def R2_c(FAmax, MBmax, Ssym, a, u, AD, IBT):
    """
    R2 Determining the required minimum clamp load Fkerf 
       (Section 5.4.1)
       
    The required minimum clamp load Fkerf is determined
    while taking into account the following requirements:
    c) Prevention of opening (Sec 5.3.2)
    
    FAmax : Axial Load
    MBmax : Working moment (bending moment) at the bolting point
    AD    : Sealing area (at most interface area less the through
            hole for the bolt)
    a     : Distance of the substitutional line of action of the
            load FA from the axis of the imaginary laterally 
            symmetrical deformation solid
    u     : Edge distance of the opening point U from the axis of the
            imaginary laterally symmetrical deformation solid
    Ssym  : Distance of the bolt axis from the axis of the imaginary
            laterally symmetrical deformation solid
    IBT   : Moment of gyration of the interface area
    """
    
    # c)
    FKA = ((FAmax * (AD * (a * u - Ssym * u) / (IBT + Ssym * u * AD)))
           + MBmax * (u * AD / (IBT + Ssym * u * AD))) # (R2/3)
    #
    return FKA
    #