Analysis of Local Stresses and Strains in Ti-6A1-4V Widmanstätten

2009 ◽  
pp. 200-200-16 ◽  
Author(s):  
RE Smelser ◽  
JL Swedlow ◽  
JC Williams
Keyword(s):  
Local Stresses

Numerical analysis of the variation of local stresses with the groove thickness

2018 ◽  
Author(s):  
Carlos Geovane Alves ◽  
Jorge Alberto Rodriguez Duran ◽  
Bruno Gomes Tavares
Keyword(s):  
Numerical Analysis ◽  
Local Stresses

Elastic Stress Singularities: Implications for the Attachment of Tendon to Bone

2011 ◽  
Author(s):  
Yanxin Liu ◽  
Victor Birman ◽  
Chanqing Chen ◽  
Stavros Thomopoulos ◽  
Guy M. Genin
Keyword(s):  
Stress Distribution ◽  
Abrupt Change ◽  
Elastic Stress ◽  
Insertion Site ◽  
Stress Singularities ◽  
Local Stresses ◽  
Material Mismatch ◽  
Moduli Of Elasticity

The material mismatch at the attachment of tendon to bone is amongst the most severe for any tensile connection in nature. This is related to the large difference between the stiffness of tendon and bone, whose moduli of elasticity vary by two orders of magnitude. Predictably, such an abrupt change in the stiffness realized over a very narrow insertion site results in high local stresses. One of the implications of the stress distribution is a potential for stress singularities at the junction of the insertion to the bone.

scholarly journals Mapping of scatter in fatigue life assessment of welded structures—a round-robin study

2021 ◽  
Author(s):  
Gustav Hultgren ◽  
Mansoor Khurshid ◽  
Peter Haglund ◽  
Zuheir Barsoum
Keyword(s):  
Fatigue Life ◽  
Round Robin ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Fatigue Life Estimation ◽  
Box Structures ◽  
Load Carrying ◽  
Local Stresses ◽  
Sources Of Variation ◽  
Global And Local

AbstractA round-robin study has been carried out within a national project in Sweden with the addition of an international participant, where several industrial partners and universities are participating. The project aims to identify variation and sources of variation in welding production, map scatter in fatigue life estimation, and define and develop concepts to reduce these, in all steps of product development. The participating organisations were asked to carry out fatigue life assessment of welded box structures, which is a component in load-carrying structures. The estimations of fatigue life have also been compared with fatigue test results. Detailed drawings, loads and material data were also given to the participants. The participants were supposed to use assessment methods based on global and local stresses using the design codes or recommendations they currently use in-house. Differences were identified between both methods and participants using the same codes/recommendations. Applicability and conditions from the cases in the codes were also identified to be differently evaluated between the participants. It could be concluded that for the applied cases the nominal stress method often overestimated the fatigue life and had a high scatter in the estimations by different participants. The effective notch method is conservative in comparison to the life of tested components with little scatter between the results derived by the participants.

States of local stresses in the Sea of Marmara through the analysis of large numbers of small earthquakes

2015 ◽  
Vol 665 ◽  
pp. 37-57 ◽  
Author(s):  
Yasemin Korkusuz Öztürk ◽  
Nurcan Meral Özel ◽  
Ali Değer Özbakir
Keyword(s):  
Sea Of Marmara ◽  
Large Numbers ◽  
Local Stresses

Strengthening of steel decks for cable-stayed bridge using ultra-high performance concrete: A case study

2020 ◽  
Vol 23 (16) ◽  
pp. 3373-3384
Author(s):  
Lei Wang ◽  
Xiaochao Su ◽  
Yafei Ma ◽  
Ming Deng ◽  
Jianren Zhang ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Fatigue Cracking ◽  
Strengthening Effect ◽  
Steel Bridge ◽  
Ultra High Performance Concrete ◽  
Cable Stayed Bridge ◽  
Local Stresses ◽  
Orthotropic Steel Decks ◽  
Strengthening Method

