A PhD opportunity in the field of computational and applied mechanics is available in the department of Civil and Environmental engineering at the University of Illinois at Urbana-Champaign.

Qualifying candidates must have a strong background in mechanics and mathematics. Familiarity with scientific computing in one of the widely used programming languages (e.g. Fortran, C++ or Python)is required.

Primary focus will be on multiscale modeling of fractures in heterogeneous quasi-brittle materials with applications in the field of earthqauke dynamics and bone mechanics 

If you are interested please send your C.V. to : elbanna2@illinois.edu

Job Description

Title: Materals Scientist- Solar Wafering R&D   

Reporting to: Director, Solar R&D

Location:St. Peters, MO (Corporate)                 

­­­­­­­­­­­­­­­­­­­­­_______________________________________________________________________

SUNEDISON is a global leader in the manufacture and sale
of wafers and related intermediate products to the semiconductor and solar
industries. With R&D and manufacturing facilities in the U.S., Europe and
Asia, SUNEDISON enables the next generation of high performance semiconductor
devices and solar cells. At SUNEDISON, we are looking for talented individuals who are original thinkers, with
the ability to succeed in a team environment and the capacity to assume
increasing responsibility in a highly successful global organization.

Primary Responsibility:

Develop and demonstrate new slicing technologies for silicon solar wafers. Develop and
test new materials and new equipment for slicing silicon. Collaborate in the
development of new quantitative models for slicing processes and product
properties from slicing. Support Sunedison’s solar factories with travel up to
50% of the time.  Proactively communicate and collaborate with management, team members and fellow scientists.

Candidate Qualifications:

Education: PhD in Materials Science is preferred. In-depth knowledge of
materials science with detailed knowledge of fracture mechanics, friction and
abrasion science and mechanical properties of ceramics is desired.  The candidate should have hands-on expertise
with ceramics testing and characterization equipment and experience in
mathematical modeling of ceramic behavior and properties.

Job related experience: Experience in silicon processing is desired but not required.

Other competencies: Data-driven, detail-oriented, persistent, highly collaborative

The candidates are requested to send their
resumes to Dr. Larry Shive at LShive@SunEdison.com and give reference to posting on iMechanica. 

Hi everyone

i'm working on crack analysis via finite volume and my goal is to calculate SIF with interaction integral

I have some issues and quastions:

1-i found interaction integral is little path dependence!!!

2-what is the best weight  function for interaction integral?

3-what range of domain size is good for the M-integral?

4-and my bigest problem is sometimes i got worse answer with finer mesh!!! (also with uniform distribution)

5-is my model unstable or something like that???

P.S: stationary crack

One Post-Doc position is now available at the Institut für Angewandte Mechanik of the Technische Universität Braunschweig, Germany, within the ERC Starting Researcher Grant "INTERFACES". The position is a full-time fixed-term position for 2 years with the possibility of renewal.

The successful applicant will conduct research on topics related to interface mechanics, contact and fracture mechanics, multiscale and multiphysics methods, and isogeometric analysis. Targeted experimental validation of computational methods is also foreseen. The selected individual will be also expected to engage in teaching of classes for Master courses in English.

Applicants should possess the following qualifications/attributes:

(a) a PhD degree in computational mechanics;

(b) outstanding background in continuum mechanics and numerical methods, and excellent programming skills;

(c) strong motivation and enthusiasm to carry out high-quality research;

(d) proficiency in English and possibly also in German.

If you meet the above requirements and are interested in this position, please email your CV, including your detailed transcripts, a list of publications, copy of the most relevant publications and a short personal statement explaining why you are interested in the position to prof. Laura De Lorenzis, l.delorenzis@tu-braunschweig.de, as soon as possible.

Hello

How should i model crack propagation in MSC PATRAN with VCCT Modoule? is there any manual about that 

The
Center for Mechanics of Solids, Structures and Materials has immediate openings
for two post-doctoral positions, dealing with (i) laboratory experiments on hydraulic
fracture and (ii) ductile failure in metals. The primary focus in both
investigations is on performing laboratory experiments that are then followed
by appropriate analyses. Candidates with a strong background in solid mechanics
and experience in experimental solid mechanics are encouraged to contact Professor
Ravi-Chandar (ravi@utexas.edu).

