Concomitant Strength Relationship for Lumber

Abstract

The concomitant relationship between the bending and tensile strength properties of a common machine stress rated grade of dimension lumber was studied. Test specimens, subjected to a tensile proof load with the survivors tested to destruction in bending, provided the necessary conditional information for the development of multivariate statistical models. Maximum likelihood solutions showed excessive instability in the parameter estimates, while a modified least squares approach for limited dependent variables proved to be far more stable. The latter approach lead to a general solution to the concomitant problem.