Strain-Life Approach: Application for Fatigue Design of Ship Superstructure Critical Detail

2014 ◽  
Vol 617 ◽  
pp. 197-202 ◽  
Author(s):  
Sergei Petinov
Keyword(s):  
Empirical Relationship ◽  
Local Stress ◽  
Local Strain ◽  
Ship Hull ◽  
Fatigue Properties ◽  
Block Type ◽  
Service Reliability ◽  
Expansion Joint ◽  
Fatigue Design ◽  
Critical Detail

Strain-Life approach to fatigue analysis of structures being developed since early 1960s recently was considered applicable in Civil Engineering, in particular, for fatigue evaluation of bridge structure with integrated abutments. To exemplify the approach and display the problems of its implementation in fatigue design, in-service reliability of structures, an example of fatigue design of a ship superstructure critical detail is presented. The detail is located at expansion joint ending in the superstructure which is frequently applied in ship design aimed at reducing stresses in a long superstructure caused by the general bending deformation of ship hull. Specific of the detail is the high local stress concentration which may result in fatigue damage menacing integrity of the ship hull. In the example of fatigue design of the expansion joint the modified «Strain-Life» criterion for fatigue of material is applied along with empirical relationship providing evaluation of the local strain. This version of the approach allows assessment of fatigue properties of the detail without utilizing Neuber’s formula and presenting the loading history in the block-type format. The results of analysis allowed selection of the expansion joint detail of the superstructure geometry and construction procedure at a shipyard providing necessary reliability.

Fatigue Assessment of Ship Superstructure at Expansion Joint

2013 ◽  
Vol 155 (A4) ◽  
Keyword(s):  
Stress Distribution ◽  
Block Type ◽  
Expansion Joint ◽  
Fatigue Assessment ◽  
Fatigue Design ◽  
Construction Procedure ◽  
History Of ◽  
Distribution Transformation ◽  
Selection Of

Despite the long history of application of subdivided superstructures and deckhouses, and efforts of ship designers and researchers a sensible solution in design of reliable details at the cut endings was not found yet. It may be explained as consequence of controversial requirements in design of the cut endings. Fatigue design of the superstructure details is addressed to solution of the problem. Presented is an example of fatigue design of the cut ending in a fast ship superstructure based on application of modified «Strain-Life» criterion for fatigue and subsequent approach which utilizes Neuber's formula and material cyclic properties. To realize the approach a procedure of the long-term stress distribution transformation to the block-type format is developed. Efficiency of the developed technique is illustrated by comparing the results with those of application standard S-N criteria based techniques. The results of analysis allowed selection of the expansion joint detail of the superstructure geometry and construction procedure providing necessary reliability.

FATIGUE ASSESSMENT OF SHIP SUPERSTRUCTURE AT EXPANSION JOINT

2021 ◽  
Vol 155 (A4) ◽  
Author(s):  
S V Petinov ◽  
R V Guchinsky
Keyword(s):  
Stress Distribution ◽  
Block Type ◽  
Expansion Joint ◽  
Fatigue Assessment ◽  
Fatigue Design ◽  
Construction Procedure ◽  
History Of ◽  
Distribution Transformation ◽  
Selection Of

Despite the long history of application of subdivided superstructures and deckhouses, and efforts of ship designers and researchers a sensible solution in design of reliable details at the cut endings was not found yet. It may be explained as consequence of controversial requirements in design of the cut endings. Fatigue design of the superstructure details is addressed to solution of the problem. Presented is an example of fatigue design of the cut ending in a fast ship superstructure based on application of modified «Strain-Life» criterion for fatigue and subsequent approach which utilizes Neuber’s formula and material cyclic properties. To realize the approach a procedure of the long-term stress distribution transformation to the block-type format is developed. Efficiency of the developed technique is illustrated by comparing the results with those of application standard S-N criteria based techniques. The results of analysis allowed selection of the expansion joint detail of the superstructure geometry and construction procedure providing necessary reliability.

Enhanced fatigue resistance and lattice dynamics induced by the strong local strain in Fe-doped KTa1-xNbxO3 single crystal

2021 ◽  
Author(s):  
Xiaolin Huang ◽  
Peng Tan ◽  
Yu Wang ◽  
Yao Zhang ◽  
Xiangda Meng ◽  
...  
Keyword(s):  
Single Crystal ◽  
Fatigue Resistance ◽  
Lattice Dynamics ◽  
Piezoelectric Materials ◽  
Local Strain ◽  
Lead Free ◽  
Fatigue Properties ◽  
Practical Applications ◽  
Local Structures ◽  
The Impact

Improvement of durability is greatly important for the practical applications of lead-free-doped piezoelectric materials. However, the promotional mechanism of anti-fatigue properties and the impact on local structures from ion dopants...

