The Influence of Internal Factor on Crack Resistance of Shell Mold for Investment Models

Abstract

The evolution of stress–strain state (SSS) of multilayer shell mold (SM) has been simulated upon variation of properties between the layers during cooling of casted steel. A mathematical model has been developed and the stress state of SM has been theoretically investigated in the case of absence of interrelation between the layers in multilayer composite material. The complex three-component system (liquid metal, solid metal, ceramic shell mold) has been analyzed. The solid metal and the SM are considered as isotropic. In order to solve the formulated problem, the theory of small elastic deformations and the equations of heat conductance have been applied as well as verified numerical methods. The SSS evolution in shell molds can be traced by time steps. The thickness of solidified metal is determined by the equation of interphase transition. Heating of axisymmetric SM during pouring of liquid metal is analyzed. The stress state has been estimated by stresses and displacements occurring in SM. During cooling of liquid metal at the contact between the shell mold and supporting filler (SF), the surface between them can be detached. In this case, the contact problem is solved. The calculations for the case of complete sliding of layers have been carried out with consideration of the compiled algorithm for problem solving by using the developed numerical schemes and software. The obtained numerical results are presented in the form of diagrams and plots. The obtained results have been analyzed in detail. The inconsistency of the previously proposed concept about applicability of sliding between the layers in multilayer composite material in terms of its strain state has been demonstrated. The experimental results can be useful for analysis of other functional multilayer shell systems.