عملکرد لنگر تولیدی حاصل از مخزن مستغرق متحرک در کاهش دامنه پاسخ سکوی ثابت برجی

In this paper, a concept is presented for decreasing the response amplitude of fixed offshore platforms using a movable submerged tank. The idea is based on utilization of the tank’s buoyancy and inertia forces to reduce the responses of the platform. In this concept, a four-legged platform is investigated in which braces are removed in lower levels, and the movable submerged tank including substantial amount of buoyancy force is added. As a result of the tank oscillation, the upward buoyancy force causes a reversible moment which depends on the tank position and time. Actually, tank movement changes the internal forces distribution pattern that could produce time dependent stiffness. The non-linear and large displacement effects are considered in the static analyses using a program developed by employing MATLAB software. Results of static analyses indicate the tank efficacy in decreasing the displacement amplitude of the platform. The performance of the concept can be improved by taking an appropriate volume and oscillation amplitude for the tank. It is noteworthy that the tank should be placed in enough proper depth for preventing any uncontrolable wave loads additionally, results show that the tank usage in less stiffened platform could be more efficient, in other word, the tank efficiency will be increased by depth magnification.