نتایج جستجو برای: crack trajectory

تعداد نتایج: 71556  

1998

In the short crack regime of the fatigue process, grain boundaries in steels are barriers against crack growth. In this paper, we use: (1) a method involving crack density; and (2) a method of dimensional analysis, to evaluate the effects of grain size and grain-boundary resistance on short crack behaviour and fatigue life. The results show that the fatigue life increases with a decrease in gra...

2008
Herzl Chai Guruswami Ravichandran

Chipping in glass plates from line-wedge contact loading is studied as function of the wedge’s subtended angle 2β, its inclination angle φ, and the distance h from a corner having a subtended angle 90◦−θ . A brittle-fracture analysis in conjunction with the FEM technique is used to elucidate the role of geometric variables on chip morphology and chipping load. Closedform relations are developed...

In the vibration of a cracked structure with small amplitude oscillations, the crack necessarily is not fully open or fully closed. Therefore, in order to provide a realistic model for the crack, one should relate the stiffness and damping at the crack location to the amount of the opening of the crack. In this study, a continuous model for vibration of a beam with a fatigue crack under low amp...

Journal: :iranian journal of science and technology transactions of mechanical engineering 2015
f. azimpour h. akbulut h. ghaffarzadeh jahanpasand h. akbari khantakhti

nowadays, textile and woven fabric composites are taken into consideration forapplications in high mechanical properties and every in-plane direction. however, developments inmodelling and characterisation of the fabric reinforced composite materials are considered more inthe effects of element types used in the mesh generation of the crack tip. the type of elementselected for the crack tip, a ...

1998
Ting Zhu Wei Yang

Fatigue crack growth has been observed recently in ferroelectrics under cyclic electric loading[ Does the crack grow by electric breakdown\ or by the stress _eld near the crack tip< The present paper provides a mechanistic explanation for the electric!_eld!induced fatigue crack growth[ The non!uniform electric _eld near an insulated crack tip might cause domain switching which in turn produces ...

Auto-navigating of unmanned aerial vehicles (UAV) in the outdoor environment is performed by using the Global positioning system (GPS) receiver. The power of the GPS signal on the earth surface is very low. This can affect the performance of GPS receivers in the environments contaminated with the other source of radio frequency interference (RFI). GPS jamming and spoofing are the most serious a...

Journal: :Physical review letters 2008
Lihe Qian Hiroyuki Toda Kentaro Uesugi Masakazu Kobayashi Toshiro Kobayashi

We present a combined novel methodology to study the three-dimensional complex geometry of a tortuous crack and identify the essential features of the crack and its propagation inside a heterogeneous material. We find that some severe damage events occur unexpectedly below a local mode-I crack within the sample; we realize that the severe plastic zone of the local mode-I crack is shifted down b...

2003
Elmoiz Mahgoub Xiaomin Deng Michael A. Sutton

This paper investigates the phenomenon of slant fracture observed in stable tearing tests of many ductile materials, where an initially flat crack, loaded under remote Mode I conditions, tends to grow into a slant crack and stay in the slant configuration until final fracture. In an effort to identify potential reasons why cracks prefer to grow in a slant manner, three-dimensional finite elemen...

Journal: :international journal of transportation engineering 0
seyed mohammad farnam ph.d candidate, department of civil engineering, bu-ali sina university, hamedan, iran fereydoon rezaie associate professor, department of civil engineering, bu-ali sina university, hamedan, iran

initial cracks occur in high strength concrete sleepers for various reasons, such as shrinkage and wrong curing and long lifetime of over 50 years of sleepers. these cracks may lead to complete failure of the structure. in order to more accurately design the sleepers, fracture mechanics (not strength of materials) should be incorporated. in order to achieve this purpose, it is important to fore...

Although, experimental studies have reported fracture at the corner of Steel Plate Shear Walls (SPSW), no study has been performed to investigate the crack effect, yet. Therefore, in this paper, the effect of crack at the corner of SPSWs on the seismic behavior of the system was investigated. Two probable cracks, that have been studies at the corner of SPSWs utilizing extended Finite Element me...

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