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Modal Analysis

Hi everyone,

While Performing modal analysis, I Gave RHO(Density) value in 7.8 x 10^-6(Kg/mm3) for steel material, I got some Modal frequency.

But, If same given in tone/mm3 ( 7.8 x 10^-9) I got some other frequency. Yeah it is obvious that natural frequency is a function of mass matrix but I am confused which to use?

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OptiStruct

v2022.0

Accepted answers

Rajashri_Saha

Hi Parthiban,

As you are using E=200000MPA, then you can go for density as 7.8e-9 ton/mm3.

You can refer the below consistent unit system.

As you can see for 7.8e-6 density value, E value should be 210GPA or 0.21mN/mm2.

Hope this answers your query.

Thanks

Rajashri

All comments

Parthiban B

My Elastic modulus value is 200000 MPa (200 GPa)

Rajashri_Saha

Hi Parthiban,

As you are using E=200000MPA, then you can go for density as 7.8e-9 ton/mm3.

You can refer the below consistent unit system.

As you can see for 7.8e-6 density value, E value should be 210GPA or 0.21mN/mm2.

Hope this answers your query.

Thanks

Rajashri

Parthiban B

Hi Parthiban,

As you are using E=200000MPA, then you can go for density as 7.8e-9 ton/mm3.

You can refer the below consistent unit system.

As you can see for 7.8e-6 density value, E value should be 210GPA or 0.21mN/mm2.

Hope this answers your query.

Thanks

Rajashri

Thanks Rajashri,

Rajashri_Saha

Thanks Rajashri,

Hi Parthiban,

You can mark the queries as resolved where you got the correct answers.

You can look into the previous queries and mark them as resolved too.

That will be helpful for us.

Thanks

Rajashri