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lobo12121-Visitor
1-Visitor
November 22, 2012
Question

Matrix units

  • November 22, 2012
  • 2 replies
  • 4067 views

Hi,

I am currently working in a composite materials project and I am trying to obtaing my ABD matrix for a lamina composed of 49 plies. I already obtain my A, B and D matrix individual, which each matrix has different units. A has ksi*in, B has ksi*in^2 and D has ksi*in^3. Each matrix is a 3x3. What I want to do now is to create a 6x6 matrix which consists of ABD together as shown. But I am getting and error when putting everything together which says "the form of this values must match." I also defined each expression for each matrix, but I dont know if this contributes to the error.

How can I make this matrix unitless so it can be evaluated.

Any suggestions will be appreciated. Thanks.

2 replies

V
24-Ruby IV
ValeryOchkov24-Ruby IV
24-Ruby IV
November 22, 2012

Only in Mathcad Prime we can have matrix with different physical quantity - mass and time for example.

See please the item 2 in this poll http://communities.ptc.com/polls/1141

W
Werner_E25-Diamond I
25-Diamond I
November 22, 2012

Unfortunately in Mathcad 15 all elements in a matrix have to be of the same unit.

You will have to strip off your units, create your ABD, make the evaluations you need and add the appropriate units manually.

BTW, you could create your matrix ABD using ABT:=augment(stack(A,B),stack(B,D)).

You can get rid of the units by divison by UnitsOf([variable]), so

22.11.png

will do the job.

WE

V
24-Ruby IV
ValeryOchkov24-Ruby IV
24-Ruby IV
November 22, 2012

Werner Exinger wrote:

Unfortunately in Mathcad 15 all elements in a matrix have to be of the same unit.

WE

Sorry not same units but same dimensions (physical quantity).

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