scholarly journals Profile and Areal Surface Parameters for Fatigue Fracture Characterisation

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3691
Author(s):  
Wojciech Macek ◽  
Ricardo Branco ◽  
Mirosław Szala ◽  
Zbigniew Marciniak ◽  
Robert Ulewicz ◽  
...  
Keyword(s):  
Structural Steel ◽  
Fatigue Tests ◽  
Surface Parameters ◽  
Rupture Area ◽  
Trace Back ◽  
Modern Engineering ◽  
Texture Parameters ◽  
Optical Profilometer ◽  
Structural Failures ◽  
Total Fracture

Post-mortem characterisation is a pivotal tool to trace back to the origin of structural failures in modern engineering analyses. This work compared both the crack propagation and rupture roughness profiles based on areal parameters for total fracture area. Notched and smooth samples made of weather-resistant structural steel (10HNAP), popular S355J2 structural steel and aluminium alloy AW-2017A under bending, torsion and combined bending–torsion were investigated. After the fatigue tests, fatigue fractures were measured with an optical profilometer, and the relevant surface parameters were critically compared. The results showed a great impact of the loading scenario on both the local profiles and total fracture areas. Both approaches (local and total fracture zones) for specimens with different geometries were investigated. For all specimens, measured texture parameters decreased in the following order: total area, rupture area and propagation area.

scholarly journals Profile and Areal Surface Parameters for Fatigue Fracture Characterisation

2020 ◽  
Author(s):  
Wojciech Macek ◽  
Ricardo Branco ◽  
Mirosław Szala ◽  
Zbigniew Marciniak ◽  
Robert Ulewicz ◽  
...  
Keyword(s):  
Structural Steel ◽  
Fatigue Tests ◽  
Surface Parameters ◽  
Rupture Area ◽  
Trace Back ◽  
Modern Engineering ◽  
Texture Parameters ◽  
Optical Profilometer ◽  
Structural Failures ◽  
Total Fracture

Post-mortem characterisation is a pivotal tool to trace back to the origin of structural failures in modern engineering analyses. This work presents a comparison of both the crack propagation profiles and the rupture roughness profiles based on areal parameters for total fracture area. Notched and smooth samples made of weather-resistant structural steel (10HNAP), popular S355J2 structural steel and aluminium alloy AA2017A under bending, torsion, and combined bending-torsion are investigated. After the fatigue tests, fatigue fractures are measured with an optical profilometer, and the relevant surface parameters are critically compared. The results show a great impact of the loading scenario on both the local profiles and the total fracture areas. In this work, the results of both approaches (local and total fracture zones) for specimens with different geometries are investigated. For all specimens, measured texture parameters decreased in the following order: total area, rupture area, and propagation area.

scholarly journals Influence Of Large Non-Metallic Inclusions On Bending Fatigue Strength Hardened And Tempered Steels

2015 ◽  
Vol 15 (3) ◽  
pp. 33-40
Author(s):  
T. Lipiński ◽  
A. Wach ◽  
E. Detyna
Keyword(s):  
Fatigue Strength ◽  
Structural Steel ◽  
Treatment Options ◽  
Fatigue Tests ◽  
Relative Volume ◽  
Heat Processing ◽  
Industrial Plant ◽  
Boron Steel ◽  
Metallic Inclusions ◽  
Steel Sections

Abstract The article discusses the effect of large oxide impurities (a diameter larger than 10 μm in size) on the fatigue resistance of structural steel of high purity during rotary bending. The study was performed on 7 heats produced in an industrial plant. The heats were produced in 140 ton electric furnaces. All heats were desulfurized. The experimental material consisted of semi-finished products of high-grade, carbon structural steel with: manganese, chromium, nickel, molybdenum and boron. Steel sections with a diameter of 18 mm were hardened from austenitizing by 30 minutes in temperature 880°C and tempered at a temperature of 200, 300, 400, 500 and 600°C for 120 minutes and air-cooled. The experimental variants were compared in view of the heat treatment options. Fatigue tests were performed with the use of a rotary bending machine at a frequency of 6000 cpm. The results were statistical processed and presented in graphic form. This paper discusses the results of the relative volume of large impurities, the fatigue strength for various heat processing options.

scholarly journals Research on the micro and dynamic characteristics of combination surface based on fractal theory

2020 ◽  
Vol 11 (1) ◽  
pp. 1-27
Author(s):  
Chunxia Zhu ◽  
Zhibiao Yan
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Characteristics ◽  
Optimization Design ◽  
Contact Stiffness ◽  
Fractal Theory ◽  
Joint Surface ◽  
Tangential Contact ◽  
Surface Parameters ◽  
Mechanical Joint ◽  
Texture Parameters

