Distribution of Aspect Ratio of Fatigue Crack at Notch Root Depending on Crack Initiation Point of Annealed Steel, JIS S45C

2017 ◽  
Vol 893 ◽  
pp. 240-244 ◽  
Author(s):  
Takahiro Matsueda ◽  
Masayuki Ishida ◽  
Koshiro Mizobe
Keyword(s):  
Stress Concentration ◽  
Aspect Ratio ◽  
Crack Initiation ◽  
Notch Root ◽  
Strength Prediction ◽  
Key Factors ◽  
Civil Structures ◽  
Initiation Point ◽  
Crack Shape ◽  
The Relationship

Aspect ratio of crack is one of key factors of fatigue strength prediction in engineering design and civil structures using fracture mechanics. Their empirical shapes are changed by stress concentration. However, it was not clear how stress concentration affects empirical results including crack shape and size. In this study, in order to investigate the relationship between stress concentration and crack geometry, the aspect ratio of cracks at notch root was observed and discussed. We succeeded to capture two important relationships which are between stress concentration and crack shape, and between crack initiation point at notch root and crack shape, respectively.

Modified Method to Predict Fatigue Crack Shape Based on Empirical Observation

2017 ◽  
Vol 748 ◽  
pp. 396-399
Author(s):  
Takahiro Matsueda ◽  
Tatsurou Nakashima
Keyword(s):  
Aspect Ratio ◽  
Notch Root ◽  
Nondestructive Inspection ◽  
Strength Prediction ◽  
Key Factors ◽  
Civil Structures ◽  
Empirical Observation ◽  
Crack Shape ◽  
Modified Method ◽  
The Relationship

Aspect ratio of crack is one of key factors of fatigue strength prediction in engineering design and civil structures using fracture mechanics and nondestructive inspection. However the author proposed the method to predict crack shape, it has the error caused by stress distribution of notch. In this study, in order to investigate the relationship between predicted crack shape and empirical observed it, the aspect ratio of cracks at notch root was observed, analyzed and discussed. We obtained the two important conclusions which are between predicted crack shape and empirical observed it. Predicted aspect ratio of crack was 17% bigger than that of observation result. The aspect ratio of crack should be defined considering scale of crack and notch shape.

The Relationship Between Fracture Toughness and Stress Concentration Factors for Several High-Strength Aluminum Alloys

1964 ◽  
Vol 86 (4) ◽  
pp. 709-717 ◽  
Author(s):  
J. H. Mulherin ◽  
D. F. Armiento ◽  
H. Markus
Keyword(s):  
Fracture Toughness ◽  
Stress Concentration ◽  
Notch Root ◽  
High Strength ◽  
Root Radius ◽  
Concentration Factors ◽  
Toughness Parameter ◽  
Stress Concentration Factors ◽  
High Strength Aluminum Alloys ◽  
The Relationship

For the case of an elliptical notch in an infinite solid, a relationship between the stress concentration factor and the fracture toughness parameter was examined. Edge-notched specimens from three high-strength aluminum alloys were tensile loaded to failure. The resulting data were analyzed in the light of this relationship. It was indicated that a predicted proportionality between the fracture toughness parameter and the square root of the notch root radius exists. Further examination of the relationship based upon the proportionality showed that fracture occurs at a fixed state of strain within a plastic zone having a size proportional to the original root radius. However, a departure from the predicted behavior was evident with the introduction of plane strain components at the notch root. It was also demonstrated that the use of specimens with intermediate root radii for either the evaluation of a single material or as a basis of comparison between materials can lead to invalid conclusions. The reversion of fracture toughness data from blunt notch specimens to stress concentration factors is shown for one alloy. Due to a constancy in the ratio of the fracture parameter to the nominal stress, the resulting factor lacks sensitivity.

A New Evaluation Method to Calculate Crack Initiation Limit with Modified Crack Aspect Ratios in Notched Specimen of Carbon Steels

2014 ◽  
Vol 563 ◽  
pp. 80-84 ◽  
Author(s):  
Takahiro Matsueda
Keyword(s):  
Aspect Ratio ◽  
Crack Initiation ◽  
Evaluation Method ◽  
Notch Root ◽  
Fatigue Crack Initiation ◽  
Carbon Steels ◽  
Notched Specimen ◽  
Aspect Ratios ◽  
Key Factor ◽  
Initiation Stress

Aspect ratio is a key factor to calculate stress intensity factor (SIF) K using fracture mechanics. While cracks are approximated to be semi-circle or semi-ellipse for simply evaluation, their shapes are changed by stress concentration source. In this study, a new method to modify aspect ratio of a crack at a notch root is proposed. Modified aspect ratio in this method succeeded to decrease prediction error of fatigue crack initiation stress, σw1 which was calculated using experimental value.

