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Ruobing Bai's picture

Journal Club for March 2019: Fatigue of hydrogels

Fatigue of hydrogels

Ruobing Bai (1,2), Zhigang Suo (1)

(1) John A. Paulson School of Engineering and Applied Sciences, Kavli Institute for Bionano Science and Technology, Harvard University

(2) Department of Mechanical and Civil Engineering, California Institute of Technology

 

rajan_prithivi's picture

Critical porosity in the fatigue of additively manufactured IN718 via crystal plasticity modeling

 

 

https://doi.org/10.1016/j.matdes.2018.04.022

 

Highlights

 

1. Critical porosity is estimated in additively manufactured IN718 via crystal plasticity.

2. Porosity is characterized using high resolution tomography.

3. Non-local damage indicator parameters identify the location of fatigue crack initiation.

Emilio Martínez Pañeda's picture

Mode I crack tip fields: strain gradient plasticity theory versus J2 flow theory

I hope some of you may find this work interesting. We show, analytically and numerically, that strain gradient plasticity predicts the existence of an inner elastic field adjacent to the crack tip, reminiscent of a dislocation-free zone. The fact that elastic strains dominate plastic strains near the crack tip implies a paradigm-shift with respect to previous crack tip asymptotic studies in plasticity and gradient plasticity, which neglect elastic strains. 

 

Emilio Martínez-Pañeda, Norman A. Fleck

Urgent: 2 fully-funded PhD theses at Synopsis (Exeter) / Cardiff University / University of Luxembourg in machine learning/biomedical simulations/3D medical image processing

Synopsys NE Ltd (https://www.synopsys.com/simpleware.html), Cardiff University and University of Luxembourg invites applications for 2 Early Stage Researcher position (Doctoral Candidate) as part of the Rapid Biomechanics and Simulation for Personalized Clinical Design (RAINBOW) MCSA European Training Network. RAINBOW is funded under the European Union’s Horizon 2020 research and innovation program.
 

MMSLab-CNR's picture

A model updating procedure to enhance structural analysis in the FE code NOSA-ITACA

https://www.researchgate.net/publication/331034322_A_model_updating_proc... This paper describes the model updating procedure implemented in NOSA-ITACA, a finite-element code for the structural analysis of masonry constructions of historical interest. The procedure, aimed at matching experimental frequencies and mode shapes, allows fine-tuning calculation of the free parameters in the model.

MMSLab-CNR's picture

Modal analysis of historical masonry structures: Linear perturbation and software benchmarking

https://www.sciencedirect.com/science/article/pii/S0950061818322116 The mechanical behavior of masonry materials has a common feature: a nonlinear behavior with high compressive strength and very low tensile strength. As a consequence, old masonry buildings generally present cracks due to permanent loads and/or accidental events. Therefore, the characterization of the global dynamic behavior of masonry structures should take into account the presence of existing cracks.

MMSLab-CNR's picture

Call for Abstract - Frontiers in Built Environment, Earthquake Engineering

Dear colleagues, Given the recent establishment of the so-called Urban Seismology field and the lack of dedicated journals for the topic, together with Professor Maria Todorovska (University of Southern California, USA), Dr. Riccardo Maria Azzara (INGV, Italy), Dr. Michele Palermo and Dr. Simonetta Baraccani (University of BOlogna, Italy), we would like to establish a network of researchers dealing with this very challenging topic.

MMSLab-CNR's picture

Modal analysis performed by NOSA-ITACA code

The following picture shows a screenshot of the NOSA-ITACA desktop enviroment during a modal analysis. In particular the first and the third mode shape of the San Frediano bell Tower in Lucca (Italy) are shown. The structure is discretized into 45641 eight-node brick elements (element no. 8, NOSA-ITACA element library) with 136923 degrees of freedom. For more details sees: R.M. Azzara, G. De Roeck, E. Reynders, M. Girardi, C. Padovani and D.

Bin Liu's picture

Criteria for selecting a reasonable and better measure of anisotropy

Published in Physcal Review Letters: https://doi.org/10.1103/PhysRevLett.122.045502. Many materials are anisotropic. However, there is no widely accepted measure for characterizing the degree of elastic anisotropy. Here, assuming that the limiting case of extreme anisotropy should possess a positive semidefinite stiffness matrix, we propose three criteria to evaluate measures of anisotropy and show that the existing measures in the literature do not satisfy all of the proposed criteria.

Jingjie Yeo's picture

Multiscale Design of Graphyne‐Based Materials for High‐Performance Separation Membranes

https://doi.org/10.1002/adma.201805665 Computational modeling and simulations play an integral role in the bottom‐up design and characterization of graph‐n‐yne materials. Here, the state of the art in modeling α‐, β‐, γ‐, δ‐, and 6,6,12‐graphyne nanosheets for synthesizing graph‐2‐yne materials and 3D architectures thereof is discussed.

Jingjie Yeo's picture

Paraffin-enabled graphene transfer

https://doi.org/10.1038/s41467-019-08813-x We report a transfer approach using paraffin as a support layer, whose thermal properties, low chemical reactivity and non-covalent affinity to graphene enable transfer of wrinkle-reduced and clean large-area graphene.

marc53042's picture

Postdoctoral Research Fellow Position at the University of São Paulo, Brazil.

We are looking for a candidate with a Ph.D. degree to study fracture problems in bimetallic pipelines,  API X65 internally clad with alloy 625. The project has direct application to offshore exploration in Brazil deepwater fields. The project is going to be funded by the Petrobras company. The chosen candidate will develop a parametric model to model the welded joint of this type of pipes using python/Abaqus, being the numerical model as close as possible to the real geometry.

Bent F. Sørensen's picture

Micromechanical model for prediction of fatigue limit of fibre composites

We have published a paper called "Micromechanical model for prediction of the fatigue limit for unidirectional fibre composites" in Mechanics of Materials. See the link here.

Emilio Martínez Pañeda's picture

The role of plastic strain gradients in the crack growth resistance of metals [code included]

I hope some of you will find our recent paper in the Journal of the Mechanics and Physics of Solids interesting. The Abaqus user element (UEL) subroutine developed to implement strain gradient plasticity theories with energetic and dissipative higher order stresses (Gudmundson 2004, Fleck and Willis 2009) can be downloaded from www.empaneda.com/codes

The role of plastic strain gradients in the crack growth resistance of metals

Emilio Martínez-Pañeda, Vikram S. Deshpande, Christian F. Niordson, Norman A. Fleck

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