scholarly journals Fatigue design and testing of automotive stabilizer bars

2018 ◽  
Vol 188 ◽  
pp. 02014
Author(s):  
Efstratios Giannakis ◽  
Elli Sivena ◽  
Michail Malikoutsakis ◽  
Georgios Savaidis
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Shear Stresses ◽  
Main Body ◽  
Torsional Loading ◽  
Road Vehicles ◽  
Fatigue Design ◽  
Two Sides ◽  
Design And Testing

Stabilisers are components of the axle suspension system of cars trucks, trains and other moving road vehicles that connect the movement of the two sides of the suspension (right and left) to keep the vehicle levelled. Stabilizers experience bending and torsion at operation. In particular, their arms experience bending while the main body mainly torsional loading. In both cases, the highly stressed area is the surface, where the maximum tensile and shear stresses are acting. High strength steels and special treatments, thermal and/or mechanical, are used for the stabilisers’ manufacturing. The present study deals with necessary input data for fatigue life assessments based on the FKM guideline [1]. In addition, fatigue tests are conducted to calculate the stress-life curves of two different manufacturing processes.

Fatigue and Burst Analysis of Hy-140(T) Steel Pressure Vessels

1970 ◽  
Vol 92 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. M. Barsom ◽  
S. T. Rolfe
Keyword(s):  
Yield Strength ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
High Yield ◽  
Corrosion Properties ◽  
Burst Analysis

Increasing use of high-strength steels in pressure-vessel design has resulted from emphasis on decreasing the weight of pressure vessels for certain applications. To demonstrate the suitability of a 140-ksi yield strength steel for use in unwelded pressure vessels, HY-140(T)—a quenched and tempered 5Ni-Cr-Mo-V steel—was fabricated and subjected to various burst and fatigue tests, as well as to various laboratory tests. In general, results of the investigation indicated very good tensile, Charpy, Nil Ductility Transition Temperature (NDT), low-cycle fatigue, and stress-corrosion properties of HY-140(T) steels, as well as very good burst tests results, in comparison with existing high-yield strength pressure-vessel steels. The results also indicate that the HY-140(T) steel should be an excellent material for its originally designed purpose, Naval hull applications.

X-ray Fractographic Study on Alumina and Zirconia Ceramics

1990 ◽  
Vol 34 ◽  
pp. 719-727 ◽  
Author(s):  
Sumio Tanaka ◽  
Yukio Hirose ◽  
Keisuke Tanaka
Keyword(s):  
Fracture Toughness ◽  
Residual Stress ◽  
Fracture Surface ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Fracture Mechanisms ◽  
Zirconia Ceramics ◽  
X Ray ◽  
Fractographic Study

The residual stress left on the fracture surface is one of the important parameters in X-ray fractographic study. It has been used to analyze fracture mechanisms in fracture toughness and fatigue tests especially of high strength steels.In this paper, X-ray fractography was applied to brittle fracture of alumina (Al2O3) and zirconia (ZΓO2) ceramics.

Fatigue Performance of High Strength and Large Diameter Mooring Chain in Seawater

2019 ◽  
Author(s):  
Yan-Hui Zhang ◽  
Philip Smedley
Keyword(s):  
Large Diameter ◽  
High Strength ◽  
Crack Size ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Link Failures ◽  
Fatigue Design ◽  
Steel Grades ◽  
Chain Links ◽  
Mooring Chain

Abstract Fatigue design recommendations provided by API RP 2SK, ISO 19901-7 and DNVGL-OS-E301 for studless chain links are based on data of steel grades R3 and R4 and mainly of link diameter of 76mm. Mooring systems utilising larger diameter links and higher strength steels (e.g. grade R5) are now in operation. Consequently, industry expressed a need for fatigue test data in seawater of higher steel grade and larger diameter chain to confirm whether the existing fatigue design guidance is applicable. A joint industry project (JIP) was launched by TWI to investigate fatigue performance of high strength and large diameter mooring chain in free corrosion seawater. A test rig was designed and manufactured which was capable of testing studless mooring chain links up to 127mm link diameter under tension-tension loading. Twenty-three full-scale fatigue tests were conducted on high strength steel grades (R4 and R5) and larger diameter chains (76mm and 127mm) generating 72 link failures. Magnetic particle inspections (MPI) were carried out to characterise the location of cracking, crack size and crack growth rate. This paper describes the results obtained in the JIP.

