抄録
The Agency of Industrial Science and Technology (AIST), the Ministry of International Trade and Industry Japan (MITI), started the Large-Scale Project entitled “The Research and Development Project of Manganese Nodule Mining System” in 1981. The mining system in the Project is a hydraulic mining system in which nodules are collected by a towed collector on the sea bed and transported in a slurry of seawater and nodules through the lifting pipes onto the mining ship.
The many activities on the research and development of each subsystem have been performed under the management of“The Technology Research Association of Manganese Nodule Mining System (TRAM) ”promoted by the AIST, MITI and supported by NEDO (New Energy and Industrial Technology Development Organization) .
The functions of the pipe strings in this project are the nodule transfer channel and also a means of towing the collecotr on the sea bed. The pipe strings are subjected severe static axial stresses due to the dead weight. In addition to the aboves, the fluctuating axial and bending stresses are produced in the pipes due to the roll, pitch, yaw, heave, sway and surge motion of the mining ship. Under these circumstances, the strength design of the pipe string should be carefully performed. This paper presents the design considerations of the lifting pipes.