Challenging the Terms of Order: Representations of the Detroit Rebellions, 1967–1968

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Jordan T. Camp
Keyword(s):  
State Violence ◽  
Rapid Expansion ◽  
Capitalist Development ◽  
Civil Structures ◽  
Us History ◽  
Political Struggles ◽  
Stuart Hall ◽  
The Relationship ◽  
The City ◽  
John Clarke

While many analysts have commented on the representation of 1968 campus events and antiwar demonstrations, less attention has been paid to the global significance of the dramatic struggles in industrial Detroit during the period. The meanings of events in the city were intensely fought over. As Stuart Hall, Chas Critcher, Tony Jefferson, John Clarke, and Brian Roberts observed, the events of 1968 were “an act of collective will, the breaks and ruptures stemming from the rapid expansion in the ideology, culture and civil structures of the new capitalism . . . in the form of a ‘crisis of authority.’” In Detroit the crisis of authority was expressed in the form of popular political struggles against racism, state violence, and the contradictions of life in the industrial capitalist city. This article asks and answers the following research questions about the struggle over the meaning of this decisive turning point in US history: What was the relationship between racial ordering, uneven capitalist development, and mass antiracist and class struggles? How did Black working-class organic intellectuals resist and alter hegemonic definitions of the situation? How are the dialectics of insurgency and counterinsurgency to be best theorized during this precise historical conjuncture? 

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part I: Introduction and Details on the Organization of the Program

1986 ◽  
Vol 14 (4) ◽  
pp. 201-218 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Aspect Ratio ◽  
Comprehensive Evaluation ◽  
Test Method ◽  
Interactive Effects ◽  
Data Analyses ◽  
Main Effect ◽  
Systematic Determination ◽  
Relationship Of ◽  
The Relationship

Abstract This four-part series of papers addresses the problem of systematic determination of the influence of several tire factors on tire treadwear. Both the main effect of each factor and some of their interactive effects are included. The program was also structured to evaluate the influence of some external-to-tire conditions on the relationship of tire factors to treadwear. Part I describes the experimental design used to evaluate the effects on treadwear of generic tire type, aspect ratio, tread pattern (groove or void level), type of pattern (straight rib or block), and tread compound. Construction procedures and precautions used to obtain a valid and functional test method are included. Two guiding principles to be used in the data analyses of Parts II and III are discussed. These are the fractional groove and void concept, to characterize tread pattern geometry, and a demonstration of the equivalence of wear rate for identical compounds on whole tread or multi-section tread tires.

Examining Organizational, Cultural, and Individual-Level Factors Related to Workplace Safety and Health Awareness and Risks: A Systematic Review and Metric Analysis (Preprint)

2018 ◽  
Author(s):  
Edmund W. J. Lee ◽  
Han Zheng ◽  
Htet Htet Aung ◽  
Megha Rani Aroor ◽  
Chen Li ◽  
...  
Keyword(s):  
Systematic Review ◽  
Citation Count ◽  
Workplace Safety ◽  
Key Factors ◽  
Health Awareness ◽  
Individual Level ◽  
Metric Analysis ◽  
Safety And Health ◽  
The Impact ◽  
The Relationship

BACKGROUND Promoting safety and health awareness and mitigating risks are of paramount importance to companies in high-risk industries. Yet, there are very few studies that have synthesized findings from existing online workplace safety and health literature to identify what are the key factors that are related to (a) safety awareness, (b) safety risks, (c) health awareness, and (d) health risks. OBJECTIVE As one of the first systematic reviews in the area of workplace health and safety, this study aims to identify the factors related to safety and health awareness as well as risks, and systematically map these factors within three levels: organizational, cultural, and individual level. Also, this review aims to assess the impact of these workplace safety and health publications in both academic (e.g., academic databases, Mendeley, and PlumX) and non-academic settings (e.g., social media platform). METHODS The systematic review was conducted in line with procedures recommended by Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). First, Proquest, ScienceDirect and Scopus were identified as suitable databases for the systematic review. Second, after inputting search queries related to safety and health awareness and risks, the articles were evaluated based on a set of inclusion and exclusion criteria. Third, the factors identified in the included articles were coded systematically. Fourth, the research team assessed the impact of the articles through a combination of traditional and new metric analysis methods: citation count, Altmetric Attention Score, Mendeley readers count, usage count, and capture count. RESULTS Out of a total of 4,831 articles retrieved from the three databases, 51 articles were included in the final sample and were systematically coded. The results revealed six categories of organizational (management commitment, management support, organizational safety communication, safety management systems, physical work environment, and organizational environment), two cultural (interpersonal support and organizational culture), and four individual (perception, motivation, attitude and behavior) level factors that relate to safety and health awareness and risk. In terms of impact, the relationship between citation count and the various metrics measuring academic activity (e.g., Mendeley readers, usage count, and capture count) were mostly significant while the relationship between citation count and Altmetric Attention Score was non-significant. CONCLUSIONS This study provides a macro view of the current state of workplace safety and health research and gives scholars an indication on some of the key factors of safety and health awareness and risks. Researchers should also be cognizant that while their work may receive attention from the scholarly community, it is important to tailor their communication messages for the respective industries they are studying to maximize the receptivity and impact of their findings. CLINICALTRIAL N.A.

