Stresses Around Pin-Loaded Hole in Finite Orthotropic Laminates

Abstract

Stress were calculated for finite orthotropic laminates under pin-loadings using a two-dimensional finite-element method. The analysis considered an ideal case of no friction and no slip at the pin-shet interface. Both pin and sheets are assumed to be elastic. Four differnt graphite/epoxy laminates were analyzed: quasi-isotropic [0˚/45˚±90˚]s, 0˚, [±45˚]s, and [0˚/±45˚]s. Computed results are presented for selected combinations of sheet-width-hole-diameter ratio, w/d, and edge-distance-hole-diameter ratio, e/d. Contact stresses for the orthotropic laminates were significantly differnt from the usually assumed cosine distribution. Contact stresses and contact angles depend upon materials orthotropy and sheet geometry.

The maximum tangential stresses are influenced appreciably by the w/d values. The maximum tangential stress generally occurs near the separation of pin contact. However, for the [±45˚]s laminate, the maximum tangential stress depends on the w/d values and occurs at Θ~=45˚ orΘ~=120˚ .