meaning of the suspension roll rate comment

mush ab
mush ab Altair Community Member
edited October 2023 in Community Q&A

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What does "C(3,3)" "C(3,9)" and so on mean? what do the numbers in brackets refer to?

Sorry i'm still a beginner, Help me please

Thank you

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Answers

  • GTT Adam
    GTT Adam
    Altair Employee
    edited October 2023

    Hi! The matrix indexes shown refer to the suspension compliance matrix, outlined on the Suspension Design Factors help page: https://help.altair.com/hwdesktop/mv/topics/motionview/suspension_design_factors_r.htm

    As written in the help page:
     
    "The primary input for SDF calculations is the compliance matrix for the suspension.
    For non-steerable suspensions, the compliance matrix is the partial derivatives of the left and right wheel center displacements with respect to forces and moment forces at the wheel centers. To compute the first column of the compliance matrix, for example, MotionSolve applies a unit force in the global X direction to the left wheel center, performs a static analysis, and the resulting change in position and orientation of the left and right wheel centers becomes the first column of the 12 x 12 matrix. The process is repeated for the remaining 11 columns.
    In the documentation for SDF parameters, terms in the compliance matrix are referenced using C(i,j):
    • i = 1-6 X Y Z RX RY RZ displacements of the left wheel center
    • i = 7-12 X Y Z RX RY RZ displacements of the right wheel center
    • j = 1-6 X Y Z RX RY RZ forces on the left wheel center
    • j = 7-12 X Y Z RX RY RZ forces on the right wheel center

    When reading entries in the compliance matrix, i is the degree of freedom which is being displaced by a force in the j degree of freedom. For example, C(3,9) is the vertical displacement of the left wheel center due to a unit vertical force at the right wheel center."

     

    Hope this helps!

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