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.

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.

Investigation on Fatigue Properties of Cold Stretched Austenitic Stainless Steel

2011 ◽  
Author(s):  
Cunjian Miao ◽  
Jinyang Zheng ◽  
Li Ma ◽  
Duyi Ye
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Design Method ◽  
Low Cycle Fatigue ◽  
Rolling Direction ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Fatigue Properties ◽  
Fatigue Design

Cold stretched pressure vessels from austenitic stainless steel (ASS), which are sometimes subjected to alternative loads during operation, have been widely used for storage and transportation of liquefied gases. Understanding how the fatigue properties respond to cold stretching is the basis for establishing fatigue design method of such vessels. This paper involves in the fatigue properties of ASS with 9% plastic deformation by pre-stretching parallel to the rolling direction at room temperature. For this purpose, low-cycle fatigue tests at total strain amplitudes ranging from ±0.4 to 0.8% of cold stretched ASS EN 1.4301 (equivalents include UNS S30400, AISI 304) are performed, while the martensite contents are measured during the fatigue cycles. A comparison study of cyclic stress-strain behavior and fatigue lives is carried out for both cold stretched and solution annealed specimens. Based on the testing results, a S-N curve of cold stretched ASS is obtained, which is compared with the design curves given by the standards such as ASME BPVC VIII-2. These works may help to establish a favorable foundation for the development of fatigue design in cold stretched pressure vessel.

Fatigue Design of Leaf Spring Based on Proving Ground

2004 ◽  
Vol 261-263 ◽  
pp. 1295-1300
Author(s):  
Il Seon Sohn ◽  
Dong Ho Bae ◽  
Won Seok Jung ◽  
S.J. Park
Keyword(s):  
Design Method ◽  
Maximum Load ◽  
Fatigue Tests ◽  
Design Criterion ◽  
Bending Test ◽  
Leaf Spring ◽  
Bending Fatigue ◽  
The Road ◽  
Fatigue Design ◽  
Test Result

The suspension system of vehicle is directly influenced to ride and handling. Therefore, suspension part should have enough endurance during its lifetime to protect passenger. Spring is one of major suspension part of vehicle. Thus, in this paper, a fatigue design method for leaf spring based on proving ground response was proposed. At first, stress and displacement of leaf spring are measured through the proving ground test. And next, the maximum load acting on leaf spring assembly under driving condition was defined from the road load response. On the base of these results, fatigue tests for leaf spring assembly and 3-point bending fatigue tests for material of leaf spring were carried out. From the above, the maximum load-fatigue life relation of leaf spring material and assembly was defined, and 3-point bending test result has good agreement with leaf spring assembly fatigue test result. Thus, it is expect that economical fatigue design criterion for leaf spring assembly can be determined from fatigue data of simple smooth specimen by 3 point bending fatigue tests.

Design and Research of Double-Drum Winch with Anti-Pressure Wheel

2012 ◽  
Vol 479-481 ◽  
pp. 1709-1713
Author(s):  
Kai An Yu ◽  
Tao Yang ◽  
Chang Zhi Gong
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Finite Element Methods ◽  
Design Method ◽  
New Method

In view of the problems of large stress and severe bearing heating in double-drum winch at present, this paper adopted a new method to enhance bearing capacity for double-drum winch by adding anti-pressure wheels between two drums. Finite element methods were used to analyze the strength of 4000kN-traction double-drum winches with anti-pressure wheels and without anti-pressure wheels respectively. The results of the analysis revealed that the stress of the cylinder bearing decreased from 264MPa to 167MPa. The new method by adding anti-pressure wheels had remarkably improved the endurance of the bearing. Therefore, the design method can be widely used in large-traction double-drum winch.

Public Policy Administration

1985 ◽  
Vol 47 ◽  
pp. 1-16
Author(s):  
Richard A. Brumback
Keyword(s):  
Rhode Island ◽  
General Level ◽  
American Government ◽  
Introductory Course ◽  
The Past ◽  
Business Colleges ◽  
Business College ◽  
Large Numbers ◽  
The Subject ◽  
One Year

The teaching of an introductory course in American Government can be a difficult and frustrating endeavor under even the best of circumstances. Given the general level of cynicism and/or lack of interest by large numbers of Americans regarding politics and politicians, the task of generating student enthusiasm, or even mild interest, toward the subject matter can indeed be an arduous one. When the teaching of such a course takes place in a business college, and when the student audience is “captive” to a college requirement that all students must take the course, the task can be rendered considerably more formidable.For the past six years I have been teaching such courses at business colleges — one year at Bryant College in Rhode Island, and the following five years at Bentley College in Massachusetts.

Finite Element Analysis of Creep Damage Behavior Near the Cavity on Bimaterial Interface

2006 ◽  
Vol 324-325 ◽  
pp. 951-954 ◽  
Author(s):  
Qing Min Yu ◽  
Zhu Feng Yue ◽  
Yong Shou Liu
Keyword(s):  
Finite Element ◽  
Elastic Moduli ◽  
Elastic Stress ◽  
Creep Damage ◽  
Ductile Material ◽  
Bimaterial Interface ◽  
Modulus Ratio ◽  
Element Analysis ◽  
Damage Law ◽  
The Difference

Fracture along an interface between materials plays a major role in failure of material. In this investigation, finite element calculations with Kachanov–Rabotnov damage law were carried out to study the creep damage distribution near the interface cavity in bimaterial specimens. The specimens with central hole were divided into three types. The material parameters of K-R law used in this paper were chosen for a brittle material and ductile material. All calculations were performed under four load cases. Due to the difference between elastic moduli of the bounded materials, the elastic stress field as a function of the Young’s modulus ratio (R=E1/E2) was determined. At the same time, the influence of model type on elastic stress distribution near the cavity was considered. Under the same conditions, the material with larger modulus is subjected to larger stress. The creep damage calculations show that the location of the maximum damage is different for each model. The distributions of creep damage for all three models are dependent on the material properties and load cases.

