Scale and Surface Machining Quality Effect on Fatigue Properties for China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 363-368
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Y. Li
Keyword(s):  
Fatigue Cracks ◽  
Cast Steel ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Surface Machining ◽  
Linear Effect ◽  
Steel Wheel ◽  
Damage Process ◽  
China Railway ◽  
Random Fatigue

Synthetic method is studied on assessing scale and surface machined effect on fatigue lives of China railway grade B cast steel wheel. Three kinds of specimens are applied for revealing the non-linear effect with scale kinetics at a least of cost. And 8 to 9 samples are applied for each kind of specimen to reveal the random fatigue behaviour. Assessing work is carried out on a phase of fatigue lives with scale kinetics at a specified strength. Results reveal that fatigue cracks were initiated from the specimen surface having a bigger site and the fatigue damage process companied with less plastic deformation than the material specimens. Random effects on fatigue lives and effect factors are constructed for measuring effects. Statistical character of the test data has been well described.

Random Fatigue Limits of China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 347-351
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Z.G. Wang
Keyword(s):  
Test Data ◽  
Fatigue Cracks ◽  
Cast Steel ◽  
Test Method ◽  
Present Material ◽  
Steel Wheel ◽  
China Railway ◽  
Shrinkage Cavities ◽  
Random Fatigue

Random fatigue limits are experimentally studied on China grade B cast steel wheel. Test data were obtained by employing a so-called small sampling up-and-down test method. Results reveal that fatigue cracks of the present material were commonly initiated from the casting flaw of shrinkage cavities and grew with typical fatigue river-like flowers and striations. To address the scattered test data, randomness of fatigue limits are comparably measured by the existent four approaches, i.e. conventional, Dixon-Mood, Zhang-Kececioglu, and Zhao-Yang approaches. It is verified that Zhao-Yang approach is appropriately applied for the present assessment on random fatigue limits of China grade B cast steel wheel.

Random Critical Fracture Toughness Values of China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 381-386
Author(s):  
Lei Chen ◽  
Yong Xiang Zhao ◽  
Guo Xiang Song
Keyword(s):  
Fracture Toughness ◽  
Structural Damage ◽  
Cast Steel ◽  
Comparison Method ◽  
Growth Direction ◽  
Steel Wheel ◽  
Quantitative Measurements ◽  
Critical Fracture ◽  
Plastic Dissipation ◽  
Damage Process

Fracture surface observations and statistical deriving are applied for investigating the random critical fracture toughness values of China grade B cast steel wheel. Results reveal that: the crack grows to show fabric like stripes along the growth direction with few of dimples. Cleavage flowers appear under higher magnification. Cracked structural damage process is verified with few of plastic dissipation. At the same time, code based evaluated results indicate that significant scatter exists for the toughness values. Lognormal modeling is constructed appropriately with a comprehensive statistical comparison method. It is verified that random characters and quantitative measurements have been well depicted for the present critical fracture toughness values.

Fatigue Behaviour of Ti-6Al-4V Alloy in Vacuum and at Low Temperature

2008 ◽  
Vol 41-42 ◽  
pp. 83-90 ◽  
Author(s):  
J.H. Zuo ◽  
Z.G. Wang ◽  
En Hou Han
Keyword(s):  
Low Temperature ◽  
Fatigue Fracture ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Sample Surface ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Fatigue Fracture Surface ◽  
Cracks Propagation

Investigations have been conducted on the fatigue behavior of Ti-6Al-4V alloy with the bimodal microstructure in air at room temperature, in vacuum at room temperature and in vacuum at low temperature (100K), respectively. The results show that the fatigue life of this alloy is longer in vacuum and/or at low temperature than that in air at room temperature. The combination of vacuum and low temperature can much improve the fatigue properties of this alloy because of their purifying effect on fatigue cracks propagation. SEM observation of fatigue fracture surface indicates that all the fatigue cracks initiate in the sample surface when Nf ≦106 cycles. The above three testing conditions lead to different modes of fatigue crack propagation and therefore much different morphology of fatigue fracture.

