A novel reduced‐order modeling method for nonlinear buckling analysis and optimization of geometrically imperfect cylinders

Abstract

A novel reduced-order modeling method with two-step strategy is proposed for nonlinear buckling analysis of axially compressed thin-walled cylinder. The nonlinear response analysis up until the buckling point is achieved quickly by solving the small-scale reduced-order model, accounting for the geometrically nonlinear behavior. The buckling point is determined accurately using an efficient buckling detection algorithm, where the stiffness information of the reduced-order model is extrapolated based on an eigenvalue analysis until a singular tangent stiffness is obtained. Then, the nonlinear buckling fiber angle optimization scheme of laminated composite cylinders is constructed in the MATLAB's MultiStart scheme with gradient-based algorithms. The proposed two-step reduced-order modeling strategy is adopted to calculate the nonlinear buckling objection function at a much lower cost. Numerical results for axially compressed cylinders with various geometric imperfection fields demonstrate the good performance of the proposed strategy in both nonlinear buckling analyses and lamination optimizations.

Effects of geometry and material factors on the behavior of stiffened offshore pipe structures under hydrostatic pressure

“…Geometric imperfections can arise in the process of transportation, manufacturing, welding, and fabrication, affecting cylinder shell stability and load-bearing capacity. Determining limit points is the primary goal of nonlinear buckling analysis [12]. The recommended interaction equation for combined axial compression and external pressure is shown in equations (8)(9)(10).…”

“…. S R θ = (12) where P is the critical buckling load, P0 is the initial load input, S is the arc length, R is the radius of the cylinder shell, and 𝜃𝜃 is the displacement of the shell cylinder.…”

A stress‐influence‐function with adaptive strength feature approach for stress constrained continuum topology optimization via small‐loop sequential strategy

“…1 During the past few decades, a large number of studies on structural optimization have been published. [2][3][4][5][6][7][8][9][10] Compared to the continuum topology optimization concerning structural compliance, [11][12][13][14][15][16][17][18] the stress constrained continuum topology optimization is still tough work. Most likely, several challenges arise when considering stress constraints in continuum topology optimization.…”

A comparison of geometric imperfection models for collapse analysis of ship-type stiffened plated grillages

“…It is a standard procedure to consider the initial geometric imperfection in buckling analysis of stiffened plated structures, which is also recognised as one of the most important influencing parameters. Many studies are available in the literature to investigate the buckling capacity of stiffened plated structures with initial geometric imperfection [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. For a ship-type stiffened plated grillage, three different types of geometric imperfections are considered, local plate distortion, column-type distortion and stiffener sideway distortion.…”