Visnyk LNAU: Architecture and Farm Building 2018 №19: 70-73
DEVELOPMENT OF MINIMIZATION METHODS FOR RESIDUAL STRESSES AND DEFORMATIONS IN WELDED METAL
I. Dobrianskyy, Doctor of Technical Sciences
L. Dobrianska, Candidate of Economic Sciences
A. Hrytsevytch, Senior Lecturer
Lviv National Agrarian University
Methods for residual stresses determining are subdivided into estimated and experimental ones. Taking into account the complexity of the phenomena occur-ring during welding there is currently no single calculation method for stresses determining accompanying the welding process, as well as the residual stresses in the construction after welding. One can only note that the less assumptions are introduced in the design approaches the more complicated is the technique of the calculations.
The main tasks for longitudinal stress determining are based on known as-sumptions and hypotheses that do not always allow obtaining a result which is confirmed by experiments. However the considerable complexity and severity of these calculations is a significant barrier to their practical use.
In order to clarify the calculation methods the reliability of the mathematical modeling results of heat treatment process of plate systems by moving heat sources with known experimental data is compared. The approach to determining the amount of thermal energy that is redistributed to the welding plate through the local thermal effect is proposed.
The parameters of technological welding process are determined taking into account ratio of deflection, that is, the electrode diameter, voltage and current strength are chosen. Having overlaid weld seam in accordance with the indicated calculation scheme the rolled element practically does not undertake a residual deflection caused by the field of residual stresses occurring in the process of local thermal influence.
The developed method allows to carry out the redistribution of thermal stresses on fixed sites along the length of the rolling profile in order to increase the bearing capacity of the weld plate.
stress, welded joints, deformation, numerical simulation
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