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### good summary.

Wed, 2017-11-01 20:02

In reply to Journal Club for November 2017: In-situ Mechanics Experiments on Battery Materials

good summary.

the following was a experimental results of dendrite.

Direct in situ observation and explanation of lithium dendrite of commercial graphite electrodes
Zhansheng Guo,Jianyu Zhu,Jiemin Fengb and Shiyu Du
Lithium-ion batteries (LIBs) have some serious safety problems, such as lithium dendrite formation during charging/discharging cycles that may cause internal short-circuiting, fires, and even explosions. A new double-scale in situ experimental setup, which can record all phenomena during the electrochemical testing, was developed. Lithium dendrite growth behavior of commercial LIBs during small-currentdensity charging at room temperature was observed in situ. The formation, growth, and dissolution of lithium dendrites, and dead lithium residue were all observed and recorded using this new experimental test system. A detailed model of lithium electrodeposition and dissolution processes was proposed. The electrode structures were determined by X-ray diffraction (XRD). The surface morphologies were examined by scanning electron microscopy (SEM). The texture and surface morphology of the graphite active layer affected lithium dendrite initiation as well as its growth processes

### Look up the BAQUS example 2.1

Wed, 2017-11-01 13:37

In reply to Time domain testing of viscoelastic material in Abaqus

Look up the BAQUS example 2.1.1
'Viscoelastic rod subjected to constant axial load'

Subscribe to and seek assistance from the ABAQUS mailing list
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### subroutine for the cohesive zone method

Tue, 2017-10-31 23:10

Dear Prof. Gao,

I am a new learner of CZM. I know that you are willing to share a subroutine about the cohesive zone element. I have searched your webpage, but I couldn't find it. Could you send it to me? My email address is E0256440@u.nus.edu.

### Please contace me if you are

Tue, 2017-10-31 21:08

In reply to Postdoc seeking in field of Mechanical or Materials Science Engineering

Please contace me if you are interested in my background. Thanks very much.

### Congratulations!

Mon, 2017-10-30 17:13

In reply to Jie Yin of Temple U wins EML YIA

Congratulations Jie! Proud of your achievement.

### Congratulations, Jie!

Sun, 2017-10-29 15:50

In reply to Jie Yin of Temple U wins EML YIA

Congratulations, Jie!
Great to hear the wondeful news.

### Как открыть ресторан или пекарню?

Sat, 2017-10-28 18:00

In reply to TAMU- Assistant, Associate, or Full Professor

Как открыть ресторан или кафе? Все ответы Вы можете найти у нас на форуме Ресторанного франчайзинга.
На форуме ресторанного франчайзинга будет:
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### Deviatoric and Skew Tensors

Sat, 2017-10-28 08:52

In reply to What's the difference between deviatoric tensor and skew tensor?

There two different additive decompositions of a tensor: Symmetric & Skew, and Spherical & Deviatoric. The Skew and Deviatoric tensors are both traceless (The first principal invariant is zero in each case). A Skew tensor is antisymmetric and has only zero elements along the diagonal when represented by the components provided by the Cartesian coordinate system. The diagonal components of a deviatoric tensor are not necessarily zero; but in order for the tensor to still be traceless, the sum of these add to zero.

Symmetrical as well as shpherical tensors are also both symmetric in the sense of being indistinguishable from their transposes. In the case of spherical tensors, off diagonal elements (Cartesian Representation) all vanish. In regualr symmetric tensors that are not spherical, off diagonal elements do not necessarily vanish.

### Как открыть ресторан или пекарню?

Thu, 2017-10-26 11:37

In reply to Symposium on Electro-chemo-mechanics of energy materials (USNC/TAM 2018)

Как открыть ресторан или пиццерию? Все ответы Вы можете найти у нас на форуме Ресторанного франчайзинга.
На форуме ресторанного франчайзинга будет:

30 И БОЛЕЕ БРЕНДОВ РЕСТОРАННОГО ФРАНЧАИ?ЗИНГА
6 ДОКЛАДОВ МЕЖДУНАРОДНЫХ СПИКЕРОВ С РЕАЛЬНЫМИ КЕИ?САМИ И ИСТОРИЯМИ УСПЕХА
14 ЧАСОВ ОБРАЗОВАТЕЛЬНОИ? СЕССИИ
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### Как открыть ресторан или хинкальную?

Wed, 2017-10-25 13:14

In reply to Ph.D. Position in Computational Solid Mechanics

Как открыть ресторан или кофейню ? Все ответы Вы можете найти у нас на форуме Ресторанного франчайзинга.
На форуме ресторанного франчайзинга будет:

30 И БОЛЕЕ БРЕНДОВ РЕСТОРАННОГО ФРАНЧАИ?ЗИНГА
6 ДОКЛАДОВ МЕЖДУНАРОДНЫХ СПИКЕРОВ С РЕАЛЬНЫМИ КЕИ?САМИ И ИСТОРИЯМИ УСПЕХА
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Wed, 2017-10-25 05:54

Also to add about the error, are you sure it's not the  xxx elements have missing property definitions ?

