| A flat steel flange clamped by 14 bolts was modelled by three dimensional finite element analysis to evaluate the apparent stiffness and stress distributions in compression of the flange. The bolt load was applied via an extremely stiff washer to eliminate the effect of bolt head deflection on the results. Member stiffness ratios were calculated from the finite element results and compared with those calculated by commonly used theory. The dimensionless stiffness was found to vary with bolt aspect ratio d/L in a nearly linearly fashion, with slope equal to that predicted by a simple cylindrical model. The conical frustum model, with a half angle of 32.8{dollar}spcirc{dollar}, predicted stiffnesses within a few percent of those measured. The interflange pressure along the bolt circle was calculated for different bolt spacings and a range of aspect ratios. |
