*Article* **Estimating of the Static and Dynamic Behaviors of Orthogrid-Stiffened FRP Panel Using Reduced-Order Plate Model**

**Peng Wang 1,2, Yifeng Zhong 1,2,\* , Zheng Shi 1,2, Dan Luo 1,2 and Qingshan Yi 1,2**


**Abstract:** The orthogrid-stiffened FRP panel (OSFP) is a generic structural element in weight-sensitive structure applications. Based on the variational asymptotic method, a 2D reduced-order plate model (2D-RPM) of OSFP was constructed through matching the strain energy of the original panel for static and dynamic analyses. The local field distributions were recovered using the recovery relationship and global response. The relative influences of select parameters on the effective performance of the OSFP were revealed by parametric studies. The comparative results showed that the effective performance of the OSFP predicted by the 2D-RPM were consistent with those predicted by the 3D finite element model, but the computational efficiency was greatly improved. The stiffener height had the greatest influence on the natural frequency of the panel. The layup configurations of laminates had significant influences on the equivalent stiffness and buckling load of the OSFP but had little effect on the vibration modes, which could be varied by adjusting the stiffening forms.

**Keywords:** variational asymptotic method; reduced-order plate model; orthogrid-stiffened panel; free-vibration analysis; global buckling
