Recent content by Ekaterina Wiktorski

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    Torque&Drag in a drillpipe (Johancsik, 1984)

    Hi! Is anyone experienced With T&D calculations using above mentioned model: ? I have a trouble to understand what exactly F1 is and how to calculate it. I know it is an axial force, so it is drag? And once you calculate drag for one element, you use it as F1 to calculate drag in 2ns element...
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    What is the Difference Between Ixy and Iz in Moment of Inertia for Pipes?

    OK, it became a bit more clear, thank you very much for your input.
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    What is the Difference Between Ixy and Iz in Moment of Inertia for Pipes?

    Right, I see now. I want to calculate displacement in pipe using dynamic eq. [M]{U''}+[C]{U'}+[K]{U}={F}, where U is displacement, and U' and U'' are its derivateves. M, C, K are matrices of mass, damping and stiffness. Matrices are defined, and some of the expressions contain Ixy and Iz (area...
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    What is the Difference Between Ixy and Iz in Moment of Inertia for Pipes?

    OK, thank you! I understand that it is a confusing question, let's say z in the vertical axis. I wanted to see your opinions on this one, as I didn't see the difference between body's moment of inertia in different axes...
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    What is the Difference Between Ixy and Iz in Moment of Inertia for Pipes?

    Hi, I've been always using eq. I=Pi*(D^4-d^4)/64 to find moment of inertia of a pipe. Recently I've seen that moment can be in different directions, and then it is expressed differently. So what is the difference between Ixy and Iz?
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