A Plane Stress Failure Criterion for Inorganically-Bound Core Materials

Inorganically-bound core materials are widely used in foundry processes, but their mechanical failure behavior remains poorly understood. Prior research has established the importance of core geometry optimization for production efficiency. However, no validated mechanical failure criterion exists for these materials. This gap limits the use of finite-element simulations in core design. Existing models fail to account for the unique stress states in core materials. The absence of a predictive model hinders optimization of core handling and decoring processes. Cohesive frictional material behavior is not well-represented in current criteria. This uncertainty drives the need for new testing methods and failure models. The lack of a validated criterion affects both simulation accuracy and production outcomes.

This study aimed to develop a validated mechanical failure criterion for inorganically-bound core materials. The goal was to enable finite-element simulations of core geometries. The research focused on creating testing methods for cohesive frictional materials. These methods were designed to induce bi-axial stress states in specimens. The objective was to validate failure criteria in principal stress space. The study sought to combine existing models into a unified material model. The focus was on predicting fracture forces using finite-element calculations. The ultimate purpose was to improve core design and production processes.

The researchers developed novel testing methods for inorganically-bound core materials. These methods induce multiple bi-axial stress states in the specimens. The approach is applicable to cohesive frictional materials in general. The testing was specifically tailored for sand core applications. The methods allow validation of failure criteria in principal stress space. The study combined the Mohr-Coulomb model with the Weakest-Link theory. This combination forms a consistent mechanical material model. The model was tested using a Brazilian test to predict fracture forces.

The study found that the Mohr-Coulomb model accurately describes fracture in plane stress states. The model was adapted to a new failure criterion for inorganic core materials. The criterion combines the Mohr-Coulomb model with the Weakest-Link theory. The new model successfully predicted the fracture force of a Brazilian test. The prediction was based on stress fields from finite-element calculations. The model accounts for bi-axial stress states in the specimens. The approach was validated using experimental data from the testing methods. The results support the use of the model in finite-element simulations.

The authors propose that the Mohr-Coulomb model accurately describes inorganic core material fracture. The model was adapted to a failure criterion combining two mechanical theories. The new criterion was validated using a Brazilian test and finite-element simulations. The study supports the use of the model for predicting core fracture forces. The approach allows for the optimization of core geometries in production processes. The model is applicable to cohesive frictional materials in general. The results suggest the model can improve simulation accuracy in core design. The study provides a validated criterion for future finite-element calculations.