Damping caused by microplasticity in porous 316L steels

Abstract

Damping in porous structures is enhanced by localized stresses in comparison with corresponding dense materials. An analytical model for mechanical damping in porous materials is suggested for the 'microplastic' range of deformation on the basis of the statistical mechanics of micro-heterogeneous materials. Two types of heterogeneity are considered: one-level porosity (directly sintered powder steels) and two-level porosity (larger pores in a carcass with smaller pores) on one hand, and fatigue-induced cracks on the other. Special emphasis is placed on the crackrelated contribution to damping using a Dugdale approach to crack-induced microplasticity.

Damping Performance of Material Candidates for Service at 350K

“…The mechanical damping capacity of the alloy depends on the material itself and the test conditions. The internal factors of the alloy embody in the composition of the alloy and the microstructure after heat treatment, while the test parameters are generally specified by the amplitude, frequency and temperature applied to the mechanical vibration [4]. Gray cast iron is a traditional damping material whose damping performance mainly depends on the microstructure morphology of graphite [5,6], however, poor mechanical property due to high graphite content constrains the application of cast iron [7].…”