scholarly journals IMPROVEMENT OF CROSS SECTION OF COMPRESSED ELEMENTS BY TOPOLOGICAL RATIONALIZATION

2020 ◽  
Vol 4 (157) ◽  
pp. 25-31
Author(s):  
V. Shmukler ◽  
O. Lugchenko ◽  
A. Nazhem
Keyword(s):  
Cross Section ◽  
Rational Design ◽  
Limit State ◽  
Computational Procedure ◽  
Retaining Walls ◽  
Deformation Energy ◽  
Minimum Volume ◽  
New Energy ◽  
New Criterion ◽  
Energy Principles

The article describes the procedure of direct (rational) design of vertical compressed elements (columns, pylons, stiffening diaphragms, retaining walls). This technology is an exclusive modification of topological (bionic) rationalization. It is based on new energy principles and algorithms for sequential construction of geometric and / or physical-mechanical "image" of the structure. The example of the formation of energy-equivalent columns shows the sequence of computational operations of the method. The solution is built analytically in order to show the nuances of the necessary operations. At the same time, these examples show that the introduced optimization criteria in the form of en → const and U → inf U (here en is the value of the normalized density of potential deformation energy, and U is the potential energy of deformation) determine, including the minimum volume of constructs, as well as their minimum deflections. A fundamental element of the approach is the use of a new criterion of the limit state, which provides an estimate of the intensity of the element. In this case, the properties of the material and the type of stress-strain state are taken into account. The obtained analytical solution was used as a control test for the general computational procedure of the method. In this regard, the article presents the results of the analytical and numerical solution. The efficiency of the computational procedure is confirmed by the speed of its convergence and the minimum difference of geometric parameters (topology) of the structure with test examples. The technological sequence of computational operations of the method is completed by the construction of elements (pylons) with a simple external and complex internal geometry. Keywords: deformation, energy, iteration, voids, cavity, rationalization.

scholarly journals Topological optimization of the plate

2020 ◽  
pp. 112-119
Author(s):  
Valery Shmukler ◽  
Olena Lugchenko ◽  
Ali Nazhem
Keyword(s):  
Numerical Solutions ◽  
Limit State ◽  
Computational Procedure ◽  
Topological Optimization ◽  
Power Structures ◽  
Plate Design ◽  
New Energy ◽  
Forward Engineering ◽  
New Criterion ◽  
The Given

The paper provides the procedure of forward-engineering (intelligent) plate design. This technology is an exclusive modification of topological (bionic) optimization. It is based on the new energy principles and the algorithms for successive construction of geometric and/or physical-mechanical “pattern” of a structure. The sequence of computational operations of the method in question is illustrated on example of forming plate of energetically uniform strength.   The solution is built analytically to show the nuances of the operations required. The decision of the future analytically helps to show the nuances of the necessary operations. At the same time, on the given supports, it is shown that the introduced optimization criteria determine, at the same time together, the minimum volume of constructs, and also their minimum deflections. A fundamental element of the given approach is the use of a new criterion for the limit state, which provides an estimate of the element’s stress. In this case, the properties of the material and the type of the stress and strain state are taken into account. The analytical solution obtained was used as a checkup test for the general computational procedure of the method in question. In this connection, the paper features the results of analytical and numerical solutions. The efficiency of the computational procedure is confirmed by the rate of its convergence and the minimal variation of geometrical construction parameters (topology) with test cases. The technological sequence of computational operations of the method in question is completed by the construction of elements (plate) with basic external and complex internal geometry, which provides a holistic set of positive power structures, such as minimum consumables in a fixed brutal state, or maximum weight in a fixed organization.

scholarly journals Global cross sections for Anosov flows

2015 ◽  
Vol 36 (8) ◽  
pp. 2661-2674
Author(s):  
SLOBODAN N. SIMIĆ
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Anosov Flow ◽  
Anosov Flows ◽  
New Criterion ◽  
Volume Preserving

We provide a new criterion for the existence of a global cross section to a volume-preserving Anosov flow. The criterion is expressed in terms of expansion and contraction rates of the flow and generalizes known results of this type.

Limit State of Torsion of Ship Hulls with Large Hatch Openings

2001 ◽  
Vol 45 (02) ◽  
pp. 95-102
Author(s):  
Yuren Hu ◽  
Bozhen Chen
Keyword(s):  
Cross Section ◽  
Structural Reliability ◽  
Limit State ◽  
Safety Margin ◽  
Plastic Shear ◽  
Torsional Moment ◽  
Limit States ◽  
Ship Hulls ◽  
Design Values ◽  
Bound Theorem

The limit state of torsion of ship hulls with large hatch openings is studied. A method to determine the distribution of the plastic shear flow on the hull cross section in the limit state by using the lower-bound theorem is presented together with the corresponding linear programming problem. The limit torsional moment of the hull cross section is obtained based on the distribution of the shear stress in the limit state. Three example limit states for typical containerships of different sizes with large hatch openings are calculated. The calculated limit torsional moments are compared with the design values of wave torque calculated by using the equations given by main classification societies in their rules. A rough estimate of the safety margin is obtained. The results show that for large containerships, it is necessary to pay attention to the safety with respect to torsion. The present method can serve as an effective tool in structural reliability analysis of ships with large hatch openings when the failure mode of torsion is taken into account.

