The Failure Theory for Isotropic Materials: Proof and Completion

2019 ◽  
Vol 87 (5) ◽  
Author(s):  
Richard M. Christensen

Abstract This work represents the completion of the many developments in recent years on failure theory for homogeneous and isotropic materials. Presented here is the resulting failure formalism in final and technically complete form. Significant further results are also given for the verification of the failure formalism. The scope of this paper goes from the history of misguided failure theory investigations right up to the present final tested forms ready for applications. For every predicted failure level in terms of the stresses, there is an accompanying ductility level. This ranges from brittle failure up to fully ductile failure. The entire theory is calibrated by only two specified parameters (failure properties). Nothing else is needed. The seemingly interminable, actually centuries long search for the missing theory of failure has finally been brought to a resolute and successful conclusion.

2016 ◽  
Vol 83 (6) ◽  
Author(s):  
Richard M. Christensen

The ductile/brittle failure theory for homogeneous and isotropic materials is extended to give a rational and mathematically rigorous measure for the ductility of failure. This new failure number methodology is completely developed and proved to be valid and general. It applies to all isotropic materials as subjected to any and all states of stress. Not only does the failure theory predict the safety or failure for any given stress state, it then projects the quantitative ductility level for the failure stress state. Many important examples are given with detailed interpretations of the results and with guides for general usage.


2015 ◽  
Vol 83 (2) ◽  
Author(s):  
Richard M. Christensen

A recently developed ductile/brittle theory of materials failure is evaluated. The failure theory applies to all homogeneous and isotropic materials. The determination of the ductile/brittle transition is an integral and essential part of the failure theory. The evaluation process emphasizes and examines all aspects of the ductile versus the brittle nature of failure, including the ductile limit and the brittle limit of materials' types. The failure theory is proved to be extraordinarily versatile and comprehensive. It even allows derivation of the associated ductile/brittle transition temperature. This too applies to all homogeneous and isotropic materials and not just some subclass of materials' types. This evaluation program completes the development of the failure theory.


2014 ◽  
Vol 81 (11) ◽  
Author(s):  
Richard M. Christensen

Continuing from Part I (Christensen, 2014, “Failure Mechanics—Part I: The Coordination Between Elasticity Theory and Failure Theory for all Isotropic Materials,” ASME J. Appl. Mech., 81(8), p. 081001), the relationship between elastic energy and failure specification is further developed. Part I established the coordination of failure theory with elasticity theory, but subject to one overriding assumption: that the values of the involved Poisson's ratios always be non-negative. The present work derives the physical proof that, contrary to fairly common belief, Poisson's ratio must always be non-negative. It can never be negative for homogeneous and isotropic materials. This is accomplished by first probing the reduced two-dimensional (2D) elasticity problem appropriate to graphene, then generalizing to three-dimensional (3D) conditions. The nanomechanics analysis of graphene provides the key to the entire development. Other aspects of failure theory are also examined and concluded positively. Failure theory as unified with elasticity theory is thus completed, finalized, and fundamentally validated.


2019 ◽  
Vol 86 (9) ◽  
Author(s):  
Richard M. Christensen

The problem of special interest is the nature of the mode of failure in uniaxial compression at the brittle limit. This problem is known by observation to undergo a splitting mode of failure. The present work gives a full theoretical treatment and proof for this mode of failure. The general failure theory of Christensen for isotropic materials provides the basis for the derivation. The solution demonstrates the depth of technical capability that is required from the failure theory to treat such a classically difficult problem.


2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Richard M. Christensen

This overview/survey assesses the state of the discipline for the failure of homogeneous and isotropic materials. It starts with a quick review of the many historical but unsuccessful failure investigations. Then, it outlines the dysfunctional current state of the field for failure criteria. Finally, it converges toward the technical prospects that can and very likely will bring much needed change and progress in the future.


2020 ◽  
Vol 5 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Laurence B. Leonard

Purpose The current “specific language impairment” and “developmental language disorder” discussion might lead to important changes in how we refer to children with language disorders of unknown origin. The field has seen other changes in terminology. This article reviews many of these changes. Method A literature review of previous clinical labels was conducted, and possible reasons for the changes in labels were identified. Results References to children with significant yet unexplained deficits in language ability have been part of the scientific literature since, at least, the early 1800s. Terms have changed from those with a neurological emphasis to those that do not imply a cause for the language disorder. Diagnostic criteria have become more explicit but have become, at certain points, too narrow to represent the wider range of children with language disorders of unknown origin. Conclusions The field was not well served by the many changes in terminology that have transpired in the past. A new label at this point must be accompanied by strong efforts to recruit its adoption by clinical speech-language pathologists and the general public.


