Experimental investigation of the failure behavior of notched wall-thinned pipes

Kim, Jin Weon; Park, Chi Yong

doi:10.1016/j.nucengdes.2006.02.005

Cited by 7 publications

(8 citation statements)

References 9 publications

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“…(4) and (5), S 1000 nÀwt represents the fatigue strength of wall-thinned curved plate specimens at 10 3 cycles, while S 1;000;000 nÀwt denotes the fatigue strength of wall-thinned curved plate specimens at 10 6 cycles. Also, S 1000 n describes the fatigue strength of the standard specimen at 10 6 cycles, and S 1;000;000 n is the fatigue strength of wall-thinned curved plate specimens at 10 6 cycles.…”

Section: Prediction Of Fatigue Life Of the Wall-thinned Curved Plate mentioning

confidence: 99%

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Fatigue life prediction for an API 5L X42 natural gas pipeline

Hong

Koo

Seok

et al. 2015

Engineering Failure Analysis

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Section: Prediction Of Fatigue Life Of the Wall-thinned Curved Plate mentioning

confidence: 99%

“…Specifically, since earthquake-induced damage of gas pipelines can lead to gas leaks and fire, resulting in property damage and endangering lives, the integrity of gas pipelines is of considerable importance [2][3][4][5]. Therefore, seismic design is needed to determine the importance and fatigue characteristics of pipe structure [6,7].…”

Section: Introductionmentioning

confidence: 99%

Fatigue life prediction for an API 5L X42 natural gas pipeline

Hong

Koo

Seok

et al. 2015

Engineering Failure Analysis

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“…Furthermore, previous studies have evaluated the fatigue life of the target structure based on the test results of standard testing specimens [11,12]. Therefore, the fatigue life of the actual product can be significantly shorter than the fatigue life predicted using the standard testing specimens [13][14][15][16], because the fatigue life of the actual product is influenced not only by the stress-concentrated shape of the structure, but also by the inhomogeneous material distribution and the surface condition according to the manufacturing process such as heat treatment [17][18][19][20]. For example, because the center-link chain of this study is produced by forging the raw material, its mechanical properties and such as surface roughness are affected by the material inhomogeneity of the interior and exterior of the product [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Methods of Improving Mechanical Integrity of Center-Link Chains for a Trolley Conveyor System

Han

Lee²,

Choi

et al. 2019

Int. J. Precis. Eng. Manuf.

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The purpose of this study is to identify the causes of the continuous failure of center-link chains for a trolley conveyor system by analyzing their failure characteristics under static and dynamic loading conditions and to propose methods for securing their mechanical integrity. For this purpose, center-link chains were minimally processed to prepare testing specimens with their original surface property and structural dimension maintained. These specimens were used to measure the tensile strength (1172.1 MPa), elongation (8.7%), yield strength (1073.4 MPa), hardness (44.1 HRC), and surface roughness (R a = 10.5 μm). A three-point bending fatigue test (R = 0.1) resulted in a fatigue limit of 746.7 MPa. The results confirmed that the rough surface of the center-link chain caused a reduction in the elongation and fatigue limit and an increase in the scattering of the surface hardness and fatigue life, which were the direct causes of frequent chain failure in the field. To improve the fatigue life of the center-link chain, two methods were reviewed in this study. The first method was to reduce its surface roughness through surface machining of the center-link chain, and the second was to modify its shape design to allow improved structural integrity, even if the current surface roughness is retained. In the case of the first method, the results of the fatigue test using the specimen with reduced surface roughness (from R a = 10.5 to 0.9 μm) by surface machining demonstrated reduced scattering and increased fatigue limit (from 746.7 to 920.3 MPa). As for the second method, a stiffener was added and two design variables (slope angle and fillet radius) of the stiffener were selected to propose a new design that can reduce the maximum stress ~ 1.6 times compared to the conventional design. While both methods for improving the structural integrity of the center-link chain were effective enough to improve the fatigue life of the chain, the second method, which requires only the initial mold manufacturing cost for modifying the shape design of the chain, was finally selected, because it exhibited better economic feasibility than the first method that increases the product cost and overall process time due to addition of the surface machining process.

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“…For instance, tubes used in the heat exchangers of air conditioners are obtained by the extruding and drawing of raw materials. These processes result in differences in material uniformity, which subsequently affect various properties including surface roughness and hardness . Furthermore, when the materials are eventually fitted for heat exchanger products through further processes such as bending, cutting, and welding, they cause dents and grooves on the material surfaces.…”

Section: Introductionmentioning

confidence: 99%

Effects of external operating environments on fatigue of heat‐exchanger copper tubes

Han

Lee²,

Choi

et al. 2018

Fatigue Fract Eng Mat Struct

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The purpose of this study is to analyze the effects of surface defects (eg, notches) and external environment conditions (eg, operating temperature, the number of re‐weldings) on the static strength and fatigue of C1220T‐O copper tubes used in the heat exchangers of air conditioners. Instead of using standardized specimens, as is done in general rotary bending fatigue tests, special specimens were fabricated in this study by inserting metal plugs on both ends of the copper tubes to perform fatigue tests on the actual tube product, and then the fatigue characteristics were evaluated using stress‐life (S‐N) curves. Regarding the welding conditions (maximum 1000°C and 10 seconds), the grain size grew (grain size number decreased), and the hardness decreased as the number of re‐weldings increased. The effects of the operating temperatures on the fatigue life were examined at a room temperature of 25°C and a heat exchanger operating temperature of 125°C, resulting in the same fatigue limit (70.21 MPa) at both room and operating temperatures. However, the fatigue limit of 37.46 MPa measured in the notched specimens (radius of 3 mm, depth of 0.2 mm) was lower than that obtained from those without notches. The material constant (1.07) used in the Peterson equation was then computed from the fatigue notch factor (1.87 = 70.21/37.46), and the stress concentration factor (2.18) of the notched tube specimens was obtained from the structural analysis. This material constant can be used to predict a decrease in the fatigue limit over varying notch sizes in copper tubes (C1220T‐O).

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Experimental investigation of the failure behavior of notched wall-thinned pipes

Cited by 7 publications

References 9 publications

Fatigue life prediction for an API 5L X42 natural gas pipeline

Fatigue life prediction for an API 5L X42 natural gas pipeline

Methods of Improving Mechanical Integrity of Center-Link Chains for a Trolley Conveyor System

Effects of external operating environments on fatigue of heat‐exchanger copper tubes

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