scholarly journals SELECTION OF SHAPE AND DIMENSIONS OF SUPPORT ELEMENT OF PAIRED ORTHOGONAL WALKING MOVER

2021 ◽  
pp. 12-16
Author(s):  
V. V. Arykantsev ◽  
V. V. Chernyshev ◽  
N. G. Sharonov
Keyword(s):  
Bearing Capacity ◽  
Contact Area ◽  
Optimal Size ◽  
Supporting Surface ◽  
Walking Machine ◽  
Size And Shape ◽  
Support Element ◽  
Supporting Element ◽  
Selection Of

The paper describes the principle of choosing the optimal size and shape of the supporting element of a walking machine, provided that the maximum possible contact area with the supporting surface is provided for moving on snow or soils with a low bearing capacity. The study was carried out for an orthogonal walking propulsion device, but it can also be used for walking mechanisms of other types.

Optimum Selection of Hydraulic Devices for Water Hammer Control in the Pipeline Systems Using Genetic Algorithm

2003 ◽  
Author(s):  
Bong Seong Jung ◽  
Bryan W. Karney
Keyword(s):  
Genetic Algorithm ◽  
Steady State ◽  
Optimization Problems ◽  
System Optimization ◽  
Water Hammer ◽  
Pipeline System ◽  
Optimal Size ◽  
Protection Strategy ◽  
Hydraulic Devices ◽  
Selection Of

Genetic algorithms have been used to solve many water distribution system optimization problems, but have generally been limited to steady state or quasi-steady state optimization. However, transient events within pipe system are inevitable and the effect of water hammer should not be overlooked. The purpose of this paper is to optimize the selection, sizing and placement of hydraulic devices in a pipeline system considering its transient response. A global optimal solution using genetic algorithm suggests optimal size, location and number of hydraulic devices to cope with water hammer. This study shows that the integration of a genetic algorithm code with a transient simulator can improve both the design and the response of a pipe network. This study also shows that the selection of optimum protection strategy is an integrated problem, involving consideration of loading condition, device and system characteristics, and protection strategy. Simpler transient control systems are often found to outperform more complex ones.

scholarly journals DETERMINATION OF DEFORMATION IN MESH COMPOSITE STRUCTURE UNDER THE ACTION OF COMPRESSIVE LOADS

2020 ◽  
Vol 17 (35) ◽  
pp. 599-608 ◽  
Author(s):  
Alexander A. OREKHOV ◽  
Yuri A. UTKIN ◽  
Polina F. PRONINA
Keyword(s):  
Composite Material ◽  
Carbon Fiber ◽  
Bearing Capacity ◽  
Polymer Composite ◽  
Experimental Studies ◽  
Polymer Composite Material ◽  
Lightweight Mesh ◽  
Carbon Filler ◽  
Selection Of

One of the significant innovative technologies is the creation of large-sized structures that work for a long time in space and meet stringent restrictions on overall mass characteristics. Among these structures, in the first place, is the section of bearing truss (BT). This article presents the results of experimental studies of sectors of load-bearing trusses of mesh design for compression. Recently, composite mesh cylindrical shells are used as spacecraft housings. The mesh shell is a supporting structure to which the instruments and mechanisms of the spacecraft are attached. The truss section is made of cross-linked polymer composite material with carbon fibers. The objective of the tests is to confirm the possibility of creating a lightweight mesh construction using a carbon fiber reinforced polymer composite material. To achieve this goal, the authors were assigned the following tasks: selection of carbon filler of polymer composite materials (PCM); selection of PCM binder; determination of the degree of carbon fiber reinforcement; choice of the number and orientation paths of spiral ribs, number of ring ribs and the sizes of individual ribs. As a result of the research, the calculated indicators for ensuring the bearing capacity and stiffness under the application of axial compressive load were obtained. At the same time, with the determination of bearing capacity, the deformation characteristics of the structure were twice determined in order to confirm their repeatability, as well as linear nature of the dependence of axial and radial deformations as a result of the applied load.

Mechanical Properties and Mineralogical Composition of Potash Ore as a Factor in Selecting the Processing Method

2021 ◽  
Vol 1022 ◽  
pp. 17-26
Author(s):  
Yana V. Kuskova ◽  
Nikita A. Lipnitsky
Keyword(s):  
Mechanical Properties ◽  
Mining Industry ◽  
Mineralogical Composition ◽  
Core Material ◽  
Correct Selection ◽  
Dry Cleaning ◽  
Size And Shape ◽  
Natural Size ◽  
Selection Of ◽  
Intergranular Space

The correct selection of technology for processing potash ore depends on its mineralogical composition, the natural size and shape of grains, as well as on the amount and size of halite grains located in the intergranular space of sylvinites. The study of seams and mineralogical and petrographic studies of potash ore were carried out in order to determine the natural size of sylvinite grains, their shape, and the content of halite in the intergranular space.Moreover, the influence of these parameters on the beneficiation ability of the ore using dry cleaning process was determined. In addition, the data on laboratory studies using electric separation is provided in the paper. The results of the provided studies can be used by specialists of the mining industry when considering the influence of the mineral composition, size and shape of grains of potash ore in order to select the separation method at the early stages of development of potash deposits. The study of core material and mechanical properties, mineralogical and petrographic studies together with studies on beneficiation ability of ore presented in the article can be used, for example, in the preparation of a feasibility report.

