Optimum design of fatigue-resistant composite laminates using hybrid algorithm

This paper proposes a procedure for the optimum design of composite laminates under probabilistic considerations. The problem is formulated to consider the minimization of laminate weight as the objective function and the reliability requirements as the constraints. Both system-level and element-level reliabilities are considered. The first-order reliability method (FORM) is used to estimate the reliability of each ply group, and system reliability is computed based on series or parallel system assumptions. The Tsai-Wu strength criterion is adopted to derive the limit state function of individual ply groups in the laminate. The gradient and sensitivity information of the objective function and the constraints with respect to the design variables are obtained by using sensitivity analysis based on the composite plate theory. Thus the proposed procedure brings together modern concepts of reliability analysis, composite laminate behavior and nonlinear optimization to develop a rational and practical procedure for the optimum design of composite laminates. Numerical examples are presented to demonstrate the effectiveness of the proposed method.

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Optimum design of composite laminates for minimum thickness

Computers & Structures ◽

10.1016/j.compstruc.2008.05.003 ◽

2008 ◽

Vol 86 (21-22) ◽

pp. 1974-1982 ◽

Cited By ~ 40

Author(s):

Mustafa Akbulut ◽

Fazil O. Sonmez

Keyword(s):

Optimum Design ◽

Composite Laminates ◽

Minimum Thickness

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Optimum Design of Composite Pressure Vessel Based on 3-Dimensional Failure Criteria

Volume 2: Computer Technology and Bolted Joints ◽

10.1115/pvp2019-93816 ◽

2019 ◽

Author(s):

J. Sakai ◽

Y. H. Park

Keyword(s):

Optimum Design ◽

Pressure Vessel ◽

Composite Laminates ◽

Three Dimensional ◽

Weight Ratio ◽

High Strength ◽

Failure Criteria ◽

Pressure Vessels ◽

Fiber Reinforced ◽

3D Elasticity

Abstract Anisotropic composite cylinders and pressure vessels have been widely employed in automotive, aerospace, chemical and other engineering areas due to high strength/stiffness-to-weight ratio, exceptional corrosion resistance, and superb thermal performance. Pipes, fuel tanks, chemical containers, rocket motor cases and aircraft and ship elements are a few examples of structural application of fiber reinforced composites (FRCs) for pressure vessels/pipes. Since the performance of composite materials replies on the tensile and compressive strengths of the fiber directions, the optimum design of composite laminates with varying fiber orientations is desired to minimize the damage of the structure. In this study, a complete mathematical 3D elasticity solution was developed, which can accurately compute stresses of a thick multilayered anisotropic fiber reinforced pressure vessel under force and pressure loadings. A rotational variable is introduced in the formalism to treat torsional loading in addition to force and pressure loadings. Then, the three-dimensional Tsai-Wu criterion is used based on the analytical solution to predict the failure. Finally, a global optimization algorithm is used to find the optimum fiber orientation and their best combination through the thickness direction.

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