Mechanical Properties of Density Graded Foams: Tensile Properties

This work presents the production and characterization of functionally graded polymer foams produced by compression molding. For the conditions tested (temperature gradient, molding time, type and concentration of Expancel microbeads), it was possible to reach density reduction between 2 and 45% for symmetric and asymmetric polyethylene foams. Tensile properties (modulus and stress at 1% deformation) were then measured to relate with their respective density profiles. From the experimental data obtained, a simple finite element analysis was performed to determine the tensile properties of asymmetric foams. The results show that excellent predictions were obtained with a maximum deviation of 7% for all the conditions tested.