The Automated Computational Mechanics Laboratory (ACML) at The Ohio State University announces a new PhD position available for Spring 2014. The related research project focuses on the application of an advanced finite element method for simulating damage and crack propagation in heterogeneous composites. Applicants with strong background in computational solid mechanics are encouraged to apply by 09/15/2013. Please also send a copy of your CV, a two-page SOP, and the contact information of at least three references to Dr. Soheil Soghrati (Soghrati.1@osu.edu). 

How to model Bimodulus Material in ANSYS or any Finite Element Analysis software to find out Neutral axis shift in simple bend test.

there is a phd position on investigation of fracture mechanism of spot welds in automotive steels, 

the funding is available for UK/EU nationals

please go to

http://www.shef.ac.uk/mecheng/phd/projects/deformation-spot-welding 

for further information.

This is a call of interest for a post-doc position (1 year renewable up to 3 years) at the IMT Institute for Advanced Studies Lucca, Italy (www.imtlucca.it), in the field of computational damage and fracture mechanics. The activities are in the framework of the ERC Starting Grant IDEAS "Multi-field and multi-scale Computational Approach to design and durability of Photovoltaic Modules" (Prof. Paggi, Principal Investigator).

For more details about the project, see:

http://staff.polito.it/marco.paggi/CA2PVM.htm

and for the research unit Multiscale analysis of materials - MUSAM:

http://musam.imtlucca.it

Topic:

Computational fracture and damage mechanics models for silicon photovoltaics

Activities:

- Development of new damage mechanics and fracture mechanics models for modelling fracture in mono or polycrystalline silicon solar cells.

- Implementation of the models in the finite element analysis programme FEAP.

- Numerical simulations of photovoltaic modules in multi-physics, including the effect of thermo-mechanical deformations and comparison with experimental results.

- General support to the research/didactic activities of the research unit.

Required skills:

- Excellent track record of publications in computational mechanics;

- Programming in Fortran;

- Documented experience in implementing user element subroutines in FEAP, ABAQUS or similar finite element software.

Salary and benefits:

A competitive salary at the European level will be provided. Benefits include the accommodation inside the university campus

for up to 1 month from the job starting date and lunch and dinner in the university canteen for the whole scholarship duration.

Date of appointment:

As soon as possible, presumably by Spring 2014 (February or March 2014).

Please send your statement of interest by email to:

Prof. Marco Paggi

marco.paggi@imtlucca.it

including:

- detailed CV;

- full list of publications;

- 3 selected articles published in international journals (possibly related to the topic of the call).

Deadline extended for NT2F12 congress which will be held in Transilvania University of BRASOV.

Brasov is one of the largest and most cherished cities of the country. Surrounded on three sides by mountains, it was a perfect place for a medieval settlement.

The old city, founded by the Teutonic Knights in 1211, is one of the best preserved cities in all of Europe. It was thotoughly restored to the delight of an increasing number of tourist. It is the capital city of Brasov Country, in central Romania, in Transylvania, at the foot of the Carpathian Mountains. Brasov also makes a fabulous base for exploring the surrounding countryside where the air is clean and the people friendly.

Direct link to NT2F12: http://www.dimeg.poliba.it/NT2F/NT2F/Home_NT2F12.html
Link to NT2F website: http://www.dimeg.poliba.it/NT2F/

http://www.romaniatourism.com/brasov.html

Applications are invited for few open positions in the area of
multiscale simulation of fatigue and fracture of advanced alloys and
nano-material based composites. Primary focus of this research is investigation
of fatigue and fracture behavior of nanomaterials and to develope various
constitutive models for continuum, based on large scale atomistic simulations.
Research effort will include development of analysis and design methods toward
improving material/structural behaviour using computer simulation. Interested
candidates should have preferably MTech/ME degree in
mechanical/civil/aerospace/material engineering discipline with good knowledge
of basic finite element method, solid mechanics/material science/ physics, and
preliminary experience in finite element simulations (Preferably Nastran,
LsDyna, and Abaqus) and molecular dynamics (LAMMPS). Exposure to computer
programming with C/C++/fortran and Matlab would be advantageous. Candidates
having experimental background in material/structural mechanics/nano-materials
with interests in multiscale response of materials and structures are also
welcome to apply.

