The Multiaxial Equivalent of Stressed Volume

2009 ◽  
pp. 265-265-15 ◽  
Author(s):  
WT Tucker ◽  
CA Johnson
Keyword(s):  
Stressed Volume

scholarly journals Fatigue strength characterization of Al-Si cast material incorporating statistical size effect

2018 ◽  
Vol 165 ◽  
pp. 14002 ◽  
Author(s):  
Roman Aigner ◽  
Martin Leitner ◽  
Michael Stoschka
Keyword(s):  
Size Effect ◽  
Extreme Value Distribution ◽  
Ct Scanning ◽  
Element Analysis ◽  
Cast Material ◽  
Stressed Volume ◽  
Alloy Casting ◽  
Weakest Link ◽  
Testing Region ◽  
Strength Characterization

Cast aluminium components may exhibit material imperfections such as shrinkage and gas pores, or oxide inclusions. Therefore, the fatigue resistance is significantly influenced by the size and location of these inhomogenities. In this work, two different specimen geometries are manufactured from varying positions of an Al-Si-Cu alloy casting. The specimen geometries are designed by means of shape optimization based on a finite element analysis and exhibit different highly-stressed volumes. The numerically optimized specimen curvature enforces a notch factor of only two percent. To enable the evaluation of a statistical size effect, the length of the constant testing region and hence, the size of the highly-stressed volume varies by a ratio of one to ten between the two specimen geometries. Furthermore, the location of the crack initiation is dominated by the comparably greatest defects in this highly-stressed volume, which is also known as Weibull’s weakest link model. The crack initiating defect sizes are evaluated by means of light microscopy and modern scanning electron microscope methods. Finally, the statistical size effect is analysed based on the extreme value distribution of the occurring defects, whereby the size and location of the pores is non-destructively obtained by computed tomography (CT) scanning. This elaborated procedure facilitates a size-effect based methodology to study the defect distribution and the associated local fatigue life of CPS casted Al-Si lightweight components.

International Conference on Gears 2019

2019 ◽  
Keyword(s):  
Applied Sciences ◽  
High Performance ◽  
Stressed Volume ◽  
Cd Rom ◽  
International Conference ◽  
University Of Technology ◽  
Surface Durability ◽  
Tooth Flank ◽  
Plastic Gears ◽  
Beijing China

Der Bericht ist ausschließlich als PDF-Dokument erschienen! Drei Konferenzen in einer, auf 1.874 Seiten finden Sie jede Menge aller neueste Informationen zum Thema Gears. Die beiden anderen Konferenzen waren: 3rd International Conference on High Performance Plastic Gears 2019 und 3rd International Conference on Gear Production 2019 Achtung: Dieser VDI-Bericht ist ausschließlich als PDF-Datei auf CD-ROM lieferbar! Auszug aus dem 22-seitigen Inhaltsverzeichnis: Foreword 1 K. Stahl, Technische Universität München (TUM), Garching International Conference on Gears 2019 Flank strength Influence of gear surface roughness on pitting and micropitting life 3 E. Bergstedt, Prof. U. Olofsson, KTH, Stockholm, Sweden; J. Lin, Beijing University of Technology, Beijing, China; P. Lindholm, ABB Corporate Research, Västerås, Sweden Influence of stressed volume of tooth flank on the surface durability 15 A. Kubo, Research Institute for Applied Sciences, Ooicho, Kyoto, Japan Transfer of the tooth fl...

Near-Interface Crack Initiation in Thermal Barrier Coatings

1999 ◽  
Vol 586 ◽  
Author(s):  
Z. Zhang ◽  
T. E. Bloomer ◽  
J. Kameda ◽  
S. Sakurai
Keyword(s):  
Tensile Stress ◽  
Thermal Barrier Coatings ◽  
Volume Effect ◽  
Thermal Barrier ◽  
Cracking Behavior ◽  
Barrier Coatings ◽  
Stressed Volume ◽  
Four Point Bending ◽  
Principal Tensile Stress ◽  
Similar Mode

ABSTRACTThe delamination behavior of thermal barrier coatings (TBC) in transition ducts of inservice used combusters has been characterized using a protruded four-point bending testing technique recently developed by the authors. A reinforced protruded TBC specimen allowed the formation of TBC cracks adjacent to the TBC/alumina interface in a similar mode to inservice TBC failure. Finite element stress analysis showed that a peak transverse stress appeared in a protruded TBC part away from the interface and a large principal tensile stress operated on planes inclined to the interface. It was found that the onset of near-interface TBC cracks in the protruded TBC specimen did not occur under the high transverse and principal tensile stresses. The critical local tensile stress for the onset of TBC cracks near the interface, estimated to be 127 MPa, was lower than that of the near-center TBC. The near-interface TBC cracking behavior in the protruded TBC tests is discussed in light of the residual stress distribution and stressed volume effect.

