Analysis of thin isotropic rectangular and circular plates with multiquadrics

A computational method based on radial basis functions has been applied to the linear solution of thin plates. This meshless numerical methodgives high flexibility in the analysis of irregular geometries, due to its insensivity to spatial dimension. The multiquadrics approach is used in this paper. The numerical solution is compared with Kirchhoff theory for plates.Виконано лінійний розрахунок напружено-деформованого стану тонких пластин числовим методом, що базується на використанні мультіквадратичних радіальних базисних функцій. Показано, що даний метод є досить гнучким при розрахунках об’єктів зі складною геометрією, оскільки не потребує сіткового розбиття і нечутливий до їх просторових координат. Отримані числові результати порівнюються з даними розв’язків на основі теорії пластин Кірхгофа.Выполнен линейный расчет напряженно-деформированного состояния тонких пластин численным методом, базирующемся на использовании мультиквадратических радиальных базисных функций. Показано, что данный метод оказывается весьма гибким при расчетах объектов со сложной геометрией, поскольку не требует сеточного разбиения и нечувствителен к их пространственным координатам. Полученные численные результаты сравниваются с данными решений на основе теории пластин Кирхгофа

Analysis of laminated doubly-curved shells by alayerwise theory and radial basis functions collocation, accounting for through-the-thickness deformations

In this paper, the static and free vibration analysis of laminated shells is performed by radial basis functions collocation, according to a sinusoidal shear deformation theory (SSDT). The SSDT theory accounts for through-the-thickness deformation, by considering a sinusoidal evolution of all displacements with the thickness coordinate. The equations of motion and the boundary conditions are obtained by the Carrera's Unified Formulation, and further interpolated by collocation with radial basis functions

Radial Basis Functions collocation and a Unified Formulation for bending, vibration and buckling analysis of laminated plates, according to a variation of Murakami's zig-zag theory

In this paper, we propose to use the Murakami's zig-zag theory for the static and vibration analysis of laminated plates, by local collocation with radial basis functions in a finite differences framework. The equations of motion and the boundary conditions are obtained by the Carrera's Unified Formulation, and further interpolated by a local collocation with radial basis functions and finite differences. This paper considers the analysis of static deformations, free vibrations and buckling loads on laminated composite plates

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost