Minimum cost design of hybrid cross-ply cylinders with uncertain material properties subject to external pressure

• Published in: Ocean engineering Vol. 88; pp. 310 - 317
• Main Authors: Sfiso Radebe, Isaac, Adali, Sarp
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.09.2014; Elsevier
• Subjects: Applied sciences; Buckling; Buildings. Public works; Computation methods. Tables. Charts; Cross-ply cylinder; Cylinders; Design engineering; Exact sciences and technology; External pressure; Hybrid design; Material uncertainty; Mathematical models; Minimum cost; Sensitivity; Strength of materials (elasticity, plasticity, buckling, etc.); Structural analysis. Stresses; Surface layer; Uncertainty; Hybrid design; External pressure; Minimum cost; Sensitivity; Material uncertainty; Cross-ply cylinder; Structural design; Costs; Sensitivity analysis; Glass; Cylinder; Epoxide; Graphite; Buckling
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2014.06.010

Minimum cost design of hybrid cross-ply cylinders is presented which employ high-stiffness and expensive materials in the surface layers and the low-stiffness and inexpensive layers in the middle layers to combine the advantages of the two materials. Hybrid construction takes advantage of the sandwich effect whereby most of the load is carried by the surface layers. The cylinder is subject to external pressure with the material properties displaying uncertain-but-bounded variations around their nominal values. For a given external pressure, the material cost is minimized by minimizing the thickness of the surface layers. Analysis to determine the worst-case combination of material uncertainties makes use of convex modeling to compute the least favorable solution defined here as the minimum buckling pressure. The minimum cost designs are investigated for various problem parameters such as the wall thickness and the level of uncertainty. The relative sensitivities of the buckling pressure to material properties are also studied by defining sensitivity indices. •Cross-ply cylinders subject to external pressure are designed for minimum cost.•Design is given for hybrid construction with expensive layers in the surface layers.•Material properties have uncertain-but-bounded variations around the nominal values.•Uncertainty analysis is performed using a convex modeling of the uncertainties.•Sensitivity of buckling pressure to variations in material constants is studied.