Hu C.-F.,National Taiwan University |
Fang S.-C.,North Carolina StateUniversity
Journal of Systems Science and Systems Engineering | Year: 2015
This paper considers solving a multi-objective optimization problem with sup-T equation constraints. A set covering-based technique for order of preference by similarity to the ideal solution is proposed for solving such a problem. It is shown that a compromise solution of the sup-T equation constrained multi-objective optimization problem can be obtained by solving an associated set covering problem. A surrogate heuristic is then applied to solve the resulting optimization problem. Numerical experiments on solving randomly generated multi-objective optimization problems with sup-T equation constraints are included. Our computational results confirm the efficiency of the proposed method and show its potential for solving large scale sup-T equation constrained multi-objective optimization problems. © 2015, Systems Engineering Society of China and Springer-Verlag Berlin Heidelberg.
Ulker M.B.C.,Missouri University of Science and Technology |
Rahman M.S.,North Carolina StateUniversity |
Guddati M.N.,North Carolina StateUniversity
International Journal for Numerical and Analytical Methods in Geomechanics | Year: 2012
Breaking-wave-induced dynamic response and instability of seabed around a caisson breakwater are investigated. A seabed-rubble-breakwater system is modeled using finite elements. The impact response of the porous seabed and rubble foundation is assumed to be governed by the coupled Biot equations, and three possible formulations are considered with respect to the inclusion of inertial terms. The response is presented in terms of shear stress and pore pressure distributions at three locations underneath the breakwater. The effect of seabed and wave parameters and the inertial terms on the impact response is investigated through parametric studies. Analyses show that usually partly dynamic formulation yields the largest response amplitudes as compared to the fully dynamic formulation, which is the most complete form. The instability of seabed and rubble mound as a result of instantaneous liquefaction is also studied. Breaking wave-induced pressures in some cases are found to cause liquefaction in the rubble and the seabed. The effect of some parameters on the instability is found to be significant. © 2011 John Wiley & Sons, Ltd.