Analytical tool assisting the designer of pin-lug connections

A theoretical model of a pin-lug fitting in the presence of a pin-lug gap is developed that accounts for the nonlinear link between the load and the pin-lug angular width in this progressive contact, which is assumed frictionless. This model adopts a simplified lug geometry, described by a purely flexural partial ring whose extremities are fixed to a base, solved with the virtual work principle. Based on an already available load factor regrouping the effect on the contact angular extent of the applied load, of the Young’s modulus, and of the gap, but not of the lug geometry, an enhanced load factor is developed that includes, although approximately, the influence of the lug geometry on the contact angle. This approach is useful in selecting a suitable clearance between the lug and the pin, which keeps the contact pressure to a minimum for an imposed load.