Evaluation of stress intensity factor of multiple inclined cracks under biaxial loading

A finite rectangular plate of unit thickness with two inclined cracks (parallel and non parallel) under biaxial mixed mode condition are modelled using finite element method. The finite element method is used for determination of stress intensity factors by ANYSIS software. Effects of crack inclination angle on stress intensity factors for two parallel and non parallel cracks are investigated. The significant effects of different crack inclination parameters on stress intensity factors are seen for lower and upper crack in two inclined crack.The present method is validated by comparing the results from available experimental data obtained by photo elastic method in same condition

Influence of crack offset distance on the interaction of multiple cracks on the same side in a rectangular plate

In the present work finite element method has been employed to study the interaction of multiple cracks in a finite rectangular plate of unit thickness with cracks on the same side under uniaxial loading conditions. The variation of the stress intensity factor and stress distribution around the crack tip with crack offset distance has been studied. Due to the presence of a neighbouring crack, two types of interactions viz. intensification and shielding effect have been observed. The interaction between the cracks is seen to be dependent on the crack offset distance. It is seen that the presence of a neighbouring crack results in the appearance of mode II stress intensity factor which was otherwise absent for a single edge crack. It can be said that the proximity of cracks is non-desirable for structural integrity. The von-Mises stress for different crack orientations has been computed. Linear elastic analysis of state of stress around the crack tip has also been done

Effect of Boundary Condition on Pre-Existing Crack Under Fatigue Loading

ABSTRACT In this paper, the present investigation has been conducted keeping in mind some of the problems concerning the crack propagation direction and growth under constant loading in an inclined crack geometry. The present studies mainly focused on the development and modifications in the crack growth criterion to account the biaxial, shear loading and number of stress terms. Existing criteria for the prediction of crack initiation direction have been modified taking higher order stress terms. The effective methods of experimentally determining the stress intensity factor for a body containing a crack is to analyze the isochromatic pattern obtained from a photoelastic model. The effect of biaxial load factor, crack angle, Crack length/width of specimen and length of specimen/width of specimen were studied and a regression model was developed for geometry correction to predict stress intensity factor for tearing mode and intensity factor for shearing mode. This approach is being used to predict crack growth trajectory under biaxial cyclic loading by assuming that the crack may grow in a number of discrete steps using the vectorial method. MTS criterion (Maximum Tangential Stress criterion) is used for prediction of crack initiating angle. The crack growth trajectory has been determined by cycle simulation procedure

Evaluation of stress intensity factor of multiple inclined cracks under biaxial loading

A finite rectangular plate of unit thickness with two inclined cracks (parallel and non parallel) under biaxial mixed mode condition are modelled using finite element method. The finite element method is used for determination of stress intensity factors by ANYSIS software. Effects of crack inclination angle on stress intensity factors for two parallel and non parallel cracks are investigated. The significant effects of different crack inclination parameters on stress intensity factors are seen for lower and upper crack in two inclined crack. The present method is validated by comparing the results from available experimental data obtained by photo elastic method in same condition

The Internet of Things as Smart City Enabler:The Cases of Palo Alto, Nice and Stockholm

Part 5: Smart Cities and Smart HomesInternational audienceDue to rapid urbanization, city populations are rapidly increasing all over the world creating new problems and challenges. Solving some of these problems requires innovative approaches; one increasingly popular approach is to transform cities to Smart Cities. Smart Cities implement innovative approaches based on IoT technologies and convert many services to digital services. These services are implemented within the different components of a Smart City, helping city administrators to improve the life of the citizens, addressing different service, security and administrative challenges. The objective of this paper is to explore and determine how three well-known cities - Nice, Palo Alto and Stockholm - implemented the Smart City concept. The study indicates that a successful implementation of a Smart City model requires addressing a number of critical challenges: citizen involvement, business collaboration and strong leadership prove to be key success factors in the Smart City development process

Explaining the impact of a women's group led community mobilisation intervention on maternal and newborn health outcomes: the Ekjut trial process evaluation

