Hello,
I know that the natural frequency of a structure is the square root of the ratio of equivalent stiffness (in the form of elastic modulus) to equivalent mass (in the form of density).
I have two questions about this equation.
In my model, an epoxy block was sandwiched by two Kovar blocks (structure like 'ABA'), and the bottom of these three blocks were all fixed.
Question 1:
When the elastic modulus of epoxy changes, the equivalent stiffness of the structure will change, but does the equivalent mass change also?
I am not very sure about it. I think the equivalent mass remains the same because the densities of both Kovar and epoxy remain the same. But I found in ANSYS finite element analysis that the modal effective mass varied with the elastic modulus of epoxy.
So, question 2 is:
What is the difference between equivalent mass and effective mass?
Thanks in advance.
Best regards,
Richard
I know that the natural frequency of a structure is the square root of the ratio of equivalent stiffness (in the form of elastic modulus) to equivalent mass (in the form of density).
I have two questions about this equation.
In my model, an epoxy block was sandwiched by two Kovar blocks (structure like 'ABA'), and the bottom of these three blocks were all fixed.
Question 1:
When the elastic modulus of epoxy changes, the equivalent stiffness of the structure will change, but does the equivalent mass change also?
I am not very sure about it. I think the equivalent mass remains the same because the densities of both Kovar and epoxy remain the same. But I found in ANSYS finite element analysis that the modal effective mass varied with the elastic modulus of epoxy.
So, question 2 is:
What is the difference between equivalent mass and effective mass?
Thanks in advance.
Best regards,
Richard