SIMULATION-BASED MOULD DESIGN, LIFE PREDICTION AND RELIABILITY ASSESSMENT OF A VALVE BODY

Shrinkage porosities are one of the major casting defects which affects the quality and structural integrity of cast products. Consequently, the service life and reliability of the components are questioned and need to be determined prior to put these parts in service. This study presents a simulation based methodology for mould design, life prediction, and reliability assessment of castings using simulation tools. The methodology is developed and validated for standard test specimens followed by its application on a valve body. The mould design is optimized for porosities using MAGMA Soft. Integration of predicted minimum porosity to valve body is done using MAGMAlink. The stress fields with porosity are obtained using ABAQUS which are then used to predict life and estimate reliability. Infinite life i.e. more than 10(6) cycles is predicted with minimum porosity in valve body. The reliability results for valve under normal operating pressure i.e. 1 MPa shows similar to 100 % reliability for infinite life, however, under the maximum loading conditions i.e. 2.5 MPa, the reliability is significantly compromised. A safe load-induced stress on valve is also determined based on the reliability results.