 Interested candidates may contact Prof D Roy Mahapatra (droymahapatra@aero.iisc.ernet.in) or
Vijay Kumar Sutrakar (vijay.sutrakar@gmail.com) with
detailed bio-data. 

Good mourning, i am using Abaqus software to inverstigate a crack propagation problem using Abaqus, in this regards i have created a seam crack iner the geometrie which is a plate  under a plane stress condition, my problem is how to mesh around the crack tip in order to have a regular mesh around the crack tip so i can evaluate J integral for multiple contours, the Abaqus documentation mention the swept meshing technique but i coudn't find something about a 2D problem since the sweapt meshing technique nead to mesh a section and swept it over the rest of the body, and in 2d problem we have eages, so how to use it 'some basics rules' in order to creat a regular mesh around the crack tip, i am waiting for any answer from you guys, thank you

The class started today.  I'll be teaching fracture mechanics this semester.  I'll be mostly using the class notes I wrote in 2010, but will post updated ones. 

In today's class I covered "Trouble with linear elastic theory of strength."  I have just posted updated notes of the lecture.  The new notes begin with the follwoing paragraphs.

The toughest hydrogel in the world.  We reported an exceptionally tough hydrogel:  Jeong-Yun Sun, Xuanhe Zhao, Widusha R.K. Illeperuma, Kyu Hwan Oh, David J. Mooney, Joost J. Vlassak, Zhigang Suo. Highly stretchable and tough hydrogels. Nature 489, 133-136 (2012).  A hydrogel is a three-dimensional polymer network swollen with water.  Familiar examples include jello and contact lenses.  Our hydrogel achieved a toughness of ~9,000 J/m2.  This statement raises several questions.

What is toughness?  Toughness is the ability of a material to resist the growth of crack.  Understanding toughness is a main object of this course.

What does the value 9,000 J/m2 mean?  We will talk about how to measure toughness later in the course.  For now, you can have some feel for orders of magnitude.  Jello and tofu have toughness ~10 J/m2.  Contact lenses have toughness ~100 J/m2.  Cartilage has toughness ~1,000 J/m2.  Natural ruber has toughness ~10,000 J/m2.  Our tough gel contains about 90% water, yet its toughness approaches that of the natural rubber.    

How can our hydrogel be so tough?  For now let’s have a qualitative picture.  A window glass is brittle, but a steal is tough.  That is, the ability of a window glass to resist the growth of a crack is much less than the ability of a steel to resist the growth of a crack.  This is everyday experience, but why?  The answer to such question sooner or later leads to an atomistic picture. 

You prepare a sheet of glass.  To study the growth of the crack, you cut a crack into the glass with a diamond saw.  You then pull the glass to cause the crack to grow.  The crack grows by breaking atomic bonds.  The tip of the crack concentrates stress, so that the atomic bonds at the tip of crack break.  As the tip the crack advances, a plane of atomic bonds unzips.  Atomic bonds off the plane of the crack remain elastic, and do not participate in resisting the growth of the crack.  The elasticity is visible:  after fracture, the two halves the glass fit together nicely.

Now you prepare a sheet of steel with a pre-cut crack.  You then pull the steel to cause the crack to grow.  The crack grows by breaking atomic bonds, but something else happens.  Atomic bonds off the plane of the crack no longer remain elastic:  they change neighbors.  That is, the steel off the crack plane undergoes plastic deformation.  The amount of material involved in plastic deformation is much, much more than the two planes of atoms on the surfaces of the crack.  The plastic deformation enables the steel to resist the growth of the crack much more than breaking a plane of atomic bonds.  The plasticity is visible:  after fracture, the two halves the steel do not fit together nicely.

Our hydrogel is tough because the growth of a crack does more than breaking a single layer of polymer chains.  The polymer off the plane of the crack undergoes deformation similar to plastic deformation in the steel.

We will make this picture precise as we go along in this course.  But if you absolutely cannot wait to know how our gel works, I’d be delighted if you read the paper now.   

I have updated my notes on the Griffith paper.  I added more description on the experimental determination of surface tension of solids.  Griiffith himself determined the surface tension of glass by an experimental setup.  Udin et al (1949) described a setup based on the same principle.  This setup is now known as the zero creep experiment.

In class today Chao Chen asked me to compere Inglis theory and Griffith theory, which I did at the very end of the notes.  The two theories give the same prediction: 

the strength times the squre-root of the crack length  is a material constant.

