Topological Optimization of Multilayer Structural Elements of MEMS/NEMS Resonators with an Adhesive Layer Subjected to Mechanical Loads

2021 ◽  
pp. 155-166
Author(s):  
Anton V. Krysko ◽  
Jan Awrejcewicz ◽  
Pavel V. Dunchenkin ◽  
Maxim V. Zhigalov ◽  
Vadim A. Krysko
Keyword(s):  
Adhesive Layer ◽  
Topological Optimization ◽  
Structural Elements ◽  
Mechanical Loads

scholarly journals Topological Optimization of Microstructure of Adhesives under Thermal and Mechanical Loads

2019 ◽  
pp. 1-28
Author(s):  
K. S. Bodyagina ◽  
S. P. Pavlov
Keyword(s):  
A Priori ◽  
Adhesive Layer ◽  
Optimization Methods ◽  
Topological Optimization ◽  
Shear Stresses ◽  
The Finite Element Method ◽  
Mechanical Loads ◽  
Promising Strategy ◽  
Solder Microstructure ◽  
Thickness Shear

The paper presents a mathematical model and method for solving a wide class of problems in topological optimization of an adhesive joint to obtain an optimal microstructure and gradient properties in order to reduce the level of stresses arising from both thermal and mechanical loads therein.Adhesive joints have advantages over alternative bonding methods. The paper shows that the introduction of graduating properties in thickness or along the adhesive layer is the most promising strategy to optimize the adhesive. The approach is to modify the material properties or the geometry of the adhesive, varying along the joint.In all the papers known to authors, the shape of the elements to be joined, or the shape and location of the adhesive layer, were subject to optimization. The topological optimization methods to determine the optimal distribution / change of the gradient properties of the adhesive layer itself were not used.In the paper, the stresses arising in the solder joints are analyzed; it is shown that due to the small solder thickness, shear stresses are basic in it. The shear stresses are concentrated near the ends of the solder, and have the lowest values in the middle. The objective of the optimization problem is to reduce the peak values of the shear and peeling stresses in the solder layer. The topological optimization of the solder microstructure is to find the best distribution of a given amount of solder in the region in order to reach minimum peak values of stresses. The advantage of using topological optimization is that the microstructure of the solder should not be known a priori, and, thus, any designs can be optimized without first studying the effect of the original geometric parameters on the strength of the joint.The algorithm is implemented using the finite element method and the method of movable asymptotes. A number of examples are considered in order to obtain the solder microstructure to be optimal for reducing the peak values of shear stresses and delamination in a three-layer package.The results show that optimal microstructures significantly reduce peak stresses compared to a uniform layer. The obtained results reveal the potential of the developed algorithm and show that it can find practical use.

scholarly journals Strut-and-tie models for linear and nonlinear behavior of concrete based on topological evolutionary structure optimization (ESO)

2019 ◽  
Vol 12 (1) ◽  
pp. 87-100
Author(s):  
R. M. LANES ◽  
M. GRECO ◽  
M. B. B. F. GUERRA
Keyword(s):  
Nonlinear Behavior ◽  
Structure Optimization ◽  
Internal Flow ◽  
Optimization Method ◽  
Topological Optimization ◽  
Structural Elements ◽  
Stress Concentrations ◽  
Progressive Reduction ◽  
Strut And Tie ◽  
Safety And Reliability

Abstract The search for representative resistant systems for a concrete structure requires deep knowledge about its mechanical behavior. Strut-and-tie models are classic analysis procedures to the design of reinforced concrete regions where there are stress concentrations, the so-called discontinuous regions of the structure. However, this model is strongly dependent of designer’s experience regarding the compatibility between the internal flow of loads, the material’s behavior, the geometry and boundary conditions. In this context, the present work has the objective of presenting the application of the strut-and-tie method in linear and non-linear on some typical structural elements, using the Evolutionary Topological Optimization Method (ESO). This optimization method considers the progressive reduction of stiffness with the removal of elements with low values of stresses. The equivalent truss system resulting from the analysis may provide greater safety and reliability.

scholarly journals Creation of Polymer Coatings for Improving of Protective Properties of Surfaces

2021 ◽  
Vol 12 (2) ◽  
pp. 2698-2702
Author(s):  
A.A. Orekhov, Et. al.
Keyword(s):  
Mathematical Modeling ◽  
Mechanical Properties ◽  
Polymer Coatings ◽  
Strength Properties ◽  
Structural Elements ◽  
Properties Of Coatings ◽  
Mechanical Loads ◽  
Protective Properties ◽  
Modeling Methods ◽  
Metal Plates

In this paper, the preparation of polymer coatings on the surface of metal structural elements is considered to improve their physical, mechanical and strength properties. It is shown that the behavior of substrate samples under mechanical loads can be estimated using mathematical modeling methods. The properties of coatings and the mechanical properties of coated and uncoated metal plates have been evaluated. Methods for constructing mathematical models of metal plates of various structures are proposed.