### interaction property

Wed, 2017-10-25 05:50

In reply to How to define Drucker-Prager model for soil in Abaqus

Why did you use Eulerian domain for the soil ? won't it prevent you to be able to define a good interaction between the soil and the pipe ? I notieced you have not defined any particular type of contact property between the components

### Как открыть ресторан или кафе?

Tue, 2017-10-24 14:45

In reply to Invitation to submit an abstract to Symposium #341 “Mechanics of Heterogeneous Soft Materials on Flexible Structures” at the 18th U.S. National Congress on Theoretical and Applied Mechanics (USNC/TAM)

Как открыть ресторан или кафе? Все ответы Вы можете найти у нас на форуме Ресторанного франчайзинга.
На форуме ресторанного франчайзинга будет:

30 И БОЛЕЕ БРЕНДОВ РЕСТОРАННОГО ФРАНЧАИ?ЗИНГА
6 ДОКЛАДОВ МЕЖДУНАРОДНЫХ СПИКЕРОВ С РЕАЛЬНЫМИ КЕИ?САМИ И ИСТОРИЯМИ УСПЕХА
14 ЧАСОВ ОБРАЗОВАТЕЛЬНОИ? СЕССИИ
Выставка франшиз
Зал презентации франшиз
Практические доклады: управление, маркетинг, финансы, сервис, персонал и юридические вопросы
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### Keynote speakers are now

Tue, 2017-10-24 00:02

### Abaqus mailing list

Mon, 2017-10-23 06:09

In reply to Piezoelectric Stack Modelling in ABAQUS

Subscribe to and seek assistance from the
ABAQUS mailing list
https://groups.yahoo.com/group/r
or
or from the ResearchGate discussion forum.

Search the archive of the list before posting in it.
The list does not accept attachments.

Good luck

Frank

Sat, 2017-10-21 21:43

In reply to Discussion of fracture paper #17 - What is the second most important quantity at fracture?

Thank Professor Per Ståhle very much for the further discussion on our paper.

The Eq (9) in our paper is the relation between the normalized fracture toughness KJc/Kref and constraint parameter Ap. It is established based on the experimental fracture toughness data of a specific material from specimens with different in-plane and out-of-plane constraints and finite element calculations of the parameter Ap for these specimens. This KJc/Kref -Ap relation is usually called material toughness locus, which is similar to the J1c-Q relation in the early paper by R.H.Dodds et al in this area [R.H.Dodds, C.F.Shih and T.L.Anderson. Continuum and micromechanics treatment of constraint in fracture, International Journal of Fracture, 1993, 64:101-133]. The J1c-Q relation mainly describe the relation between fracture toughness and in-plane constraint, and the KJc/Kref -Ap relation captures both in-plane and out-of-plane constraints. The studies in our previous paper have shown that the KJc/Kref -Ap relation and the constants in Eq.(9) depend on material and fracture mode. In other word, the relation and constants in Eq.(9) is different for brittle and ductile fracture and for different materials. For the engineering application of the parameter Ap, the KJc/Kref -Ap relation needs firstly to be determined by experiments or numerical simulations and the finite element calculations of the parameter Ap.

The mathematical analysis made by Prof. Ståhle’s for the KJc/Kref -Ap relation in Eq (9) in our paper may be helpful for further investigating and understanding the mechanical meaning of the parameter Ap, sorting out the complicated fracture events and effective engineering application of Ap.

Best regards

G.Z.Wang

G.Z.Wang, Ph.D, Professor
School of Mechanical and Power Engineering
East China University of Science and Technology
130 Meilong Road, Mail box 402
Shanghai 200237,China
E-mail: gzwang@ecust.edu.cn

### от хозяина 1 комнатную квартиру В Одесее

Fri, 2017-10-20 16:42

In reply to EMI-2018@MIT – ABSTRACT SUBMISSION IS NOW OPEN (October 15, 2017 – January 31, 2018)

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### Dear Professor Wang, It is

Fri, 2017-10-20 12:05

In reply to Discussion of fracture paper #17 - What is the second most important quantity at fracture?

Dear Professor Wang, It is interesting that Ap is related to the constraint even if it is in an inverse way. I was looking (Googled) for an antonym to constrain. Of the variety of suggestions the closest may have been unleash, release, flow... probably someone already has a word for it.

If we return to your paper and the background of the Ap. I can see in eq (9) that your data indicate proportionality to Ap^0.44. It is rather close to $\sqrt{A_p}$ that is related to a length scale. If one writes $A_p^{0.44}=\sqrt{A_p} A_p^{-s}$ with the s=0.06 and also assume that $|A_p-1|<1$ one can expand around small s and small $(A_p-1)$ and obtain $A_p^{1/2-s}\approx (1+s)A_p^{1/2}-sA_p^{3/2}$ the remaining part is of the order of $s(A_p-1)^3$ and only odd exponents prevail. The series is converging very fast and I wold think that only the two first terms would be enough to replace the Ap^0.44 with good accuracy.

