Jordan Journal of Civil Engineering, Volume 14, No. 2, 2020 ‐ 137 - © 2020 JUST. All Rights Reserved Received on 15/10/2019. Accepted for Publication on 24/2/2020. Finite Element Analysis of Composite Hat-Stiffened Panels Subjected to Edge Compression Load Shashi Kumar 1)* , Rajesh Kumar 2) and Sasankasekhar Mandal 3) 1) Assistant Professor, Department of Civil Engineering, Sitamarhi Institute of Technology, Sitamarhi, India. * Corresponding Author. E-Mail: Shashi351@gmail.com 2), 3) Professor, Department of Civil Engineering, Indian Institute of Technology (BHU) Varanasi, India. E-Mails: rkumar.civ@itbhu.ac.in; smandal.civ@itbhu.ac.in ABSTRACT This paper deals with optimizing smeared extensional stiffness ratio of stiffeners to that of skin of laminated composite hat-stiffened panel with the variation of pitch length stiffeners, depth of stiffeners and panel orthotropy ratio for three different plie configurations to maximize buckling capacity of the panel. Critical buckling load and global buckling mode shape of the laminated composite hat-stiffened panel are studied for the design of lightweight structures. Parametric studies of hat-stiffened panel under in-plane compressive load are presented with simply supported boundary conditions. Models are analyzed by applying Finite Element method using ABAQUS. A database is provided based on smeared stiffness approach for two different hat- stiffened (60 0 -hat-stiffened and 75 0 -hat-stiffened) panels with variation of pitch length stiffeners, depth of stiffeners, panel orthotropy ratio and smeared extensional stiffness ratio of stiffeners to that of skin with three different plie configurations. On the basis of the study, optimum smeared extensional stiffness ratio is increased with increasing of orthotropy ratio for all similar skin, but it is also increased with decreasing extensional stiffness ratio to maximize buckling capacity of hat-stiffened panel and general guidelines are developed for the design of better hat-stiffened panel. KEYWORDS: Buckling, Composite panel, Finite element (FE), Fiber-reinforced polymers (FRPs), Numerical analysis. INTRODUCTION The design of laminated composite panel should be such that it can achieve good performance with specific buckling capacity. Shear force, compressive load and their combination can be applied on stiffened panel to check its stability. In stiffened panels, generally, local buckling, global buckling and collapse occur under shear, compression and their combination. The influence of the variation of plate thickness and stiffener on the buckling strength of stiffened panels can be studied using analytical and numerical methods. Fiber- reinforced polymers (FRPs) meet this requirement to some extent since their development in 1960s. A lightweight structure is an ongoing task for the engineering community, which has been used extensively in defense, aircraft and automobiles area and now it is currently employed in structural applications. FRP-stiffened panels are being used as the load shared walls of the compressive member of structures. Composite panels are also used in multi-storey buildings to reduce the dead load of the structure. FRP-laminated panels are currently used in heritage buildings for retrofitting due to their high strength and aesthetic appearance. Bakis et al. (2002) presented a detailed study on buckling of the laminated composite stiffened structure and its application in civil engineering. Terminology Description A11, A12,A22, A66 D11, D12,D22, D66 p D1/D2 Extensional stiffness component of skin. Bending stiffness component of skin. Pitch length (center-to-center spacing of stiffeners). Panel orthotropy ratio.