Ask iMechanica

Recently, we do some work about the dynamic strain aging. In order to investigate the function of solute clouds and precipitates in DSA, we do some experiments. The solution treated LY12 alloys are tested on MTS at low temperature (173K), and the Portevin-Le Chatelier phenomenon disappeared as we expected. But, we need more information about the change of microstructure under the low temperature, what is more the micro-optical observation should be finished in a very short time when we consider the effect of natural aging. Obviously the TEM can not meet our needs.

Dear All,



     In ABAQUS manual, it is said for hyperelastic material, it is better to define it by stretch tensor U. But if I need to use deformation gradient F in the material model directly, I need to rotate the stress back to corotational frame. How should I do that?  Should I make a polar decomposition of F=R*U first, and then apply Rt*S*R? or I can use the relative spin increment already provided to do that? If so, how?

Every engineers,

I am Homo and go to learn ABAQUS, but I have many questions, i.e.:

What is difference between Section points and Integration point in ABAQUS(espesialy in beam elements )?

Waiting for your kindly response

Homo

I'm asking the group about the current and future challenges in topology optimization either from the theoretical point of view as well as the industrial or practical point of view. I think Homogenization is the current de-facto method for practical optimization and I can detect some tendencies like level set methods, mesh less methods, etc at the research level.

What do you think about which is the "predominant" current wave and which will be next wave in topology optimization in the above two fields (theoretical and practical).