scholarly journals Discussion: Application of the highly stressed volume approach to correlated results from different tensile tests of concrete

1986 ◽  
Vol 38 (136) ◽  
pp. 168-172 ◽  
Author(s):  
R. J. Torrent ◽  
J. J. Brooks ◽  
Y. S. Jenq ◽  
S. P. Shah
Keyword(s):  
Tensile Tests ◽  
Stressed Volume

scholarly journals The effect of microstructural heterogeneities on the High Cycle Fatigue scatter of cast aluminium alloys: from an elementary volume to the structure

2018 ◽  
Vol 165 ◽  
pp. 14006 ◽  
Author(s):  
Driss El Khoukhi ◽  
Franck Morel ◽  
Nicolas Saintier ◽  
Daniel Bellett ◽  
Pierre Osmond
Keyword(s):  
Size Effect ◽  
Aluminium Alloys ◽  
Fatigue Testing ◽  
Numerical Approach ◽  
Stressed Volume ◽  
Cast Aluminium ◽  
Critical Defect ◽  
Loaded Material ◽  
Critical Defect Size ◽  
Lost Foam

Cast Al-Si alloys have been widely used in automobile applications thanks to their low density and excellent thermal conductivity. A lot of components made of these alloys are subjected to cyclic loads which can lead to fatigue failure. Furthermore, the well know size effect in fatigue, whereby the fatigue strength is reduced in proportion to an increase in size, can be important. This is caused by a higher probability of initiating a crack in larger specimens (i.e. statistical size effect). This paper analyses the role of casting defects on the statistical size effect. For that, a uniaxial fatigue testing campaign (R=0.1) has been conducted using two cast aluminium alloys, fabricated by different casting processes (gravity die casting and lost foam casting), associated with the T7 heat treatment, and with different degrees of porosity. Different specimens (smooth and notched) with different stressed volumes have been investigated. The first part of this article is dedicated to the experimental characterization of the statistical size effect in both alloys via the concept of the Highly Stressed Volume. The second part investigates the effect of the Highly Stressed Volume on the critical defect size via diagram of Kitagawa-Takahashi. The results show that the presence of statistical size effect is strongly linked to the characteristics of the pore population present in the alloy. A numerical approach, linking the observed pore distribution to the volume of loaded material, is proposed and discussed.

The stop‐flow arm equilibrium pressure in preoperative patients: Stressed volume and correlations with echocardiography

2019 ◽  
Vol 63 (5) ◽  
pp. 594-600 ◽  
Author(s):  
Konstantin Yastrebov ◽  
Anders Aneman ◽  
Michel Slama ◽  
Vladimir Kokhno ◽  
Vsevolod Luchansky ◽  
...  
Keyword(s):  
Equilibrium Pressure ◽  
Stressed Volume ◽  
Stop Flow

Multiaxial fatigue life estimation of defective aluminum alloy considering the microstructural heterogeneities effect

2018 ◽  
Vol 233 (9) ◽  
pp. 1830-1842
Author(s):  
Amal Ben Ahmed ◽  
Ahmad Bahloul ◽  
Mohamed Iben Houria ◽  
Anouar Nasr ◽  
Raouf Fathallah
Keyword(s):  
Aluminum Alloy ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Multiaxial Fatigue ◽  
Cycle Fatigue ◽  
Post Heat Treatment ◽  
Stressed Volume ◽  
Good Ability ◽  
Fatigue Life Estimation ◽  
Chaboche Model

The Al–Si–Mg high-cycle fatigue behavior is mainly affected by the microstructural heterogeneities and the presence of casting defects. This attempt aims to develop an analytical approach based on the evaluation of the highly stressed volume caused by local porosities and defined as the affected area methodology. The proposed approach is able to predict the aluminum alloy fatigue response by considering the effect of microstructure described by the secondary dendrite arm spacing and its correlation with the defect size effect. A representative elementary volume model is implemented to evaluate the stress distribution in the vicinity of the defect and to determine its impact on the high-cycle fatigue resistance. Work hardening due to cyclic loading is considered by applying the Lemaitre–Chaboche model. The Kitagawa–Takahashi diagrams corresponding to different microstructures and for two loading ratios: R σ = 0 and R σ = −1 were simulated based on the AA method. Simulations were compared to the experimental results carried out on cast aluminium alloy A356 with T6 post heat-treatment. The results show clearly that the proposed approach provides a good estimation of the A356-T6 fatigue limit and exhibits good ability in simulating the Kitagawa–Takahashi diagrams for fine and coarse microstructures.

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