User functions

User functions - Help needed for simple problem - Сообщения

#1 Опубликовано: 25.04.2019 04:35:25
AndreasH

AndreasH

0 сообщений из 2 понравились пользователям.

Группа: User

test.sm (7 КиБ) скачан 28 раз(а).


Dear all. I am trying to solve an equation, eq. See attached .sm file. The equation does not have the variable directly, but via other definitions. I can't make this work. Anyone out there able to help quickly?


-Andreas-
#2 Опубликовано: 25.04.2019 06:28:57
Davide Carpi

Davide Carpi

1416 сообщений из 2873 понравились пользователям.

Группа: Moderator

Hello Andreas,

there are several issues in your worksheet.

  • The shear stress must be Tau(F) or Tau - at your choice - both in definition and in Von Mises equation;
  • Once you fix it you can see that units of Tau are wrong, it's a force while should be a stress - F/(b*L) I guess;
  • Then you should handle the unit of F; use eq(F) to define the Von Mises yeld criterion and set the unit in the first argument of solve, like eq(F*'kN) or eq(F*'N);
  • Finally give a range to solve, otherwise the default of the program you are running it is used;


test - r1.sm (11 КиБ) скачан 37 раз(а).
If you like my plugins please consider to support the program buying a license; for personal contributions to me: paypal.me/dcprojects
1 пользователям понравился этот пост
sergio 25.04.2019 06:41:00
#3 Опубликовано: 25.04.2019 08:23:38
AndreasH

AndreasH

0 сообщений из 2 понравились пользователям.

Группа: User

Thank you Davide.

Sloppy mistake on my part on the shear stress definition Tau. By the way, can the solve-function return with a unit number or does it have to return a unitless answer?

I can easily fix it of course by writing F:=solve(eq(F*'kN),F,0,1000)*'kN


-Andreas-
#4 Опубликовано: 25.04.2019 09:03:45
Davide Carpi

Davide Carpi

1416 сообщений из 2873 понравились пользователям.

Группа: Moderator

Wrote

Thank you Davide.

Sloppy mistake on my part on the shear stress definition Tau. By the way, can the solve-function return with a unit number or does it have to return a unitless answer?

I can easily fix it of course by writing F:=solve(eq(F*'kN),F,0,1000)*'kN


-Andreas-



Yes I forget it, that's the way to set the output units (solve as for now can't handle automatically input/output units of unknowns).
If you like my plugins please consider to support the program buying a license; for personal contributions to me: paypal.me/dcprojects
  • Новые сообщения Новые сообщения
  • Нет новых сообщений Нет новых сообщений