Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium

Key mechanical properties used in low-cycle strength and durability calculations are the strength (proportional limit stress, <i>σ<sub>pr</sub></i>; relative yield strength, <i>σ</i><sub>0.2</sub>; and ultimate tensile stress, <i>σ<sub>u<...

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Main Authors: Žilvinas Bazaras, Vaidas Lukoševičius, Andrius Vilkauskas, Ramūnas Česnavičius
Format: Article
Language:English
Published: MDPI AG 2021-06-01
Series:Metals
Subjects:
Online Access:https://www.mdpi.com/2075-4701/11/6/918
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author Žilvinas Bazaras
Vaidas Lukoševičius
Andrius Vilkauskas
Ramūnas Česnavičius
author_facet Žilvinas Bazaras
Vaidas Lukoševičius
Andrius Vilkauskas
Ramūnas Česnavičius
author_sort Žilvinas Bazaras
collection DOAJ
description Key mechanical properties used in low-cycle strength and durability calculations are the strength (proportional limit stress, <i>σ<sub>pr</sub></i>; relative yield strength, <i>σ</i><sub>0.2</sub>; and ultimate tensile stress, <i>σ<sub>u</sub></i>) and strain properties (proportional limit strain, <i>e<sub>pr</sub></i>; percent area reduction, <i>ψ</i>; and percent area reduction at failure, <i>ψ<sub>u</sub></i>). When selecting the key mechanical properties provided in the specifications, an error may be made due to the failure to account for a series of random factors that determine the distribution of properties. The majority of research papers dealing with statistical descriptions of the low-cycle strain properties do not look deeper into the distribution of mechanical properties and the diagram parameters of strain characteristics. This paper provides a description of the distribution patterns of mechanical properties, statistical parameters, and low-cycle fatigue curves. Log-normal distribution generated the lowest values for the coefficient of variation of one of the key statistical indicators, suggesting that log-normal distribution is superior to normal or Weibull distribution in this respect. The distribution of low-cycle strain parameters exceeded the distribution of mechanical properties considerably. Minimum coefficients of variation of the parameters were generated at normal distribution. The statistical analysis showed the lower distribution of the durability parameters compared to the distribution of parameters of the strain diagrams. The findings of the paper enable a revision of the durability and life of the structural elements of in-service facilities subject to elastoplastic loading by assessing the distribution of mechanical characteristics and low-cycle strain parameters as well as the permissible distribution limits.
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spelling doaj.art-aefcbed8ca98412dab9a373b0dd629e32023-11-21T22:51:22ZengMDPI AGMetals2075-47012021-06-0111691810.3390/met11060918Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and AluminiumŽilvinas Bazaras0Vaidas Lukoševičius1Andrius Vilkauskas2Ramūnas Česnavičius3Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentų Str. 56, 51424 Kaunas, LithuaniaFaculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentų Str. 56, 51424 Kaunas, LithuaniaFaculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentų Str. 56, 51424 Kaunas, LithuaniaFaculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentų Str. 56, 51424 Kaunas, LithuaniaKey mechanical properties used in low-cycle strength and durability calculations are the strength (proportional limit stress, <i>σ<sub>pr</sub></i>; relative yield strength, <i>σ</i><sub>0.2</sub>; and ultimate tensile stress, <i>σ<sub>u</sub></i>) and strain properties (proportional limit strain, <i>e<sub>pr</sub></i>; percent area reduction, <i>ψ</i>; and percent area reduction at failure, <i>ψ<sub>u</sub></i>). When selecting the key mechanical properties provided in the specifications, an error may be made due to the failure to account for a series of random factors that determine the distribution of properties. The majority of research papers dealing with statistical descriptions of the low-cycle strain properties do not look deeper into the distribution of mechanical properties and the diagram parameters of strain characteristics. This paper provides a description of the distribution patterns of mechanical properties, statistical parameters, and low-cycle fatigue curves. Log-normal distribution generated the lowest values for the coefficient of variation of one of the key statistical indicators, suggesting that log-normal distribution is superior to normal or Weibull distribution in this respect. The distribution of low-cycle strain parameters exceeded the distribution of mechanical properties considerably. Minimum coefficients of variation of the parameters were generated at normal distribution. The statistical analysis showed the lower distribution of the durability parameters compared to the distribution of parameters of the strain diagrams. The findings of the paper enable a revision of the durability and life of the structural elements of in-service facilities subject to elastoplastic loading by assessing the distribution of mechanical characteristics and low-cycle strain parameters as well as the permissible distribution limits.https://www.mdpi.com/2075-4701/11/6/918probabilitydurabilitylow-cycle fatiguenormal distributionslog-normal distributionWeibull distribution
spellingShingle Žilvinas Bazaras
Vaidas Lukoševičius
Andrius Vilkauskas
Ramūnas Česnavičius
Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium
Metals
probability
durability
low-cycle fatigue
normal distributions
log-normal distribution
Weibull distribution
title Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium
title_full Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium
title_fullStr Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium
title_full_unstemmed Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium
title_short Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium
title_sort probability assessment of the mechanical and low cycle properties of structural steels and aluminium
topic probability
durability
low-cycle fatigue
normal distributions
log-normal distribution
Weibull distribution
url https://www.mdpi.com/2075-4701/11/6/918
work_keys_str_mv AT zilvinasbazaras probabilityassessmentofthemechanicalandlowcyclepropertiesofstructuralsteelsandaluminium
AT vaidaslukosevicius probabilityassessmentofthemechanicalandlowcyclepropertiesofstructuralsteelsandaluminium
AT andriusvilkauskas probabilityassessmentofthemechanicalandlowcyclepropertiesofstructuralsteelsandaluminium
AT ramunascesnavicius probabilityassessmentofthemechanicalandlowcyclepropertiesofstructuralsteelsandaluminium