Influence of internal factor on crack resistance of shell mold by investment models

Abstract

The process of evolution of the stress-strain state (SSS) of a multilayer shell mold (SM) is modeled at properties change between layers during cooling of poured steel casting. A mathematical model was constructed and a theoretical study of the stress state of the SM was carried out in absence of connection between the layers in a multilayer composite. The article describes a complex three-component system: liquid metal, solid metal, and ceramic SM. Solid metal and SM are considered to be isotropic. To solve this problem, the authors used the theory of small elastic-plastic deformations and equations of thermal conductivity, as well as proven numerical methods. Evolution of SSS in SM was traced by time steps. Thickness of the solidifying metal was determined through the equation of interphase transition. The article considers the process of heating an axisymmetric SM when pouring liquid metal into it. Stress state was estimated by stresses and displacements that occur in SM. At SM contact with support filler (SF), SM surface move away from the SF is possible during cooling of liquid metal. In this case, contact problem is solved. Taking into account the compiled algorithm for solving the problem, calculations were performed for the case of complete sliding of layers using developed numerical schemes and software complexes. Obtained results of numerical calculations are clearly displayed by graphic illustrations in form of plots and graphs. Detailed analysis of the obtained results is given. There is inconsistency of the previously expressed idea about the applicability of sliding between layers in a multilayer composite from the position of reducing its stress state. The research results can be useful in calculations of other functional multilayer shell systems.