Background: Few large and rigorous evaluations of participatory interventions systematically describe their context and implementation, or attempt to explain the mechanisms behind their impact. This study reports process evaluation data from the Ekjut cluster-randomised controlled trial of a participatory learning and action cycle with women's groups to improve maternal and newborn health outcomes in Jharkhand and Orissa, eastern India (20052008). The study demonstrated a 45% reduction in neonatal mortality in the last two years of the intervention, largely driven by improvements in safe practices for home deliveries.Methods: A participatory learning and action cycle with 244 women's groups was implemented in 18 intervention clusters covering an estimated population of 114 141. We describe the context, content, and implementation of this intervention, identify potential mechanisms behind its impact, and report challenges experienced in the field. Methods included a review of intervention documents, qualitative structured discussions with group members and non-group members, meeting observations, as well as descriptive statistical analysis of data on meeting attendance, activities, and characteristics of group attendees.Results: Six broad, interrelated factors influenced the intervention's impact: (1) acceptability; (2) a participatory approach to the development of knowledge, skills and 'critical consciousness'; (3) community involvement beyond the groups; (4) a focus on marginalized communities; (5) the active recruitment of newly pregnant women into groups; (6) high population coverage. We hypothesize that these factors were responsible for the increase in safe delivery and care practices that led to the reduction in neonatal mortality demonstrated in the Ekjut trial.Conclusions: Participatory interventions with community groups can influence maternal and child health outcomes if key intervention characteristics are preserved and tailored to local contexts. Scaling-up such interventions requires (1) a detailed understanding of the way in which context affects the acceptability and delivery of the intervention; (2) planned but flexible replication of key content and implementation features; (3) strong support for participatory methods from implementing agencies

A multivariant secure framework for smart mobile health application

This is an accepted manuscript of an article published by Wiley in Transactions on Emerging Telecommunications Technologies, available online: https://doi.org/10.1002/ett.3684 The accepted version of the publication may differ from the final published version.Wireless sensor network enables remote connectivity of technological devices such as smart mobile with the internet. Due to its low cost as well as easy availability of data sharing and accessing devices, the Internet of Things (IoT) has grown exponentially during the past few years. The availability of these devices plays a remarkable role in the new era of mHealth. In mHealth, the sensors generate enormous amounts of data and the context-aware computing has proven to collect and manage the data. The context aware computing is a new domain to be aware of context of involved devices. The context-aware computing is playing a very significant part in the development of smart mobile health applications to monitor the health of patients more efficiently. Security is one of the key challenges in IoT-based mHealth application development. The wireless nature of IoT devices motivates attackers to attack on application; these vulnerable attacks can be denial of service attack, sinkhole attack, and select forwarding attack. These attacks lead intruders to disrupt the application's functionality, data packet drops to malicious end and changes the route of data and forwards the data packet to other location. There is a need to timely detect and prevent these threats in mobile health applications. Existing work includes many security frameworks to secure the mobile health applications but all have some drawbacks. This paper presents existing frameworks, the impact of threats on applications, on information, and different security levels. From this line of research, we propose a security framework with two algorithms, ie, (i) patient priority autonomous call and (ii) location distance based switch, for mobile health applications and make a comparative analysis of the proposed framework with the existing ones.Published onlin

Photoelastic Determination of Mixed Mode Stress Intensity Factors

ABSTRACT A two dimensional finite model with inclined crack at different crack angles are being analyzed in mixed mode condition using photo elasticity method for the determination of Stress Intensity Factors. The well-known Sih's equation and three points deterministic approach is used for the determination of stress intensity factors. The effects of biaxial load factor, crack angle, size factors were studied and a regression model was developed for geometry correction to predict Stress Intensity Factors. The results give a good compromise to the theoretical one. The experimental result also gives significant data for the two dimensional mixed mode loading conditions

Green Approaches to Biocomposite Materials Science and Engineering

Industrial ecology, eco-efficiency, and green chemistry are guiding the development of the next generation of materials, products, and processes. Considerable growth has been seen in the use of biocomposites in the domestic sector, building materials, aerospace industry, circuit boards, and automotive applications over the past decade, but application in other sectors until now has been limited.Green Approaches to Biocomposite Materials Science and Engineering explores timely research on the various available types of natural fibers and the use of these fibers as a sustainable alternative to synthetic fibers and polymers. Emphasizing research-based solutions for sustainability across various industries, this publication is an essential reference source for engineers, researchers, environmental scientists, and graduate-level students.Используемые программы Adobe AcrobatПромышленная экология, экоэффективность и "зеленая" химия определяют разработку материалов, продуктов и процессов следующего поколения. За последнее десятилетие наблюдался значительный рост использования биокомпозитов в быту, производстве строительных материалов, аэрокосмической промышленности, печатных платах и автомобилестроении, но применение в других секторах до сих пор было ограниченным. "Зеленые подходы к биокомпозитному материаловедению и инженерии" исследуют своевременные исследования различных доступных типов натуральных волокон и использование этих волокон в качестве устойчивой альтернативы синтетическим волокнам и полимерам. Уделяя особое внимание научно -обоснованным решениям в области устойчивого развития в различных отраслях промышленности, эта публикация является важным справочным источником для инженеров, исследователей, ученых-экологов и студентов старших курсов