Finite Element Analysis and Optimization of Long-Span Gantry NC Machining Center Structure

2011 ◽  
Vol 346 ◽  
pp. 379-384
Author(s):  
Shu Bo Xu ◽  
Yang Xi ◽  
Cai Nian Jing ◽  
Ke Ke Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Design Method ◽  
Dynamic Performance ◽  
Plate Thickness ◽  
Element Model ◽  
Wall Structure ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
Dynamic Performance Analysis

The use of finite element theory and modal analysis theory, the structure of the machine static and dynamic performance analysis and prediction using optimal design method for optimization, the new machine to improve job performance, improve processing accuracy, shorten the development cycle and enhance the competitiveness of products is very important. Selected for three-dimensional CAD modeling software-UG NX4.0 and finite element analysis software-ANSYS to set up the structure of the beam finite element model, and then post on the overall structure of the static and dynamic characteristic analysis, on the basis of optimized static and dynamic performance is more superior double wall structure of the beam. And by changing the wall thickness and the thickness of the inner wall, as well as the reinforcement plate thickness overall sensitivity analysis shows that changes in these three parameters on the dynamic characteristics of post impact. Application of topology optimization methods, determine the optimal structure of the beam ultimately.

Structure-Soil Interaction of Buried Corrugated Steel Arch Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 2112-2117
Author(s):  
Miao Xin Zhang ◽  
Bao Dong Liu ◽  
Peng Fei Li ◽  
Zhi Mao Feng
Keyword(s):  
Finite Element ◽  
Steel Structures ◽  
Internal Force ◽  
Structural Deformation ◽  
Fe Model ◽  
Soil Pressure ◽  
Load Range ◽  
Finite Element Program ◽  
Load Conditions ◽  
Peak Value

Corrugated steel plate and surrounding soils are working together to share the load in buried corrugated steel structures. It is complicated to consider the structure-soil interaction, so the finite element method has already become the chief means of complicated structure analysis. Based on a practical project, considering structure-soil interaction, by using the finite element program of ANSYS, the paper set up a 2-D FE model and analyzed the soil pressure, the structural deformation and the internal force under different load conditions in detail. The analysis shows that structure-soil interaction has brought about stresses redistribution of surrounding soils, and adverse effects of soil pressure and displacement were limited. The variation range of soil pressure on the crown of arch increases with the load increases and the peak value of soil pressure approach to the code value and a rebound appears in the vehicle load range. The tendencies of vertical soil displacement are nearly the same to different load conditions, and the peak value of moments has an obvious change and can be influenced greatly by deflective load.

ECA Methodology for Fatigue Design of Risers and Flowlines

2007 ◽  
Author(s):  
C. H. Luk ◽  
T. J. Wang
Keyword(s):  
Fracture Mechanics ◽  
Design Method ◽  
Steel Catenary Riser ◽  
Fatigue Design ◽  
Wide Range ◽  
Fatigue And Fracture ◽  
Level 3 ◽  
Fatigue Loads ◽  
Vessel Motion ◽  
Level 2

Engineering Criticality Assessment (ECA) is a procedure based on fracture mechanics that may be used to supplement the traditional S-N approach and determine the flaw acceptance and inspection criteria in fatigue and fracture design of risers and flowlines. A number of design codes provide guidance for this procedure, e.g. BS-7910:2005 [1]. However, more investigations and example studies are still needed to address the design implications for riser and flowline applications. This paper provides a review of the existing ECA methodology, presents a fracture mechanics design method for a wide range of riser and flowline fatigue problems, and shows flaw size results from steel catenary riser (SCR) and flowline (FL) examples. The first example is a deepwater SCR subjected to fatigue loads due to vessel motion and riser VIV. The second example is a subsea flowline subjected to thermal fatigue loads. The effects of crack re-characterization and material plasticity on the Level-2 and Level-3 ECA results of the SCR and flowline examples are illustrated.

Contrastive Study on Finite Element Models of High-Strength Pipelines Crossing Active Faults

2016 ◽  
Vol 850 ◽  
pp. 957-964
Author(s):  
Wei Zheng ◽  
Hong Zhang ◽  
Xiao Ben Liu ◽  
Le Cai Liang ◽  
Yin Shan Han
Keyword(s):  
Finite Element ◽  
Design Method ◽  
Active Faults ◽  
Shell Element ◽  
High Strength ◽  
Element Model ◽  
Beam Element ◽  
Finite Element Models ◽  
Fixed Boundary ◽  
Equivalent Boundary

There is a potential for major damage to the pipelines crossing faults, therefore the strain-based design method is essential for the design of buried pipelines. Finite element models based on soil springs which are able to accurately predict pipelines’ responses to such faulting are recommended by some international guidelines. In this paper, a comparative analysis was carried out among four widely used models (beam element model; shell element model with fixed boundary; shell element model with beam coupled; shell element model with equivalent boundary) in two aspects: differences of results and the efficiency of calculation. The results show that the maximum and minimum strains of models coincided with each other under allowable strain and the calculation efficiency of beam element model was the highest. Besides, the shell element model with beam coupled or equivalent boundary provided the reasonable results and the calculation efficiency of them were higher than the one with fixed boundary. In addition, shell element model with beam coupled had a broader applicability.

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