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Showing papers in "Fatigue & Fracture of Engineering Materials & Structures in 2020"


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a model for system reliability and safety at the University of Electronic Science and Technology of China, Chengdu, China Center for System Reliability & Safety.
Abstract: School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China Center for System Reliability & Safety, University of Electronic Science and Technology of China, Chengdu, China INEGI, Faculty of Engineering, University of Porto, Porto, Portugal Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology, Trondheim, Norway

128 citations


Journal ArticleDOI
TL;DR: In this article, the authors provide a state-of-the-art review on quasi-static standard tensile test for stress-strain curves measurement of metallic materials, and present novel methods with axisymmetric notched round bar specimens for accurately capturing the equivalent stressstrain curve of each material zone in weldment.
Abstract: Fatigue Fract Eng Mater Struct. 2019;1–17. Abstract For metallic materials, standard uniaxial tensile tests with round bar specimens or flat specimens only provide accurate equivalent stress–strain curve before diffuse necking. However, for numerical modelling of problems where very large strains occur, such as plastic forming and ductile damage and fracture, understanding the post‐necking strain hardening behaviour is necessary. Also, welding is a highly complex metallurgical process, and therefore, weldments are susceptible to material discontinuities, flaws, and residual stresses. It becomes even more important to characterize the equivalent stress–strain curve in large strains of each material zone in weldments properly for structural integrity assessment. The aim of this paper is to provide a state‐of‐the‐art review on quasi‐static standard tensile test for stress–strain curves measurement of metallic materials. Meanwhile, methods available in literature for characterization of the equivalent stress–strain curve in the post‐necking regime are introduced. Novel methods with axisymmetric notched round bar specimens for accurately capturing the equivalent stress–strain curve of each material zone in weldment are presented as well. Advantages and limitations of these methods are briefly discussed.

87 citations







Journal ArticleDOI
TL;DR: In this paper, the fracture toughness of polymeric foam-based composite structures has been evaluated using linear elastic fracture mechanics and different approaches to estimate the fracture-toughness of these composite materials.
Abstract: Funding information European Commission, Grant/Award Number: Horizon 2020, No. 857124; Romanian Ministry of Research and Innovation, Grant/Award Numbers: 10PFE/16.10.2018, PERFORM-TECHUPT, PN-III-P1-1.2-PCCDI-2017-0391 Abstract Polymeric foams have good capacity of absorbing energy in compression but are brittle in tension. Linear elastic fracture mechanics is successfully applied to assess the integrity of polymeric foam-based composite structures. The fracture toughness represents an important parameter. The different approaches to estimate the fracture toughness of polymeric foams are reviewed: analytical and numerical micromechanical models and experimental investigations. Focus is given on the parameters influencing the fracture toughness of polymeric foams like specimen type, solid material, density, loading speed, size effect and temperature. Data on mixed-mode loading and dynamic fracture toughness are also presented. The last part of the paper presents some results to increase the fracture toughness by reinforcing of polymeric foams.

37 citations











Journal ArticleDOI
TL;DR: In this paper, the fatigue behavior of notched and unnotched specimens produced by additively manufactured Inconel 718 is analyzed in the as-built and heat-treated conditions.
Abstract: The fatigue behaviour of notched and unnotched specimens produced by additively manufactured Inconel 718 are analysed in the as-built and heat-treated conditions. The surfaces display high roughness and defects acting as fatigue initiation sites. In the as-built condition, fine sub-grains were found, while in the heat-treated state, the sub-grains were removed and the dislocation density recovered. SN-curves are predicted based on tensile properties, hardness and defects obtained by fractography, using the √area-method.











Journal ArticleDOI
TL;DR: In this article, a non-destructive thermographic methodology is utilized to determine the fracture fatigue entropy for evaluating the fatigue damage in metals within the high-cycle fatigue regime, which is shown to play an important role in the fatigue process to trace fatigue damage as an irreversible degradation of a metallic material being subjected to cyclic elastic-plastic loading.
Abstract: Funding information China Scholarship Council; Deutsche Forschungsgemeinschaft, Grant/Award Number: STA 1133/6-1 Abstract A nondestructive thermographic methodology is utilized to determine the fracture fatigue entropy for evaluating the fatigue damage in metals within the high-cycle fatigue regime. Thermodynamic entropy is shown to play an important role in the fatigue process to trace the fatigue damage as an irreversible degradation of a metallic material being subjected to cyclic elastic-plastic loading. This paper presents a method to evaluate fatigue damage in the normalized SAE 1045 steel being based on the concept of thermodynamic entropy and its nonlinearities. The procedure looks to be applicable to constant and load increase tests proven by experiments.