Problems of Optimal Structural Design

1968 ◽  
Vol 35 (1) ◽  
pp. 102-106 ◽  
Author(s):  
W. Prager ◽  
J. E. Taylor
Keyword(s):  
Structural Design ◽  
Design Procedure ◽  
Elastic Stiffness ◽  
Uniform Method ◽  
Design Parameters ◽  
Maximum Stiffness ◽  
Subsequent Determination ◽  
Elastic Design ◽  
Optimal Plastic Design

The paper presents a uniform method of treating a variety of problems of optimal design of sandwich structures. The design procedure consists of two steps: The integration of an optimality condition, which is a differential equation for the optimal displacement field that does not involve any design parameters, and the subsequent determination of the optimal distribution of elastic stiffness or plastic resistance from the usual differential equations of the structure. Optimal elastic design for maximum stiffness, maximum fundamental frequency, or maximum buckling load, and optimal plastic design for maximum safety are treated as examples.

Development of Structural Design Guidelines for Porous Asphalt Pavement

2018 ◽  
Vol 2672 (40) ◽  
pp. 197-206 ◽  
Author(s):  
Kevin D. Hall ◽  
Charles W. Schwartz
Keyword(s):  
Structural Design ◽  
Design Procedure ◽  
Field Performance ◽  
Design Guidelines ◽  
Empirical Approach ◽  
Asphalt Pavements ◽  
Design Parameters ◽  
Extensive Literature ◽  
Porous Asphalt ◽  
Design Procedures

Porous asphalt pavements allow designers to introduce more sustainability into projects and lessen their environmental impact. Current design procedures are based primarily on hydrologic considerations; comparatively little attention has been paid to their structural design aspects. As their use grows, a design procedure and representative material structural properties are needed to ensure that porous pavements do not deteriorate excessively under traffic loads. The objective of this project was to develop a simple, easy to apply design procedure for the structural design of porous asphalt pavements. Two methodologies were considered for such a structural design procedure: ( a) the 1993 AASHTO Pavement Design Guide empirical approach, and ( b) the mechanistic–empirical approach employed by the AASHTOWare Pavement ME Design software. A multifactor evaluation indicated the empirical 1993 AASHTO design procedure to be the most appropriate platform at this time. It is noted, however, that both design procedures lack validation of porous asphalt pavements against field performance. AASHTO design parameters and associated material characteristics are recommended, based on an extensive literature review. For “thin” open-graded base structures (12 in. or less), the AASHTO procedure is performed as published in the 1993 Guide. For “thick” base structures (>12 in.), the base/subgrade combination is considered a composite system which supports the porous asphalt layer; an equivalent deflection-based approach is described to estimate the composite resilient modulus of the foundation system, prior to applying the 1993 AASHTO design procedure.

Design for static stiffness of hydrostatic bearings: double-action variable compensation of membrane-type restrictors and self-compensation

2014 ◽  
Vol 66 (2) ◽  
pp. 322-334 ◽  
Author(s):  
Yuan Kang ◽  
De-Xing Peng ◽  
Yu-Hong Hung ◽  
Sheng-Yan Hu ◽  
Chorng-Shyan Lin
Keyword(s):  
Load Capacity ◽  
Pressure Ratio ◽  
Design Parameters ◽  
Static Stiffness ◽  
Content Type ◽  
Hydrostatic Bearings ◽  
Closed Type ◽  
Maximum Stiffness ◽  
Membrane Type

Purpose – This article is the fourth part of a serial studies about constant and variable compensations of the closed-type hydrostatic plane-pad bearing, which is presented for the double-action membrane-type restrictor and self-type compensation. The paper aims to discuss these issues. Design/methodology/approach – The load capacity and static stiffness in thrust direction of the planar bearing is determined by the flow continuity equation which belongs to the same approaches as shown in previous parts of this serial studies. Findings – The results reveal that the appropriate range of recess pressure ratio and design parameters of bearing and restrictor for the infinite or maximum stiffness can be obtained. Also, the influence of design parameters on negative stiffness that should be avoided in bearing design is revealed in detail. Originality/value – The determination of design parameters of a double-action membrane-type restrictor can be yielded from finding results of this study for maximum stiffness in design of hydrostatic bearings.

