Sökning: "shape optimization"

Visar resultat 11 - 15 av 153 avhandlingar innehållade orden shape optimization.

  1. 11. Continuum sensitivity based shape and material optimization for microwave applications

    Författare :Yongtao Yang; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; gradient method; adjoint problem; optimization; radar cross section; continuum design sensitivity;

    Sammanfattning : .... LÄS MER

  3. 12. Shape and material optimization for antenna applications

    Författare :Per Jacobsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; explicit-implicit time stepping; sensitivity analysis; Nitsche s method; total scattering cross section; shape and material optimization; array antennas; finite element method;

    Sammanfattning : In this thesis, a gradient-based method for shape and material optimization fortwo antenna applications is presented: minimization of the active reflectioncoefficient for conformal array antennas; and minimization of the totalscattering cross section for cylindrical scatterers. The sensitivity of theobjective function with respect to changes of the shape and material of the geometry isexpressed in terms of the original field problem and an adjoint field problem. LÄS MER

  4. 13. Global Shape Description of Digital Objects

    Författare :Ola Weistrand; Christer Kiselman; Gunilla Borgefors; Örjan Smedby; Michael Floater; Uppsala universitet; []
    Nyckelord :Applied mathematics; shape description; shape approximation; surface parameterization; digital object; spherical harmonics; digital surface; digital image; Tillämpad matematik;

    Sammanfattning : New methods for global shape description of three-dimensional digital objects are presented. The shape of an object is first represented by a digital surface where the faces are either triangles or quadrilaterals. LÄS MER

  5. 14. Flow Control and Shape Optimization of Intermediate Turbine Ducts for Turbofan Engines

    Författare :Fredrik Wallin; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; response surface methodology; intermediate turbine duct; vortex generators; turbine intermediate case; endwall contouring; turbine center frame; body-force model; shape optimization; mid-turbine frame; flow control;

    Sammanfattning : Demands on improved efficiency, reduced emissions and lowered noise levels cause a strive towards high by-pass ratios of commercial turbofan engines. This results in an increased radial offset between the high- and low-pressure turbines. Thus the design of the intermediate turbine duct connecting the two turbines becomes more challenging. LÄS MER

  7. 15. Graded index sonic crystal noise barriers: An introduction to design and optimization

    Författare :Bart van der Aa; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shape optimal design; Broadband acoustic lens; Optimization; Outdoor sound propagation; Sonic crystal noise barrier; Graded index sonic crystal;

    Sammanfattning : Environmental noise pollution and its impact on human beings remains to be an important topic in acoustics. Conservative estimations of the World Health Organization have shown that traffic related noise alone causes a loss of approximately one million healthy life years, only within Western Europe. LÄS MER