Validating experimental and numerical methodologies on powder pressing with stereocorrelation data

• Grant number: 23/12025-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: November 01, 2023
• End date: January 31, 2024
• Field of knowledge: Engineering - Mechanical Engineering - Mechanics of Solids
• Principal Investigator: Rodrigo Bresciani Canto
• Grantee: Matheus Furlan
• Supervisor: Florent Mathieu
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: EikoSim, France
• Associated to the scholarship: 21/14452-7 - Experimental validation of numerical models for predicting failure in green compacts, BP.MS

Abstract

Numerical simulation is an important tool to reduce production costs in pressing and sintering processes. A satisfactory prediction of the final mechanical properties in green compacts is useful to rubber mold project for isostatic pressing, rubber multiaxial pressing and loading/unloading cycle control, all assisted by numerical simulations in order to avoid the occurrence of cracks/ failures.The prediction of mechanical responses via numerical simulation requires reliable material models. The complexity of constitutive models calls for a series of tests to characterize and validate them. Further, manufacturing low density specimens is challenging due to their brittleness and low mechanical resistance to withstand additional processes such as sanding and flattening. Often, the final geometry has imperfections that may lead to load eccentricity, which may not be precisely detected using conventional instrumentation (e.g., extensometers). This Research Internship Abroad (RIA) proposal aims to measure displacements and strain fields on round samples using stereocorrelation (SC). The manufacturing process of the samples consists of double action closed-die pressing at approx. 5MPa followed by isostatic pressing to eliminate density gradients from the former step. The result is a hourglass-shaped specimen due to higher volumetric strains in less dense regions. Two different tests will be analyzed, namely, closed-die pressing in a die instrumented with strain gauges on the external wall, and uniaxial compression on hourglass-shaped samples. Data from strain gauges will be confronted with the results of SC to validate the experimental procedure and apparatus (lighting, camera positioning and calibration parameters) of tests performed in Brazil. After the initial validation, SC analyses will be performed for the uniaxial compression tests. The full-field measurements will allow for establishing sample (mis)alignment during the test and highlight possible undesired bending effects.