Random Fatigue Crack Growth Rates of China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 387-392
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Guo Xiang Song
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Cast Steel ◽  
Growth Direction ◽  
Steel Wheel ◽  
Plastic Dissipation ◽  
Crack Growth Rates ◽  
Random Fatigue

Fracture surface observations and statistical deriving are applied for the present investigation on the random fatigue crack growth rates of China grade B cast steel wheel. Results reveal that: the crack grows with relative regular initial tip companied fabric like stripes along the growth direction but few of fatigue striations, and then, cleavage flowers appearing on the district of transient fracture with few of dimples. It indicates that sharp notched structural crack behaviour acts as a few of plastic dissipation process. Non-linear statistical modeling covering entire three pieces of fatigue crack growth is constructed for describing the random crack growth rates. Scattered randomness of the growth rates has been well characterized.

Scale-Induced Effects on Fatigue Properties of the Cast Steel for Chinese Railway Rolling Wagon Bogie Frames

2010 ◽  
Vol 118-120 ◽  
pp. 59-64 ◽  
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang
Keyword(s):  
Crack Path ◽  
Fatigue Cracks ◽  
Cast Steel ◽  
Fatigue Properties ◽  
Effect Factors ◽  
Bogie Frame ◽  
Fatigue Striations ◽  
Material Specimen ◽  
Long Life ◽  
Surface Observations

Scale-induced effect is investigated on the fatigue properties to the grade B cast steel for China railway rolling wagon bogie frame. Three kinds of structure-like specimens with production structural surfaces and different scales were fatigued in a manner of group tests at same stressing amplitude. Their fatigue properties are compared with those of material specimens. Fracture surface observations reveal that the fatigue cracks were initiated from the material casting shrinking cavities with/or hot ties. Distinct fatigue striations, river-like flowers, and second cracks appeared in perpendicular to the fatigue crack path. Lots of dimples appeared in the transient fracture zone to indicate a ductile fracture. Slight deference was observed that more dimples are for material specimen. To consider the scattered fatigue properties, effective sectional area-fatigue life relations are established for the structure-like specimens. And then, a probabilistic model is established for the scattered effect factors on fatigue lives. An effective application is given for constructing structural probabilistic S-N relations including super-long life regime from material S-N curves.

scholarly journals Study of Asphalt-Concrete Pavement Fatigue Modeling

2021 ◽  
Vol 16 (1) ◽  
pp. 24-36
Author(s):  
Peteris Skels ◽  
Viktors Haritonovs ◽  
Pavel Akishin ◽  
Andris Freimanis
Keyword(s):  
Fatigue Cracks ◽  
Fatigue Cracking ◽  
Element Model ◽  
Fatigue Behaviour ◽  
Asphalt Pavements ◽  
Fatigue Properties ◽  
Surface Loading ◽  
Asphalt Concrete Pavement ◽  
Cyclic Surface

Deterioration of asphalt pavements due to fatigue cracking is one of the most common highway pavement failure types. If the fatigue cracks are allowed to develop and grow, the driving comfort and safety, i.e., serviceability of the pavement, decreases. Pavement fatigue behaviour is not a straightforward mechanism and involves many factors and effects, thus computational methods are developed in order to help understand how the pavement works. This paper explores the accuracy and applicability of a less computational resource demanding procedure that uses transient material mechanical behaviour to model the long-term behaviour of a pavement structure. First, the mechanical and fatigue properties of asphalt were determined at the laboratory. Then a four-layer finite-element model was created using Ansys software. Two different models – with and without infinity elements – and two different fatigue simulation procedures – full and simplified – were considered. Material parameters were obtained by the laboratory tests and material properties degraded over time. Cyclic surface loading was applied to simulate the passing of a truck – 6 million fatigue cycles were simulated.

