Accession Number : AD0715771

Title :   Dynamic Stress Response of Lifting Lines for Oceanic Operations.

Descriptive Note : Final rept. Jul 68-Jun 69,

Corporate Author : NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF

Personal Author(s) : Liu,C. L.

Report Date : NOV 1970

Pagination or Media Count : 53

Abstract : A vertical lift system was field-tested to determine the validity of an analytical solution for predicting the dynamic stress response of lifting lines in oceanic operations. Synthetic and steel wire ropes handling spherical, cylindrical, and cubical concrete loads were lowered by winch to depths as great as 5,000 feet. The ship acceleration and the line-force fluctuation were recorded on magnetic tape, and later the time-series data were digitized and analyzed by computer. The measured response functions agree within 50% with those calculated by the analytical solution; therefore, the proposed analytical solution for frequency response calculations is recommended. A single-guideline, load-handling system was field-tested in 1,000 feet of water. The test results indicate that a shollow-water, single-line system to restrict the motion of a compact load during emplacement is feasible, and that the lift line tension is not affected by the guideline. Also, performance requirements for a motion-compensating winch were calculated on the basis of vertical motions of five ships. (Author)

Descriptors :   (*MECHANICAL CABLES, STRESSES), (*MARINE ENGINEERING, HOISTS), POWER SPECTRA, LOADS(FORCES), CORDAGE, WIRE, NYLON, OCEAN WAVES, EXPERIMENTAL DATA

Subject Categories : Machinery and Tools
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE