Numerical and Experimental Research on Residual Ultimate Strength of Hull Plates Under Uniaxial Cyclic Loads

2019 ◽  
Author(s):  
Tian Xia ◽  
Ping Yang ◽  
Cong Cui ◽  
Ziya Peng ◽  
Li Ma
Keyword(s):  
Ultimate Strength ◽  
Cyclic Load ◽  
Low Cycle Fatigue ◽  
Numerical Results ◽  
Ship Hull ◽  
Nonlinear Finite Element ◽  
Cyclic Loads ◽  
Nonlinear Finite Element Method ◽  
Cycle Fatigue ◽  
Plastic Damage

Abstract The present paper aims at obtaining insights on the strength behaviors of ship hull plates under uniaxial cyclic loads. The residual ultimate strength of ship hull plates under uniaxial cyclic load is studied by numerical analysis using nonlinear finite element method. A series of tests are also conducted for comparison and verify the reasonability of numerical results. The accumulated plastic damage and crack propagation from the low cycle fatigue damage during cyclic load are both considered in present study. From the numerical results and tests some significant conclusions are drawn to the residual ultimate strength of plates under uniaxial cyclic loads.

Research on Load Bearing Behavior of Ship Stiffened Plates under Cyclic Loads

2014 ◽  
Vol 904 ◽  
pp. 446-449
Author(s):  
Hu Wei Cui ◽  
Ping Yang ◽  
Can Shen ◽  
Liang Zhou
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Ultimate Strength ◽  
Nonlinear Finite Element ◽  
Stiffened Plates ◽  
Cyclic Loads ◽  
Nonlinear Finite Element Method ◽  
Load Bearing ◽  
Different Dimensions ◽  
Bearing Behavior

This paper adopts nonlinear finite element method to study the load bearing behavior of ship stiffened plates with different dimensions. The research focuses on the compressive ultimate strength, axial rigidity, and residual plastic deflection of the stiffened plates under cyclic compressive and tensile loads. The results indicate that the compressive ultimate strength and axial rigidity of stiffened plates decrease with the incremental cyclic loads significantly, meanwhile, the residual plastic deflection increases with the cyclic loads.

Low-cycle fatigue of ship hull damaged in collision

2019 ◽  
Vol 96 ◽  
pp. 436-454 ◽  
Author(s):  
Ivana Gledić ◽  
Joško Parunov ◽  
Pero Prebeg ◽  
Maro Ćorak
Keyword(s):  
Low Cycle Fatigue ◽  
Ship Hull ◽  
Cycle Fatigue

Low-Cycle-Fatigue Crack Closure Effect of Ship Cracked Plate Considering the Accumulative Plastic Damage

2019 ◽  
Author(s):  
Yuelin Song ◽  
Ping Yang ◽  
Ziya Peng ◽  
Wei Jiang ◽  
Kang Hu
Keyword(s):  
Stress Field ◽  
Compressive Stress ◽  
Crack Closure ◽  
Low Cycle Fatigue ◽  
Crack Tip ◽  
Cycle Fatigue ◽  
Plastic Damage ◽  
Closure Effect ◽  
Closure Level ◽  
The Relationship

Abstract In this paper, the relationship between crack closure level and the crack length is studied with experiment and numerical simulation under different low cycle fatigue (LCF) loads. The evolution mechanism of crack closure behavior is explored through the variations of the accumulative plastic strain and compressive stress near the crack-tip. The compressive residual stress is separated into two parts for comparative analysis, namely: the stress field ahead of the crack tip and the stress field of the wake region. The magnitude of the compressive stress field is obtained by the integration along the crack propagation direction of the normal stress. The results show that there is an excellent correlation between LCF crack closure level and the magnitude of the compressive stress in the plastic wake, which provides a new way to further study the complex mechanism of crack closure under LCF loads.

