Naslov
The development of the indirect method for estimation of strain life fatigue parameters

Autori
Basan, Robert ; Rubeša, Domagoj ; Franulović, Marina

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts ICM12 / - Karlsruhe : Karlsruhe Institute of Technology, 2015, 130-130

Skup
ICM 12 – 12th International Conference on the Mechanical Behavior of Materials

Mjesto i datum
Karlsruhe, Njemačka, 10.05.2015. - 14.05.2015

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
estimation method; fatigue; material parameters

Sažetak
Experiment-based determination of strain life fatigue parameters, although most accurate, quickly becomes prohibitive due to the complexity and high costs of cyclic experiments (ASTM Standard E606). Monotonic tensile tests are simple and inexpensive, and their results are usually readily available, so that one of the methods for estimation of fatigue parameters from material's monotonic properties (Muralidharan, Manson 1988, Bäumel, Seeger 1990, Ong 1993, Roessle, Fatemi 2000) is often used, especially during early phases of product development. Most of the existing methods for the estimation of strain life parameters were developed by correlating experimentally determined strain life parameters independently of each other and directly with one or more monotonic tensile material properties. In some cases, this resulted in relatively complicated expressions for the calculation of fatigue parameters, while in others, because of the poor correlation between certain fatigue and monotonic parameters, constant values were assigned to some of these fatigue parameters. Based on the previously proposed approach (Basan 2009, Basan et al. 2010) new, indirect method for estimation of strain life fatigue parameters from materials monotonic properties is proposed. Unlike the existing methods, proposed method is based on the identification and establishment of functional relationships between selected monotonic property and strain-life relations which is achieved by correlating ultimate strength Rm and individual points on strain life curves. From these established relationships, new values of fatigue parameters were then determined for each value of the ultimate strength Rm so that new functions could be derived. Main advantage of the new approach and proposed method is that fatigue parameters are not estimated individually, i.e. independently from one another. For the development and a validation of the proposed approach to the estimation of fatigue parameters, necessary data were gathered for a set of differently heat treated high-strength low-alloy 42CrMo4 steels tested at room temperature. Performance of proposed indirect estimation method was evaluated using criteria which have been extensively used in different comparisons and verifications of estimation methods reported in literature. Fatigue lives calculated using estimated values of fatigue parameters are found to be in very good agreement with those calculated using experimentally obtained fatigue parameters. Furthermore, determined values of comparison criteria are significantly higher for proposed method than those calculated for other estimation methods. Proposed method will be extended and adapted for estimation of fatigue parameters of unalloyed, low- and high-alloy steels as well as aluminium and titanium alloys in an extended paper.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo

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