Bearing Capacity of Structures Made of Materials with Different Tensile and Compression Strengths

2019 ◽  
Vol 968 ◽  
pp. 200-208
Author(s):  
Mykola Soroka
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Limit State ◽  
Analytical Calculation ◽  
Bending Moment ◽  
Maximum Load ◽  
Longitudinal Force ◽  
Plastic State ◽  
Limiting State ◽  
Tension And Compression

The paper considers the problem of the ultimate load finding for structures made of a material with different limits of tensile strength and compression. The modulus of elasticity under tension and compression is the same. It is assumed that upon reaching the ultimate strength, the material is deformed indefinitely. The calculations use a simplified material deformation diagram — Prandtl diagrams. The limiting state of a solid rectangular section under the action of a longitudinal force and a bending moment is considered. The dependences describing the boundary of the strength of a rectangular cross section are obtained. Formulas allowing the calculation of the values of the limit forces and under the action of which the cross section passes into the plastic state are derived. Examples of the analytical calculation of the maximum load for the frame and two-hinged arch are given. An algorithm is proposed and a program for calculating arbitrary flat rod systems according to the limit state using the finite element method is compiled. The proposed algorithm does not involve the use of iterative processes, which leads to an exact calculation of the maximum load within the accepted assumptions.

Reliability Based Optimization of Steel Monopod Offshore-Towers

2008 ◽  
Author(s):  
H. Karadeniz ◽  
V. Togan ◽  
T. Vrouwenvelder
Keyword(s):  
Natural Frequency ◽  
Cross Section ◽  
Sequential Quadratic Programming ◽  
Limit State ◽  
State Function ◽  
Wave Loading ◽  
Extreme Wave ◽  
Design Variables ◽  
Reliability Based Optimization ◽  
Numerical Strategy

In this work, the implementation of reliability-based optimization (RBO) of a circular steel monopod-offshore-tower with constant and variable diameters (represented by segmentations) and thicknesses is presented. The tower is subjected to the extreme wave loading. For this purpose, the deterministic optimization of the tower is performed with constraints including stress, buckling, and the lowest natural frequency firstly. Then, a reliability-based optimization of the tower is performed. The reliability index is calculated from FORM using a limit state function based on the lowest natural frequency. The mass of the tower is considered as being the objective function; the thickness and diameter of the cross-section of the tower are taken as being design variables of the optimization. The numerical strategy employed for performing the optimization uses the IMSL-Libraries routine that is based on the Sequential Quadratic Programming (SQP). In addition, to check the results obtained from aforementioned procedure, the RBO of the tower is also performed using the genetic algorithms (GA) tool of the MATLAB. Finally, a demonstration of an example monopod tower is presented.

Seismic Test Methods for Architectural Glazing Systems

1996 ◽  
Vol 12 (1) ◽  
pp. 129-143 ◽  
Author(s):  
Richard A. Behr ◽  
Abdeldjelil Belarbi
Keyword(s):  
Rational Design ◽  
Limit State ◽  
Test Methods ◽  
Test Method ◽  
Ultimate Limit State ◽  
Limit States ◽  
State Data ◽  
Design Procedures ◽  
Seismic Loadings ◽  
Ultimate Limit

An ongoing effort is being made at the University of Missouri-Rolla to develop standard laboratory test methods and codified design procedures for architectural glass under seismic loadings. Recent laboratory work has yielded some promising results regarding the development of an appropriate seismic test method for architectural glass, as well as identifying ultimate limit states that quantify the seismic performance and damage thresholds of various glass types. Specifically, a straightforward “crescendo-like” in-plane dynamic racking test, performed at a constant frequency, has been employed successfully. Two ultimate limit states for architectural glass have been defined: (1) a lower ultimate limit state corresponding to major glass crack pattern formation; and (2) an upper limit state corresponding to significant glass fallout. Early crescendo tests have yielded distinct and repeatable ultimate limit state data for various storefront glass types tested under dynamic racking motions. Crescendo tests will also be used to identify and quantify serviceability limit states for architectural glass and associated glazing components under dynamic loadings. These limit state data will support the development of rational design procedures for architectural glass under seismic loadings.

