Special Issue "Deformation, Fatigue and Fracture of Materials"
A special issue of Materials (ISSN 1996-1944).
Deadline for manuscript submissions: 31 May 2019
Prof. Dr. Filippo Berto
Deformation, fracture, and fatigue of structural components are very common problems to be managed during the design of complex products and structures. They can provoke unexpected failures or inappropriate behavior of structural components under in-service loading conditions with a shortening of the fatigue life. Aim of this Special Issue is to provide an update to the state-of-the-art on these problems, showing a clear link between material micro-nano behavior and the behavior of a real structure. Multiscale approaches are usually employed to capture these features in a unified way. Recent advanced criteria for fracture and fatigue predictions are fully considered in this Special Issue, keeping in mind the introduction and use of new advanced materials as additive materials, functionally graded materials, and multifunctional materials.
Prof. Dr. Filippo Berto
Manuscript Submission Information
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.
- local approaches
- fatigue assessment
- advanced design
- multiscale approach
- new materials
The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.
1. Tentative Title: Validation of the fracture load dependence on yield strength in the
ductile-to-brittle temperature region and a simplified method to predict fracture toughness
temperature dependence in a wide range
Authors: Toshiyuki Meshii (University of Fukui), Takashi Inoue and Go Yakushi
Tentative Abstract: The fracture toughness KJc of the material in the ductile to brittle transition
temperature (DBTT) region shows test specimen thickness (TST) effect and temperature dependence.
Master curve (MC) method, which provides an engineering approach to solve these two issues is
gathering attention. Though MC is intended to apply for arbitrary ferritic material whose yield stress
in the range of 275 to 825 MPa, one has to obtain KJc data to obtain the material dependent reference
temperature: T0. The applicable range of MC method is restricted to T0 +- 50 oC. Experiences from
many researchers show that additional pre-tests to obtain T0 are necessary and thus benefit of
“arbitrary” material applicability seems not to be enjoyed. In contrary, the authors have focused on
the mean KJc and have demonstrated that TST effect on KJc and temperature dependence of KJc are
due to “the loss in one-to-one correspondence between the J and the crack-tip stress distribution”
and that the “scaled” crack-tip stress distribution at fracture is independent of TST effect or
temperature dependence on KJc. T-scaling method was proposed and validated for this purpose. An
extension of the T-scaling method on KJc temperature dependence the was the SDS method (fracture
“load” is proportional to 1/(yield strength). In this paper, the SDS method was validated for Cr-Mo
steel JIS SCM440 and 0.55% carbon steel JIS S55C. Both tensile and fracture toughness tests were
performed for a wide range of for -166 to 100 °C for SCM440 and -166 to 20 °C for S55C. The SDS
method was validated for the DBTT region plus alpha. Finally, a simplified method was proposed
and validated to predict the KJc temperature dependence, by using the yield stress temperature
dependence and applying the SDS and using EPRI plastic J functional form.
