Low endurance fatigue behaviour of mild steel beams in reversed bending

1966 ◽  
Vol 1 (3) ◽  
pp. 239-247 ◽  
Author(s):  
R Royles
Keyword(s):  
Mild Steel ◽  
Fatigue Resistance ◽  
Fatigue Behaviour ◽  
Steel Beams ◽  
Cyclic Heating ◽  
Structural Components ◽  
Material Behaviour ◽  
Pure Bending ◽  
Axial Extension ◽  
The Moment

The behaviour of mild steel under conditions of reversed bending in the inelastic range at relatively slow rates of cycling, falls into the category of the low endurance fatigue problem in metals, where failures occur within 105 cycles. This investigation is concerned with an examination of material behaviour in reversed bending (i.e. pure bending) at three frequencies——1, 10 and 100 c/min——and strain ranges in the region from 0.5-12 per cent. Axial extension assumed some significance during the tests at the larger strain ranges, as did cyclic heating at the higher frequency. Some adjustments are made to take account of the effects of axial extension in the tests at the two lower frequencies. A moment-curvature relationship for the material in a cyclic state is established along with a fatigue resistance law for the range of deformations considered; the former being restricted to cyclic operations in the range from 1 to 10 c/min. An indication is given, supported by some experimental evidence, of how the moment-curvature relationship and fatigue resistance law can be used to predict the behaviour of mild steel structural components subjected to the type of loading under consideration.

Deep Cryogenic Treatment: Effects on Mechanical Properties of AISI 302 Stainless Steel and 18NiCrMo5 Carburized Steel

2009 ◽  
Vol 417-418 ◽  
pp. 793-796 ◽  
Author(s):  
Paolo Baldissera ◽  
Cristiana Delprete
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Tensile Properties ◽  
Fatigue Resistance ◽  
Cryogenic Treatment ◽  
Surface Hardness ◽  
Fatigue Behaviour ◽  
Structural Components ◽  
Deep Cryogenic Treatment ◽  
Carburized Steel

In this paper, the influence of deep cryogenic treatment (DCT) on mechanical properties of two commercial steels is analysed. Hardened AISI 302 stainless steel and 18NiCrMo5 carburized steel specimens were subjected to DCT after standard treatments. For both materials, the fatigue behaviour is a key property considering their usual applications requirements. Surface hardness, tensile properties and axial fatigue resistance of both materials were measured and compared with and without DCT. From the analysis of the experimental results and from their interpretation in the light of the previous literature, some useful indications are obtained about the DCT potential fallout on design and construction of structural components.

Experimental Investigation on Cold-formed Steel Beams under Pure Bending

2012 ◽  
pp. 13-20 ◽  
Author(s):  
Yeong Huei Lee ◽  
Yee Ling Lee ◽  
Cher Siang Tan
Keyword(s):  
Local Buckling ◽  
Bending Moment ◽  
Steel Beams ◽  
Pure Bending ◽  
Lateral Instability ◽  
Moment Capacity ◽  
British Standard ◽  
Cold Formed Steel ◽  
The Moment ◽  
Design Yield

This paper presents the flexural behaviour of cold-formed double lipped channels beams under pure bending action. Two channel sections are bolted back-to-back to form an I-shape structural beam member. A series of six experiment tests were carried out on beam specimens DC200 and DC250, each with 200 mm depth and 250 mm depth respectively. The thickness of beam section is 2 mm and the design yield strength is 350 N/mm2. All beams failed at local buckling at top-flange due to lateral instability of the cold-formed steel structural members. The moment resistance for DC200 is 17.87 kNm and DC250 is 31.53 kNm. The experimental results are compared to theoretical resistance prediction based on British Standard and Eurocode. The comparison showed that the experimental moment capacity is lower than the theoretical bending moment resistance but higher than theoretical buckling moment resistance from Eurocode. This showed that a better agreement is achieved between experimental data and Eurocode buckling moment resistance for cold-formed steel beam under pure bending. Kertas kerja ini membentangkan sifat lenturan rasuk keluli tergelek sejuk di bawah tindakan lenturan tulen. Dua channel dihimpunkan berkembar dan diperketatkan dengan bolt untuk membentuk rasuk struktur bentuk-I. Satu siri ujian lenturan telah dijalankan ke atas spesimen rasuk DC200 dan DC250, dengan kedalaman 200 mm dan 250 mm masing-masing. Ketebalan keratan rasuk adalah 2 mm dan kekuatan reka bentuk adalah 350 N/mm2. Semua rasuk gagal pada momen kilasan sisi di bahagian atas bebibir akibat ketakstabilan sisi anggota keluli tergelek sejuk. Rintangan momen bagi DC200 adalah 17.87 kNm dan DC250 adalah 31.53 kNm. Keputusan eksperimen dibanding dengan ramalan teori yang berdasarkan British Standard dan Eurocodes. Perbandingan tersebut menunjukkan bahawa rintangan momen lenturan eksperimen adalah lebih rendah daripada ramalan teori momen lenturan tetapi lebih tinggi daripada ramalan teori momen rintangan kilasan sisi mengikut Eurocode. Ini menunjukkan bahawa persetujuan baik dicapai di antara keputusan eksperimen dengan ramalan teori Eurocode momen rintangan kilasan sisi bagi rasuk keluli tergelek sejuk.

