Problem 4.35 - Allowable Stress/Safety Factor

Problem Statement

A small truss is constructed with solid square wood members and subjected to a load of F = 30 kN. Determine the minimum dimension, a, of the member so that the truss will have a factor of safety of 2. All members have the same cross-section. The wood has a failure stress of σ_fail = 50 MPa.

Picture with a truss pointing down. The horizontal bar AC has angled components AD and CD where the two components meet. There is a member DB that intersects with the horizontal. [Problem adapted from © Kurt Gramoll CC BY NC-SA 4.0]