both 2-D plane stress and 3-D solid examples are presented to demonstrate the proposed approach.
Received January 27, 2000
Communicated by J. Sobieski 相似文献
58.
本文用模态分析法详细分析了压电双晶片力、振动、粗糙度传感器的位移特性及灵敏度特性,并给出了灵敏度与压电材料参数及晶片几何尺寸的关系。 相似文献
59.
Biaosong Chen Gang Liu Jian Kang Yunpeng Li 《Structural and Multidisciplinary Optimization》2008,36(1):83-92
Stiffened storage tank is an important structural component in spacecraft. Its structural weight is one of the key criterions
in the design phase. This paper focuses on the design optimization of the structure by using finite element method, structural
sensitivity analysis techniques, and sequential linear/quadratic programming aimed to reduce the structural weight. Design
variables include the numbers of stiffeners, stiffeners’ section dimensions, and shell thickness distribution. Detailed finite
element modeling processes are presented, which are the ways to construct the stiffener (beam orientation and offset) and
shell elements and the ways to determine the analysis model and structural boundary conditions. A brief introduction to sensitivity
analysis and optimization solution algorithm is also given. Main attention is paid to the studies of design optimization of
the tank structure, including the selection of design cases, evaluation, and comparison of the optimal results. There are
six design cases considered in the design procedures. Numerical results show that by using the above computational techniques,
the structural weight is effectively reduced. In this work, MSC.Patran/Nastran is employed to construct the Finite Element
Model (FEM), and JIFEX, which is developed in our group, is used to conduct the structural design optimization.
JIFEX is a structural analysis and optimization software package developed by Gu and colleagues in the Dalian University of
Technology Department of Engineering Mechanics. Among its many functions is the ability to analyze and optimize piezoelectric
smart structures. 相似文献
60.
Ian R. Chittick Joaquim R. R. A. Martins 《Structural and Multidisciplinary Optimization》2008,36(1):59-70
A new subspace optimization method for performing aero-structural design is introduced. The method relies on a semi-analytic
adjoint approach to the sensitivity analysis that includes post-optimality sensitivity information from the structural optimization
subproblem. The resulting coupled post-optimality sensitivity approach is used to guide a gradient-based optimization algorithm.
The new approach simplifies the system-level problem, thereby reducing the number of calls to a potentially costly aerodynamics
solver. The aero-structural optimization of an aircraft wing is performed using linear aerodynamic and structural analyses,
and a performance comparison is made between the new approach and the conventional multidisciplinary feasible method. The
new asymmetric suboptimization method is found to be the more efficient approach when it adequately reduces the number of
system evaluations or when there is a large enough discrepancy between disciplinary solution times. 相似文献