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Updated: 16 hours 47 min ago

Deadline is approaching soon.

Wed, 2019-07-17 18:11

In reply to Call for Abstracts: Topic on Mechanics Modeling of Soft Robots in ASME IMECE 2019

The deadline will be next Monday, 7/22, 2019. You are welcoem to submit your abstract by the date. Look forward to seeing you this November in Salt Lake City! 

The deadline will be next

Wed, 2019-07-17 18:08

In reply to Call for Abstracts: Topic on Mechanics and Manufacturing of Soft Materials and Soft Robots in ASME IMECE 2019

The deadline will be next Monday, 7/22, 2019. You are welcoem to submit your abstract by the date. Look forward to seeing you this November in Salt Lake City! 

Position has been filled

Tue, 2019-07-16 10:16

In reply to Seeking Postdoctoral scholar for a join NIST-JHU project on dynamic response of soft materials

Thank you to all those who applied. The position has been filled.

Misprint

Mon, 2019-07-15 14:33

In reply to A comment on "A dimensionless measure for adhesion and effects of the range of adhesion in contacts of nominally flat surfaces" by M. H. Muser

there is obviously a small misprint in my equation reporting mMuser's delta_gamma_rss, missing the range of attraction. The conclusion is unchanged of course. Thanks for the friend who has noticed that and told me. 

Abstract deadline extended

Fri, 2019-07-12 02:41

In reply to TMS 2020: Fracture Modeling of Composite Materials

The deadline to submit abstracts has been extended to July 15th, 2019.

Abstract deadline extended

Fri, 2019-07-12 02:41

In reply to TMS 2020: Mechanical response of materials investigated through novel in-situ experiments and modeling

The deadline to submit abstracts has been extended to July 15th, 2019.

Very nice Professor. It's

Tue, 2019-07-09 13:06

In reply to PhD RA Position in Mechanical Engineering at Temple University for Fall 2019 or Spring 2020

Very nice Professor. It's enjoyable to work with Dr. Ling Liu.

One of the troubles with the

Tue, 2019-07-09 11:55

In reply to Very nice work

One of the troubles with the fiber-fragmentation test is that not everyone who uses it may realize that one can get mutliple cracks in fibers, films and laminates even when there is no sliding at the interface.

Yes, if the problem is such that the inteface slides, then the test can give a shear strength.  However, fracture mechanics with only toughness, and no strength parameter, can also give fragmentation lengths.

One needs to be much more careful than I have sometimes seen to determine whether it is toughness or strength controlling the fragmentation.

This is of course, not to say that the fragmentation test isn't useful; it is to say that I have seen it used without being convinced that authors have fully appreciated possible ambiguities.

Congratulations KT

Wed, 2019-07-03 22:57

In reply to 2019 Warner T. Koiter Medal – Professor K. T. Ramesh

Many congratulations KT for this well-earned recognition! 

Congratulations!

Wed, 2019-07-03 22:56

In reply to 2019 Daniel C. Drucker Medal - Professor John Bassani

Many Congratulations John!

Congratulations JN!

Wed, 2019-07-03 22:55

In reply to 2019 Stephen P. Timoshenko Medal - Professor J. N. Reddy

Many Congratulations JN! Your enthusiasm and dedication to the profession are infectious.

Looking forward to the ceremony! 

 

 

congratulations KT!

Wed, 2019-07-03 14:46

In reply to 2019 Warner T. Koiter Medal – Professor K. T. Ramesh

Look forward to meeting you in November.

 

Roy

Huge congratulations for the well-deserved honor!

Wed, 2019-07-03 10:08

In reply to 2019 Warner T. Koiter Medal – Professor K. T. Ramesh

Dear KT, 

Huge congratulations for the well-deserved honor! I look forward the award ceremony in November.

This position is now closed. 

Tue, 2019-07-02 19:04

In reply to Postdoctoral Fellowship in Computational Mechanics At Duke University

This position is now closed.  

