scholarly journals Evaluation Method for Fatigue Failure Modes in Load-Carrying Fillet Welded Cruciform Joints.

2001 ◽  
pp. 313-318 ◽  
Author(s):  
Shigenobu KAINUMA ◽  
Takeshi MORI ◽  
Mitsuru ICHIMIYA
Keyword(s):  
Fatigue Failure ◽  
Evaluation Method ◽  
Failure Modes ◽  
Cruciform Joints ◽  
Load Carrying

Fatigue Failure Modes in Self-Piercing Riveted Aluminium Alloy Joints

Volume 3 ◽  
2004 ◽  
Author(s):  
L. Han ◽  
K. Young ◽  
R. Hewitt ◽  
A. Chrysanthou ◽  
J. M. O’Sullivan
Keyword(s):  
Aluminium Alloy ◽  
Fatigue Failure ◽  
Failure Modes ◽  
Surface Condition ◽  
Fatigue Behaviour ◽  
Alloy Sheet ◽  
Static Tests ◽  
Failure Patterns ◽  
Interfacial Conditions ◽  
Sheet Surface

Self-piercing riveting, as an alternative joining method to spot-welding, has attracted considerable interest from the automotive industry and has been widely used in aluminium intensive vehicles. One of the important factors that need to be considered is the effect of cyclic loading in service, leading to possible fatigue failure. The previous work reported in the public domain on the behaviour of self-piercing rivets has mainly focused on static tests. The work which is reported in this paper is concerned with the fatigue behaviour of single-rivet joints, joining two 2mm 5754 aluminium alloy sheets. The investigation also examined the effect of interfacial conditions on the fatigue behaviour. A number of fatigue failure mechanisms were observed based on rivet fracture, sheet fracture and combinations of these. The investigation has shown that they were dependent on the applied load and the sheet surface condition. Three-parameter Weibull analysis, using Reliasoft Weibull ++5.0 software, was conducted to analyse the experimental results. The analysis enabled the prediction of early-type failure (infant mortality failure) and wear-out failure patterns depending on the condition of the self-piercing riveted joints and the alloy sheet surface.

Development of Ultimate Strength Evaluation Method for Piping Subjected to Seismic Loads

2013 ◽  
Author(s):  
Hideo Machida ◽  
Hiromasa Chitose ◽  
Tatsuhiro Yamazaki
Keyword(s):  
Power Plants ◽  
Evaluation Method ◽  
Failure Modes ◽  
Limit State ◽  
Seismic Loading ◽  
Earthquake Resistance ◽  
State Function ◽  
Limit State Function ◽  
Input Acceleration ◽  
Resistance Tests

This paper reports the results of the study on the failure modes and limit loads of piping in nuclear power plants subjected to cyclic seismic loading. By investigating the past fracture tests and earthquake resistance tests, it became clear that dominant failure mode of piping was fatigue, and the effect of ratchet strain was negligible. Until now, the stress generated with the acceleration of an earthquake was classified into the primary stress. However, the relationship between the input acceleration and the seismic response displacement of the pipe observed from earthquake resistance tests is non-linear, and increasing rate of displacement is lower than that of input acceleration in elastic-plastic stress condition. Therefore, the seismic loading can be treated as displacement controlled loading. To evaluate the reliability-based critical acceleration, a limit state function was defined taking the variations in the fatigue strength or some parameters into consideration. By using the limit state function, the reliability was evaluated for the typical piping of boiling water reactor (BWR) plants subjected to cyclic seismic loading, and a partial safety factors were calculated. Based on these results, a fatigue curve corresponding to the target reliability was proposed.

An Extended System Aggregation Method for Hybrid Production Lines with Multiple Failure Rate and Unreliable Limited Buffers

2012 ◽  
Vol 459 ◽  
pp. 432-436
Author(s):  
Jun Liu ◽  
Ye Nan Wang ◽  
Jian Hua Li ◽  
Rui Shen Chen
Keyword(s):  
Evaluation Method ◽  
Failure Modes ◽  
Extended System ◽  
Production Lines ◽  
Aggregation Method ◽  
Hybrid Production ◽  
Production Models ◽  
Limited Buffers ◽  
Performance Evaluation Method ◽  
Stochastic Events

In this study, a new system performance evaluation method is introduced to the two-machine line. After that, the extended system aggregation model is developed and corresponding aggregation formulations are deduced.Different from traditional production models, the production line features unreliable buffers and multiple stochastic failure modes of the machines. The method is applicable to analyzing the cases arising from two or more stochastic events or more complex production lines

scholarly journals Investigation of creep and fatigue in high temperature polymer matrix composites using a micromechanical approach

