Inerter

[Gholamreza]

Hello Developers,
In order to model new type of dampers I need to define new material to work with relative acceleration. As far as I know, the built-in functions in OpenSees usually work with displacements and velocities at each step but I need a function which works with acceleration. I know I should write some codes. I wonder to know if I simply change the velocity to acceleration in ViscousDamper material, I will get the resistance force based on relative acceleration or not ? your advice is highly appreciated.

[fmk]

you need to create an element that will work with the accelerations and pass these to the materials (assuming you intend to imple=ment materials as well) .. the materials get strain and strain rates from the elements and not the nodes directly.