Fatigue Reliability Curves for China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 352-356
Author(s):  
H.Q. Liang ◽  
Yong Xiang Zhao ◽  
Y. Li
Keyword(s):  
Test Data ◽  
Fatigue Cracks ◽  
Cast Steel ◽  
Growth Direction ◽  
Extrapolation Method ◽  
Fatigue Reliability ◽  
Cyclic Plastic ◽  
Steel Wheel ◽  
Fatigue Striations ◽  
Long Life

Four grouped rectangle specimens with thirty four samples, plus eighteen samples for fatigue limits, are tested for constructing the fatigue reliability curves of China grade B cast steel wheel. It reveals that fatigue cracks commonly initiated from the surface weakest phases and grew with typical fatigue striations and sub-cracks perpendicular to the growth direction. Cyclic plastic seems to be strengthened as cyclic stressing level increasing. Fatigue reliability curves are constructed on a consideration of addressing the real super long life. They are evaluated by a concurrent probability extrapolation method. And the measured curves verified that appropriate description has been reached on the test data.

Influence of corrosion on fatigue behaviour of old crane runway steel

2019 ◽  
Vol 54 (7-8) ◽  
pp. 416-423
Author(s):  
Stanislav Seitl ◽  
Petr Miarka ◽  
Pavel Pokorný ◽  
Jan Klusák
Keyword(s):  
Crack Initiation ◽  
Cross Sections ◽  
Fatigue Cracks ◽  
Element Model ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Experimental Measurements ◽  
Stress Concentrations ◽  
The Finite Element Model ◽  
Surface Crack Initiation

Experimental measurements of fatigue properties of old steel used for a crane runway were performed to capture the influence of corrosion on fatigue life of the material. Basquin’s law was used to quantify the fatigue properties of old steel with different cross sections and with different surface of specimens (polished and corroded). The finite element model was prepared to assess and quantify the various stress distribution in specimens with circular and rectangular cross sections. Fracture surfaces of the three kinds of specimens (circular polished, rectangular polished and rectangular corroded) were studied and they showed the surface crack initiation. The following fatigue cracks developed from the surface and expanded into specimen with radiation pattern. Observed crack initiation areas confirmed the ones expected according to stress concentrations.

Random Fatigue Cracking Thresholds of China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 375-380
Author(s):  
Bing Yang ◽  
Yong Xiang Zhao ◽  
Guo Xiang Song
Keyword(s):  
Growth Rate ◽  
Cast Steel ◽  
Fatigue Cracking ◽  
Growth Direction ◽  
Test Results ◽  
Dissipation Process ◽  
Steel Wheel ◽  
Fatigue Striations ◽  
Plastic Dissipation ◽  
Random Fatigue

Fracture surface observations and statistical deriving are applied experimentally for the present investigation on random fatigue cracking thresholds of China grade B cast steel wheel. Results reveal that: the crack grows with relative regular initial tip companied fabric like stripes along the growth direction but few of fatigue striations and then, cleavage flowers appearing on the district of transient fracture with few of dimples. This indicates that sharp notched structures may be subjected to a little plastic dissipation process. In the same time, non-linear statistical modeling is constructed for describing the random crack growth and then, random fatigue cracking thresholds are measured at specified growth rate. The measurements hold a same growth rate which can not be obtained directly from test results.

Chemical Composition and Physical Properties for China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 42-46
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Guo Xiang Song
Keyword(s):  
Chemical Composition ◽  
Physical Properties ◽  
Shot Peening ◽  
Chemical Elements ◽  
Cast Steel ◽  
Steel Wheel ◽  
Metallic Compounds ◽  
China Railway ◽  
Hardness Values ◽  
Quenching And Tempering

Chemical composition and physical properties are measured and inspected for China railway grade B cast steel wheel. The wheel shows slight higher for chemical elements C and Cr, much higher for Al and Mo, and significant lower for P and S comparing to the AAR code. Gross pearlites plus net-like continuum ferrites appear in wheel hub; ferrites exhibit also net-likely but dis-continuously in web with a shot peening effect; and in rim, dis-continuous ferrites with few of net-like signs distribute randomly due to a quenching and tempering effect. Bigger hardness values appear in rim; and the values in web and hub appear a decrease in sequence. Major flaw affecting material condense is shrinkage porosities. Flawed content is closely between hub and web. More condense appears in rim. Material inclusions are non-metallic compounds of MnS and Al2O3. They appear sphere-like shapes having around 8 μm diameters.

Sign in / Sign up

Export Citation Format

Share Document