engleski

Creep buckling analysis of the functionally graded beam

Paper presents the buckling analysis of the functionally graded (FG) beam exposed to the creep conditions. Columns under sustained loads are generally unstable in the regime of creep. That means that their stability loss may occur during some final period of exploitation even for loads lower than critical buckling load. In such a context, it is more reasonable, instead of defining the stability by critical buckling load to define it in terms of critical buckling time, the duration of loading at which buckling deflections tends to infinity. Problem is approached through two phases. In first phase a pre-buckling behavior is modeled through load deflection manner to reach appropriate instantaneous response of structure for applied load at zero time while in second phase a time integration scheme is used to reach critical buckling time. The finite element simulations are run out using 3D finite element commercial code. The simulations were created by dividing the beam into several layers in order to approximate functionally graded material properties distribution. Gradation of material properties is achieved by assigning each layer of different properties. The finite element mash is created using solid finite elements. The creep material behaviour is modelled assuming the creep laws based on experimental data available in literature. The isothermal conditions are adopted for simplicity. The creep is considered under isothermal conditions. Several test examples are run in order to determine critical buckling times for various material parameter. The effects of material distribution on stability state of the beam is considered. The set of the creep buckling, deflection vs time, curves are displayed presenting the responses of different functionally graded material.

Creep buckling ; functionally graded beam ; large displacements

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