Failure Analysis of Railroad Components

2021 ◽  
pp. 754-777
Author(s):  
Hans Iwand ◽  
Joel Hassebrock
Keyword(s):  
Fatigue Life ◽  
Failure Analysis ◽  
Safety Factor ◽  
Case Histories ◽  
Manufacturing Defects ◽  
Railroad Industry ◽  
Primary Mode ◽  
Mode Of Failure ◽  
Engineering Environment ◽  
Corrosion Pitting

Abstract Because of the tough engineering environment of the railroad industry, fatigue is a primary mode of failure. The increased competitiveness in the industry has led to increased loads, reducing the safety factor with respect to fatigue life. Therefore, the existence of corrosion pitting and manufacturing defects has become more important. This article presents case histories that are intended as an overview of the unique types of failures encountered in the freight railroad industry. The discussion covers failures of axle journals, bearings, wheels, couplers, rails and rail welds, and track equipment.

scholarly journals Microstructural and Fracture Surface Study of Friction Stir Welded AA5082-AA7075 Butt Joints

2020 ◽  
Vol 5 (1) ◽  
pp. 49-56
Author(s):  
Gaurav Kumar ◽  
◽  
Rajeev Kumar ◽  
Ratnesh Kumar
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Fracture Surface ◽  
Microstructural Analysis ◽  
Butt Joints ◽  
Friction Stir ◽  
Three Samples ◽  
Mode Of Failure ◽  
Microstructural Behavior ◽  
Scanning Electron

In this study, experiments were performed to analyze the fracture surface and microstructural behavior of friction stir welded (FSW) AA5082-AA7075butt joints. Three samples at varying speeds and constant feed were prepared to identify optimum tool speed to produce FSW AA5082-AA7075 butt joints having maximum tensile strength and fatigue life. A scanning electron microscope (SEM) was used to analyze microstructure and fracture surfaces. The samples prepared exhibited a considerable difference in their fatigue life and tensile strength. Microstructural analysis showed the refinement of grains present in the stir zone (SZ), also known as the weld nugget, and thermo-mechanically affected zone (TMAZ). The study of the fracture surface showed that the mode of failure was ductile in nature

Fatigue life evaluation and failure analysis of light beam direction adjusting mechanism of an automobile headlight exposed to random loading

2017 ◽  
Vol 233 (2) ◽  
pp. 224-231
Author(s):  
Nana Wang ◽  
Jinxiang Liu ◽  
Qing Zhang ◽  
Hailin Yang ◽  
Mu Tang
Keyword(s):  
Fatigue Life ◽  
Failure Analysis ◽  
Light Beam ◽  
Random Vibration ◽  
Real Life ◽  
Bench Test ◽  
Beam Direction ◽  
Random Loading ◽  
Test Analysis ◽  
Road Surface Roughness

Failure of the light beam direction adjusting mechanism (LDAM) of an automotive headlight might occur after hundreds of driving hours, though the strength of components conforms to the requirement specified in the random vibration bench test standard. In order to determine the causes of the failure, fatigue life prediction and failure analysis based on numerical method of the LDAM exposed to random loading both in bench test and field experiment were carried out. In the bench test analysis, the Dirlik method was utilized to calculate the lifetime by taking the power spectrum density in the frequency domain. In the fatigue analysis for the field experimental loading, to consider the effect of nonuniform temperature distribution, a numerical process in time domain is developed to calculate the lifetime of the LDAM subjected to the random vibration caused by road surface roughness. As a result, the predicted life and failure locations are in good agreement with real life and actual failure regions, respectively.

3D Finite Element Analysis of High-Pressure Common Rail Diesel Engine Connecting Rod

2011 ◽  
Vol 354-355 ◽  
pp. 531-534
Author(s):  
Bin Zheng ◽  
Yong Qi Liu ◽  
Rui Xiang Liu ◽  
Jian Meng
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Life Cycle ◽  
Fatigue Life ◽  
Diesel Engine ◽  
Principal Stress ◽  
Safety Factor ◽  
Maximum Principal Stress ◽  
Connecting Rod ◽  
3D Finite Element

In this paper, with the ANSYS, stress distribution, safety factor and fatigue life cycle of high-pressure common rail diesel engine connecting rod were analyzed by using 3D finite element method. The results show that the position of maximum principal stress is transition location of small end and connecting rod shank at maximum compression condition. The value of stress is 253.98 MPa in dangerous position. Safety factor is 2.67. The position of maximum principal stress is medial surface of small end at maximum stretch condition. The value of stress is 87.199 MPa in dangerous position. The fatigue life cycle of connecting rod is 2.6812×108. Fatigue safety factor is 1.5264.

The Effect of Manufacturing Defects on the Fatigue Behaviour of Ti-6Al-4V Specimens Fabricated Using Selective Laser Melting

2014 ◽  
Vol 891-892 ◽  
pp. 1519-1524 ◽  
Author(s):  
Qian Chu Liu ◽  
Joe Elambasseril ◽  
Shou Jin Sun ◽  
Martin Leary ◽  
Milan Brandt ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Selective Laser Melting ◽  
Fatigue Crack Initiation ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Metallic Materials ◽  
Laser Melting ◽  
Manufacturing Defects ◽  
Materials Properties

Additive Manufacturing (AM) technologies are considered revolutionary because they could fundamentally change the way products are designed. Selective Laser Melting (SLM) is a metal based AM process with significant and growing potential for the manufacture of aerospace components. Traditionally a material needs to be listed in the Metallic Materials Properties Development and Standardization (MMPDS) handbook if it is to be considered certified. However, this requires a considerable amount of test data to be generated on the materials mechanical properties. Therefore, the MMPDS certification process does not lend itself easily to the certification of AM components as the final component can have similar mechanical properties to wrought alloys combined with the defects associated with traditional casting and welding technologies. These defects can substantially decrease the fatigue life of a fabricated component. The primary purpose of this investigation was to study the fatigue behaviour of as-built Ti-6Al-4V (Ti64) samples. Fatigue tests were performed on the Ti-6Al-4V specimens built using SLM with a variety of layer thicknesses and build (vertical or horizontal) directions. Fractography revealed the presence of a range of manufacturing defects located at or near the surface of the specimens. The experimental results indicated that Lack-of-Fusion (LOF) defects were primarily responsible for fatigue crack initiation. The reduction in fatigue life appeared to be affected by the location, size and shape of the LOF defect.

Sign in / Sign up

Export Citation Format

Share Document