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Thermal Stress Static analysis

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Dear Concerned,

I have comsol 4.2 version package. In this regard i am facing a problem to define spatially varying force on a boundary in 2D space. For instance, if i have a line extending along x-axis with length of 100mm. I only want to apply normal force to this line on a small region like 10 mm from the right edge. Is this possible without creating extra point on the line at a distance of 10 mm from right extremity and rather define the variation of force using a function defined over x-coordinate.





Please help me in this regard, looking forward to any guidance.

4 Replies Last Post 20 feb 2013, 01:11 GMT-5
Sergei Yushanov Certified Consultant

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Posted: 1 decade ago 18 feb 2013, 07:47 GMT-5
Himanshu,

Use the following expression for the force on line along x-axis:
F0*(x<=100[mm])*(x>=90[mm])

Regards,
Sergei
Himanshu, Use the following expression for the force on line along x-axis: F0*(x=90[mm]) Regards, Sergei

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 18 feb 2013, 09:58 GMT-5
Hi

you can also use aDefinition Function rect() to define a region, either referring to "x","y","z" or "s" along a 2D edge

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Good luck
Ivar
Hi you can also use aDefinition Function rect() to define a region, either referring to "x","y","z" or "s" along a 2D edge -- Good luck Ivar

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Posted: 1 decade ago 18 feb 2013, 13:35 GMT-5
Sergei,

Thanks for your support, yes I validated it on a 2-D body, but still i want a more flexible variation of force.
This time the force has parabolic variation with respect to a User defined Coordinate System and moreover this parabolic force is translating on the body as a transient analysis.

The force to be specific is the side thrust on cylinder liner of Diesel Engine , and even translates along the stroke of the piston.

Looking forward to hearing from you. thanks for prompt reply.

Regards ,

Himanshu
Sergei, Thanks for your support, yes I validated it on a 2-D body, but still i want a more flexible variation of force. This time the force has parabolic variation with respect to a User defined Coordinate System and moreover this parabolic force is translating on the body as a transient analysis. The force to be specific is the side thrust on cylinder liner of Diesel Engine , and even translates along the stroke of the piston. Looking forward to hearing from you. thanks for prompt reply. Regards , Himanshu

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 20 feb 2013, 01:11 GMT-5
Hi

well then express the force depending on (x,y,z,t) via some equation, you can also add coordinate systems, or use the default boundary coordinate system (check carefully the orientation per boundary !) to ease the expression

With COMSOL, most GUI entries can be written as full equations even depending on dependent variables, but mind the notation (COMSOL has many "implicit fields such as all dependent and related variables)

--
Good luck
Ivar
Hi well then express the force depending on (x,y,z,t) via some equation, you can also add coordinate systems, or use the default boundary coordinate system (check carefully the orientation per boundary !) to ease the expression With COMSOL, most GUI entries can be written as full equations even depending on dependent variables, but mind the notation (COMSOL has many "implicit fields such as all dependent and related variables) -- Good luck Ivar

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