Ultimate Strength Design of Racks for Jack-Up Units

1986 ◽  
Vol 108 (3) ◽  
pp. 413-423
Author(s):  
Hiroshi Honda
Keyword(s):  
Ultimate Strength ◽  
Cross Section ◽  
Elastic Stress ◽  
Shear Fracture ◽  
Design Method ◽  
Design Criteria ◽  
Fracture Test ◽  
Strength Design ◽  
The Subject ◽  
Jack Up

The subject of paper discusses an approach taken in evaluating the load acting on racks for jack-up units (the jack load) together with its computed results. The fracture test of a full-scale rack for a jack-up unit and a finite-element elastic stress analysis for this rack were also conducted. These results led to new design criteria for the ultimate strength design method of racks for jack-up units, when exposed to a combination of loads including stormy conditions. Typically, the ultimate strength of the racks was evaluated on the assumption that the cross section of the rack tooth plastically collapses at its root. During this investigation, it was shown, however, that the ultimate strength of the racks needs to be evaluated also on the premise that the rack tooth is subject to shear fracture caused by its mating pinion tooth.

Fatigue Design of Racks for Jack-Up Units

1986 ◽  
Vol 108 (3) ◽  
pp. 403-412
Author(s):  
Hiroshi Honda
Keyword(s):  
Finite Element ◽  
Elastic Stress ◽  
Design Method ◽  
Fatigue Tests ◽  
Load Range ◽  
Fatigue Design ◽  
Draft Proposal ◽  
The Subject ◽  
One Year ◽  
Jack Up

The subject paper presents the methods and results of fatigue tests for both torch-cut and machined racks using 40.4 mm module and finite-element elastic stress analyses for these racks. Further, the results of the analysis of fluctuating jack load range distribution over a one-year period for a jack-up rig is presented. The author proposes a fatigue design method of racks for jack-up units based on the foregoing results. The proposed fatigue design method was compared with those of ASME Boiler and Pressure Vessel Code, DNV’s Classification Notes, and the draft proposal of ISO for the strength design of gears, resulting in the conclusion that a single conventional fatigue design method as presented by ASME, ISO and DNV is insufficient for the fatigue design of these racks.

Design criteria for steel I columns under axial load and biaxial bending

1976 ◽  
Vol 3 (3) ◽  
pp. 466-473
Author(s):  
D. A. Ross ◽  
W. F. Chen
Keyword(s):  
Ultimate Strength ◽  
Axial Load ◽  
Bending Moment ◽  
Design Criteria ◽  
Biaxial Bending ◽  
Design Code ◽  
Simple Modification ◽  
Strength Design ◽  
Depth Ratio

The design code, Canadian Standard S16.1-1974, permits ultimate strength design steel H columns subjected to axial load and biaxial bending moment. However, this is permitted only for sections in which the flange width to section depth ratio is equal to or greater than 0.8. In this paper a simple modification to the previous formulas is proposed which enables the restriction on flange width to section depth ratio to be removed so that they are also applicable to steel I columns.

Analytical and High-Resolution EM Study of Crystalline Phases formed at Metal-Ceramic Interface

1990 ◽  
Vol 48 (2) ◽  
pp. 426-427
Author(s):  
N. Merk ◽  
A. P. Tomsia ◽  
G. Thomas
Keyword(s):  
Cross Section ◽  
Dissimilar Materials ◽  
Ceramic Materials ◽  
Electron Micrograph ◽  
Scanning Electron Micrograph ◽  
Structural Applications ◽  
Metal Ceramic ◽  
The Subject ◽  
Ceramic Compounds ◽  
Scanning Electron

A recent development of new ceramic materials for structural applications involves the joining of ceramic compounds to metals. Due to the wetting problem, an interlayer material (brazing alloy) is generally used to achieve the bonding. The nature of the interfaces between such dissimilar materials is the subject of intensive studies and is of utmost importance to obtain a controlled microstructure at the discontinuities to satisfy the demanding properties for engineering applications . The brazing alloy is generally ductile and hence, does not readily fracture. It must also wett the ceramic with similar thermal expansion coefficient to avoid large stresses at joints. In the present work we study mullite-molybdenum composites using a brazing alloy for the weldment.A scanning electron micrograph from the cross section of the joining sequence studied here is presented in Fig. 1.

Application of the Strength Design Method for Flexural Members at Prestress Transfer

PCI Journal ◽  
2003 ◽  
Vol 48 (5) ◽  
pp. 62-74 ◽  
Author(s):  
Panya Noppakunwijai ◽  
Maher K. Tadros ◽  
Chuanbing Sun
Keyword(s):  
Design Method ◽  
Flexural Members ◽  
Strength Design

Factored axial compressive resistance of schifflerized angles

1991 ◽  
Vol 18 (6) ◽  
pp. 926-932 ◽  
Author(s):  
Seshu Madhava Rao Adluri ◽  
Murty K. S. Madugula
Keyword(s):  
Key Words ◽  
Design Method ◽  
Design Criteria ◽  
Design Practice ◽  
Buckling Mode ◽  
Flexural Buckling ◽  
Mode Of Failure ◽  
Current Design ◽  
Similarities And Differences ◽  
Compressive Resistance

The concept of schifflerization of 90° equal-leg angle is presented and its application in triangular-base latticed steel towers is explained. The similarities and differences between schifflerized angles and regular 90° angles are discussed. The current design practice for schifflerized angles is reviewed and its limitation is highlighted. A design method which includes the effect of the torsional-flexural buckling mode of failure is proposed. For ready use of designers, the factored axial compressive resistances of schifflerized angles are tabulated for both the present and proposed design methods. Key words: buckling, compressive resistance, design criteria, schifflerized angles, stability, standards, steel, struts, towers, guyed towers.

Design charts for reinforced concrete L-sections

1976 ◽  
Vol 3 (4) ◽  
pp. 479-483
Author(s):  
Maher K. Tadros
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Normal Force ◽  
Basic Assumptions ◽  
Design Charts ◽  
Strength Design

The object of this paper is to present charts for the ultimate strength design of L-sections subjected to combined normal force and bending. The method of derivation of these charts is briefly described. It is general and applicable to other odd-shaped sections. It also conforms to the basic assumptions adopted in the CSA Standard A 23.3-1973. The charts can be used either for the determination of the dimensions of the section or for the check of its capacity.

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