Hi all,

 I am working on simulation of necking in a uniaxial tension test using sheet specimens of 1 mm sheet thickness. I have given stress strain data upto a plastic strain of 1 , I am using 4 elements in the thickness direction of the sheet.My job is able to complete but with lot of warning messages as follows:

1) The strain increment has exceeded fifty times the strain to cause first yield at 286 points

2) The system matrix has 174 negative eigenvalues.

I am doing analysis in ANSYS which requires the contact pair to be defined. I am unable to select an appropriate value of Pinball region, Penetration Tolerance and normal penalty stiffness. Does any body have an idea how to select the good values for better solution? If you have anykind of material related to contact pair kindly email me at hijazi.19 [at] gmail.com (hijazi[dot]19[at]gmail[dot]com)

 Thanks

Dear Prof.Barber,

     This is the proof of the theorem I mentioned before. This proof is recorded in a book

  (titled as variational principle in elasticity and its applications)  written by Prof.Hai Chang Hu, one of the inventors of the well-known Hu-Washizu generalized variational principle. It is written in Chinese. I translated it into English. Of course, all errors and misunderstandings are due to me. I think this proof is elegant and accessible to most of the students with engineering background.

Hi Every one

Greetings!!!

 I am a new entrant to this site. This site seems to be very good towards technical aspect.

First of all I would like to introduce myself. I am a Ph.D student working in the area of fatigue.

- Is there anyone to support and share the knowledge in the domain of fatigue?

- Can anyone guide towards the websites that provides very good information about fatigue and related literatures.

Thanks and Regards

Gopalakrishnan Mohanam

Dear all,

do you know does any entry stored is STATEV, used in UMAT subroutine,
should remain unchanged for the next increment for the case of finite
deformation?

I know that STRESS and STRAN  will be rotated by ABAQUS but what about the STATEV?

I want to protect STATEV from any rotation by ABAQUS in order to rotate
it in UMAT by my rotation matrix but I am experiencing that it is
different value at the beginning of new increment in comparison the one
as output from previous increment.

Thanks in advance,

Marina.

Location:  Colby-Sawyer College, New London, NH, United States

Sunday, July 26, 2009 - Friday, July 31, 2009

Chair:  Jeffrey T Koberstein (Columbia University)

Vice Chair:  Chung-Yuen Hui (Cornell University)

Web Site:  http://www.grc.org/programs.aspx?year=2009&program=adhesion

Online Application:  http://www.grc.org/application.aspx?id=13784

I have updated sections of my notes on thermodynamics.  A few thoughts on learning are collected here.  Of our world the following facts are known:

Lecturers - University of Michigan-Shanghai Jiao Tong University Joint Institute