The mechanical characterization of metallic materials by instrumented spherical indentation testing is addressed. To this purpose, a Finite Element model (FE) able to simulate spherical indentation tests was developed and indentation responses corresponding to different material models were explored. Load-indentation depth curves (L-h curves), crater profile and plastic strains evolutions in the sub-indenter region were analysed. The role of friction was also accounted for. Since friction conditions between contacting bodies cannot be a priori established, a suitable range of friction coefficients (0.0-0.5) was considered. The FE model was validated by comparison with experimental spherical indentations carried out on two different materials (Al 6082-T6, AlSI H13) and a good agreement between the experimental results and numerical predictions was found. No friction effects were observed on material L-h curves, whereas modifications were found in crater profile and plastic strains evolutions. It was established that the stress-strain curve evaluation on the basis either of the strain field in the sub-indenter region or the residual crater geometry seems particularly critical whereas it appears more reliable to deduce the constitutive properties by a proper analysis of the L-h curve.
Mechanical characterization of metallic materials by instrumented spherical indentation
BEGHINI, MARCO;MONELLI, BERNARDO DISMA
2009-01-01
Abstract
The mechanical characterization of metallic materials by instrumented spherical indentation testing is addressed. To this purpose, a Finite Element model (FE) able to simulate spherical indentation tests was developed and indentation responses corresponding to different material models were explored. Load-indentation depth curves (L-h curves), crater profile and plastic strains evolutions in the sub-indenter region were analysed. The role of friction was also accounted for. Since friction conditions between contacting bodies cannot be a priori established, a suitable range of friction coefficients (0.0-0.5) was considered. The FE model was validated by comparison with experimental spherical indentations carried out on two different materials (Al 6082-T6, AlSI H13) and a good agreement between the experimental results and numerical predictions was found. No friction effects were observed on material L-h curves, whereas modifications were found in crater profile and plastic strains evolutions. It was established that the stress-strain curve evaluation on the basis either of the strain field in the sub-indenter region or the residual crater geometry seems particularly critical whereas it appears more reliable to deduce the constitutive properties by a proper analysis of the L-h curve.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
