The effect of material orientation on void growth

In this work, we have brought to light the effect of material orientation on void growth. For that purpose, we have performed finite element calculations using a cubic unit-cell model with a spherical void at its center and subjected to periodic boundary conditions. The behavior of the material is described with an elastic isotropic, plastic orthotropic constitutive model with yielding defined by Yld2004-18p criterion (Barlat et al., 2005). We have used the multi-point constraint subroutine developed by Dakshinamurthy et al. (2021) to enforce constant values of macroscopic stress triaxiality and Lode parameter in calculations that have been carried out for different stress states resulting from the combination of T=0.33, 1 and 2, with L=-1, 0 and 1 (axisymmetric tension, generalized shear and axisymmetric compression, respectively). Firstly, we have performed numerical simulations in which the loading directions are collinear with the orthotropy axes of the material, so that the principal directions of macroscopic stress and strain are parallel. Investigation of the cases for which the minor loading axis coincides either with the rolling, the transverse or the normal direction, has shown that the initially spherical void turns into an ellipsoid whose rate of growth and eccentricity depend on both stress state and material orientation. A key result is that for specific material orientations the anisotropy switches the effect of Lode parameter on void growth, reversing the trends obtained for isotropic von Mises materials. Secondly, we have carried out calculations using a novel strategy which consists of including angular misalignments within the range 0<\theta<90, so that one loading direction is parallel to one of the symmetry axes of the material, and \theta is the angle formed between the other two loading directions and the second and third orthotropy axes. In fact, to the authors’ knowledge, these are the first unit-cell calculations ever reported in which the material is modeled using a macroscopic anisotropic yield function with prescribed misalignment between loading and material axes and, at the same time, the macroscopic stress triaxiality and the Lode parameter are controlled to be constant during loading. The finite element calculations have shown that the misalignment between loading and material axes makes the void and the faces of the unit-cell to rotate and twist during loading. Moreover, the main contribution of this work is the identification of an intermediate value of the angle for which the growth rate of the void reaches an extreme value (minimum or maximum), so that the numerical results indicate that material orientation and angular misalignment can be strategically exploited to control void growth, and thus promote or delay localization and fracture of anisotropic metal products. The conclusions of this research have been shown to be valid for three different materials (aluminum alloys 2090-T3, 6111-T4 and 6013) and selected comparisons have also been performed using two additional yield criteria (CPB06ex2 and Yld2011-27p).

Peculiarities of industrial nature management in the conditions of modern decentralization

The aim of the study was to determine the features of industrial development in modern decentralization. Materials and methods. This study is based on the study of literature sources that characterize the problems of industrial nature management, features of development and operation, geospatial features of industry. The most well-known literary sources are analyzed, namely monographs, reporting materials, articles, reports concerning the problems of industrial nature management in the conditions of modern decentralization. Results. Decentralization contributes to the development of the economy, as the authorities respond more quickly to the demands and needs of society. Decentralization processes are improving the so-called investment climate, resulting in economic growth. That is why it is important to consider the factors influencing the development of industry in today's decentralization. We highlight the political and legal, economic, socio-demographic, technological factors of industrial development. On their example, we will consider features of development of the industry in the conditions of modern decentralization. Conclusion. The analysis of development factors and structural transformations in industry has revealed a number of sharp contradictions that create many risks for the existence of the industry itself, as well as the economy and social sphere of the country. This poses a number of serious challenges to the country to overcome such contradictions as: the inconsistency of the general trend of the industry with the development of world industry in structural and technological terms; continuation of structural and organizational degradation of production with preservation of its export-raw material orientation and corresponding dependence on external conditions; increasing technological simplification and primitivization of production; inconsistency of domestic production with the needs of the population; the progressive decline of processing industries, including high-tech and fund-generating, for the domestic consumer market; high depreciation of fixed assets and unattractive investment of the industry, including for foreign investors; remoteness of the financial sector from servicing long-term investment needs of production; "Conservative" distribution of investment resources; lack of a mechanism for redistribution of investment resources in favor of promising industries. The identified contradictions and the resulting risks to the further functioning of the industry must be resolved as soon as possible for progressive changes and industrial development in the future.

Homogenization Method to Calculate the Stiffness Matrix of Laminated Composites

New analytical models have been developed for predicting equivalent Young’s and shear moduli of laminate composites. Sets of procedures and calculations are presented in order to obtain equivalent properties in all levels, lamina and laminate. An ultimate path to predict the mechanical properties of laminated composites on the perspective of the material, orientation, and thickness has been developed. By calculating the mechanical properties using Chamis model then an Objectif function with five norms, these norms allow the mechanical properties to be examined and the ultimate answer to be predicted. Another model discusses an alternative concept of equivalent lamina elements (ELEs) by first using Chamis model for hybrid composites. Next, the ELEs are laminated in the direction and integrated into the compliance matrix for each ply. In addition, four new Generalization models for equivalence in thickness and in angle are presented in this paper. The analytical results are validated against other developed models in published articles as well as experimental results. Numerical case studies were conducted to assess the precision of results from the suggested models. The results demonstrated the capability and efficiency of the presented models for predicting the mechanical properties of multi-layer/multi-material laminate composites under different orientation conditions.

Robert C. Kraut's Japan : cataloguing and contextualizing post World War Two photographic albums of Japan and the South Pacific

This applied thesis examines three albums created by US Army Air Force personnel Robert C. Kraut from 1945-46. The albums were donated by Toronto based artist Max Dean to the Art Gallery of Ontario (AGO), and serve as a case study for the process of cataloguing and contextualizing albums for future researchers and museum staff. This paper includes a literature survey examining care and handling, social and historical evolutions, and cataloguing practices related to both photographic albums and scrapbooks. An historical analysis of the photographic album as a medium, vernacular photography and the donation process of the albums into the AGO's collection follows. A detailed analysis of the narrative, material orientation, annotation, layout and materiality qualities for each album is included. A cataloguing methodology that both accounts for the albums’ unique layouts and holds to the established conventions for cataloguing albums at the AGO is discussed and described in detail.

Robert C. Kraut's Japan : cataloguing and contextualizing post World War Two photographic albums of Japan and the South Pacific

This applied thesis examines three albums created by US Army Air Force personnel Robert C. Kraut from 1945-46. The albums were donated by Toronto based artist Max Dean to the Art Gallery of Ontario (AGO), and serve as a case study for the process of cataloguing and contextualizing albums for future researchers and museum staff. This paper includes a literature survey examining care and handling, social and historical evolutions, and cataloguing practices related to both photographic albums and scrapbooks. An historical analysis of the photographic album as a medium, vernacular photography and the donation process of the albums into the AGO's collection follows. A detailed analysis of the narrative, material orientation, annotation, layout and materiality qualities for each album is included. A cataloguing methodology that both accounts for the albums’ unique layouts and holds to the established conventions for cataloguing albums at the AGO is discussed and described in detail.