Strain Rate Dependent Constitutive Model with Failure for Impact Loading of Metal Powder
2013 (English)Conference paper, Presentation (Refereed)
Few studies have been conducted to investigate the strain rate behavior of metal powders. To achieve better understanding of the strain rate dependency of metal powders, it's necessary to conduct dynamic experiments and numerical simulations e.g. using finite element method. High strain rate experiments of iron powder material have been conducted using the split Hopkinson pressure bar method . The dynamic testing is performed using a modified split Hopkinson pressure bar (Kolsky bar). A specimen is placed between two elastic bars. The impact loading is achieved by a projectile accelerating inside an air gun, which impacts the end of an input bar creating elastic wave propagation. The powder material used for the experiments was a press-ready premix containing Distaloy AE, 0.5% graphite and 0.6% Kenolube. This process is modeled and simulated by using finite element method. In order to model the impact process a constitutive relation describing the powder behavior taking into account the strain-rate and density variations are proposed . The stress and strain history in the specimen during impact is validated against the experimental measurements. To capture the global response caused by cracking during impact, a failure criterion is implemented. In conclusion, the proposed material model captures the increase in yield stress due to higher strain rates and the decrease in stress due to cracking.
Place, publisher, year, edition, pages
Research subject Solid Mechanics
IdentifiersURN: urn:nbn:se:ltu:diva-27545Local ID: 10ac1f4d-e4b1-421d-9510-665901a905d4OAI: oai:DiVA.org:ltu-27545DiVA: diva2:1000729
International Symposium on Impact Engineering : 02/09/2013 - 06/09/2013
Godkänd; 2013; 20131003 (gusgus)2016-09-302016-09-30Bibliographically approved