Study on Micro-Mechanism of Crack Initiation and Propagation Induced by Inclusion in Ultra-High Strength Steel

2007 ◽  
Vol 353-358 ◽  
pp. 1185-1190 ◽  
Author(s):  
Yan Ping Zeng ◽  
Hong Mei Fan ◽  
Xi Shu Wang ◽  
Xi Shan Xie
Keyword(s):  
Crack Initiation ◽  
High Strength Steel ◽  
Harmful Effect ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Ultra High Strength Steel

Specially designed SEM in-situ tensile and fatigue tests have been conducted to trace the entire process of crack initiation and propagation till fracture in an ultra-high strength steel MA250. TiN is a typical inclusion and its average size is in the range of 8~10μm in MA250 steel. The micro-mechanism of the effect of TiN inclusion on crack initiation and propagation at tensile and fatigue tests both have been studied in detail. Experimental results show the harmful effect of TiN on tensile and fatigue properties both. This work is helpful to establish the practical life prediction model for the characteristic inclusion parameters in ultra-high strength steel components. It also enlightens us to eliminate TiN in the further development of ultra-high strength steels.

scholarly journals Expulsion investigation and fracture characteristics in spot welded advanced high strength auto steels

2021 ◽  
Author(s):  
Chao Ma
Keyword(s):  
Control Strategies ◽  
Fatigue Crack Initiation ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Rate Of Change ◽  
Dynamic Resistance ◽  
Monitoring And Control ◽  
Advanced High Strength Steels ◽  
Electrode Force

Increased use of advanced high strength steels in resistance spot welding (RSW) is necessary for manufacturing safe and affordable vehicles. Unfortunately, the investigation of expulsion monitoring and control of advanced high strength steels (AHSS) is limited. A data acquisition system was designed for monitoring weld expulsion via the measurement of voltage, current, dynamic resistance, electrode force and displacement. Three control strategies were proposed on the basis of the rate of change in the dynamic resistance, the electrode force and the electrode displacement. Micro-hardness tests, tensile shear tests and fatigue tests were carried out. The expulsion effects on the mechanical properties, fracture modes, and metallurgical features were investigated using optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Fatigue crack initiation locations were also observed, which were verified by the theorectical stress analysis. In addition, the causes of interfacial fracture were discussed in relation to weld parameters.

X-Ray Measurement of Residual Stress Near Fatigue Fracture Surfaces of High Strength Steel

1985 ◽  
Vol 29 ◽  
pp. 265-270 ◽  
Author(s):  
Yukio Hirose ◽  
Keisuke Tanaka
Keyword(s):  
Residual Stress ◽  
Fatigue Fracture ◽  
High Strength Steels ◽  
Diffraction Method ◽  
High Strength ◽  
Fatigue Tests ◽  
Fracture Mechanisms ◽  
Aqueous Environment ◽  
X Ray ◽  
Fracture Surfaces

The residual stress left on the fracture surface is one of the important parameters in X-ray fractography and has been used to analyse fracture mechanisms in fracture toughness, stress corrosion cracking and fatigue tests especially of high strength steels.In this study, the distribution of residual stress near fatigue fracture surfaces made in air and in 3.5% NaCl solution was measured by the X-ray diffraction method. The effect of aqueous environment on the plastic deformation near fatigue fracture surfaces was discussed on the basis of the residual stress distribution.

scholarly journals Increasing fatigue performance in AHSS thick sheet by surface treatments

2018 ◽  
Vol 165 ◽  
pp. 22015
Author(s):  
Sergi Parareda ◽  
Antoni Lara ◽  
Henrik Sieurin ◽  
Héber D´Armas ◽  
Daniel Casellas
Keyword(s):  
Surface Roughness ◽  
Fatigue Life ◽  
Residual Stresses ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Surface Treatments ◽  
Thick Sheet ◽  
Steel Grades ◽  
Mechanical Surface

