Skip to main content

research

2nd spatial derivatives from isoparameteric elements

Submitted by Wenbin Yu on
Forums
Computational Mechanics Forum
Choose a channel featured in the header of iMechanica
research
Free Tags
FEM

Based on my limited knowledge of FEM, I find it is difficult to use isoparametric elements for any problem whose governing
functional involve the second (or higher) partial derivatives of the unknown
functions. I hope some computational mechanicians can help me on this. Currently, I have a formulation derived from micropolar elasticity which has a functional involving second partial derivatives of the displacements. Thanks a lot for any of your suggestions.

Material model for high cycle fatigue

Submitted by Chali Alindunesiy on
research
finite element analysis
Fatigue
numerical simulation

In fatigue analysis, it is common to use S-N curve from database for spesific material, and some time for spesific way of loading. Is there any way to predict fatigue from direct simulation? For example, giving cyclic loading (10^5 times) and the material will suffer damage and eventually failed. In some FEM codes (MARC, LSDYNA, etc) there is Lemaitre-Chaboche model used to analyze material behavior under low cycle cyclic loading.

 Thanks in advance

Chali

ABAQUS unit conversion for nanometer length.

Submitted by wanbot on
research

Hi all,

I ran a pre-buckling analysis using ABAQUS.  I chose nanometer as my length unit. So for the Young's modulus, since my sample has 100 GPa for the Young's modulus, I put 0.0000001 as the value for the Young's modulus under the material property in the ABAQUS.

However, the resulted eigenvalue (~2 nN) was not as what I expected (~2uN). Based on the calculation based on the Euler buckling theory, the critical load should be around 2 uN. 

lamb wave simulation

Submitted by mharoon on
Forums
Ask iMechanica
Choose a channel featured in the header of iMechanica
research
Free Tags
wave propagation
ansys
lamb waves

Hi,

 

     I am trying to simulate lamb wave propagation in steel plates using Ansys. I am completely new to this and would really appreciate any guidance with regards to examples or tutorials, speicifically for this problem. I know and am using the general tutorials out there. Thanks in advance for your help.

 

Haroon

schmid factor in the single plasticity code of Huang

Submitted by Wang Guofeng on
research

 Hello

In the code of Prof.Huang, the schmid factor was defined.

For slip deformation tensors

slpdef4=s1m2+s2m1 

slpdef5=s1m3+s3m1

slpdef6=s2m3+s3m2 

For slip spin tensors

slpspn4=(s1m2+s2m1)/2

slpspn5=(s1m3+s3m1)/2

slpspn6=(s2m3+s3m2)/2

 I can't understand the difference of 1/2. Please give me some explanations.

thanks 

 

wang 

Subscribe to research