How to solve an equation contains 2 variable range - Part Two

Forum|Forum|13 years ago
March 28, 2013
1 reply
1651 views

Dear Expert,

I'm stuck in preparing my calc sheet in determining local buckling check with few variables which are:

1) x - is the variable range for external pressure

2) i - is the variable range for bending moment.

my problem are:

1) when look at the variable range for bending moment (M), why there is still Mo=0 as i already specify i is for range 1,2 till n. This will led to an equation divide by zero

2) I'm not sure LBCin programme is correct, my aim is to check for example at External Pressure = 0MPa what is the LBCin value when bending moment (M) is from 20Nm,30Nm and so on. Then External pressure increase =0.1MPa with bending moment (M) is from 20Nm,30Nm and so on. And further on

Appreciate your assistant on the matters.

Thank you

Regards

-Akmal-

1_LocBuck-xmcd.zip

Other

A

AndyWesterman

12-Amethyst

Hello Akmal,

If you type "ORIGIN=" in your worksheet it should return the value 0 (default).

This is the origin for all vectors, matrices etc in the worksheet & as you use element 0 for the array P.r probably shouldn't change it.

Mathcad will initialise all elements up to the maximum value with 0

2 options that I can think of, either initialise with

Which starts the array at element 0

or

NaN is a symbol for mathcad that means Not-A-Number & may work around the divide by zero problem that you are having.

Regards

Andy

P

ptc-5029428

Author

1-Visitor

Dear Andy,

i've tried both of them but still it has divide by zero.

anyway if later i manage to solve "divide by zero" the problem, i still have problem in determine my LBC value as it takes too long to calculate and i have to stop it.

The LBC is dependent on:

1) Sigma_y and Ax value where they are suppose to be linked to changes of external pressure Prx.

2) Sigma_X and sigma_XCR where they are link to the variation of bending moment.

i ammend a bit on the spreadsheet i sent earlier with some remark for clearer picture

Regards

-Akmal-

1_LocBuck2-xmcd.zip