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|Horechko O. M., Horechko R. R.
|№ 1 (64)
Structural elements fixed in the construction are often exposed to thermal factors, as a result of which they have initial stresses and strains that affect their static and dynamic characteristics change. In this work, the research of influence of temperature initial loading on elastic structural elements on their eigenfrequencies is carried out. The formulation of problems for determining the elastic elements of structure vibrational characteristics in their modeling by the theory of plates and three-dimensional elastic body is presented. The real elements of complex geometry structures, even in an elastic formulation, do not have an analytical solution of these problems. The necessity of using multiphysics modeling packages for the research of such problems is substantiated. The accuracy of the natural frequencies calculation for used elastic bodies models on the known from the literature examples is checked. For unstressed bodies, such examples are the results of eigenfrequencies calculation in rectangular plates with different boundary conditions variants at the edges and at separate points. For initially stressed bodies, an example of the exact analytical solution of the vibration problem of a rectangular plate supported on all edges is used for this purpose. The problem of heating a flat panel clamped by four holes is studied in a three-dimensional formulation with the computational experiment help. The influence of its heating on the change of eigenfrequencies is analyzed. The same dependence of the change of first natural frequency with the temperature change for this task and the panel clamped on all edges is shown. The obtained results make it possible to conclude the temperature stresses significant influence on the fundamental frequency of structural elements. This effect decreases on higher oscillations with increasing frequency.
Keywords: heat transfer, vibration, thermoelasticity, finite element method, computer simulation.