2021 ◽  
Author(s):  
Alireza Sayyidmousavi
Keyword(s):  
High Temperature ◽  
Fatigue Failure ◽  
Polymer Matrix ◽  
Failure Criterion ◽  
Failure Modes ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Difficult Situation ◽  
Strain Evolution ◽  
Micromechanical Approach

Polymer matrix composites (PMC’s) are widely used in critical aerospace structures due to their numerous advantageous mechanical properties. Recently, PMC’s have been considered for high temperature applications where viscoelasticity arising from the time dependent nature of the polymer matrix becomes an important consideration. This inherent viscoelasticity can significantly influence deformation, strength and failure response of these materials under different loading modes and environmental factors. With a potentially large number of plies of different fiber directions and perhaps material properties, determining a fatigue failure criterion of any degree of generality through experiments only, may seem to be an unrealistic task. This difficult situation may be mitigated through the development of suitable theoretical micro or macro mechanical models that are founded on considering the fatigue failure of the constituting laminas. The micro‐approach provides a detailed examination of the individual failure modes in each of the constituent materials i.e. fiber, matrix. In this work, a micromechanical approach is used to study the role of viscoelasticity on the fatigue behavior of polymer matrix composites. In particular, the study examines the interaction of fatigue and creep in polymer matrix composites. The matrix phase is modeled as a vicoelastic material using Schapery’s single integral constitutive equation. Taking viscoelsticity into account allows the study of creep strain evolution during the fatigue loading. The fatigue failure criterion is expressed in terms of the fatigue failure functions of the constituent materials. The micromechanical model is also used to calculate these fatigue failure functions from the knowledge of the S‐N diagrams of the composite material in longitudinal, transverse and shear loadings thus eliminating the need for any further experimentation. Unlike the previous works, the present study can distinguish between the strain evolution due to fatigue and creep. The results can clearly show the contribution made by the effect of viscoelasticity to the total strain evolution during the fatigue life of the specimen. Although the effect of viscoelsticity is found to increase with temperature, its contribution to strain development during fatigue is compromised by the shorter life of the specimen when compared to lower temperatures.

scholarly journals Fatigue assessment of load-carrying welded cruciform joints

2013 ◽  
Vol 38 (3) ◽  
pp. 51-58
Author(s):  
T.I. Letova ◽  
S.V. Petinov
Keyword(s):  
Cruciform Joints ◽  
Fatigue Assessment ◽  
Load Carrying

scholarly journals Wear Mechanism of Abrasive Gas Jet Erosion on a Rock and the Effect of Abrasive Hardness on It

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Yong Liu ◽  
Huidong Zhang ◽  
Pathegama Gamage Ranjith ◽  
Jianping Wei ◽  
Xiaotian Liu
Keyword(s):  
Plastic Deformation ◽  
Fatigue Failure ◽  
Failure Modes ◽  
Gas Jet ◽  
Abrasive Particles ◽  
Erosion Models ◽  
Different Types ◽  
Field Geometry ◽  
Abrasive Hardness ◽  
Wear Tests

The existing erosion models of abrasive gas jet tend to neglect the effects of the rebounding abrasive. To address this shortcoming, abrasive wear tests were conducted on limestone by using an abrasive gas jet containing different types of particles and with different standoff distances. The results indicate that erosion pits have the shape of an inverted cone and a hemispherical bottom. An annular platform above the hemispherical bottom connects the bottom with the side of the pit. The primary cause of the peculiar pit shape is the flow field geometry of the gas jet with its entrained particles. There is an annular region between the axis and boundary of the abrasive gas jet, and it contains no abrasive. Particles swirling around the axis form a hemispherical bottom. After rebounding, the abrasive with the highest velocity enlarges the diameters of both the hemispherical bottom and erosion pit and induces the formation of an annular platform. The surface features of different areas of the erosion pit are characterized using a scanning electron microscope (SEM). It can be concluded that the failure modes for different locations are different. The failure is caused by an impact stress wave of the incident abrasive at the bottom. Plastic deformation is the primary failure mode induced by rebounding particles at the sides of the hemispherical bottom. The plastic deformation induced by the incident abrasive and fatigue failure induced by the rebounding abrasive are the primary failure modes on the annular platform. Fatigue failure induced by rebounding particles is the primary mode at the sides of the erosion pits. The rock failure mechanism that occurs for particles with different hardness is the same, but the rock damaged by the hard abrasive has a rougher surface.

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