DIMENSION ACCURACY CONTROL IN THE CONSTRUCTION OF WELDED STEEL SHIPS

For some time, the shipbuilding industry has been changing its production procedures into assembly type processes. Adequate systems for tolerancing and accuracy control are mandatory for such procedures. The development of these systems has, however, been lagging to some extent due to the complexity of the problems involved--both in the actual measuring of dimensional errors and the theory for handling the type of deviations experienced. Part I of this treatise examines the elements constituting a tolerancing system for the construction of ship hulls. It is concluded that a good description of dimensional errors of plates as well as a theory for error propagation from such deviations, has been lacking. Part II presents an exploratory data-analysis performed on measurements of edge straightness taken on steel plates cut by parallel oxygen cutters in two Norwegian shipyards. Systematic and random errors of the same magnitude of order are revealed. It is concluded that deviations from straightness in cuts should be modeled as continuous, stationary Gaussian stochastic processes. In Part III semi-empirical models are developed for the probability of gaps between plates positioned for butt-welding and for the main statistics connected with propagating errors. An underlying assumption is that systematic errors may be adjusted to an order of magnitude less than the random cut-deviations.

  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Ocean Engineering, 77 Massachusetts Avenue
    Cambridge, MA  USA  02139
  • Authors:
    • Ringard, M R
  • Publication Date: 1974-1

Subject/Index Terms

Filing Info

  • Accession Number: 00057111
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Report/Paper Numbers: PhD Thesis
  • Files: TRIS
  • Created Date: Jul 31 1974 12:00AM