CONSTITUTIVE MODELING OF GEOMATERIALS FROM NONUNIFORM MATERIAL TESTS

As the name implies, a non-uniform material test has a non uniform dis tribution of stresses anal strains within the specimen. An example is a triaxial test with end friction. Unlike the conventional material te sts, points in the specimen in a non-uniform material test are subject ed to widely varying stress paths. In this paper a method to extract t he material constitutive behavior from a non-uniform material test is presented. This method employs the use of a neural network material mo del in a finite element analysis. The measured boundary forces and dis placements are applied in the finite element analysis to generate the input and output vectors for training the neural network material mode l. This method has been applied to a series of triaxial compression te sts with end friction on sand. (C) 1998 Elsevier Science Ltd. All righ ts reserved.