Sökning: "multiple necking"

Hittade 2 avhandlingar innehållade orden multiple necking.

  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. Dynamic neck formation in elastic-plastic tensile bars

    Författare :Kristina Nilsson; Mekanik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dynamic loading; necking; inertia; localization zones; numerical simulation; finite elements; non-linear;

    Sammanfattning : The time development of neck formation in ductile elastic-plastic bars is analyzed numerically in order to obtain a qualitative description of the features of dynamic neck localization under impact conditions. The full time history is visualized using contour plots of the time development of a strain rate parameter. LÄS MER