2. Tentative Title: Application of the T-scaling method to account for the notch acuity
dependence on the apparent notch fracture toughness in the ductile-to-brittle temperature region
Authors: Toshiyuki Meshii (University of Fukui), Masayoshi Yamashita and Hiroki Nakano
Tentative Abstract: Current defect assessment procedures based on fracture mechanics usually
assume flaws to be infinitely sharp. While this assumption may be appropriate for fatigue cracks, for
non-sharp flaws such as porosity, mechanical damage or weld undercut, it can be an
over-conservative assumption that can lead to pessimistic assessments of structural integrity and a
significant underestimation of the true safety margin against fracture. Irwin has studied notch and
pre-cracked fracture toughness in the lower shelf region and suggested that notch KIc is in proportion
to the square root of notch radius ρ, but is not continuous with the pre-cracked KIc (i.e., when zero is
substituted to ρ in the fitted KIc and ρ relationship, the obtained value differs from that of the
pre-cracked specimen KIc). In contrast, Begley et al. have made a similar study in the upper shelf
region and suggested that JIc ∝ ρ. In addition, they showed that notch JIc is continuous with the
pre-cracked JIc. Studies of this issue in the ductile-to-brittle transition temperature (DBTT) region
are few. In this paper, the effects of notch acuity on notch fracture toughness in the lower shelf and
DBTT region was studied for 0.55% C steel JIS S55C with 0.5TSE(B) specimen. The notch size ρ
was selected as 50, 150 and 375 μm. Fatigue pre-cracked specimens were also studied. The
experimental results showed that the notch KIc ∝ ρ 1/2, but is not continuous with the pre-cracked KIc
at lower shelf temperature of -166 °C. The DBTT notch fracture toughness KJc ∝ ρ1/2 and was
continuous with the pre-cracked KJc. By running elastic-plastic finite element analysis, the mid-plane
crack-opening stress distribution on the x1-axis, was shown that the scaled stress distribution at
fracture load could be T-scaled for pre-cracked and notch specimen. Thus, notch and pre-cracked KJc
has a reason to be continuous. The reason for notch size effect on Jc was explained as the difference
in load for notched specimens to reach the stress level of the pre-cracked specimen. The apparent
notch KJc dependence on notch acuity was also one of the “the loss in one-to-one correspondence
between the J and the crack-tip stress distribution.”
3. Tentative Title: Innovative elastoplastic J2-flow model with a unified simulation for failure effects of twisted metal tubes under monotonic and cyclic loadings
Authors: Lin Zhan, Si-Yu Wang, Hui-Feng Xi, Heng Xiao
Affiliation: School of Mechanics and Construction Engineering, MOE Key Lab of Disaster Forecast and Control in Engineering, Jinan University, 510632 Guangzhou, China
Tentative Abstract: New elastoplastic J2-flow equations with combined hardening are proposed without assuming the usual notion of yielding. Novel results are obtained based on these equations. First, fatigue failure effects under cyclic loading conditions are automatically incorporated as direct consequences of intrinsic constitutive features, without involving any assumed damage-like variables and any additional failure criteria of ad hoc nature. Second, both Swift effects and fatigue failure effects of twisted metal tubes under monotone and cyclic loadings may be simultaneously treated for the first time. As such, coupling effects of both finite strain and large rotation may be in a direct, unified manner simulated for both free-end and fixed-end torsion. Finally, numerical examples for model validation are presented and compared with experimental data and accurate agreement is achieved.
4. Tentative Title: Tensile strength, ductility, and fracture behavior of trimodal nanostructured metals
Authors: Guo, X. 1; Yang, G. 2; Wu, W. 1; Zhu, L.L. 3; Weng, G.J. 4,*
Affiliations: 1 School of Mechanical Engineering, Tianjin University, Tianjin 300072, China
2 Automotive Engineering Research Institute, China Automotive Technology and Research Center, Tianjin 300300, China
3 Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, Zhejiang, China
4 Department of Mechanical and Aerospace Engineering, Rutgers University, New Brunswick, NJ 08903, USA
Tentative Abstract: Trimodal nanostructured (NS) metals incorporate the advantages of a strong NS metallic matrix phase, a ductile coarse-grained (CG) inclusion phase, and a hard ceramic reinforcement phase. Its benefits are multifaceted, but its deformation and fracture behavior remain relatively unknown. In this work, we conduct a computational study based on the mechanism-based strain gradient plasticity, Johnson–Cook failure criterion, and Drucker–Prager plasticity model, on these two important issues. Our specific objectives are on the influence of distribution and shape of CG regions, and the influence of size and volume fraction of ceramic reinforcement on these mechanical properties. It is found that, among others, the trimodal NS metals with staggered arrangement of CG regions are stronger and more ductile than those with array arrangement of CG regions. The results further show that the size of ceramic reinforcement particles is also important. Several other interesting features of microstructural effects on the overall strength and ductility are also discussed.
Tentative Keywords: Trimodal nanostructured metals; Johnson–Cook failure criterion; Coarse-grained regions; Ceramic reinforcement; Volume fraction