OPTIMAL COOLING OF HEATED THIN-WALLED SYSTEMS UNDER HEAT-REFLECTION BREAKDOWN
N. I. Obodan, N. A. Guk
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. Вып.4. С. 80-85.
Behavior of a thin-walled system (plate) located in a thermal field and subjected to cooling after heat-reflection breakdown is considered. Under forced cooling a residual stress field appears in a system which can bring both to local collapse in the neighborhood of a defective part and to plate splitting in zones distant from breakdown spot. To prevent these effects it is necessary to define cooling law optimizing the process with relation to toughness and fastness assurance. A mathematical model is presented by thermoelasticity equations with additional deformations. Solution of a heat conductivity problem in a finite element form is used to describe temperature field. A problem of cooling control is formulated; optimal control is shown to be a step function having a finite number of break points. Construction algorithm for a cooling function is presented. Calculation results are given: cooling of a plate with the use of a construction algorithm for a cooling control function is shown to lead to appearance of residual stress of an essentially lower amplitude.
|
English
