ABSTRACT:

The Agency of Industrial Science and Technology [AIST), the Ministry of International Trade and Industry Japan [MITI), continues the Large-Scale Project entitled "The Research and Development Project of Manganese Nodule Mining System" since 1981. Many activities on the research and development of the system have already been performed. One of the most important structural elements is the lifting pipes with its function as the nodule transfer channel and a mean of towing the collector on the sea bed. The pipes are stored on the deck of the mining ship and are lowered to the sea water by the on-site assembly technique using the connector. Based on comprehensive expertises, the threaded joint is selected as a connector. It is one of the most important things to clarify the strength of the connectors in the design stage of the system. This paper presents the structural behavior of the connectors under severe stress conditions. The strain measurement tests were performed through make-up, tension and bending loadings. An FEM analysis was also carried out to clarify the detail stress distributions and the seal capacity using the elements which are able to treat the contact problem. Both results of the experiments and calculations are compared and the stress/strain behaviors are presented.

INTRODUCTION

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 have been performed under the management of "The Technology Research Association of Ocean Mineral Resources Mining System (TRAM)" promoted by the AIST, MITI and supported by the "New Energy and Industrial Technology Development Organization (NEDO)" (Wakabayashi, 1986, Kajitani, 1988, and Oyama, 1990).

This content is only available via PDF.
You can access this article if you purchase or spend a download.