For a crack in an elastic body subject to a load, the elastic energy stored in the body is a function of two independent variables: the displacement of the load, and the area of the crack. The energy release rate is defined by the partial derivative of the elastic energy of the body with respect to the area of the crack.

This definition of the energy release rate assumes that the body is elastic, but invokes no field theory. Indeed, the energy release rate can be determined experimentally by measuring the load-displacement curves of identically loaded bodies with different areas of the cracks. No field need be measured.

We are seeking outstanding candidates for a Postdoctoral Research Associate Position at the Institute of High Performance Computing, Singapore. The position requires a Ph.D degree in physics, chemistry, materials science, chemical engineering, mechanical engineering or equivalent experience.

Additional requirements include:

. Knowledge in mechanics of materials

. Experience in molecular dynamics simulation . Proficiency in programming using Fortran and/or C/C++ . A record of technical publications is a plus . Must have strong oral and written communication skills in English.

This is a preprint that is going to appear on Applied Physics Letters. It is somewhat related to a paper by Kaushik Dayal on complex crystalline structure via phase field simulation that was posted here. 

Austenite-Martensite Interface in Shape Memory Alloys

C. H. Lei, L. J. Li, Y. C. Shu, and J. Y. Li

Abstract

Dear All

I am modeling a workpiece supported in fixtures and being machined. I use the FEM ( Ansys) to simulate this set up. I need to know at the stiffness of wp at the wp-fixture contact point  . Stiffness is found by applying unit force at one contact point while fixing all others.. Inverse of displaceemnt gives the stiffness in that direction. I have two questions reg this.

1. I can use the element death technique to model the material removed for each cut. Let the original material be of 100 mm height and 20 mm is removed in 4 strokes ( 5 mm in each stroke of the cutter). Let the stiffness be 'k' units after this removal. Now if a take a virgin wp of height 100-20= 80 mm, will the stiffness be the same 'k' or different?

The Department of Civil Engineering of the University of Minnesota (USA) and the Solid Mechanics Laboratory of the Ecole Polytechnique (France) have established a joint PhD program in Civil Engineering.

Please, see the document attached for a detailed description of the program, host institutions and participating faculties.

For queries about applying to the program or any other questions, please contact Bojan Guzina (guzina@wave.ce.umn.edu) and Marc Bonnet (bonnet@lms.polytechnique.fr).

Hi everyone,

In order to simulate nonlocal damage in trabecular bone structures in
ABAQUS, I need to implement the constitutive laws into the user element
subroutine (UEL), since it is not possible to implement nonlocal FE in
UMAT, as far as I know!

I would be very much grateful if someone, who has experience in this
regard, esp how to implement 3D elements, e.g. C3D8, into a UEL code,
shares some knowledge.

Best,

Hadi

Subra Suresh, the Dean of Engineering, of the Massachusetts Institute of Technology, is in line to become the next Director of the National Science Foundation (NSF), according to this post at Science.

The NSF director must be confirmed by the Senate, although it would be unusual for a nominee to attract any opposition.

Subra is a well known researcher in the field of mechanical behavior of materials.  His books on fatigue and thin films are widely read.  In recent years, his research has been focused on molecular and cellular biomechanics. He is iMechanica user 190. 

I am looking for the value of Bulk viscosity and shear viscosity of PMMA at room temperature . If anybody has any idea i request for a help to supply the value to me

Thanking you

Best regards..

muna 

The University of Michigan and Shanghai Jiao Tong University have established a Joint Institute in Shanghai committed to building a world-class academic institution with educational and research missions. The UM-SJTU Joint Institute invites applications for lecturers to support its mechanical and electrical/computer engineering programs. With its unique academic mission in China, the JI offers an extraordinary academic environment. The JI is modeled on world-class US universities. The students are among China’s best.

Mechanical and Materials Engineering: Dynamics, Solid Mechanics, Fluids, Heat Transfer, Thermodynamics, Principles of Materials, etc. (All undergraduate courses in typical USA curriculum)

The University of Michigan and Shanghai Jiao Tong University have established a Joint Institute in Shanghai with a commitment to build a world-class academic research and educational institution. The UM-SJTU Joint Institute invites applications for tenure-track (Assistant, Associate, and Full Professor) positions in all emerging fields of mechanical engineering and related disciplines. These positions are open to top caliber applicants from around the world. With its unique academic mission in China and connection to SJTU’s established research, the JI offers faculty extraordinary opportunities to develop major research programs.

