Title

THE MOMENT OF INERTIA METHOD TO CALCULATE NONPROPORTIONALITY FACTORS IN MULTIAXIAL HISTORIES

THE MOMENT OF INERTIA METHOD TO CALCULATE NONPROPORTIONALITY FACTORS IN MULTIAXIAL HISTORIES

Authorship

Meggiolaro, Marco Antonio; Castro,; de, Jaime Tupiassú Pinho

Meggiolaro, Marco Antonio

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Castro,

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de, Jaime Tupiassú Pinho

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DOI

10.5151/2594-5327-23505

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Abstract

This work studies further an approach to evaluate equivalent stress and strain ranges in non-proportional (NP) histories, called the Moment Of Inertia (MOI) method. The MOI method assumes that the load path contour in the deviatoric stress or strain diagram behaves as a homogeneous wire with unit mass. The center of mass of such wire gives then the mean component of the path, while the moments of inertia of the wire can be used to obtain the equivalent stress or strain ranges. In this work, the MOI method is also generalized to calculate as well the non-proportionality factor Fnp of a loading history, using an alternative sub-space of the deviatoric stress or strain space. Experimental results for 14 different multiaxial histories prove the effectiveness of the MOI method to predict the observed non-proportionality factors.

This work studies further an approach to evaluate equivalent stress and strain ranges in non-proportional (NP) histories, called the Moment Of Inertia (MOI) method. The MOI method assumes that the load path contour in the deviatoric stress or strain diagram behaves as a homogeneous wire with unit mass. The center of mass of such wire gives then the mean component of the path, while the moments of inertia of the wire can be used to obtain the equivalent stress or strain ranges. In this work, the MOI method is also generalized to calculate as well the non-proportionality factor Fnp of a loading history, using an alternative sub-space of the deviatoric stress or strain space. Experimental results for 14 different multiaxial histories prove the effectiveness of the MOI method to predict the observed non-proportionality factors.

Keywords

Multiaxial fatigue; Non-proportional loading; Non-proportionality factor.

Multiaxial fatigue; Non-proportional loading; Non-proportionality factor.