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Strength of Materials

, Volume 50, Issue 6, pp 894–900 | Cite as

On the Material Damage Evaluation by the Elastic Modulus Deterioration Parameter

  • M. R. Muzyka
Article
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The assessment methods of the normal elastic modulus of plastically deformed materials according to their hardness values and the material damage evaluation via the deteriorated elastic module are described. The normal elastic modulus was found to be very sensitive to the structural state changes. The deformed material state differs from the undeformed one by the accumulation of scattered damages of different nature. It was established that when assessing the material damage degree in the operation process, the most informative indicator of the elastic modulus deterioration is the so-called “aftereffect deteriorated module” (i.e., taken after some operation period), which is used as a measure of material deterioration and defined as the ratio between the deteriorated elastic modulus and its current value. The results on derived relations between the elastic modulus and the material damageability parameter are presented. A stable correlation between the elastic modulus and the Weibull homogeneity parameter is found. The latter describes the scatter degree of hardness characteristics, correlates with the change in the physical and mechanical properties of the material, and is calculated by the scatter degree of hardness values via the known Humbel formula. The metal hardness values determined at the loading/operation stage are found to more accurately characterize the actual level of accumulated damage in the metal than those in the unloaded state, but exhibit a higher scatter than the latter. Dependences, which control the respective current value of the material elastic modulus in structural elements at a particular operation stage, are derived, and the aftereffect deteriorated modulus is used to assess the material damage. It is shown that for all investigated materials, the plastic deformation leads to the elastic modulus reduction. This reduction with the rise in deformation was also observed after the preliminary plastic deformation of the material, which was realized in the current study by the material unloading after achieving various degrees of plastic deformation.

Keywords

normal elastic modulus aftereffect deteriorated modulus hardness scatter parameter of hardness characteristics damageability 

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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • M. R. Muzyka
    • 1
  1. 1.Pisarenko Institute of Problems of StrengthNational Academy of Sciences of UkraineKyivUkraine

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