Could it be that there is a main a process that has a length scale $\sqrt{A_p}$ and another process that is a volume related phenomenon scaling with $A_p^{3/2}$? The ratio between the effects the respective phenomena are causing would be s. Could this help to sort out the complicated events that preceeds fracture? What are your thoughts?

I hope this is not misunderstood. I definitely think that the exponential form used in the paper is the most effective engineering approach. Per

### WCFA 2017 - Design and Fatigue of Weldments - Timetable released

Thu, 2017-10-19 15:35

In reply to WCFA workshop on Design and Fatigue of Weldments

We have finally the programme of the meeting, see it here: http://www.pragtic.com/dfw/Program_WCFA_2017.pdf. Note that we start in less than month, if you think about attending do not miss the opportunity to apply!

Best regards

Jan Papuga

Thu, 2017-10-19 04:41

In reply to Discussion of fracture paper #17 - What is the second most important quantity at fracture?

Thank Professor Per Ståhle very much for these valuable discussion, comments and suggestions for our paper entitled "Fracture assessment based on unified constraint parameter for pressurized pipes with circumferential surface cracks" which has been published in Engineering Fracture Mechanics 175 (2017), pp. 201–218.

It is well-known that the conventional fracture mechanics assumes that the single parameter KI or J can describe crack-tip field in laboratory specimens and engineering components at fracture, and the structural component exhibits the same fracture resistance, Kc, or Jc, at the onset of unstable fracture as the laboratory specimen. However, it has been shown that the crack-tip field is affected by specimen or component geometries, crack sizes, load modes etc. This is the crack-tip constraint effect, which leads to that the fracture assessment in low constraint structural components using the conventional fracture mechanics methodologies may be excessively conservative. Thus, in addition to KI or J, it needs a second parameter (constraint parameter) to describe accurately the crack-tip field. The constraint contains in-plane and out-of-plane constraints. The in-plane constraint is directly affected by the length of the un-cracked specimen ligament, while the out-of-plane constraint is affected by the specimen thickness. The widely-used constraint parameters T-stress and Q based on crack-tip stress field only can quantify the in-plane constraint effect. But in actual engineering structures, both in-plane and out-of-plane constraints exist simultaneously. Therefore, it is necessary to develop a new methodology of fracture assessment to incorporate both in-plane and out-of-plane constraints.

It has been shown in our previous work [Fatigue & Fracture of Engineering Materials and Structures,2013,36: 504-514. Fatigue & Fracture of Engineering Materials and Structures,2014, 37:132–145. Engineering Fracture Mechanics, 2014,115: 296-307. International Journal of Fracture, 2014, 190: 87-98. Fatigue & Fracture of Engineering Materials and Structures,2016, 39: 1461–1476. Theoretical and Applied Fracture Mechanics, 2015, 80: 121-132] that the parameter Ap based on crack-tip equivalent plastic strain can characterizeboth in-plane and out-of-plane constraints, and also it can be used for both brittle fracture under small-scale-yield (SSY) condition and ductile fracture under large-scale-yield (LSY) condition for steels and welded joints. In other words, the effects of geometry and load on different classes fracture in specimens and components of different materials may be captured or covered by the parameter Ap. In this paper, the capability of fracture assessment based on the unified constraint parameter Ap has been investigated for pressurized pipes with circumferential surface cracks. As suggested by Prof. Ståhle, the story does not end here. We will do more further work for the extensive application and verification of the parameter Ap. It may include the engineering methodology of the use of the parameter, the applicability of the parameter for more specimens and components with different in-plane and out-of-plane constraint levels, different materials and welded joints, and different fracture modes (such as brittle fracture, ductile fracture initiation, ductile crack growth, fatigue and SCC crack growth, etc.).

For the questions in Prof. Ståhle’s discussion, our response or comments are as follows.

(1)   The second most important quantity is related to both in-plane and out-of-plane constraint. Its name may be unified constraint parameter. Based on the further studies of its physical and mechanics meanings, a more suitable name may be given.

(2)   The statistical size effects and loss of constraint could affect the brittle cleavage fracture toughness of steels. The experimental investigation that separates the statistical effect from the loss of constraint on cleavage fracture toughness has been done by Rathbun et al. [Rathbun HJ, Odette GR, Yamamoto T, Lucas GE. Influence of statistical and constraint loss size effects on cleavage fracture toughness in the transition—A single variable experiment and database. Engng Fract Mech 2006;73:134-58]. The statistical size effect also has been considered in the Master Curve approach in ASTM E1921. The fracture toughness in our paper is based on the experimental fracture toughness data, and the calculation of the parameter Ap is related to fracture J-integral of the experiment data. Because the combined effects of constraint loss and statistical size have been reflected in the experimental fracture toughness data, the correlation of the fracture toughness with the parameter Ap may relate to both constraint loss and statistical size effects.

Best regards

G.Z.Wang

G.Z.Wang, Ph.D, Professor
School of Mechanical and Power Engineering
East China University of Science and Technology
130 Meilong Road, Mail box 402
Shanghai 200237,China
E-mail: gzwang@ecust.edu.cn