Interactive Strength of Two Structural Parameters

An empirical approach based on load test data is commonly used to develop the interactive failure envelope. The failure envelope is normally expressed as functions of two nondimensional ratios; each ratio is the force of stress at failure and the corresponding independent strength. The independent strength is the strength of the structural parameter under consideration without the presence of the other structural parameter. Once the equation defining the interactive failure envelope has been developed, the design envelope is normally constructed by replacing the two independent strengths with the corresponding independent allowable forces or stresses. This approach is a scalar reduction from the failure envelope. A new vectorial concept is presented for constructing the design envelope from a given failure envelope.