Fatigue Failure Analysis Using the Theory of Critical Distance

2011 ◽  
Vol 462-463 ◽  
pp. 663-667 ◽  
Author(s):  
Ruslizam Daud ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Al Emran Ismail
Keyword(s):  
Stress Concentration ◽  
Fatigue Failure ◽  
Notch Root ◽  
High Stress ◽  
Critical Distance ◽  
Future Research ◽  
Element Analysis ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Elastic Fracture

This paper explores the initial potential of theory of critical distance (TCD) which offers essential fatigue failure prediction in engineering components. The intention is to find the most appropriate TCD approach for a case of multiple stress concentration features in future research. The TCD is based on critical distance from notch root and represents the extension of linear elastic fracture mechanics (LEFM) principles. The approach is allowing possibilities for fatigue limit prediction based on localized stress concentration, which are characterized by high stress gradients. Using the finite element analysis (FEA) results and some data from literature, TCD applications is illustrated by a case study on engineering components in different geometrical notch radius. Further applications of TCD to various kinds of engineering problems are discussed.

scholarly journals Comparison of the sensitivity of Western blotting between PVDF and NC membranes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yufang Xiang ◽  
Yuanyuan Zheng ◽  
Shaobo Liu ◽  
Gang Liu ◽  
Zhi Li ◽  
...  
Keyword(s):  
Western Blotting ◽  
Polyvinylidene Fluoride ◽  
Staining Intensity ◽  
Detection Sensitivity ◽  
Key Factors ◽  
Post Translational Modifications ◽  
Factors Affecting ◽  
Molecular Weights ◽  
Direct Blue ◽  
The Relationship

AbstractWestern blotting (WB) is one of the most widely used techniques to identify proteins as well as post translational modifications of proteins. The selection of electroblotted membrane is one of the key factors affecting the detection sensitivity of the protein which is transferred from gel to membrane in WB. The most common used membranes are polyvinylidene fluoride (PVDF) and nitrocellulose (NC) membranes. Which membrane of these two is more suitable for WB has not been reported so far. Here, by incubating proteins which were transferred to PVDF or NC membranes with a series of antibodies and different types of lectins, we investigated the relationship between the binding ability of these two membranes to proteins or glycoproteins and the molecular weight of the target protein. The antibody re-probed ability of the two membranes was also explored. Moreover, we verified the above results by directly incubating proteins having different molecular weights onto PVDF or NC membranes. Bound proteins were stained with direct blue-71, and the staining intensity was quantitated by scanning and densitometry.

scholarly journals High coverage COVID-19 mRNA vaccination rapidly controls SARS-CoV-2 transmission in long-term care facilities

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Pablo M. De Salazar ◽  
Nicholas B. Link ◽  
Karuna Lamarca ◽  
Mauricio Santillana
Keyword(s):  
Long Term Care ◽  
Mitigation Strategies ◽  
Key Factors ◽  
Modeling Framework ◽  
High Coverage ◽  
Term Care ◽  
Early Effect ◽  
Care Facilities ◽  
The Relationship

Abstract Background Residents of Long-Term Care Facilities (LTCFs) represent a major share of COVID-19 deaths worldwide. Measuring the vaccine effectiveness among the most vulnerable in these settings is essential to monitor and improve mitigation strategies. Methods We evaluate the early effect of the administration of BNT162b2-mRNA vaccine to individuals older than 64 years residing in LTCFs in Catalonia, Spain. We monitor all the SARS-CoV-2 documented infections and deaths among LTCFs residents once more than 70% of them were fully vaccinated (February–March 2021). We develop a modeling framework based on the relationship between community and LTCFs transmission during the pre-vaccination period (July–December 2020). We compute the total reduction in SARS-CoV-2 documented infections and deaths among residents of LTCFs over time, as well as the reduction in the detected transmission for all the LTCFs. We compare the true observations with the counterfactual predictions. Results We estimate that once more than 70% of the LTCFs population are fully vaccinated, 74% (58–81%, 90% CI) of COVID-19 deaths and 75% (36–86%, 90% CI) of all expected documented infections among LTCFs residents are prevented. Further, detectable transmission among LTCFs residents is reduced up to 90% (76–93%, 90% CI) relative to that expected given transmission in the community. Conclusions Our findings provide evidence that high-coverage vaccination is the most effective intervention to prevent SARS-CoV-2 transmission and death among LTCFs residents. Widespread vaccination could be a feasible avenue to control the COVID-19 pandemic conditional on key factors such as vaccine escape, roll out and coverage.

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