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unexpected unit of input in solid mechanic

Posted Nov 19, 2015, 8:02 p.m. EST Modeling Tools & Definitions, Parameters, Variables, & Functions 3 Replies

Chi Chen
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Hello, all. I want to simulate dynamic problem with adding physics of "solid mechanic" and study of " time-dependent". I want to setup boundary load with 25*sin(w*t), where "w" is frequency, which is 0.75 [s-1]; however, it show "unexpected unit of input".
Did anyone one know what unit is conflict with time ( t[s] ) in solid mechanic?

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3 Replies Last Post Sep 18, 2016, 5:55 a.m. EDT
Jeff Hiller COMSOL Employee

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Posted: 9 years ago Nov 20, 2015, 8:39 a.m. EST
Careful! In 3D, by default, w is the displacement in the z direction, and its dimension is a length. Better pick some other name for your angular frequency!
Besides, 2*cos(omega*t) is a scalar, whereas 2[N/m^2]*cos(omega*t) is a pressure.
Jeff
Careful! In 3D, by default, w is the displacement in the z direction, and its dimension is a length. Better pick some other name for your angular frequency! Besides, 2*cos(omega*t) is a scalar, whereas 2[N/m^2]*cos(omega*t) is a pressure. Jeff
Chi Chen
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Posted: 9 years ago Feb 2, 2016, 3:14 p.m. EST
got it, the problem has been figured out. Thanks

Best regard
got it, the problem has been figured out. Thanks Best regard
Mohamed Bahri
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Posted: 8 years ago Sep 18, 2016, 5:55 a.m. EDT
Hi
using the version 5.2, in the variable expression i try to use sinh(phi) or cosh(phi) and give them a name , the unit of (phi) is the volt wich is the variable of electrostatic module, but the color is orange and show ''unexpected unit of input'' so i can't use it in boundary condition ad i can't solve my problem
Appreciate much for your help!!
Hi using the version 5.2, in the variable expression i try to use sinh(phi) or cosh(phi) and give them a name , the unit of (phi) is the volt wich is the variable of electrostatic module, but the color is orange and show ''unexpected unit of input'' so i can't use it in boundary condition ad i can't solve my problem Appreciate much for your help!!

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