Abstract. The dynamic characteristics of the mechanical joint surface are important aspects of the dynamic theoretical analysis and optimization design of the machine tool. In this paper, the typical mechanical joint surface is taken as the research object. Through the combination of theoretical analysis and experimental analysis, the dynamic characteristics of typical joint surface parameters with different surface textures and the influence of texture parameters on the dynamic characteristics of the joint surface are studied. Based on the Hertz elastic contact theory and the contact fractal theory, the normal and tangential contact fractal models of the joint surface are derived, and then a mathematical model of the joint surface normal and tangential contact stiffness considering the domain expansion factor is established. The influence of surface texture parameters on the dynamic characteristics of the surface is further studied according to the model. In addition, the design of the experimental device and experimental scheme design are completed by the contact resonance method and the ERA algorithm, and the joint surface parameter identification experiment with texture is conducted. The normal and tangential frequency response functions of the joint surface, the dynamic characteristic parameters of the joint surface and the influence law of the joint surface parameters on the contact characteristics are obtained through the dynamic test analysis technology.

An Experimental Study on the Fatigue of Structural Steels with Various Welding Details

2008 ◽  
Vol 385-387 ◽  
pp. 593-596
Author(s):  
Byeong Choon Goo
Keyword(s):  
Experimental Data ◽  
Fatigue Strength ◽  
Structural Steel ◽  
Fatigue Tests ◽  
Structural Steels ◽  
Parent Material ◽  
Key Characteristics ◽  
Load Carrying ◽  
Weld Toe ◽  
Ground Load

A structural steel should satisfy various properties under varied conditions. Fatigue strength is one of them. When structural steels are used in the form of welded joints, fatigue strength is one of the key characteristics that should be considered. In this study, comprehensive fatigue tests of a structural steel with yielding strength of about 350 MPa and tensile strength of about 520 MPa were carried out. First, a lot of specimens: parent material plates, butt welded specimens with reinforcement removed, as-welded plates, plates with weld toe ground, load-carrying cruciform, non load-carrying cruciform, plates with transverse fillet welded rib, etc were prepared and tested. S-N curves for the above specimens were compared and analyzed. Secondly, some life-size rectangular beams were fabricated by welding and tested. It is found that annealing is detrimental to fatigue strength rather than beneficial. The experimental data and results may be used usefully by engineers.

Fatigue Behavior of Corroded Structural Steel Members in Boundary with Concrete

2007 ◽  
Vol 348-349 ◽  
pp. 245-248
Author(s):  
Shigenobu Kainuma ◽  
Naofumi Hosomi ◽  
In Tae Kim
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Structural Steel ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Steel Plates ◽  
Structural Members ◽  
Analytical Results ◽  
Steel Members ◽  
Corrosion Pit

In this research, fatigue tests were carried out to investigate the fatigue behavior of corroded structural members in boundary with concrete. Specimens were corroded by accelerated exposure tests and then used in the fatigue tests. FEM analyses were also performed on the models of the corroded surfaces of the specimens and the simulated corrosion surfaces to investigate the stress concentration at the corrosion pit in the boundary. The experimental and analytical results clarified the fatigue behaviors of corroded steel plates in boundary with concrete. The method for evaluating and predicting the fatigue life of corroded steel members were also proposed.

scholarly journals FATIGUE TESTS OF WELDED JOINTS OF WEATHERING STEEL AND STRUCTURAL STEEL WEATHERED FOR 25 YEARS

2007 ◽  
Vol 63 (3) ◽  
pp. 434-443
Author(s):  
Akimasa KONDO ◽  
Kentaro YAMADA ◽  
Akiyuki ONO
Keyword(s):  
Structural Steel ◽  
Welded Joints ◽  
Fatigue Tests ◽  
Weathering Steel

Structural Integrity – Yesterday – Today – Tomorrow

2014 ◽  
Vol 891-892 ◽  
pp. 1053-1058 ◽  
Author(s):  
Michel Guillaume ◽  
Andreas Uebersax ◽  
Georges Mandanis ◽  
Cyril Huber
Keyword(s):  
Structural Integrity ◽  
Aircraft Design ◽  
Fatigue Tests ◽  
Full Scale ◽  
Test Procedures ◽  
New Concepts ◽  
Important Means ◽  
Structural Failures ◽  
Materials Used ◽  
Static Conditions