Fatigue cracking induced by vehicle load is a prevalent problem in orthotropic steel decks. In addition, pavement debonding in steel bridge decks is another familiar issue resulting from low slip resistance in the faying surface between the steel and asphalt concrete. The present study proposed a strengthening method that uses ultra-high performance concrete to stiffen a repeatedly maintained cable-stayed bridge in order to help address these two problems. The existing issues of the real bridge and the corresponding causes were investigated. Following this, an ultra-high performance concrete paving system was designed to improve the stiffness of the orthotropic steel decks. For this paving system, a 45-mm ultra-high performance concrete layer was connected to the deck by welded shear studs. The local stresses at the typical vulnerable fatigue cracking points were determined by means of a finite element model and of a field loading test to evaluate the strengthening effect. The results showed that this strengthening method can prevent the propagation of fatigue cracks. The local stresses of the U-ribs and diaphragms were reduced by 45.4% and 40.0%, respectively. The repaired bridge has sufficient resistance against fatigue cracking based on the in situ observations.

scholarly journals Eukaryotic Probiotic Saccharomyces boulardii Application in Clinical Trails: A Review

2013 ◽  
Vol 11 (01) ◽  
pp. 23-30
Author(s):  
Rahem E. ALzaidi1 ◽  
Hanaa D. Al-Mozan ◽  
Nuha Alrikabi
Keyword(s):  
Antibiotic Resistance Genes ◽  
Saccharomyces Boulardii ◽  
Complete Sequence ◽  
Natural Resistance ◽  
Recurrent Clostridium Difficile Infection ◽  
Frequent Event ◽  
Wide Range ◽  
Local Stresses ◽  
Primary Advantage ◽  
Clinical Trails

Probiotics are live microbes that assist in restoring the symbiotic intestinal gut flora balance and thus bestow health benefits to the host. The most commonly used human probiotics are members of the Lactobacillus and Bifidobacterium species. Besides these bacteria, Saccharomyces boulardii, a yeast strain, is also widely used as a probiotic to treat a variety of conditions, including antibiotics-associated diarrhea and recurrent Clostridium difficile infection. A primary advantage of using Saccharomyces boulardii as a probiotic is that it can be used by patients undergoing antibiotic regimen due to its natural resistance to antibiotics. The genetic transfer of antibiotic resistance genes, a frequent event between pathogenic and gastrointestinal tract (GIT) bacteria, is not as frequent between yeast and bacteria. Furthermore, Saccharomyces boulardii is also tolerant to various local stresses such as the presence of gastrointestinal (GI) enzymes, bile salts, organic acids, etc. and can withstand considerable variations in pH and temperature while transiting through the human GIT. Saccharomyces boulardii is known as generally regarded as safe (GRAS)with probiotic activity against a wide range of pathogens. This yeast is often marketed in a lyophilized form, “ S. boulardii lyo”, complete sequence of the genome was performed, and a comparative analysis of the genome was performed. From clinical studies, the results of randomized controlled trials in patients repeatedly confirmed the significant positive effect in the treatment of acute and chronic diseases.

scholarly journals Модификация структуры градиентных покрытий Ti-Al-Si-Cu-N при механических испытаниях

2020 ◽  
Vol 90 (5) ◽  
pp. 817
Author(s):  
С.В. Овчинников
Keyword(s):  
Crystal Lattice ◽  
Strength Properties ◽  
Dark Field ◽  
Analysis Method ◽  
Local Stresses ◽  
Electron Microscopy Analysis ◽  
Field Electron Microscopy ◽  
Microscopy Analysis ◽  
Dark Field Electron ◽  
Gradient Coatings

The research of structural state at the indentation and scratch regions of the gradient coatings Ti-Al-Si-Cu-N was carried out with the use of dark field electron microscopy analysis method of the crystal lattice bending. It was found out that the strength properties of the substrate, which determine the degree of plastic relaxation of the applied load are significant for modifying the coating structure. The increase of the crystal lattice bending relative to undeformed state, the heterogeneity and anisotropy of its value relative to the point and axis of the load are found for the material under the indenter apex. The formation of the localized bands is shown, in which the increase of crystal sizes, decrease in the bending of the crystal lattice and residual local stresses were observed.

scholarly journals 2 Dimensional Dislocation Dynamics – A New Technique for the Simulation of Deformation Microtextures

1997 ◽  
Vol 28 (3-4) ◽  
pp. 167-179
Author(s):  
F. Roters ◽  
D. Raabe
Keyword(s):  
Cold Deformation ◽  
Dislocation Motion ◽  
Dislocation Dynamics ◽  
New Technique ◽  
Linear Elastic ◽  
Straight Line ◽  
Simulation Step ◽  
Local Stresses ◽  
A New Technique ◽  
Edge Dislocations

