Micromechanical Investigation of the Fracture Behavior of Powder Materials

• Fracture of compacted powder has been studied experimentally and numerically using a micromechanicalapproach. In the experimental investigation, the compacts are crushed in two dierent directions to accountfor general stress states and a microscopy study shows that fracture of the powder granules plays asignicant role in the fracture process. The numerical analysis is based on the Discrete Element Method(DEM) and a novel approach is presented to account for the fracture of the particles in the numericalmodel. The force-displacement relations for two particles in contact, which are needed in DEM, are derivedusing micomechanical experiments together with nite element analyses of the contact problem. The contactmodel accounts for plastic compression, elastic unloading and adhesive bonding together with frictionand tangential bonding. The model shows a very good agreement with the experimental data both for theelastic behavior during unloading and, if failure of the particles is accounted for, the fracture of the compacts.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering (hsv//eng)

Nyckelord

Powder compaction

Fracture mechanisms

Contact mechanics

Experiments

Discrete element method

Green strength

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