iMechanica

I have a question about deformation gradient in VUMAT.

When I use one element, Vumat works well and there is no any problem. Initially, only the diagonal part of deformation gradient is one, the others are zero. However, the problem is when several elements are considered, all the components of deformaiton gradient are equal to one at very beginning.

Hello everyone,

Here is the problem I have: I'm modeling the geometry of a simple straight edge crack in a 2D elastic medium using Abaqus. I assume plain stress conditions. The crack makes an angle with the horizontal, is small enough to be considered as embedded in an infinite domain (ratio crack length/size of domain < 1/10) and I apply a vertical compressive load on top of my domain. I fixed one point in displacement at the bottom of it and the whole bottom edge is constrained not to move vertically.

hi, i want yield stress and plastic strain data for aluminium and epoxy resin.actually i m doing project on composites.....

Hi, Matlab experts !

Did someone work with Prof. Houck's paper (A genetic algorithm for function optimization: A Matlab implementation, 1995) on the genetic algorithm ?.

In his paper he proposes 3 online tutorials (gademo1.m; gademo2.m; gademo3.m) for working with the function "ga" in Matlab but it's all for Matlab 5. This function syntax has changed considerabily in Matlab 7. The key point is that we cannot define "bounds" which is a matrix of upper and lower bounds on the variables with Matlab 7.

So how Matlab 7 deals with this problem ?

The Computational Physics group in the Atmospheric, Earth, and Energy Division at the Lawrence Livermore National Laboratory (LLNL) is solicitating applications for three postdoctoral appointments in the following areas. To access the full description and application instructions, please visit http://jobs.llnl.gov and search for the job numbers below:

008351: geomechanics of fluid-induced fault activation

008374: dynamic impacts into granular materials

008375: mechanics of dynamic impact and penetration into ceramics

*This issue of the Journal Club has been prepared as a group by Ankush Aggarwal, Mo Bai, Mainak Sarkar, and Jee E Rim, and with comments and suggestions from Bill Klug .

Check out the talk by Dr. Arden L. Bement, Jr., Director , National Science Foundation 
on TAM 

at  http://www.nsf.gov/news/speeches/bement/09/alb090424_tamsymp.jsp?govDel=USNSF_51

For the proceedings of the 2008 SBE&S workshop go to

I guess it is about time some one from the Cornell Fracture Group got on this site to try help answer questions related to the CFG software or other fracture mechanics related questions.  We do try to answer questions sent to us via email, but sometimes a forum like this would be best and we do appreciate other users input, feedback, and answers.

Congratulations to Tom Hughes for the election to the US National Academy of Sciences.  See the full list of the new members.

Obama spoke at the National Academy of Sciences on Apr. 27, 2009, in which he states his commitment to doubling of science funding and stem education. From his speech,

 "At such a difficult moment, there are those who say we cannot afford to invest in science, that support for research is somehow a luxury at moments defined by necessities.  I fundamentally disagree.  Science is more essential for our prosperity, our security, our health, our environment and our quality of life than it has ever been before."

hi...i am doing drilling simulation on abaqus.... 

it consist of two parts...a tool and a blank.... 

now when i am running analysis...tool touches the blank and goes back. 

i checked material data...density,elasticity...and i used surface to surface interaction with penalty as interaction property.... 

can any one tell me ...how to perform this.... 

Hi all

   I am a new ABAQUS VUMAT user. Recently, I try to substitute the explicit intergation method in VUMAT by back EULER intergation method. But the calculated equivalent stress is nonuniform for simple compression test. Would anyone pls help me find the reasons? Many thanks. Attached pls find the VUMAT subroutine and INP file.

 J.G. Liu

Ph.D

HK Polyu

Hello Everyone,

 My research is in petroleum geomechanics and I am Using Abaqus for my simulations of cracks and induced fractures in rocks around the wellbore I do have some problms and I will be happy if anybody can assist me:

1- I am interested in looking at Hoop stress at evry point around the wellbore ,but in Abaqus I can only see that in degrees of 0,90,180,270 of circular wellbore by using S1 and S2 ,naybody has a code or experience with that?

2-What is a correct method if we are interested in propping our fractures?

Thanks

Hi everybody, I'm so interested in analysis of wave propagation in solid medias. and I've started by studying some books like "Ultrasonic wave propagation in solid media"(Rose). My question is about the importance of this analysis  (propagation of high frequency elastic waves) in the structures. I know that the major application is in the field of Nondestructive Testing(NDT). but I don't know if it is usefull in vibrational analysis of mechanical structures (elastic waves with frequencies around KHz or MHz). is this study important in "dynamic response analysis" of mechanical structures in some special kind of loading like impact? I'd be gratefull if you could introduce me some examples.

I have a mechanical problem it is a part of my studies, this problem relates to mechanics of material (geometrical non-linear problems by using Newton Rahpson method (If I was right) I am struggling to solve it. The thing is because of my poor knowledge I could not find the right reference. All I want is a volunteer someone I will send him the problem then he advice me where should I go to find similar examples or at least the right sources

Hi, I am Ms Zartasha Mustansar from the University of Manchester. I am currently working towards my PhD, funded by Microsoft and the Dorothy Hodgkins Postgraduate Award scheme. I am working in the Palaeontology Research Group, headed by Dr Phil Manning, who together with my supervisor Dr Lee Margetts, are leading the development of a new discipline "Computer Aided Palaeontology".

Conference link  May 8th, 2009 -- Abstract Submission
2nd IC4N – 2009 Symposia/Special Sessions on Fundamentals of Nano-materials: experiment, theory and simulation Organizers: Traian Dumitrica (U. Minnesota, USA), Boris Yakobson (Rice U., USA)
 

There are several  fully funded graduate student openings starting Spring 2011, in the
Department of Mechanical and Aerospace Engineering at the Utah State
University (http://www.mae.usu.edu).
The openings are in the broad area of Computational Solid Mechanics. In
particular, applicants having demonstrated interest (in terms of
completed projects, authorship in journal articles or coursework) in
Fracture Mechanics are especially invited. Applicants are requested to

I suppose it is acceptable to announce the work I have online to assist students in learning mechanics and thermo.  The site is http://www.askdrthermo.com/.  Please take a look if you are interested.

Hello Guys,

 i am working on elastomers,i want to analysis the rubber hose with kevlar reinforcement,i dont know how to model the fiber in rubber model,and which element i should use,is anyone help me out.

 thanks

naim khan