Replacing Strain Measurements by Vibration Measurements for the Identification of Orthotropic Engineering Constants of Composite Sheets

摘要

A Classical Laminate Theory analysis program for composite materials needs the input of all the mechanical layer properties. Mechanical layer properties include normal Failure Strengths X_1 and X_2, the Shear Failure Strength S_(12), and Orthotropic Engineering Constants like the Young's Moduli E_1 and E_2, Poisson's ratio V_(12) and the In-plane Shear Modulus G_(12). Among others, tensile tests and rail shear tests with strain gages fixed on test beams and test plates can be used to establish those mechanical layer properties. However, testing composite material with strain gages is time consuming, expensive and requires skillful operators. This paper describes an alternative for the identification of the Orthotropic Engineering Constants based on the Impulse Excitation Method in combination with Finite Element models of the test beams and test plates. Because the method is non-destructive, tensile tests and rail shear tests can be applied afterwards on the same test specimens to measure the failure strengths, but without the need of fixing strain gages.