Fatigue Properties of Welded Joints of High-Carbon Steels

2007 ◽  
Vol 537-538 ◽  
pp. 47-54 ◽  
Author(s):  
Attila Magasdi ◽  
János Dobránszky ◽  
F. Tusz ◽  
János Ginsztler
Keyword(s):  
Fatigue Fracture ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Cyclic Load ◽  
Low Cycle Fatigue ◽  
Carbon Steels ◽  
Fatigue Properties ◽  
Welding Parameters ◽  
Cycle Fatigue ◽  
Very High

The typical tool steels of the wood-cutting industry are the unalloyed and chromium and nickel containing, low-alloyed eutectoid steels. These materials, in tempered condition have a very high, 1200-1400 MPa tensile strength. One of the major failure forms of these tools is the fatigue fracture of the tool. The high pretension and the cyclic load, caused by the cutting and the bending of the tool, easily can cause high-cycle fatigue fracture, especially at the welded area and at the heat affected zone. Thus, one of the most critical part in the manufacturing process of the bandsaw blade is the welding. We have examined the fatigue properties of three types of joints: conventional and cold wire TIG welding, MIG welding, and resistance-butt welded joints. The structure at the weld and at the heat affected zone could highly affect the life-span of the tool. Therefore the welding parameters (preheat, post welding heat treatment (PWHT), shield gas, backing gas), affecting the microstructure of the weld, also have serious affects on the fatigue properties. The influence of welding parameters on the fatigue properties were examined by low-cycle fatigue test.

Low Cycle Fatigue of Internally Pressurized Corroded Pipes Under Cyclic Bending

2009 ◽  
Author(s):  
Marcos Andre´ Baeta ◽  
Marcelo Igor Lourenc¸o ◽  
Theodoro A. Netto
Keyword(s):  
Cyclic Load ◽  
Low Cycle Fatigue ◽  
Numerical Models ◽  
Experimental Tests ◽  
Small Scale ◽  
Cycle Fatigue ◽  
Cyclic Tests ◽  
Operational Conditions ◽  
Oil Transportation ◽  
Operational Load

Corroded pipes for oil transportation can eventually experience low cycle fatigue failure after some years of operation. The evaluation of the defects caused by corrosion in these pipes is important when deciding for the repair of the line or continuity in operation. Under normal operational conditions, these pipes are subject to constant internal pressure and cyclic load due to bending and/or tension. Under such loading conditions, the region in the pipes with thickness reduction due to corrosion could experience the phenomenon known as ratcheting. The objective of this paper is to present a revision of the available numerical models to treat the ratcheting phenomenon. Experimental tests were developed allowing the evaluation of occurrence of ratcheting in corroded pipes under typical operational load conditions as well as small-scale cyclic tests to obtain the material parameters. Numerical and experimental tests results are compared.

Effects of Welding Residual Stresses on High Tensile Steel Plate Ultimate Strength: Nonlinear Finite Element Method Investigations

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Jeom Kee Paik ◽  
Jung Min Sohn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
Ultimate Strength ◽  
Plate Thickness ◽  
Primary Objective ◽  
Nonlinear Finite Element ◽  
Steel Plates ◽  
Nonlinear Finite Element Method ◽  
Element Method

The primary objective of the present paper is to examine the effects of welding residual stresses on ultimate strength of high tensile steel plates under axial compression in terms of their magnitude and pattern. The ANSYS nonlinear finite element method is employed for the purpose. The secondary objective of the present paper is to study a nonlinear finite element method modeling technique for welded plate structures with residual stresses. Three levels of residual stresses, namely slight, average, and severe, are considered. As another important parameter of influence on the plate ultimate strength, the plate thickness is also varied in the numerical computations to examine their role and trend. Important insights and conclusions developed from the present study are documented.

Low Cycle Fatigue Strength of X65 Pipeline Girth Welds

2004 ◽  
Author(s):  
Koji Gotoh ◽  
Stig Berge
Keyword(s):  
Low Cycle Fatigue ◽  
Cyclic Strain ◽  
Test Series ◽  
Cyclic Loads ◽  
Plastic Strains ◽  
Maximum Strain ◽  
Cycle Fatigue ◽  
Fatigue Design ◽  
Large Water ◽  
Girth Welds

During pipe laying at large water depth using S-lay over a stinger, the pipe may be subjected to reversed plastic strains which could lead to low cycle fatigue failure. X65 pipeline girth welds with wall thickness 22mm were tested in cyclic strain control. Undermatched and overmatched welds were tested. Two types of cyclic strain programs were applied. In the first test series the welds were subjected to a tensile-tensile cyclic strain, simulating pipe going over the stinger, to validate that a pipe going over a stinger would not violate criteria for low cycle fatigue design. In the second test series, the specimens were initially pre-strained to 2% and subsequently fatigue-cycled with a maximum strain of 2% to obtain design criteria for a pipe laying stationary over the stinger for a period of time, subjected to cyclic loads due to waves. The results are presented in terms of Δε–N curves, with proposed design curves for the two types of welds.

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