The Use of Digital Computers in Offshore Structure Analysis and Design

Abstract

Publication Rights Reserved This paper is to be presented at the Society of Petroleum Engineers of AIME Symposium on Offshore Technology and Operations to held in New Orleans, La., May 23–34, 1966, and is considered the property of the Society of Petroleum Engineers. Permission to publish is hereby restricted to an abstract of not more than 300 words, with no illustration, unless the paper is specifically released to the press by the Editor of the Journal of Petroleum Technology or the Executive Secretary. Such abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. publication elsewhere after publication in Journal of Petroleum Technology or Society of Petroleum Engineers Journal is granted on request, providing proper credit is given that publication and the original presentation of the paper Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting, and with the paper, may be considered for publication in one of the two SPE magazines. Abstract Experience with the application of digital computer programs to the analysis and design of offshore structures by Shell Oil Co.'s Construction-Design Group is described. General background on and insight into digital computers and computer programming for use in design work is presented. Program applications and programming documentation practices found desirable in design work are described. The importance of efficient application, proper problem simulation, and thorough solution checking when using digital computers in offshore structure design is treated. Introduction In late 1962, Shell Oil Co.'s construction-design group undertook a program directed toward the application of digital computer programs to offshore structure design. This paper describes the experience of the construction-design group since that time with writing and applying digital computer programs to the analysis and design of offshore structures. DIGITAL COMPUTERS AND COMPUTER PROGRAMMING This section will present some background on and insight into digital computers and computer programming for use in design work. Much of the information presented will be "old hat" to those involved in programing or program applications, but it is presented to acquaint those with an interest in technical programming or engineering design utilizing computers with these concepts. Computer Operations and Hardware A good analogy can be drawn between the common desk calculator and a digital computer. The desk calculator will receive instructions from an operator, carry out arithmetical operations and hold or accumulate numbers in different registers. The computer is able to do these same operations much faster and with much greater accuracy, but the basic difference is that the computer can be given a set of instructions, or programmed, to carry out a sequence of operations. This would be similar to the desk calculator with an operator who does only what he is instructed to do according to some prescribed sequence of instructions. The desk calculator operator must take the numbers to be operated on from a computation sheet, perform the indicated operations listed on an instruction sheet., and write the results on a computation sheet. These operations basically define the functions of the essential components of a digital computer: