Identification of the orthotropic elastic stiffnesses using the virtual fields method considering current configuration

The stiffness matrix of orthotropic materials changes as its coordinate system rotates, and the definition of virtual displacement in the Virtual Fields Method (VFM) is related to the local coordinates. Based on the reference configuration defined in the global coordinate system, the traditionally used VFM directly neglects the movements and rotation of data points, leading to inaccurate identification of constitutive parameters, even in the case of elastic deformation. The present study proposed a modified VFM using the current configuration for identifying mechanical parameters of orthotropic materials. The modified VFM was verified by using simulation tests. The effects of data points' translations and rotations on the mechanical identification was quantitatively analyzed. The results indicated that the identification accuracy of parameters Q₁₂, Q₂₂ was improved through the modified VFM using the current configuration.