Fracture Mechanics A Practical Application to Off shore Mobile 0rilling Units

Abstract

Fracture Mechanics A Practical Application to Off shore Mobile 0rilling Units Frank R. Gollhofer Frank R. Gollhofer Transworld Drilling Co. Search for other works by this author on: This Site Google Scholar Paper presented at the Offshore Technology Conference, Houston, Texas, May 1974. Paper Number: OTC-2118-MS https://doi.org/10.4043/2118-MS Published: May 05 1974 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Gollhofer, Frank R. "Fracture Mechanics A Practical Application to Off shore Mobile 0rilling Units." Paper presented at the Offshore Technology Conference, Houston, Texas, May 1974. doi: https://doi.org/10.4043/2118-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsOffshore Technology ConferenceOTC Offshore Technology Conference Search Advanced Search ABSTRACTNow reasonable criteria affecting the life of offshore structures can be determined. A sample problem shows that fracture mechanics analysis can be effectively used to establish these criteria for design, inspection and repair of such units. Fracture mechanics analysis can improve structural quality and save downtime costs. Better judgments can be made concerning material and stress level selections, inspection frequency and zones of concentration, and urgency of repair.Basic fracture mechanics analysis formulations are reviewed, and material data existing in literature are referenced and used.INTRODUCTIONHow do you avoid costly downtime caused by structural cracking of complex present day offshore mobile_ drilling units? Fracture mechanics analysis allows you to do just that Since fracture mechanics is still a relatively new method of analysis, information on test methods and material data development can be easily found in literature. This paper, however, deals with the practical application of fracture mechanics analysis, that of establishing meaningful design, inspection and repair criteria.During the design, fracture mechanics analysis helps the designer select materials, set stress allowable and design details to minimize structural cracking. After the design is established the analysis helps the designer to predict the time it takes a crack that is likely to be missed by an inspection to grow to critical proportions. The designer can then factor this time period to establish inspection frequency. This provides a high degree of assurance that all cracks will be found and repaired before a catastrophic failure occurs.Since we are concerned with the practical application of fracture mechanics, a review of the basic formulations is presented and a sample problem is developed using material data exist ing in the literature.STRESS INTENSITY FACTORThe basic premise in fracture mechanics analysis is that a flaw or crack of some form exists in all structural materials. The crack surfaces are stress free boundaries, so that portion of material near the crack tip directly influences the local stress field. A material parameter which reflects the redistribution of stress around a crack in an elastic body and which reflects mode and size of force carried through the tip region has been identified as the stress intensity factor, K. Keywords: fracture mechanics, inspection, correction factor, critical size, thickness, repair criteria, upstream oil & gas, hydraulic fracturing, criteria, engineer Subjects: Hydraulic Fracturing This content is only available via PDF. 1974. Offshore Technology Conference You can access this article if you purchase or spend a download.