Advanced High Strength Steels (AHSS) have been widely applied in the automotive industry as an affordable solution for car lightweighting, mainly in parts subjected to crash requirements. Heavy duty vehicle (HDV) can also benefit from the expertise learned in cars, but parts must be designed considering fatigue resistance, especially on trimmed areas, and stiffness. Mechanical surface treatments, as blasting or shot peening, help increasing fatigue life of AHSS in trimmed areas and will allow weight reduction in HDV through gauge downsizing. The expected decrease in stiffness through thickness reduction can be improved by design changes. However, scarce information about the effect of mechanical surface treatments on AHSS are available. Thus, the aim of this work is to evaluate the increment in fatigue life of two different steel grades (350 MPa, and 500MPa of yield strength) in thick sheet by means of mechanical surface treatment – sandblasting. High Cycle Fatigue [HCF] tests were conducted at alternating load [R=-1]. Residual stresses were measured by an X-ray tensometry prior fatigue tests. Also the surface roughness [Rz] and form is measured using an optical non-contact 3D microscope. On the other hand, the fracture surfaces of the test specimens were observed via scanning electron microscope (SEM) in order to determine the crack initiation points. The evaluation of fatigue life in terms of SN curves is also discussed, analysing how the sandblasting process modifies the surface roughness and introduce compressive residual stresses on the external layer of the material. Both phenomena enhance the fatigue strength of the evaluated steel grades.

scholarly journals A Fracture Mechanics-Based Optimal Fatigue Design Method of Under-Matched HSLA Steel Butt-Welded Joints with Imperfections

2019 ◽  
Vol 9 (17) ◽  
pp. 3609 ◽  
Author(s):  
Wen ◽  
Wang ◽  
Dong ◽  
Fang
Keyword(s):  
Fracture Mechanics ◽  
Welded Joints ◽  
Design Method ◽  
Hsla Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Engineering Structures ◽  
Fatigue Design ◽  
Load Carrying ◽  
Practical Engineering

The trend of light-weight structures leads to the wide application of high strength steels in engineering structures. When welding high strength steels, under-matched consumables could reduce the cold-cracking tendency, simplifying the preheating process. However, under-matched welds would sometimes make the high strength base metal pointless due to its weak load-carrying capacity. For the purpose of enhancing the fatigue strength of under-matched welded joints, a fracture mechanics-based optimal fatigue design method of under-matched butt-welded joints is proposed in this work. Heterogeneous mechanical features of welded joints, which are not considered in current standards and codes, are incorporated into the optimal design method. The fatigue limit of the high strength parent metal is taken as the design target, which has seldom been reported. HSLA steel Q550, with its under-matched consumable ER70S-6 composed X-shaped butt-welds, is selected for experimental verification. The experimental results indicate that the fracture mechanic based equal-fatigue-bearing-capacity (EFBC) design method established in this work is feasible and could be a valuable reference for the design of practical engineering structures.

A Study on Fatigue Fracture Mechanism of Cr-Mo Steel SCM435 in Super Long Life Range

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1697-1703 ◽  
Author(s):  
Ri Ichi Murakami ◽  
Daisuke Yonekura ◽  
Taishi Murayama
Keyword(s):  
Fatigue Fracture ◽  
Fatigue Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Microscopy Observation ◽  
Horizontal Part ◽  
Long Life ◽  
Fatigue Fracture Behavior ◽  
Fish Eye

For high strength steels, a characteristic fatigue behavior, which S-N curve comes down again in the long life region of N > 107 cycles, was reported by many researchers. Specifically, for high strength steel, the fatigue limit is temporal value because of the fish-eye fracture in the long life region over about N = 107 cycles. However, fish eye fracture does not appear for medium strength steel in super long life range. In this paper, cantilever-type rotational bending fatigue tests were carried out for quenched and tempered Cr-Mo steel (JIS: SCM435) up to 109 cycles at room temperature in air. The S-N curve showed a horizontal part in long life region over 107 cycles. In addition, fish- eye fracture was not observed and for all specimens, the crack initiation occurred from the specimen surface. The fatigue fracture behavior of SCM435 in super long life was discussed based on optical microscopy observation and scanning electron microscopy observation.

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