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Seeking a logarithmic operator for a 4th order tensor

Submitted by wvmars on
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continuum mechanics
tensors

I don't know whether this question has an answer, but I'd like to see what you all think:

Does anyone know whether or not the following operation is meaningful, whether it is described and defined algorithmically somewhere, and / or how to do it?

ln(Aij) = Bkm ln(Cijkm)

A and B are second order tensors

C is a 4th order tensor

The left hand side involves the natural logarithm of the 2nd order tensor A, which is no problem. 

Ansys composite modelling and analysis

Submitted by Hallgeirda on
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Hi Have for a period been searching for tutorials of how to build a composite (and doing an analysis, eigenvalue, Euler-buckling, first ply) model in Ansys.Have been able to find a couple of examples in the Ansys-portal examples search, have after reviewing the different options decided that shell91 will be a appropriate element type for me. (because of nonlinear capabilities)Referring to "152191 - Example of new Failure criteria (FC) method for shell91 vs. old method", shows the basics of how to build a composite specimen of 5 layers, and using new and old FC (Tsai-Wu).

3D buckling eigenvalues

Submitted by Jia-Jie Guo on
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I am using Abaqus to  calculate the critical loading for a 3D buckling beam with both ends pinned. However, the resutls are extreamly large and do not make sense. I try to calculate the 2D case and it matches with theoretical solutions very well. So I doubt that the eigenvalues in a 3D case has some meaning other than the critical loading. 

For a 2D beam buckling problem, the eigenvalues are the critical loading. What do the eigenvalues for a 3D buckling beam mean? Thank you!

Ansys Shell 91

Submitted by Hallgeirda on
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Hi

I am going to do a nonlinear analysis of a couple of composite plates, in order to investigate what happens after first ply failure of a specimen.

Doing this using Ansys shell91, but no tutorials on how to build a(composite) model is available, nor choise of failure criteria.. (Tsai-Wu, etc....)

In short I do not know a lot of how to do this, but NEED to find out, hints tips anyone??

Student

 

Stresses in Elastic Materials in Non-uniform Cooling

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Thermal stresses

Hi,

 

I am having confusions about the concepts of thermal stresses of an un-constrained elastic body when heated/cooled.

Let's say if I have an elastic body of an arbitrary geometry. If I subject it to a uniform temperature change without any constraints, then there will no thermal stresses at the end of the analysis. I guess I am right till here.

How can I model a bridge which consits of a small beam of composite that surrounded with ceramic layer

Submitted by Morteza_Kiani on
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Hi dear

I am going to model a bridge in dental work which it consists of two parts:

1: a small beam which it is made of composite 5 plys

2: a cramic part which surround the beam.

I want to model it with Abaqus. Please help me if you can. I'd appreciate if you help me and send its steps to my email: kian32m [at] yahoo.com (kian32m[at]yahoo[dot]com)

 

Spur gear geometry

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Hi,

 

I am a PhD student at Brunel University conducting my research on the noise and vibration attributed to spur gears in contact. I would like to ask for help from anyone who is an expert on gears for their opinion or direction in terms of reading material or thoughts on the limitations and design constraints of spur gear geometry. 

 

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