@Carl Love So many thanks for your explanations.

Now, and trying to finish with this..., look at the last result. It must be a number, but there appears a "d" referrencing to the "d" table.

I'm sending you the file: ADJUNT_EXCEL1_-_valorat_(COLOMBIA).mw

Regards.

@Carl Love So many thanks Carl, I think it will work.

But now how can I deal with this error? The condition is dependant on the last part of the beam each time.

Another question is, in this way, as there's no integral, there's no worry for the integration constants, right?

ADJUNT_EXCEL_-_copia_-_copia.mw

Thanks.

@Carl Love Hi there Carl,

Finally your solution worked well. Now I have been going further and that C's I told you alwas were going to be 0 are no longuer 0, and this complicates all stuff.

My question is, if I declare Y2 as a function of x by:

1st:

2nd

3rt

So that Y2 is a declared function, why I can't evaluate it at any x value either it is numeric or symbolic:

This is so embarrasing, cause if not it would be so easy...

@Carl Love The fact is that it works well writing Ay*x-p_2..., but not writing the name of this expression (Y1").

I have 8 Y's, so I expected to use their names on further steps...

I'm posting entire sheet: ADJUNT_EXCEL.mw

@Carl Love Hi Carl,

It works well with the restart, but not without it (it gives the same error).

Anything we can do?

@Carl Love I think it would be better if you can see the whole problem.

The final target is to have an expression that calculates the critical speed of a shaft in terms of some variables like diameters, weight, local forces, etc.

The main equation for this is known as the Rayleigh eq. I requires g acceleration, mass of each weight on the shaft (including the shaft) and displacement of the shaft in each Mass Center of each weight of the shaft.

As displacement is required, I have to calculate what's called displacements equation, which is the primitive of the twisting eq which is the primitive of the elastic eq.

Sorry... Now Maple Code:

FORCE REACTIONS CALCULATION (force reactions at fixed points of the shaft):

Where p's are the weights of 2 diameter sections of the shaft (expressed in N/m), L's are lengths and F's are local forces.

STRAIN LAWS

You may recognise the last one. Y1" is the elastic eq. which I have to integrate 2 times to get displacement eq.

ELASTIC EQ. INTEGRATION (DISPLACEMENT LAW)

As Maple does not include constant of integration, I have added manually.

Y11 is the twists eq. an in order to avoid C11, there's the following way: the shaft is embbeded at it's initial face, so the twist angle must be 0. So Y11(0)=0:

Then we integrate another time to get displacement eq:

Following the same strategy, displacement at x=0 must be 0, so Y1(0)=0:

DISPLACEMENT CALCULATION

In this point I want to use this completely defined Y1 eq to find displacement at some x value (or expression).

If I simply do:

Y1(2);

I get:

Error, (in int) integration range or variable must be specified in the second argument, got 2
 

Many thanks!!

@Carl Love Many thanks,

This has worked well, but I'm still experiencing problems.

What I don't understand is why Maple can't solve Y1 for a certain x. As I know, when you have defined a function, Y1(x) e.g., you can evaluate it simply doing Y1(n), being n a numberor expression.

Regards.

Thanks for your help,

It actually works, but by using "restart" I clear all expressions above. Y1" is an already defined function. The fact is that finally I want to obtain an expression to introduce it in an excel sheet, so this is not gonna take numeric values in the Maple sheet. This C1 is 0 for this case, but it may vary in some other cases and this is the reason I would prefer the Maple sheet to be automathic.

As I understand, you are avoiding all stuff above by "restart" and then you are demostrating than differential of Y1 is Y1", and then you are integrating Y1" and adding C1. For you, f is the main equation. From here I don't know how it get C1=0, and how can it take in count real algebraic value of Y1" if "restart" is over there...

Thanks a lot.