Proving Double Inner Product of Derivative of 2nd Order Tensor w/ Another

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Discussion Overview

The discussion revolves around proving a mathematical expression involving the double inner product of the material time derivative of second-order tensors A and B. The context is rooted in continuum mechanics, specifically addressing a homework problem related to tensor calculus.

Discussion Character

  • Homework-related, Technical explanation

Main Points Raised

  • Some participants seek assistance in proving the expression \dot{A}:B + A:\dot{B}=A^{\nabla J}:B+A:B^{\nabla J}.
  • Others inquire about the notation used, specifically questioning the meaning of the dot, J, and the term "inner product" in relation to the tensors involved.
  • One participant clarifies that the dot represents the material time derivative and suggests that \nabla J may refer to divergence, although they express uncertainty about this interpretation.
  • Participants express a lack of understanding regarding how to approach or prove the given expression.

Areas of Agreement / Disagreement

There is no consensus on the meaning of certain notations or the approach to proving the expression. Multiple viewpoints regarding the interpretation of terms and the proof itself remain unresolved.

Contextual Notes

Participants have not provided definitions for the notation used, and there are uncertainties regarding the assumptions behind the mathematical expression. The discussion is limited by the lack of clarity on the terms involved.

josh_machine
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Some one please help me how to prove the following:

[tex]\dot{A}:B + A:\dot{B}=A^{\nabla J}:B+A:B^{\nabla J}[/tex]

A and B are II order tensors and : represents the inner product.
 
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How do I prove the following:

[tex]\dot{A}:B + A:\dot{B}=A^{\nabla J}:B+A:B^{\nabla J}[/tex]
 


Where did you get this notation from? What is your dot? What is your J? What do you mean by "inner product", for what kind of tensors? Any reference to some place where your original notation is defined?
 


The dot represents material time derivative. A and B are second order tensors, eg Stress.
I myself am not clear what [tex]\nabla J[/tex] means here. However, I guess it represents divergence.

This was as a homework question for a Continuum Mechanics course. I have not got any luck trying to understand or prove this expression. Any insight will be greatly appreciated.
 

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