Early airplanes were designed using purely static conditions and mainly tested only with simple wing tests. But despite the significant advances in design, manufacturing and testing capabilities, structural failures may still occur. Thus new concepts are required to ensure safe operations over the lifetime of an airframe. In 1952 Juerg Branger developed a concept for a fatigue simulator at the Federal Swiss Aircraft Factory (F+W). The Pilatus P3 trainer became the first airplane to be tested in Emmen, Switzerland to demonstrate the safety of the airframe over a lifetime of 2500 FH. This first test demonstrated the importance of full scale fatigue tests to ensure the structural integrity of the airframe. Due to the intense usage of the fighters deployed by the Swiss Air Force, further full scale fatigue tests were undertaken on the Venom, the Mirage III, and the F/A-18. As the complexity of the materials used in modern aircraft design increases, more and more analysis is being taken over by highly sophisticated software and test procedures. Structural integrity is still an important means to ensure safe operations in aviation for all types of airplanes.

Effect of Vibration during Welding on the Fatigue Strength of Structural Steel Weldments

2007 ◽  
Vol 124-126 ◽  
pp. 1329-1332 ◽  
Author(s):  
Chin Hyung Lee ◽  
Gab Chul Jang ◽  
Hyun Chan Park ◽  
Kyong Ho Chang
Keyword(s):  
Fatigue Strength ◽  
Structural Steel ◽  
Arc Welding ◽  
Mechanical Vibration ◽  
Base Material ◽  
Fatigue Tests ◽  
Steel Bridge ◽  
Flux Cored Arc Welding ◽  
Service Load ◽  
Improve Reliability

During repair welding of steel bridge under service load, vibration occurs due to the dynamic loads like wind and vehicles, etc. However, the effect of vibration during welding on the fatigue strength of weldments is not yet clearly understood. In this paper, the effect of vibration during welding on the fatigue strength of structural steel weldments was investigated in order to improve reliability in the repair welded joints of steel bridge. The base material used in this investigation was SM 490A steel of weldable grade. Flux Cored Arc Welding (FCAW) process was used to fabricate the single ‘V’ butt joints. Welding was performed on the steel under the mechanical vibration of given frequency. The applied frequency was resonant frequency. Also, weldments under no vibration during welding were prepared. Fatigue tests were conducted using a servo hydraulic controlled 50tonf capacity UTM with a frequency of 5Hz under constant amplitude loading. Effect of vibration during welding on the fatigue strength of weldments was analyzed in detail.

scholarly journals Fracture Areas Quantitative Investigating of Bending–Torsion Fatigued Low-Alloy High-Strength Steel

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1620
Author(s):  
Wojciech Macek
Keyword(s):  
Fatigue Life ◽  
Surface Topography ◽  
High Strength ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Void Volume ◽  
Variation Method ◽  
Rupture Area ◽  
The Impact ◽  
Maximum Stresses

In this study, the impact of pseudo-random non-proportional bending-torsion fatigue loadings proportion on the fatigue life and the fracture surface topography was analyzed. Investigation was carried out for 24 specimens made of S355J2 steel with 11 different ratios of maximum stresses λ. For these cases, after the fatigue tests, the surface topography measurements were carried out using an optical profilometer, using the focus variation method. Three fracture zones were analyzed for each specimen: (1) total; (2) propagation; (3) rupture, taking into account the root average square height Sq and void volume Vv parameters. The results pointed that ratio of maximum stresses λ is the most influenced on volume surface parameters represented by void volume at a given height Vv, in the rupture area. A new fatigue loading parameter P was used, depending on fatigue life T and ratio of maximum stresses λ, which shows very good correlation in 4th degree type of fit, to void volume Vv parameter for the rupture area.

scholarly journals Effect of Aqueous Environment on High Cycle and Very-High-Cycle Fatigue Behavior for a Structural Steel

2011 ◽  
Vol 462-463 ◽  
pp. 355-360
Author(s):  
You Shi Hong ◽  
Gui An Qian
Keyword(s):  
Fatigue Strength ◽  
Structural Steel ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Aqueous Environment ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

In this paper, rotary bending fatigue tests for a structural steel were performed in laboratory air, fresh water and 3.5% NaCl aqueous solution, respectively, thus to investigate the influence of environmental media on the fatigue propensity of the steel, especially in high cycle and very-high-cycle fatigue regimes. The results show that the fatigue strength of the steel in water is remarkably degraded compared with the case tested in air, and that the fatigue strength in 3.5% NaCl solution is even lower than that tested in water. The fracture surfaces were examined to reveal fatigue crack initiation and propagation characteristics in air and aqueous environments.

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