scholarly journals TOPOLOGICAL OPTIMIZATION OF SHORT FIBERS REINFORCED COMPOSITE STRUCTURES CONSIDERING THE MATERIAL ANISOTROPY DETERMINED BY THE CALCULATION OF THEIR INJECTION MOLDING PROCESS

2020 ◽  
Vol 22 (5) ◽  
pp. 114-119
Author(s):  
E.I. Kurkin ◽  
◽  
E.A. Kishov ◽  
O.E. Lukyanov ◽  
O.U. Espinosa Barcenas ◽  
...  
Keyword(s):  
Injection Molding ◽  
Composite Structures ◽  
Topological Optimization ◽  
Injection Molding Process ◽  
Structural Elements ◽  
Short Fibers ◽  
Material Anisotropy ◽  
Molding Process ◽  
Sequential Convex Programming ◽  
Reinforced Composite

A methodology is presented for solving the related problem of topological optimization of short-reinforced composites structures, considering the attributes of the material anisotropy by fully solving the injection molding problem. The methodology is considered on the example of optimizing a bracket loaded with a shearing force. The solution is performed in the Ansys Topology Optimization module using the Sequential Convex Programming method. The anisotropic formulation of the problem involves the calculation of the injection molding process in the Autodesk Moldflow system on a mesh reduced by intermediate iterations of topological optimization, and updating the material properties at intermediate steps of the algorithm based on a C program. It is shown that the anisotropy of the material can lead to the displacement of weld lines beyond the main load-bearing structural elements and to increase the stiffness of short-reinforced composite materials structures.

Neue kostengünstige rostfreie Stähle für den Einsatz bei korrosionsgefährdeten Stahlbetontragwerken / New and inexpensive stainless steels for use in reinforced concrete structures in agressive environment

1999 ◽  
Vol 5 (6) ◽  
pp. 589-598
Author(s):  
A. Rechsteiner ◽  
M. O. Speidel
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Mechanical Load ◽  
Swiss Federal Institute ◽  
Structural Elements ◽  
Wide Spread ◽  
Mechanical Loads ◽  
Federal Institute ◽  
Duplex Steel ◽  
Metal Research

Abstract Stainless steel is essentially applied in structural elements in which chemical and mechanical loads are combined and which hardly allow periodic checks. Fixations are typical examples. In case of failure dramatic consequences have to be expected. This is also valid for steel reinforcement in concrete. It is exposed to combined chemical and mechanical load, it can hardly be controled and damage leads at least to enormous costs of repair. Due to the fact that up to now the expenditures for construction are rarely considered together with the expenditures for maintenance, the use of stainless steel is still exceptional. If it is possible, however, to produce cheap steel with a corrosion resistance comparable to steel 1.4401 or even better, wide spread use of stainless steel as concrete reinforcement should be possible. New types of austenitic and duplex steel as being developed in the Laboratory for metal research of Swiss Federal Institute of Technolog (ΕΤΗ) in Zurich without Ni seem to be promising materials. In this case it is tried to replace expensive components by cheap ones such as nitrogen.

Cross-belt sorter - a model and analysis of selected mechanical loads

2020 ◽  
Vol 2 (3) ◽  
pp. 139-148
Author(s):  
Tomasz Piatkowski
Keyword(s):  
Analytical Model ◽  
Structural Elements ◽  
Motion Velocity ◽  
Mechanical Loads ◽  
Frictional Properties ◽  
Numerical Research ◽  
Sorting Efficiency ◽  
Drive Systems

This article presents the results of numerical research on operational mechanical loads, carried out for the main structural elements of a cross-belt sorter: tracks and trolleys with trays. The goal of the research was to collect data required at the stage of designing new solutions of the sorters. A novelty is an analytical model that allows to determine the influence of the motion velocity of trolleys, frictional properties and mass of sorted objects on the forces transmitted from the trolleys to the track, the sorting efficiency and power required by the drive systems.

scholarly journals Structural elements based on the metamaterials

2020 ◽  
pp. 211-219
Author(s):  
S. A Yurgenson ◽  
E. V Lomakin ◽  
B. N Fedulov ◽  
A. N Fedorenko
Keyword(s):  
Topology Optimization ◽  
Mechanical Characteristics ◽  
Distribution Density ◽  
Periodic Structures ◽  
Topological Optimization ◽  
Structural Elements ◽  
Metal Consumption ◽  
Radiation Sources ◽  
Design Cycle ◽  
High Degree

The article discusses an approach to creating structural elements by forming periodic structures in the structure, developed based on the results of topological optimization. In the article, a metamaterial is understood as a structure with a complex internal periodic organization of strength elements, the details of which are significantly smaller than the typical dimensions of the final structural product. In this paper, the analysis is devoted to panels with a filler based on periodic structures to achieve the required mechanical characteristics. The transition from the results of the topological optimization is carried out on the basis of engineering analysis, taking into account the particularities of loading, fastening and operational effects on the structure. The use of topology optimization makes it possible to determine the distribution density of periodic structures in the material and to shorten the design cycle of a conventionally optimal design. As a first step solution, authors consider panels based on sandwich panels with the pyramidal fillers. Their application is considered in the aircraft, shipbuilding and construction industries. As basic technological solutions, efficient technologies are proposed - laser radiation sources and a high degree of automation. With these technologies, efficiency and costs of testing and certification of manufacturing are reduced in comparison to the standard approaches, when results of the topology optimization are made using expensive additive manufacturing. The proposed elements make it possible to reduce the metal consumption while achieving the same rigidity and strength of the structure. Another advantage of the proposed structures is their modularity and the ability to optimize the panel filling density without significantly changing the manufacturing process and design. As an application, we considered the possibility of creating a large-span panel for civil constructions, which is characterized by high specific loads with a significant span length (20 m).