In the Inglis theory, the constant involves atomic strength and atomic size.  In the Griffith theory, the constant involves Young’s modulus and surface energy.  If we adopt any simple-minded atomic model, we can show that the two constants are essentially the same.

Both theories work well for silica glass.  Neither works for steel.  Both theories survived to this day, in somewhat different forms.  In general terms, the Inglis theory has evolved into the stress approach to fracture, and the Griffith theory has evolved into the energy approach.  The two approaches are, of course, equivalent.  We will talk more about both approaches in coming lectures.

I have an open position for a Post-doctoral researcher in the area of biomimetic materials, starting immediately. The successful candidate will explore and optimize bioinspired microarchitectures to increase the mechanical performance of engineering materials (glasses, ceramics, polymers).  This work will expand on our recent progress on overcoming the brittleness of glass (http://barthelat-lab.mcgill.ca/publications.html). Materials and systems of interest include nacre-like ceramic / polymeric composites, multilayered conch-shell like composites and fish-scale inspired flexible protective systems.

The candidate will use combinations of modeling (theoretical and finite elements), design optimization, innovative fabrication methods (3D printing, 3D laser engraving) and mechanical testing.

Required background: Mechanics of materials, composites, fracture mechanics, experimental mechanics and finite elements.

Preferred but not required: background in biological / biomaterials / biomimetic materials.

Send full CV to francois.barthelat@mcgill.ca
Website: http://barthelat-lab.mcgill.ca/

The Department of Civil and Environmental Engineering at the National University of Singapore (NUS) is recruiting 2 post-doctorate research fellows to pursue research on ice-structure interaction in the Keppel-NUS Corporate Laboratory. As part of the S$75 million collaboration between Keppel Corporation and NUS, the team comprising of Prof. Andrew Palmer, Dr. Bai Wei, and Dr. Pang Sze Dai, seeks to develop solutions for offshore rigs to meet the challenges of harsh arctic environments in oil and gas exploration and production.

The candidate should posses a PhD degree with strong background in solid mechanics. Relevant expertise in ice physics/mechanics, ice-structure interaction or proficient in LS-DYNA software will be positively considered. The appointment will be for two years in the first instance, and renewable for up to five years depending on performance. The remuneration and benefits are internationally competitive, and commensurate with qualifications and experience. Leave and medical benefits will be provided.  Review of applications will begin immediately and continue until the position is filled. Only shortlisted candidates will be notified and the fellowships can be offered immediately for suitable candidates. Successful candidates have an opportunity to be considered for a position in Keppel Corporation at the end of their fellowship.

To apply, please email the following documents to Dr. Pang Sze Dai at ceepsd@nus.edu.sg
1.   Cover letter
2.   A research statement summarizing the key research experience & expertise
3.   Curriculum Vitae including a list of publications (with three sample publications)

About National University of Singapore (NUS)
NUS is a leading global university centered in Asia. In the 2012 QS World University Rankings, NUS is ranked 25th in the overall ranking and 5th in Civil Engineering.

About Keppel Corporation
Keppel Corporation is the world's largest builder of offshore oil rigs. It has built close to half the world's jack-ups since 2000. Today, they are the global leader in the design, construction and repair of mobile offshore rigs.

Information about working and living in Singapore is available at: http://www.contactsingapore.sg/

In our recent paper, atomistic and continuum modelling of temperature-dependent fracture of graphene, we directly calculate J integral using the data obtained from molecular dynamics simulations. Fig. 1 outlines the calculation procedure of JIC. Fig. 1(a) shows the changes in potential energy with time (or applied strain) in an armchair graphene sheet with a size of 7.6 nm × 7.6 nm. A crack, length of ~0.7 nm, is placed in the centre of the sheet. Periodic boundary conditions are used along in plane directions. Simulation temperature is 1 K, and strain rate is 0.001 ps-1. Fig 1(b) shows the variation in potential energy during the crack propagation. It can be seen that the potential energy increases just after the crack starts to propagate (around point d). This is due to the chemical potential energy release from carbon-carbon bond breaking overcomes the strain energy release by crack propagation. As more bonds break, the strain energy release due to crack propagation starts to govern the total strain energy release. The crack propagation at various stages (marked as d to g in Fig. 1(b)) is shown in Fig. 1(d) to Fig. 1(g). The figures show that the crack propagates symmetrically. The out of plane deformation of the sheet, as shown in the video 1, prevails.