For both mechanicians and physicists, linking continuum concepts to the underlying microscopic characteristics of materials has remained a major preoccupation. Certainly, with the recent advent of the so-called "multiscale" modeling approaches, this topic has been brought to a sharp focus. Cauchy stress is one such continuum concept that has courted a fair amount of controversy.

Hello everyone,

As reported in some references, Maxwell stress of a dielectric  elastomer subjected to electric field can be determined by the following formula

P=e*E^2    (1) -------e=e0*e1, e0 is the dielectric permittivity of vacuum, e1 is the relative dielectric permittivity of the elastomer, and E is the applied electric field.

However I found another expression from  “Electrodynamics of Continuous Media”. (Landau and E.M. Lifshitz.,Course of Theoretical Physics. Vol. 8. 2nd Edition. Butterworth-Heinemann. Oxford. 1984. L.D. ), which is  described as follow,

(sigma)ik=(e/4/pi)(EiEk-1/2E^2 deltaik)     -(2)   pi=3.14

Fracture mechanics without invoking any field theory. In Lecture 1 on Fracture of Rubber, we considered the extension of a crack in an elastic body subject to a load. Following Rivlin and Thomas (1953), we regarded the elastic energy stored in the body as a function of two independent variables: the displacement of the load, and the area of the crack. The partial derivative of the elastic energy with respect to the area of the crack defined the energy release rate.

Hello,

I seek help from the forum regarding the following. Because I am very new to mechanics.

I have a continuum damage mechanics model with me. I have set up a problem of a typical three point bending test on a notched beam. The notch in the center of the specimen and extends from the bottom face up to the middle of the thickness. It is a plane stress problem. Now I want to simulate load-displacement curve obtained from the experiment (s).

A number of 3 year research schoolarships and PhD positions in the areas of mechanical engineering, process engineering and applied mathematics is available in the Post-Graduate School "Micro-Macro-Interactions in Structured Media and Particle Systems", Otto-von-Guericke-University Magdeburg, Germany.

Further information can be found at  http://www.uni-magdeburg.de/gkmm/free-position-new-gk.htm

Hi,

I'm doing some investigation on a marine current turbine, for a project using the Lifting Line Theory. 

I found out some problems regarding some assumptions one has to make when projecting a turbine, such as cavitation number, tip speed ratio, Reynolds number, etc...

Any information of any bibliography you might have might became handy, so I appreciate if you share it.

Thank You!

Joao

Hi every body,I'm a senior student in mechanics and really I need an
example of wave propagation in a thin plate to conduct my project. At
now,main problem for me is how to apply load to get answers with
obvious wave propagtion contour plot without any thing more in just one
refelection.

Thanks in advance,

Hadishah

I am trying to run UHYPER in ABAQUS 6.9EF1. I have the following questions:

1) How can I get the nodes
ID associated with element# NOEL in UHYPER subroutine?

2) How can I get the
coordinates of the displaced nodes associated with element# NOEL in UHYPER
subroutine in the middle of the simulation? I tried to use GETVRN but it seems it does not work in
UHYPER.

3) How can I get the deformation gradient tensor using
GETVRM for element# NOEL in UHYPER? I have also tried using USDFLD and
GETVRM but it returns zero for everything.

The Fluid Dynamics and Solid Mechanics group at Los Alamos National Laboratory is currently seeking candidates for two post-doctoral positions in the areas of theoretical and computational solid mechanics.

Further information and application instructions can be found at http://www.hr.lanl.gov/JobListing/SingleJobAd.aspx?JobNumber=218796

The AMD executive committee (EC) just announced the student travel awards and best paper contest for IMECE 2010. Between 10 and 15 students will be selected for travel grants of $750 each. The students who receive travel awards will also become eligible to participate in the best paper contest. This is a great opportunity for young students to present their work and meet other researchers during IMECE 2010.

A rubber band can be stretched several times its original length. This large deformation may hide its brittleness: the strain to rupture can be markedly reduced by the presence of a crack. This lecture describes fracture mechanic of highly deformable materials, such as rubbers and gels.

Demonstrate in class the effect of a crack on a rubber band. Use a wide rubber band. Show the class that the rubber band can be stretched several times its original length. Then use scissors to cut a crack into the rubber band. Pull the rubber band to rupture. Note that the strain to rupture is markedly reduced by the crack. Pass the scissors and some rubber bands around. Invite every student to try.