rigid body force

armin najarian · August 1, 2015, 02:20

hi.
i creat a rigid body in cfx and i want to give it a special harmonic froce in rigid body's ceter of mass.
the problem is that my rigid body moves and i dont know how to set this force that always be in the center of mass.

(my problem is transient and the rigid body should move with this force.)
thanks a lot

fresty · August 1, 2015, 18:05

Correct me if i am wrong but as it is a rigid body defined with its mass & mass moments of inertia so any force applied (assuming you're talking about external force in rigid body definition) would always be acting at the center of mass... have you tried anything yet that led you to your question? Any images or details would be helpful..

armin najarian · August 2, 2015, 03:38

thank u a lot.
u solved my question
i have 2 another questions.
1-does the external force be continuous?
2-i choose a new coordinate for the rigid body. in the initial condition which coordinate will be considered?
new coordinate or the main coordinate?

armin najarian · August 2, 2015, 03:44

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armin najarian · August 2, 2015, 03:45

Quote:

Originally Posted by fresty

Correct me if i am wrong but as it is a rigid body defined with its mass & mass moments of inertia so any force applied (assuming you're talking about external force in rigid body definition) would always be acting at the center of mass... have you tried anything yet that led you to your question? Any images or details would be helpful..

can u understand my 2 another questions?

fresty · August 2, 2015, 08:31

Would give my best shot at trying to comprehend...
1) The external force is continuous
2) It would consider the same coordinate system as selected in the Basic Settings tab

August 1, 2015, 02:20	rigid body force	#1
armin najarian New Member armin najarian Join Date: Aug 2015 Posts: 14 Rep Power: 11	hi. i creat a rigid body in cfx and i want to give it a special harmonic froce in rigid body's ceter of mass. the problem is that my rigid body moves and i dont know how to set this force that always be in the center of mass. (my problem is transient and the rigid body should move with this force.) thanks a lot

August 1, 2015, 18:05		#2
fresty Senior Member Join Date: Aug 2014 Location: UK Posts: 213 Rep Power: 13	Correct me if i am wrong but as it is a rigid body defined with its mass & mass moments of inertia so any force applied (assuming you're talking about external force in rigid body definition) would always be acting at the center of mass... have you tried anything yet that led you to your question? Any images or details would be helpful.. armin najarian likes this.

August 2, 2015, 08:31		#6
fresty Senior Member Join Date: Aug 2014 Location: UK Posts: 213 Rep Power: 13	Would give my best shot at trying to comprehend... 1) The external force is continuous 2) It would consider the same coordinate system as selected in the Basic Settings tab armin najarian likes this.

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August 2, 2015, 03:38		#3
armin najarian New Member armin najarian Join Date: Aug 2015 Posts: 14 Rep Power: 11	thank u a lot. u solved my question i have 2 another questions. 1-does the external force be continuous? 2-i choose a new coordinate for the rigid body. in the initial condition which coordinate will be considered? new coordinate or the main coordinate?

August 2, 2015, 03:44		#4
armin najarian New Member armin najarian Join Date: Aug 2015 Posts: 14 Rep Power: 11	2.PNG 1.PNG 3.PNG