A new technique for the simulation of microtexture evolution during cold deformation which is based on 2 dimensional (2D) dislocation dynamics is presented. In the simulation all involved dislocations are regarded as infinite straight line detects which are embedded in an otherwise isotropic linear elastic medium. As the model is 2D only edge dislocations are considered.In the first simulation step the net local stresses are derived and used to calculate the resulting dislocation motion. Dislocation multiplication, annihilation and reactions are taken into account. Thermal activation is included. In the second step the local misorientations arising from the dislocation distribution are calculated.This method shows in microscopic detail how misorientations are generated and distributed within grains during plastic deformation.

scholarly journals Detection of epimuscular myofascial forces by Golgi tendon organs

2021 ◽  
Author(s):  
Huub Maas ◽  
Wendy Noort ◽  
Hiltsje A. Smilde ◽  
Jacob A. Vincent ◽  
Paul Nardelli ◽  
...  
Keyword(s):  
Force Feedback ◽  
Unit Length ◽  
Connective Tissues ◽  
Lateral Gastrocnemius ◽  
Golgi Tendon Organs ◽  
Local Stresses ◽  
The Central Nervous System ◽  
Synergistic Muscles ◽  
Tendon Organs ◽  
Sensory Encoding

AbstractSkeletal muscles embed multiple tendon organs, both at the proximal and distal ends of muscle fibers. One of the functions of such spatial distribution may be to provide locally unique force feedback, which may become more important when stresses are distributed non-uniformly within the muscle. Forces exerted by connections between adjacent muscles (i.e. epimuscular myofascial forces) may cause such local differences in force. The aim of this exploratory study was to investigate the effects of mechanical interactions between adjacent muscles on sensory encoding by tendon organs. Action potentials from single afferents were recorded intra-axonally in response to ramp-hold release (RHR) stretches of a passive agonistic muscle at different lengths or relative positions of its passive synergist. The tendons of gastrocnemius (GAS), plantaris (PL) and soleus (SO) muscles were cut from the skeleton for attachment to servomotors. Connective tissues among these muscles were kept intact. Lengthening GAS + PL decreased the force threshold of SO tendon organs (p = 0.035). The force threshold of lateral gastrocnemius (LG) tendon organs was not affected by SO length (p = 0.371). Also displacing LG + PL, kept at a constant muscle–tendon unit length, from a proximal to a more distal position resulted in a decrease in force threshold of LG tendon organs (p = 0.007). These results indicate that tendon organ firing is affected by changes in length and/or relative position of adjacent synergistic muscles. We conclude that tendon organs can provide the central nervous system with information about local stresses caused by epimuscular myofascial forces.

Applicability of Design Rules for Openings in Shells, ASME B&PV Code, Section VIII, Division 2 - A Case Study

2021 ◽  
Author(s):  
Gurumurthy Kagita ◽  
Krishnakant V. Pudipeddi ◽  
Subramanyam V. R. Sripada
Keyword(s):  
Stress Analysis ◽  
Failure Modes ◽  
Element Analysis ◽  
Design Rules ◽  
Area Method ◽  
Replacement Method ◽  
Local Stresses ◽  
Pressure Area ◽  
Section Viii ◽  
Division 2

Abstract The Pressure-Area method is recently introduced in the ASME Boiler and Pressure Vessel (B&PV) Code, Section VIII, Division 2 to reduce the excessive conservatism of the traditional area-replacement method. The Pressure-Area method is based on ensuring that the resistive internal force provided by the material is greater than or equal to the reactive load from the applied internal pressure. A comparative study is undertaken to study the applicability of design rules for certain nozzles in shells using finite element analysis (FEA). From the results of linear elastic FEA, it is found that in some cases the local stresses at the nozzle to shell junctions exceed the allowable stress limits even though the code requirements of Pressure-Area method are met. It is also found that there is reduction in local stresses when the requirement of nozzle to shell thickness ratio is maintained as per EN 13445 Part 3. The study also suggests that the reinforcement of nozzles satisfy the requirements of elastic-plastic stress analysis procedures even though it fails to satisfy the requirements of elastic stress analysis procedures. However, the reinforcement should be chosen judiciously to reduce the local stresses at the nozzle to shell junction and to satisfy other governing failure modes such as fatigue.

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