High-strain low-endurance fatigue behaviour of B.S.968-steel beams in reversed bending

1967 ◽  
Vol 2 (1) ◽  
pp. 28-33 ◽  
Author(s):  
B D Threlfall
Keyword(s):  
Mild Steel ◽  
High Strain ◽  
Fatigue Behaviour ◽  
High Yield ◽  
Steel Beams ◽  
Plastic Bending ◽  
General Similarity

Experiments in repeated reversed plastic bending on beams of high-yield steel to B.S. 968 are reported; the results are compared with similar previous work on beams of mild steel to B.S. 15. General similarity is noted, but an appreciably shorter life is found for high-yield-steel beams under similar proportions of their full plastic moments.

The Residual Stresses Generated by Deep Rolling and their Stability in Fatigue & Application to Deep-Rolled Crankshafts

2006 ◽  
Vol 524-525 ◽  
pp. 45-50 ◽  
Author(s):  
H. Michaud ◽  
Jean Michel Sprauel ◽  
F. Galzy
Keyword(s):  
Residual Stresses ◽  
Fatigue Resistance ◽  
Experimental Validation ◽  
Crack Arrest ◽  
Cyclic Fatigue ◽  
Rolling Process ◽  
Fatigue Behaviour ◽  
Deep Rolling ◽  
Bending Fatigue ◽  
Compressive Residual Stresses

In this work, the effect of steel grade on the fatigue resistance of deep-rolled crankshafts is analysed. In the first part of this paper, the mechanisms leading to the increase of the fatigue resistance brought by the deep rolling treatment, is presented. This reinforcement is mainly linked to crack arrest due both to a decrease of the in-depth stress concentration factor and to remaining compressive residual stresses induced by the deep rolling. In a second part, an analytical model of residual stresses generation by deep-rolling and fatigue is presented. In this model the low cyclic fatigue behaviour of the steel is taken into account, and the residual stress stability with bending fatigue cycling can be predicted. After a presentation of the experimental validation on two different microstructures (baintic and ferrito- perlitic), this model is used for analysing the main parameters of the deep-rolling process and fatigue resistance.

The Fatigue Behaviour of a High Strength CrNi-Steel Regarding Fretting Fatigue

2012 ◽  
Author(s):  
Thomas Christiner ◽  
Johannes Reiser ◽  
István Gódor ◽  
Wilfried Eichlseder ◽  
Franz Trieb ◽  
...  
Keyword(s):  
High Strength ◽  
Contact Problems ◽  
Fatigue Behaviour ◽  
Fretting Fatigue ◽  
Service Performance ◽  
Fatigue Properties ◽  
Material Behaviour ◽  
Reliable Prediction ◽  
Damage And Failure ◽  
Lubrication Conditions

In many assemblies of moving components, contact problems under various lubrication conditions are lifetime-limiting. There, relative motion of contacting bodies, combined with high loads transmitted via the contact surface lead to fretting fatigue failure. For a reliable prediction of in service performance load type, different damage and failure mechanisms that may be activated during operation have to be known. In this contribution selected results of a currently conducted research project are presented. The aim of this study was to examine the material behaviour of a surface stressed steel. The influence of the fretting regime on fatigue properties has been investigated.

scholarly journals Reliability of beams designed in accordance with Brazilian codes

2014 ◽  
Vol 7 (5) ◽  
pp. 723-746 ◽  
Author(s):  
D. M. Santos ◽  
F. R. Stucchi ◽  
A. T. Beck
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Composite Beams ◽  
Reinforced Concrete Beams ◽  
Steel Beams ◽  
Structural Elements ◽  
Pure Bending ◽  
Design Standards ◽  
Limit Values ◽  
Relative Safety

This paper presents an investigation on the safety of structural elements submitted to pure bending, produced in reinforced concrete, in steel and steel-concrete composites, and designed according to Brazilian codes NBR8681:2003, NBR6118:2007 and NBR8800:2008. The study allows a comparison of the relative safety of beams produced with these materials and designed using these codes. Comparative studies between the performances of different materials are difficult to find in the published literature. The present study shows that reliability indexes for reinforced concrete beams are satisfactory; however, results for steel beams are below limit values established in international design standards. Reliability indexes found herein for steel-concrete composite beams are intermediate to concrete and steel beams.