scholarly journals Rational design of small indolic squaraine dyes with large two-photon absorption cross section

2015 ◽  
Vol 6 (1) ◽  
pp. 761-769 ◽  
Author(s):  
Chun-Lin Sun ◽  
Qing Liao ◽  
Ting Li ◽  
Jun Li ◽  
Jian-Qiao Jiang ◽  
...  
Keyword(s):  
Cross Section ◽  
Rational Design ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Two Photon Absorption ◽  
Squaraine Dyes ◽  
Two Photon ◽  
Bio Imaging

Assisted by theoretical analysis, we designed a small indolic squaraine with δ > 8000 GM at 780 nm, which is ideal for both in vitro and in vivo bio-imaging applications.

scholarly journals CONSOLIDATION ZONES FEATURES FORMATION OF A GROUND AROUND SQUARE SHAPED PILES

2018 ◽  
Vol 1 (50) ◽  
pp. 167-173
Author(s):  
O. V. Malyshev
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Analytical Method ◽  
Lateral Surface ◽  
Analytical Methods ◽  
Rational Design ◽  
Initial State ◽  
Compaction Zone ◽  
Analytical Expressions ◽  
Efficiency And Reliability

Necessity to resolve the problem of concerning the analytical dimensions definition and constructing forms of compacted zones of ground around the lateral surface of square cross section pile in normal to pile axis direction are shown in this article. Various analytical methods of ground compacted zones radius determination around cylindrical elements driven into the ground considering its initial state were analyzed. Graph-analytical method of ground compaction zones construction around square cross-section piles was developed. Efficiency of the developed methodology and analytical expressions using possibility to determine the radius of compaction zone of a ground around the driven or jacked-in elements is confirmed by comparing obtained solutions with the experimental data. The developed methodology allows increasing the efficiency and reliability of piles and pile foundations use due to their rational design.

scholarly journals Strengthening of Concrete Column by Using the Wrapper Layer of Fibre Reinforced Concrete

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5432
Author(s):  
Peter Koteš ◽  
Martin Vavruš ◽  
Jozef Jošt ◽  
Jozef Prokop
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Limit State ◽  
Fibre Reinforced Concrete ◽  
Limit States ◽  
Load Bearing Capacity ◽  
Concrete Core ◽  
Fibre Concrete ◽  
Special Cases ◽  
Ultimate Limit

Structures and bridges are being designed on the proposed and requested design lifetime of 50 to 100 years. In practice, one can see that the real lifetime of structures and bridges is shorter in many cases, in some special cases extremely shorter. The reasons for the lifetime shortening can be increased of the load cases (e.g., due to traffic on bridges, or due to other uses of a structure), using the material of lower quality, implementation of new standards and codes according to Eurocode replacing older ones. During the whole lifetime the structures must be maintained to fulfil the code requests. If the constructions are not able to fulfil the Ultimate Limit States (ULS) and the Serviceability Limit State (SLS), the structures or bridges have to be strengthened (whole or its elements). The purpose of the paper is the presentation of using a layer of the fibre concrete for a columns’ strengthening. Using the fibre reinforced concrete (FRC) of higher tensile strength makes it possible to increase the load-bearing capacity of the cross-section the column. The contact between the old concrete (core of column) and newly added layer (around column) is very important for using that method of strengthening. In the article, there is also a comparison of the surface modification methods.

scholarly journals An effective way to rock mass preparation on metallic and nonmetallic quarries Ukraine

2019 ◽  
Vol 109 ◽  
pp. 00031
Author(s):  
Kostiantyn Ishchenko ◽  
Volodymyr Konoval ◽  
Liudmyla Lohvyna
Keyword(s):  
Cross Section ◽  
Rational Design ◽  
Complex Structure ◽  
Experimental Studies ◽  
Variable Cross Section ◽  
Ore Deposits ◽  
Variable Cross ◽  
Borehole Charge ◽  
Novel Method ◽  
Comparative Results

A method in experimental studies and industrial-polygon particular conditions justifying the choice of a rational design of an explosive charge. The comparative results of the evaluation of the stress wave’s amplitudes studies and the character of crushing hard media from the explosion of the charge explosives-variable and constant cross section. The dependences of the particle size distribution of various designs explosive charges destroyed by the explosion are constructed. In industrial conditions, the rationale for the explosive boreholes location according to the massif structure. Adjusted boreholes location grid on rational parameters blasting unit, determined using a novel method of breaking rock complex structure. A new design of a combined borehole charge of variable cross section has been proposed. Industrial tests performed and evaluation of the effectiveness of the proposed method blasting locally fractured rocks and ore deposits on non-metallic minerals. Recommendations on their use are given.

Sign in / Sign up

Export Citation Format

Share Document