{"title":"Stability Optimization of Functionally Graded Pipes Conveying Fluid","authors":"Karam Y. Maalawi, Hanan E.M EL-Sayed","country":null,"institution":"","volume":55,"journal":"International Journal of Structural and Construction Engineering","pagesStart":1296,"pagesEnd":1302,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/2646","abstract":"This paper presents an exact analytical model for\r\noptimizing stability of thin-walled, composite, functionally graded\r\npipes conveying fluid. The critical flow velocity at which divergence\r\noccurs is maximized for a specified total structural mass in order to\r\nensure the economic feasibility of the attained optimum designs. The\r\ncomposition of the material of construction is optimized by defining\r\nthe spatial distribution of volume fractions of the material\r\nconstituents using piecewise variations along the pipe length. The\r\nmajor aim is to tailor the material distribution in the axial direction so\r\nas to avoid the occurrence of divergence instability without the\r\npenalty of increasing structural mass. Three types of boundary\r\nconditions have been examined; namely, Hinged-Hinged, Clamped-\r\nHinged and Clamped-Clamped pipelines. The resulting optimization\r\nproblem has been formulated as a nonlinear mathematical\r\nprogramming problem solved by invoking the MatLab optimization\r\ntoolbox routines, which implement constrained function\r\nminimization routine named \u201cfmincon\" interacting with the\r\nassociated eigenvalue problem routines. In fact, the proposed\r\nmathematical models have succeeded in maximizing the critical flow\r\nvelocity without mass penalty and producing efficient and economic\r\ndesigns having enhanced stability characteristics as compared with\r\nthe baseline designs.","references":null,"publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 55, 2011"}