The Study on the Fatigue Test and Reliability for the Steel of Train Wheel

2012 ◽  
Vol 198-199 ◽  
pp. 146-149
Author(s):  
Wen Qin Han ◽  
Jin Yu Zhou
Keyword(s):  
Fatigue Life ◽  
Safety Evaluation ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Design Standards ◽  
Design Data ◽  
Fatigue Design ◽  
Grouping Method ◽  
Fluctuation Method ◽  
Curve Equation

To obtain fatigue design data of the train wheel steel , the fatigue tests were carried out for the steel of K type and B type train wheel separately, which fatigue limit was measured using the fluctuation method, the fatigue life of two kinds of wheel steels were tested using the grouping method at the three stress levels, two different materials and different structures have an influence on the fatigue properties of the wheels using reliability principle. The fatigue life distribution of the B type is scattered relatively . S-N curve equation and P-S-N curve equation of the two kinds of steel were calculated . The theoretical basis were put up for developing design standards and safety evaluation of the both wheel.

Calculation of Local Elastic Constants at a Metallic Grain Boundary

1989 ◽  
Vol 153 ◽  
Author(s):  
M. D. Kluge ◽  
J. F. Lutsko ◽  
D. Wolf ◽  
S. R. Phillpot
Keyword(s):  
Grain Boundary ◽  
Elastic Constant ◽  
Atomistic Simulation ◽  
Local Stress ◽  
Local Strain ◽  
Simulation Method ◽  
Structural Disorder ◽  
Dramatic Reduction ◽  
High Angle ◽  
Inhomogeneous Systems

AbstractA new atomistic-simulation method for calculating the full local elastic-constant tensor in terms of local stress and local strain for inhomogeneous systems is described. Results of simulations of an isolated high-angle twist grain boundary are presented. A dramatic reduction in resistance to shear parallel to the grain boundary is observed, and its relation to structural disorder is discussed.

Estimation of Maximum Pressure Stress Intensity in a Welding Tee

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Martin Blackman
Keyword(s):  
New York ◽  
Empirical Relationship ◽  
Local Stress ◽  
Pressure Vessels ◽  
Maximum Pressure ◽  
Element Analysis ◽  
Pipe Bend ◽  
Process Piping ◽  
American Society ◽  
Pressure Stress

The required thickness of welding tees is neither specified in ASME (2012, “Factory-Made Wrought Buttwelding Fittings,” American Society of Mechanical Engineers, New York, Standard No. B16.9-2012) nor is a clear calculation method provided in codes such as ASME (2016, “Process Piping,” American Society of Mechanical Engineers, New York, Standard No. B31.3-2016). This can lead to uncertainty regarding the pressure capacity of a tee fitting, particularly one that has suffered from erosion or corrosion. Code methods including area replacement (ASME, 2016, “Process Piping,” American Society of Mechanical Engineers, New York, Standard No. B31.3-2016) or pressure-area (ASME, 2015, “Boiler and Pressure Vessel Code Section VIII Division 2,” American Society of Mechanical Engineers, New York, Standard No. BPVC-VIII-2-2015; BSI, 2014, “Unfired Pressure Vessels Part 3: Design,” BSI, London, UK, Standard No. BS EN 13445-3) do not directly account for the effect which the curvature of the crotch region may have on the stress state in the tee. The approach adopted in this work is to liken the geometry of the tee crotch to the intrados of a torus or pipe bend. The shell theory applicable to the torus is adapted for the tee in order to derive a relationship for circumferential membrane stress. An equivalent tube radius is assigned by determining the local radius of shell curvature in the plane passing through the crotch center of the curvature. The actual stresses in the tee crotch are significantly reduced by the adjoining straight portions. This effect is difficult to quantify theoretically and has thus been investigated by means of finite element analysis (FEA)-based assessments. An empirical relationship was then established providing a conservative correlation between the theoretical stresses and the program calculated local stress intensities.

Experimental Study on the Fatigue Properties and Reliability for the Steel of Elastic Oil Sump

2013 ◽  
Vol 300-301 ◽  
pp. 1377-1380
Author(s):  
Bin Li ◽  
Zong De Liu ◽  
Peng Duan
Keyword(s):  
Large Scale ◽  
Stress Ratio ◽  
Cyclic Stress ◽  
Probabilistic Methods ◽  
Life Assessment ◽  
Fatigue Properties ◽  
Test Results ◽  
Design Data ◽  
Cyclic Stress Ratio ◽  
Fatigue Design

The elastic oil sump is commonly used as support parts in large-scale thrust bearing. It often operates under fluctuating load conditions during service. So, fatigue analysis of the material of the elastic oil sump is of great significance. In order to obtain the fatigue design data of the material of the elastic oil sump, the systematic tests on uniaxial tension-compression fatigue at room temperature are made. The fatigue limits and the fatigue life curves of the steel of the elastic oil sump are determined at different cyclic stress ratio. The P-S-N equations are calculated by the probabilistic methods. The test results provide a theoretical basis for the safety of life assessment of the elastic oil sump.

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