Iteration loop
 

Not even sure I'm in the right place for this question, and from the looks of this forum, most of you are out of my league, so hopefully this will be an easy question for you. I have a variable, "k", that is directly dependant upon another variable "P". The way I have been calculating "k" is by assuming a "P" to start with. Once I have "k", a series of other variables are calculated, ultimately arriving at a calculated "P". I then go and input the calculated "P" to arrive at another "k" and calculated "P" and so on and so forth, iterating manually. I want to set up the equations so the "k" assumes a "P", then uses the calculated "P" in a loop that eventually converges. I'm looking to get the actual "P" and "k" out of the iteration. Any help would be greatly appreciated

Iteration loop
 

It sounds like a problem for which the solver addin will work wonderfull.

If not. can you be a SPECIFIC in your question?
This NG is very good at answering specific questions... but you'll have to
DESCRIBE the problem before we can solve it.



keepITcool

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"?B?QnJhZA==?=" wrote:

Not even sure I'm in the right place for this question, and from the
looks of this forum, most of you are out of my league, so hopefully
this will be an easy question for you. I have a variable, "k", that
is directly dependant upon another variable "P". The way I have been
calculating "k" is by assuming a "P" to start with. Once I have "k",
a series of other variables are calculated, ultimately arriving at a
calculated "P". I then go and input the calculated "P" to arrive at
another "k" and calculated "P" and so on and so forth, iterating
manually. I want to set up the equations so the "k" assumes a "P",
then uses the calculated "P" in a loop that eventually converges. I'm
looking to get the actual "P" and "k" out of the iteration. Any help
would be greatly appreciated.

Iteration loop
 

Variables: delta, P, I, k, k.sum, P.actua

Constants (known): h, E,

Equations: delta=P*h^3/(3*E*I), k=1/delt

There is a delta, P, & k for 5 different members (in my case, shearwalls). "I" & "h" are known, but may be different for each member, so there may be a different delta & k result for each member

Member1 delta1=P1*h1^3/(3*E*I1), k1=1/delta
Member2 delta2=P2*h2^3/(3*E*I2), k2=1/delta
Member3 delta3=P3*h3^3/(3*E*I3), k3=1/delta
Member4 delta4=P4*h4^3/(3*E*I4), k4=1/delta
Member5 delta5=P5*h5^3/(3*E*I5), k5=1/delta

k.sum=k1+k2+k3+k4+k

I initially set P=100 to find k. Then k is used in a series of cells/formulas to determine a calculated P (the equations are too complex/lengthy to list here). Let's just say for simplicity's sake that P1.actual=V*k1/k.sum. I then want to use P1.actual in place of P1 to determine a new delta1 & k1. From that a new P1.actual is calculated, which in turn is used to find a new delta1 & k1. I want this iteration to continue until convergence so I can find an unknown, but exact P.actual, delta, & k for each member. Hope this is descriptive enough. Feel free to email me @ if you need to

Brad