2020 ◽  
pp. 160-198
Author(s):  
Макарий Веретенников

Статья посвящена содержанию, общим принципам построения и характерным особенностям календаря, или месяцеслова, Русской Православной Церкви. Автор использует методы анализа и синтеза. В итоге делаются нижеследующие обобщения. Месяцеслов был принесён на Русь из Византии в достаточно завершённом виде, однако в процессе исторического развития он дополнился особенными русскими праздниками. Календарь-месяцеслов - это грандиозный собор святых, подвизавшихся в разных местах на протяжении веков, единение Церкви Небесной и земной, история святости и история нашей Церкви. Месяцесловным памятям посвящены составленные гимнографами богослужебные тексты, которые поются и читаются в храмах. Традиционно почитается день кончины угодников Божиих, память открытия мощей святых, перенесения их святых мощей или же день канонизации угодников Божиих, реже - день их рождения. Фенологические наблюдения русского народа связаны с повседневной деятельностью и увязаны с месяцесловом, что свидетельствует о его проникновении в повседневную жизнь русского человека. The article is devoted to the content, General principles of construction and characteristic features of the calendar, or mesyatseslov, of the Russian Orthodox Church. The author uses methods of analysis and synthesis. As a result, the following generalizations are made. The mesyatseslov was brought to Russia from Byzantium in a fairly complete form, but in the course of historical development it was supplemented with special Russian holidays. The calendar-mesyatseslov is a grandiose council of saints who have labored in different places over the centuries, the unity of the Church of Heaven and earth, the history of holiness and the history of our Church. Liturgical texts composed by hymnographers, which are sung and read in churches, are dedicated to the mesyatseslovs memory. Traditionally, the day of the death of saints, the memory of the discovery of the relics of saints, the transfer of their Holy relics, or the day of the canonization of saints, less often - the day of their birth are honored. Russian people’s phenological observations are related to their daily activities and are linked to mesyatseslov, which indicates its penetration into the daily life of the Russian people.


2020 ◽  
Vol 384 (2) ◽  
pp. 222-232
Author(s):  
P. V. Menshikov ◽  
G. K. Kassymova ◽  
R. R. Gasanova ◽  
Y. V. Zaichikov ◽  
V. A. Berezovskaya ◽  
...  

A special role in the development of a pianist as a musician, composer and performer, as shown by the examples of the well-known, included in the history of art, and the most ordinary pianists, their listeners and admirers, lovers of piano music and music in general, are played by moments associated with psychotherapeutic abilities and music features. The purpose of the study is to comprehend the psychotherapeutic aspects of performing activities (using pianists as an example). The research method is a theoretical analysis of the psychotherapeutic aspects of performing activities: the study of the possibilities and functions of musical psychotherapy in the life of a musician as a “(self) psychotherapist” and “patient”. For almost any person, music acts as a way of self-understanding and understanding of the world, a way of self-realization, rethinking and overcoming life's difficulties - internal and external "blockages" of development, a way of saturating life with universal meanings, including a person in the richness of his native culture and universal culture as a whole. Art and, above all, its metaphorical nature help to bring out and realize internal experiences, provide an opportunity to look at one’s own experiences, problems and injuries from another perspective, to see a different meaning in them. In essence, we are talking about art therapy, including the art of writing and performing music - musical psychotherapy. However, for a musician, music has a special meaning, special significance. Musician - produces music, and, therefore, is not only an “object”, but also the subject of musical psychotherapy. The musician’s training includes preparing him as an individual and as a professional to perform functions that can be called psychotherapeutic: in the works of the most famous performers, as well as in the work of ordinary teachers, psychotherapeutic moments sometimes become key. Piano music and performance practice sets a certain “viewing angle” of life, and, in the case of traumatic experiences, a new way of understanding a difficult, traumatic and continuing to excite a person event, changing his attitude towards him. It helps to see something that was hidden in the hustle and bustle of everyday life or in the patterns of relationships familiar to a given culture. At the same time, while playing music or learning to play music, a person teaches to see the hidden and understand the many secrets of the human soul, the relationships of people.


1984 ◽  
Vol 16 (1-2) ◽  
pp. 281-295 ◽  
Author(s):  
Donald C Gordon

Large-scale tidal power development in the Bay of Fundy has been given serious consideration for over 60 years. There has been a long history of productive interaction between environmental scientists and engineers durinn the many feasibility studies undertaken. Up until recently, tidal power proposals were dropped on economic grounds. However, large-scale development in the upper reaches of the Bay of Fundy now appears to be economically viable and a pre-commitment design program is highly likely in the near future. A large number of basic scientific research studies have been and are being conducted by government and university scientists. Likely environmental impacts have been examined by scientists and engineers together in a preliminary fashion on several occasions. A full environmental assessment will be conducted before a final decision is made and the results will definately influence the outcome.


2016 ◽  
Vol 43 (2) ◽  
pp. 59-127 ◽  
Author(s):  
Devrimi Kaya ◽  
Robert J. Kirsch ◽  
Klaus Henselmann

This paper analyzes the role of non-governmental organizations (NGOs) as intermediaries in encouraging the European Union (EU) to adopt International Accounting Standards (IAS). Our analysis begins with the 1973 founding of the International Accounting Standards Committee (IASC), and ends with 2002 when the binding EU regulation was approved. We document the many pathways of interaction between European supranational, governmental bodies and the IASC/IASB, as well as important regional NGOs, such as the Union Européenne des Experts Comptables, Économiques et Financiers (UEC), the Groupe d'Etudes des Experts Comptables de la Communauté Économique Européenne (Groupe d'Etudes), and their successor, the Fédération des Experts Comptables Européens (FEE). This study investigates, through personal interviews of key individuals involved in making the history of the organizations studied, and an extensive set of primary sources, how NGOs filled key roles in the process of harmonization of international accounting standards.


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