Optimal design of elasto-plastic structures under displacement constraints

  &nbsp

Topology Optimization for Loads with Multiple Points of Application

The optimal design for loads with multiple points of application is herein investigated by using a formulation of displacement-constrained minimum volume topology optimization. For each one of the several points in which a moving force may be applied, a static load case is introduced, and a local enforcement is implemented to control the relevant displacement. Inspired by some recent contributions in stress-based topology optimization of large-scale structures, an Augmented Lagrangian approach, is adopted to handle efficiently the arising multi-constrained problem, in conjunction with mathematical programming. The results of some numerical simulations are shown to comment on optimal shapes for loads with multiple points of application, as compared to classical solutions for fixed loads

Comparative Study on the Optimal Topologies

The topology optimization is a leading tool in structural design. Due to the rapidly spreading need of the industry, commercial software are available in the market. Generally, these software are suitable for solving one subtask (preprocessing, postprocessing, stress calculation, etc.) but need some user manipulation to interconnect to one that is better for some other subproblem. This is the reason why we write a study on the available software and make suggestions on their usability. The purpose of this research is to briefly introduce selected software such as Rhino 3D, Grasshopper, Peregrine, Karamba, Galapagos, polyTop and PolyStress using topology optimization theory. Due to the demand to apply them for industrial applications, the additional goal is to make suggestions to make these software programs more user-friendly and to create algorithms to connect with software used in the industry, such as Consteel. This work also discusses the connected algorithms and optimization methods such as layout optimization by Peregrine, and topology optimization by polyTop and PolyStress. Several illustrative videos are provided as supplements. In addition to the text of this paper one can see demonstrations of the applications by the use of the provided YOUTUBE links

HUBUNGAN PARITAS DENGAN KEJADIAN PERDARAHAN POSTPARTUM NARRATIVE REVIEW

Angka kematian ibu merupakan tolak ukur derajat kesehatan suatu negara. Penyebab utama kematian ibu adalah perdarahan, di Indonesia tercatat 30,1 % kematian ibu disebabkan oleh perdarahan. Narrative review ini disusun untuk mereview mengenai kejadian perdarahan postpartum secara khusus di Indonesia. Untuk mengetahui hubungan antara paritas dengan kejadian perdarahan postpartum. Metode yang digunakan yaitu mengidentifikasi research question dengan framework PEOS identifikasi artikel yang publikasi dari tahun 2010-2020 menggunakan database yang relevan (Academia.edu, google schoolar, dan microsoft academic) dengan kata kunci, Hasil artikel digolongkan menggunakan data charting. Dalam pencarian di database diperoleh 913 artikel, setelah dilakukan penyaringan judul dan relevansi abstrak, didapatkan 10 artikel yang memenuhi kriteria. Hasil review 10 artikel menunjukan bahwa ada hubungan antara paritas dengan kejadian perdarahan post partum. Perdarahan postpartum juga dapat disebabkan oleh berbagai faktor lainnya antara lain usia ibu, riwayat obstetri, berat badan janin, pendidikan, dan anemia

Forest-Poverty Dynamics: Current State of Knowledge

This chapter reports on evidence about the role of forests and trees in alleviating poverty and supporting wider human well-being. It considers how, whether, where, when and for whom forests and trees are important in forest-poverty dynamics. We organise the evidence according to four possible relationships between forest products and ecosystem services and poverty: 1) helping households move out of poverty; 2) supporting well-being through subsistence, food security and cultural and spiritual values; 3) mitigating risks; and 4) decreasing well-being by generating negative externalities that could significantly contribute to trapping or moving households into poverty. The evidence shows that these relationships are strongly context-dependent, varying with geography and social, economic and political contexts. However, across contexts, we most commonly observe that forest and tree products and services help the poor to secure and stabilise their livelihoods, rather than either helping them exit poverty or driving them into poverty.Peer reviewe

Les concessions d'exploitation forestière menacent-elles les tourbières en République démocratique du Congo ?

peer reviewed[No abstract available

Milestones in the 150-Year history of topology optimization: A review

Structural optimization is one of the most intensively investigated research areas in engineering. Recently, topology optimization has become the most popular engineering subfield. The starting date of structural optimization cannot be precisely determined. Michell's optimization paper, published in 1904, is considered as the first publication in this subfield. However, his paper starts with a statement that his work is a generalization of Maxwell's idea presented in the paper published in 1870. The authors of this review paper consider that this date can be accepted as the starting date of topology optimization. This paper is an overview of subjectively selected state-ofart achievements in topology optimization during its history of 150 years. The selection of the achievements is a rather difficult task because, in the early period of the history of topology optimization, a lot of meetings were classified and the results were not available for the public. The optimization community has almost no knowledge about the publications in topology optimization in the 1950s. Around that time, one can find some information on workshops and meetings connected to the Cambridge University or Oxford University with researchers such as Foulkes, Cox, Hemp, and Shield, who published significant results and these communications are generally not known for the reason mentioned above. After the 1970s, this situation has changed and there were more possibilities to find publications due to the changes and thanks to digitalization. As indicated earlier here subjectively selected works are overviewed from the 150-year history focusing on the first hundred twenty years

Lightweight design with displacement constraints using graded porous microstructures

A multi-scale approach of topology optimization is proposed to design lightweight components for given loads and displacement limits. Hexagonal close-packed arrangements of circular/spherical holes allow defining 2D/3D isotropic/transversely isotropic microstructures whose macroscopic elastic properties depend on the radius of the cavities, namely the density of the porous material. An interpolation law is implemented to handle two-material structures with void, distributing both solid and graded material within a certain density range. An Augmented Lagrangian approach is adopted to handle multiple displacement constraints, along with the enforcement of a minimum amount of graded porous microstructure to be used in the optimal design. The proposed method defines: (i) boundaries of the component, and, (ii) possible internal arrangements of circular/spherical holes with graded radius. Also, when boundaries of a hollow component are prescribed, the method can be used to equip it with an optimal infill. Numerical examples are presented, concerning two- and three- dimensional problems, for different types of loads. Features of the proposed procedure are discussed, as well as peculiar properties of the optimal solutions, with special regard to coated structures. Fabrication of the porous layouts by means of additive manufacturing techniques is outlined