Strategies that simplify the control of quadrupedal stance. II. Electromyographic activity

1988 ◽  
Vol 60 (1) ◽  
pp. 218-231 ◽  
Author(s):  
J. M. Macpherson
Keyword(s):  
Muscle Synergy ◽  
Muscle Synergies ◽  
Electromyographic Activity ◽  
Supporting Surface ◽  
Force Vector ◽  
Tuning Curves ◽  
Hindlimb Muscles ◽  
Vector Generation ◽  
High Level ◽  
Selection Of

1. This study tested the hypothesis that muscle synergies underlie the invariance in the direction of corrective forces observed following stance perturbations in the horizontal plane. Electromyographic activity was recorded from selected forelimb and hindlimb muscles of cats subjected to horizontal translations of the supporting surface in 16 different directions. The responses of muscles were quantified for each perturbation, and tuning curves were constructed that related the amplitude of muscle response to the direction of platform movement. 2. Muscle tuning curves tended to group into one of two regions, corresponding to the two directions of force vectors. A few muscles showed clearly different recruitment patterns. The same direction of correction force vector was produced by different patterns of muscle activity, and the particular EMG pattern depended on the direction of platform movement. Therefore a simple muscle synergy organization could not account for the invariance in force vector generation. 3. It is concluded that there is a hierarchy of control in the maintenance of stance in which the vector of force exerted against the ground is a high level, task-dependent controlled variable and the selection of muscles to activate in order to produce the vector is controlled at a lower level. It is proposed that muscles are controlled using a modified synergy strategy. In this scheme, a synergy is not simply a fixed group of muscles, constrained to act as a unit. Rather, muscles are organized as a task-dependent synergy that is tuned or modified as needed by the addition or subtraction of other muscles.

scholarly journals FEM Modeling of Structure and Properties of Diamond-SiC-(Al) Composites Developed for Thermal Management Applications

2008 ◽  
Vol 59 ◽  
pp. 173-176
Author(s):  
Paulina Unifantowicz ◽  
T. Boguszewski ◽  
Łukas Ciupiński ◽  
E. Fortuna ◽  
Małgorzata Lewandowska ◽  
...  
Keyword(s):  
Finite Element ◽  
Thermal Management ◽  
Contact Area ◽  
Volume Fraction ◽  
Structure And Properties ◽  
Fem Modeling ◽  
Design Rules ◽  
Multi Phase ◽  
Complex Architecture ◽  
Selection Of

Thermal management materials frequently have multi-phase composite character with complex architecture of the constituents. As a result, design rules are needed which can be used in selection of the phases and optimizing their volume fractions. The study shows that such are provided by finite element modeling of these composites. This is demonstrated for a diamond-SiC-Si-(Al) composites, which have been optimized in terms of the volume fraction of SiC, contact area between the components and presence of open porosity.

Analysis of a Struck Ship With Damage Opening: Influence From Model and Material Properties Uncertainties

2010 ◽  
Author(s):  
Per Hogstro¨m ◽  
Jonas W. Ringsberg ◽  
Erland Johnson
Keyword(s):  
Material Properties ◽  
Shear Failure ◽  
Forming Limit ◽  
Model Description ◽  
Current Investigation ◽  
Sea State ◽  
Size And Shape ◽  
Constitutive Material Model ◽  
Damage Stability ◽  
Selection Of

The conditions for damage stability and survivability of a ship struck in a collision in arbitrary sea-state are, from a structural point of view, determined by the size and shape of the damage opening in its side shell. In the current investigation, explicit finite element analyses (FEA) are presented of a ship-to-ship collision scenario in which the damage opening of a struck ship is calculated for a selection of damage degradation models and realistic material properties, here referred to as model and material properties uncertainties. The model uncertainty is considered as a possible (user-related) insecurity in the selection of the most appropriate damage criterion for the analysis; the shear failure and the forming limit diagram (FLD) criteria were compared in the current investigation. The uncertainty in material properties is accounted for in the constitutive material model description and the material parameters used in the two criteria. The size and shape of the damage openings predicted by the FEA are used in damage stability analyses in which the struck ship is subjected to wave motions in an arbitrary sea-state and flooding into the damage opening. The survivability of the struck ship is estimated for all of the damage opening cases. One of the main conclusions is that the high degree of accuracy that a researcher on structure analysis strives for has to be considered together with the natural variation of the sea-state that defines the characteristics in the following damage stability analysis. Consequently, by adoption of a holistic approach, in which structural integrity and damage stability research are combined using a systematic parameter (sensitivity) and collision-scenario-based analysis, simplified models and criteria can be developed more efficiently and with higher precision. It will also be clearer which variables are the most important to focus on when analyzing the survivability or risk for capsizing.

Analysis on Selection of Tip-Structure of Steel Tubular Pile

2014 ◽  
Vol 1065-1069 ◽  
pp. 283-287
Author(s):  
Xin Wang ◽  
Jian Chong Yang ◽  
Jian Hong Liang
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
High Strain ◽  
Dynamic Test ◽  
Ultimate Bearing Capacity ◽  
Clay Layer ◽  
Static Test ◽  
Stiff Clay ◽  
Selection Of

Three types of tip-structure include open-end, semi-closed and full close are tested to verify the feasibility of improving the ultimate bearing capacity in stiff clay layer. Driving pile trials are carried out in the site. This paper presents the analysis of set, driving stresses and bearing capacity according to the survey of set, driving monitoring, high strain dynamic test and the axial compression static test. It is proved that the closed end is the most feasible structure in stiff clay layer.

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