scholarly journals Experimental Study on the Effectiveness of Polyurethane Flexible Adhesive in Reduction of Structural Vibrations

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2364 ◽  
Author(s):  
Natalia Lasowicz ◽  
Arkadiusz Kwiecień ◽  
Robert Jankowski
Keyword(s):  
Large Strain ◽  
Adhesive Layer ◽  
Free Vibrations ◽  
Polymer Layer ◽  
Structural Elements ◽  
Damping Properties ◽  
Adhesive Layers ◽  
Damping Characteristics ◽  
Third Stage ◽  
Polymer Adhesive

The aim of the present study is to consider the idea of using polyurethane flexible adhesive in to reduce the vibrations in structures exposed to dynamic loads and evaluate their damping properties in relation to large deformations. Firstly, two aluminium cantilever beams, simulating structural elements (without and with polyurethane layer in the form of tape), were analysed, in order to check the damping of the unconstrained polymer layer. In the second stage of the study, a composite beam consisting of two aluminium flat beams bonded with polymer adhesive was considered, so as to check the damping of the constrained polymer layer. Dynamic parameters, such as modes of free vibrations, corresponding natural frequencies and damping ratios, were determined and compared. The third stage of the investigation was aimed at solving the problem of the additional mass of the applied polymer layer, which influences the frequencies and damping of the tested structure. A special separating procedure is proposed that makes it possible to calculate the corrected real values of the polymer layer’s damping. The results of the study clearly show that the response of the composite aluminium beam with and without polymer adhesive layer is mainly influenced by the layers’ thickness and the large strain deformation, in terms of its damping characteristics. The use of polymer adhesive layers in constrained and unconstrained conditions leads to a significant reduction in the vibrations of tested beams, while preserving their stiffness at nearly the same level. The applied analysis procedure made it possible for us to separate the damping properties of the analysed polymer layers and evaluate them independently with respect to the influence of integrated structural elements on damping.

scholarly journals Improving the reliability of propulsion systems with a varying propeller thrust for ice-class vessels

2020 ◽  
Author(s):  
А.П. Сеньков ◽  
В.И. Кузнецов ◽  
Д.В. Никущенко ◽  
А.И. Фрумен
Keyword(s):  
Mechanical Strength ◽  
Structural Elements ◽  
Large Magnitude ◽  
Propulsion Systems ◽  
Mechanical Loads ◽  
Noise And Vibration ◽  
Fixed Part ◽  
Propeller Thrust

Пропульсивные системы на основе гребных электрических установок (ГЭУ) «Азипод» или винторулевых колонках (ВРК) позволяют изменять направление тяги гребного винта относительно корпуса судна, за счет чего обеспечивают судам высокую маневренность и повышают безопасность плавания. Движительный модуль ГЭУ «Азипод» и поворотная часть ВРК присоединяются к неподвижной части гребной установки, закрепленной на корпусе судна, как консоль, на опоре вращения. В результате опора вращения находится под воздействием целой системы сил и моментов большой величины, в том числе под воздействием ударов льдин при плавании во льдах. Высокие механические нагрузки на опору вращения снижают надежность пропульсивных установок на судах ледового класса, вызывают деформации элементов конструкции судов, увеличивают шумы и вибрации. Для повышения механической прочности и надежности гребной установки предлагается закрепить нижнюю часть движительного модуля ГЭУ «Азипод» или поворотной части ВРК во второй опоре вращения. Такая конструкция снизит нагрузки на верхнюю опору вращения, повысит механическую прочность и надежность гребной установки. Уменьшит шумы и вибрации. Propulsion systems based on Azipod propulsion systems or propeller-driven columns allow you to change the direction of propeller thrust relative to the hull of the vessel, thereby providing ships with high maneuverability and improving sailing safety. The Azipod propulsion module and the rotary part of the helical steering column are attached to the fixed part of the rowing installation, mounted on the hull of the vessel, like a console, on a rotation support. As a result, the rotation support is under the influence of a whole system of forces and moments of large magnitude, including under the influence of impacts of ice when swimming in ice. High mechanical loads on the rotation support reduce the reliability of propulsion systems on ice-class vessels, cause deformation of ship structural elements, and increase noise and vibration. To increase the mechanical strength and reliability of the rowing installation, it is proposed to fix the lower part of the Azipod propulsion module or the rotary part of the helical column in the second rotation support. This design will reduce the load on the upper support of rotation, increase the mechanical strength and reliability of the rowing installation. Reduce noise and vibration.

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