Estimate of Coffin–Manson curve shift for the porous alloy AlSi9Cu3 based on numerical simulations of a porous material carried out by using the Taguchi array

Tomažinčič, Dejan (author), Klemenc, Jernej (author)

In real engineering applications, machine parts are rarely completely homogeneous; in most cases, there are at least some minor notch effects or even more extensive inhomogeneities, which cause critical local stress concentrations from which fatigue fractures develop. In the present research, a shift of the Coffin–Manson ε$_a$–N material curve in a structure with random porosity subjected to dynamic LCF loads was studied. This allows the rest of the fatigue life prediction process to remain the same as if it were a homogeneous material. Apart from the cyclic σ–ε curve, which is relatively easy to obtain experimentally, the ε$_a$–N curve is the second most important curve to describe the correlation between the fatigue life N and the strain level ε$_a$. Therefore, the correct shift of the ε$_a$–N curve of the homogeneous material to a position corresponding to the porous state of the material is crucial. We have found that the curve shift can be efficiently performed on the basis of numerical simulations of a combination of five porosity-specific geometric influences and the associated regression analysis. To model the modified synthetic ε$_a$–N curve, five geometric influences of porosity by X-ray or µ-CT analysis are quantified, and then the porosity-adjusted coefficients of the Coffin–Manson equation are calculated. The proposed approach has been successfully applied to standard specimens with different porosity topography.

• Language: English
• Keywords: low-cycle fatigue, aluminium alloys, porosity, Coffin–Manson relationship, Taguchi, multivariate regression analysis
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 24 str.
• Numbering: Vol. 15, iss. 6, art. 2269
• PID: 20.500.12556/RUL-135574
• UDC: 620.178.3:669.715
• ISSN on article: 1996-1944
• DOI: 10.3390/ma15062269
• COBISS.SI-ID: 101646083
• Publication date in RUL: 21.03.2022

Record is a part of a journal

• Title: Materials
• Shortened title: Materials
• Publisher: MDPI
• ISSN: 1996-1944
• COBISS.SI-ID: 33588485

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 18.03.2022

Secondary language

• Language: Slovenian
• Keywords: malociklično utrujanje, aluminijeve zlitine, poroznost, soodvisnost Coffin-Manson, Taguchi, multivariatna regresijska analiza

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0182
• Name: Razvojna vrednotenja