The stress distribution in, and the collapse of, triangular gusset-plates connecting the members of engineering structures.

The case is considered of a triangular gusset plate fixed to structural members along two edges, and remaining entirely free along the third edge, which is unstiffened. The structural members are pivoted together at the intersection point of their clamping edges, that is, at the vertex of the triangular plate, and they are assumed to be stiff, and to remain practically straight when the gusset plate is deformed due to change in the angle between them. If the angle between the structural members is progressively increased, the plate will eventually commence to fail in tension near the centre of the free edge. Experiments are described for the determination of the stress distribution leading to this failure. If, on the other hand, the angle between the members is progressively decreased, then at first, stresses will be set up of opposite sign to those first mentioned, but distributed according to the same pattern. As further decrease in the angle takes place, however, transverse displacements will commence, and collapse will follow. Experiments are described for the determination of the collapse conditions. Experiments are also described relating to the collapse of plates which do not extend the whole distance from the free edge to the pivot-point of the members. The results of the experimental work are considered from a theoretical point of view, and approximate expressions are given connecting the conditions of failure with the change in angle between the members, and with the applied torque or moment about the pivot-point of the members. Whilst the methods used are applicable to plates of scalene triangular form, the work has been mainly limited to plates in the form of right-angled isosceles triangles, clamped along their equal sides, and this conforms to the majority of practical applications in engineering design