PhD scholarship available (Automotive Safety/Biomechanics)

Tue, 2019-07-02 01:05

In reply to Postdoctoral and graduate student positions available

Applications are invited for multiple postgraduate (PhD or Masters by Research) positions to work with Dr. KM Tse in Mechanical and Product Design Engineering at the Swinburne University of Technology, Melbourne, Australia.  

The project focuses on automotive occupant and pedestrian safety. A variety of experiences and interests are welcome; we will consider proposed research in both numerical and experiment in all areas under the very general heading of classical mechanics / biomechanics. Topics of interest include but are not limited to continuum mechanics, biomechanics, product design engineering, impact engineering. Experience in product design, sensor and actuator in protective equipment, CAE and experimental impact tests and/or another manufacturing areas will be viewed favorably.

The project uniquely combines engineering design with materials, modelling and manufacturing skills, which will qualify the candidate for an excellent career in automotive R&D industry, and/or academia.

TWO full Postgraduate Scholarships are available, under Swinburne-Automotive Engineering Graduate Program (AEGP) funded by Australia’s Department of Industry Innovation and Science.

The deadline for the EOI is 31st Aug 2019. 

Interested parties should send a CV to ktse@swin.edu.au and indicate their research interests and anticipated time frame. Review of applications will be ongoing.

For students of dislocations and plasticity

Tue, 2019-06-25 12:27

In reply to On the Structure of Linear Dislocation Field Theory

I have uploaded, on imechanica, the final version of this paper and the publication information.

The imechanica version is marked up in blue in four places. I recommend this paper to students who want to learn about the big picture connections (with details) between plasticity theory and the theory of dislocations, including inertia, without getiing mired in intricate computations that might give the impression that the mathematical theory of dislocations has to do only with Green's function gymnastics (nothing wrong with the latter).

A theory is not a method, and a method is not a theory.

Very nice work

Mon, 2019-06-17 23:12

In reply to Journal Club for July 2019: Cohesive strength, interfacial toughness, and their roles in the adhesion of ice

Dear Dr. Thouless, 

Really nice work. Congratulations! I am fully convienced and very happy to know that understanding fracture mechanics is really important for deicing. 

With the similar mechanics background is fiber fragmentation test in single-fiber composite for measuring interfacial strength. It is an another elegant experiment in my mind. 

Best, 

shengqiang

 

 

comment

Mon, 2019-06-17 23:11

In reply to problem about the Jacobian matrix (DDSDDE) in UMAT

After two years, I would like to add a comment about my new understanding of this question. 

∂σ/∂ε is the tangent stiffness, which is not consistent with the time integration algorithm. That means it cannot achieve the quadratic convergence in the Newton-Raphson iteration.

∂Δσ/∂Δε is the consistent tangent stiffness, which consistent with the time integration algorithm where the finite time increment is used.

Details can be referred to Simo and Taylor (1985)

In constituitive models without time intergation, eg. (nonlinear) elasticity, these two are essentially the same. In contrast, for plasticity, viscoelasticity, viscoplasticity, etc, which with time integration, the two tangent stiffness are different, and the consistent tangent stiffness should be used.

 

Simo JC, Taylor RL. Consistent tangent operator for rate-independent elastoplasticity. Comput Methods Appl Mech Eng. 1985;48:101–18.  

Thanks

Mon, 2019-06-17 22:53

In reply to Dear YTH

Thans afallah!

Yes, I agree. And we have

Wed, 2019-06-12 11:53

In reply to it could be both

Yes, I agree. And we have explored both the L_sgp/a and L_sgp/Rp non-dimensional groups in our recent JMPS paper (https://www.sciencedirect.com/science/article/pii/S0022509618307890). Where L_sgp is the gradient length scale, a is the crack length and Rp is the plastic zone size. And I wish we didn't need L_sgp in our models but you need a length scale parameter if you want to capture a size effect. Nevertheless, I share your Occam's razor philosophy as well.

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