Effect of Lu¨ders Bands on the Bending Capacity of Steel Tubes

2010 ◽  
Author(s):  
Julian F. Hallai ◽  
Stelios Kyriakides
Keyword(s):  
Limit State ◽  
Solution Procedure ◽  
Inhomogeneous Deformation ◽  
Pure Bending ◽  
Steel Tubes ◽  
Deformation Regime ◽  
Bending Capacity ◽  
The Moment ◽  
T Values ◽  
Structural Instabilities

In several offshore applications hot-finished pipe that often exhibits Lu¨ders bands is bent to strains of 2–3%. Lu¨ders banding is a material instability that leads to inhomogeneous plastic deformation in the range of 1–4%. It can precipitate structural instabilities and collapse of the pipe. Experiments and analysis are used to study the interaction of the prevalent structural instabilities under bending with Lu¨ders banding, with the objective of providing guidance to the designer. Pure bending experiments on tubes of various D/t values reveal that Lu¨ders bands result in the development of inhomogeneous deformation in the structure, in the form of coexistence of two curvature regimes. Under rotation controlled bending, the higher curvature zone(s) gradually spreads while the moment remains essentially unchanged. For relatively low D/t tubes with relatively smaller Lu¨ders strain, the whole tube eventually is deformed to the higher curvature, subsequently entering the usual hardening regime where it continues to deform uniformly until the expected limit state is reached. For higher D/t tubes and/or for materials with longer Lu¨ders strain, the structure collapses during the inhomogeneous deformation regime. This class of problems is analyzed using 3D finite elements and an elastic-plastic constitutive model with an up-down-up material response. It will be demonstrated that the solution procedure followed can simulate the experiments with consistency.

scholarly journals Flexural Behavior of Steel Beam Strengthening by Prestressing Strands

2018 ◽  
Vol 7 (4.20) ◽  
pp. 572
Author(s):  
Dr. Mohammed M. Rasheed ◽  
Mr. Ali F. Atshan ◽  
Mr. Kamal Sh. Mahmoud
Keyword(s):  
Reference Beam ◽  
Flexural Behavior ◽  
Radius Of Curvature ◽  
Steel Beams ◽  
Steel Beam ◽  
Bottom Flange ◽  
Moment Capacity ◽  
External Prestressing ◽  
Prestressing Strands ◽  
The Moment

Seven simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of the beams have the same steel section, clear span length and the strengthening samples which implemented by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthening by external prestressing strands and consists of six steel beams divided according to the eccentricity location of prestressing strand with jacking stress (815 MPa). From experimental results, it was found that the moment curvature curves behavior for the tested beams are stiffer and with less ductility than the reference beams and the ultimate moment capacity is increased with increasing the eccentricity location. While, the maximum radius of curvature at bottom flange decreases with increasing the eccentricity location as compare with the reference beam.   

The Fatigue Properties of Duplex Stainless Steels: Role of Microstructure

2008 ◽  
Vol 378-379 ◽  
pp. 101-114 ◽  
Author(s):  
Jean Bernard Vogt
Keyword(s):  
Fatigue Resistance ◽  
Stainless Steels ◽  
Load Transfer ◽  
Volume Fraction ◽  
Low Cycle Fatigue ◽  
Fatigue Behaviour ◽  
Cyclic Softening ◽  
Duplex Stainless Steels ◽  
Fatigue Properties

The paper analyzes the role of microstructure on the low cycle fatigue behaviour of duplex stainless steels. The alloys are investigated in their as received condition and after ageing at 475°C. The fatigue resistance and the cyclic accommodation of these DSS are strongly controlled by the volume fraction of α and γ "phases which is related to the chemical composition in particular nitrogen. It is shown that DSS with a high fraction of austenite present a good combination of fatigue resistance and cyclic softening especially in the aged condition. The mutual interaction between ferrite and austenite referred to load transfer is beneficial for increasing the fatigue resistance. Alloying with nitrogen appears to be a promising way to master an optimised microstructure leading to high mechanical resistant DSS.

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