Sökning: "cohesive elements"

Visar resultat 1 - 5 av 26 avhandlingar innehållade orden cohesive elements.

  1. 1. Simulation of dynamic instabilities during high rate deformation of ductile bars and plates

    Författare :Kristina Nilsson; Mekanik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; numerical simulation; non-linear; wave propagation; multiple necking; necking; buckling; fracture; Mechanical engineering; Maskinteknik; finite elements; cohesive elements; dynamic; J2-flow theory; J2-deformation theory; viscoplastic; background inertia;

    Sammanfattning : In this thesis, some of the phenomena occurring in plates and cylindrical bars subjected to dynamic loading are investigated. Numerical simulations using a dynamic finite element code are performed for a number of different sized specimens with various initial surface imperfections. Typically imposed loading velocities are in the range 10m/s.. LÄS MER

  3. 2. Microstructure and deformation behaviour of ductile iron under tensile loading

    Författare :Keivan Amiri Kasvayee; Anders E.W. Jarfors; Ehsan Ghassemali; Lennart Elmquist; Kenneth Hamberg; Jönköping University; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ductile iron; digital image correlation DIC ; in-situ tensile test; pit etching; Microscale deformation; micro-crack; finite elements analysis FEA ; cohesive elements;

    Sammanfattning : The current thesis focuses on the deformation behaviour and strain distribution in the microstructure of ductile iron during tensile loading. Utilizing Digital Image Correlation (DIC) and in-situ tensile test under optical microscope, a method was developed to measure high resolution strain in microstructural constitutes. LÄS MER

  4. 3. Cohesive and Spectroscopic properties of the Lanthanides within the Hubbard I Approximation

    Författare :Inka Laura Marie Locht; Igor Di Marco; Olle Eriksson; Annalisa Fasolino; Mikhail I. Katsnelson; Tim Wehling; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lantanides; rare earths; cohesive properties; volume; bulk modulus; magnetism; magnetic properties; photoemission spectroscopy; XPS; BIS; Hubbard I Approximation; DMFT; DFT; RSPt; Full Potential Linear Muffin-tin orbitals; 4f electrons; localization; bonding; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : We describe the rare-earth elements using the Hubbard I approximation. We show that the theory reproduces the cohesive properties, like the volume and bulk modulus, and we find an excellent agreement between theory and experiment for the (inverse) photo emission spectra of the valence band. LÄS MER

  5. 4. Perpendicular to grain fracture analysis of wooden structural elements - Models and applications

    Författare :Henrik Danielsson; Byggnadsmekanik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fracture mechanics; cohesive zone modeling; Weibull theory; wood; glulam; orthotropy; heterogeneity; hole; dowel; asymmetric loading;

    Sammanfattning : This thesis concerns experimental and theoretical work regarding perpendicular to grain fracture in wooden structural elements. The experimental part concerns strength tests of glulam beams with a hole. LÄS MER

  7. 5. Elastic properties and structural stabilities of elements and compounds

    Författare :Lars Fast; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Physics; Fysik; fysik; Physics;

    Sammanfattning : A first principles study of the elastic and structural properties of selected elements and compounds is presented. The theoretical basis for these investigations is the density functional theory, in combination with a full potential linear muffin-tin orbital method. LÄS MER