Fig. 1 Calculation of energy release rate of graphene. (a) Variation of potential energy with time. (b) and (c) variation of potential energy during the crack propagation. (d) to (g) show the crack propagation in graphene. The corresponding positions of Fig. (d) to (g) in the potential energy-time curve are marked in Fig. (b)

The slope of the piece wise continuous curves in Fig 1(c) is proportional to the critical value of J integral (JIC). Figure 2 shows the variation of JIC with the propagated crack length (2ap), which has been normalized with respect to the width of the sheet (w). The value of 2ap/w is approximately 0.1 when a crack starts to propagate since w is kept around 10 times the initial crack length (2a) to avoid the effects of finiteness. When 2ap/w reaches 1, the periodic cracks start to interact with each other. Therefore Fig. 2 shows the value of JIC up to 0.8 of 2ap/w, where the periodic cracks do not interact with each other for the smallest sheet considered (i.e. w = 7.6 nm).

Fig. 2 Variation of JIC of armchair graphene with propagated crack length (2ap) for various initial crack lengths (2a). The solid symbols indicate the average value of JIC (JIC,avg) at various crack lengths. The left most solid symbol is the JIC,avg for 2a = 0.73 nm and other marks are in ascending order of initial crack lengths. The right most symbol is the JIC,avg for 2a = 3.63 nm.

Video 1: Crack induced ripples and fracture of an armchair graphene sheet with a central crack. The colour of atoms indicates the out of plane movement of atoms.

In armchair graphene sheets, crack propagates perpendicular to the applied strain, whereas crack propagation in zigzag sheets occurs at an angle to the straining direction. This occurs due to different bond structure along armchair and zigzag directions as shown in Fig. 1. Videos 1 and 2 show the fracture of armchair and zigzag sheets, respectively.

Fig. 1: Armchair and zigzag directions of graohene

Video 1: Fracture of an armchair graphene sheet. The colour of atoms indicates the out of plane (z) movement of atoms.

Video 2: Fracture of a zigzag graphene sheet. The colour of atoms indicates the out of plane (z) movement of atoms.

In our recent study, published in Int. J. Fract., we found that quantized fracture mechanics theory [1] is more accurate compared to Griffith’s energy balance criterion in predicting the fracture strength of graphene. Figure 2 compares the fracture strength of armchair (2a) and zigzag (2b) graphene given by molecular dynamics, quantized fracture mechanics theory, and Griffith’s criterion.

Fig. 2: Comparison of the ultimate strength of (a) armchair and (b) zigzag sheets given by molecular dynamics, Griffith, and quantized frature mechanics.

Reference
[1] Pugno NM, Ruoff RS (2004) Quantized fracture mechanics. 
Philos Mag 
84:2829-2845

Dear Colleague,

this is to inform you that the research unit MUSAM "Multi-scale Analysis of Materials" (http://musam.imtlucca.it) at the IMT Institute for Advanced Studies Lucca (Italy) has opened 1 Post-doctoral Fellow position (1 year but renewable for a maximum of 3 years in total) on Computational mechanics applied to solar energy materials, related to the ERC Starting Grant CA2PVM
(http://musam.imtlucca.it/CA2PVM.html) and under my supervision.

The link to the call is:
http://www.imtlucca.it/faculty/positions/junior_faculty_recruitment_prog...

The link to the application form is:

http://www.imtlucca.it/faculty/positions/young-research-fellows_position...

The deadline for the online application is March 21, 2014 at 12:00 (Italian time).

Please distribute this message to any candidate you might believe could be interested in the topic.

Thank you very much in advance for your attention and best regards, Marco Paggi

______________________________________
Prof. Dr. Ing. Marco Paggi
Associate Professor of Structural Mechanics Research unit MUSAM - Multi-scale Analysis of Materials, Director

IMT Institute for Advanced Studies Lucca
Piazza San Francesco 19
55100 Lucca, Italy

E-mail: marco.paggi@imtlucca.it
Mobile: +393403403416
Tel: +39 0583 4326 604
Fax: +39 0583 4326 565
http://www.imtlucca.it/marco.paggi
http://musam.imtlucca.it