Structural Design and Optimization of a 3-Axis Miniaturized Machine Tool with High Precision Positioning Stages

2007 ◽  
Vol 339 ◽  
pp. 321-326
Author(s):  
J.H. Lee ◽  
Wei Wang ◽  
Sung Hwan Kweon ◽  
Young Shin Kim ◽  
Young Moon Lee ◽  
...  
Keyword(s):  
Machine Tool ◽  
Structural Design ◽  
Evaluation Method ◽  
Error Function ◽  
Design Procedure ◽  
Design Parameters ◽  
Volumetric Error ◽  
Design And Optimization ◽  
Suitable Structure ◽  
Previous Design

The procedure of structural design on miniaturized machine tool (mMT) is proposed and structural optimization by applying robustness evaluation method is presented in this paper. The design procedure of a kind of mMT which is a 3-axis miniaturized milling machine tool (mMMT) is discussed and three different structures of mMMT are proposed based on previous design procedure. The most suitable structure is selected using robustness evaluation method, which is Taguchi method, due to volumetric error function. The design parameters of selected structure are optimized.

scholarly journals Some Remarks on the Choice of Ductility Class for Earthquake-Resistant Steel Structures

2013 ◽  
Vol 21 (3) ◽  
pp. 1-10
Author(s):  
Miroslava Matejčeková-Farhat ◽  
Rudolf Ároch
Keyword(s):  
Structural Design ◽  
Design Procedure ◽  
Steel Structures ◽  
Design Parameters ◽  
Eurocode 8 ◽  
Design Practice ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
Design Requirements ◽  
National Practice

Abstract The implementation of the Eurocodes in current structural design practice has brought about a new emphasis on the design of earthquake-resistant structures. In some European countries, new earthquake zones have been defined; henceforth, the design requirements of many ongoing projects have changed as well. The choice of the ductility class of steel structures as one of the key design parameters, the consequences of this choice on design procedure, and some applications of the Eurocode 8 design criteria by comparing French and Slovak national practice are discussed, using a practical example of a structure.

scholarly journals Normative and methodological principles for transverse webs structural design as applicable to cargo tank area of double hull oil tankers

2020 ◽  
Author(s):  
К.В. Плотников
Keyword(s):  
Design Process ◽  
Structural Design ◽  
Design Procedure ◽  
Direct Analysis ◽  
Design Parameters ◽  
Element Analysis ◽  
Structural Rules ◽  
Functional Relations ◽  
Oil Tankers ◽  
Double Hull

Статья посвящена вопросам проектирования поперечных танкерных рам крупнотоннажных нефтеналивных судов, размеры корпусных конструкций которых должны соответствовать требованиям Общих Правил МАКО (CSR). Требования Правил CSR можно разделить на общие нормативные предписания аналитико-эмпирического характера (prescriptive-требования) и требования к выполнению проверочных расчётов (в первую очередь с использованием МКЭ). В работе рассмотрены алгоритмы проектирования поперечных рам нефтеналивных судов в соответствии с prescriptive requirements, а также предложена методика и алгоритм проектирования таких конструкций, включающие и МКЭ-анализ, которые могут использоваться в практике конструкторских бюро. Приведено обоснование необходимости анализа и обобщения проектных решений в части рамных конструкций на реальных судах, которые могут быть использованы при разработке специализированного программного обеспечения. Поскольку напряжённо-деформированное состояние рамной конструкции зависит от соотношения характеристик изгибной жесткости составляющих её балок, целесообразным является построение алгоритма проектирования, частью которого является решение оптимизационно-поисковой задачи определения требуемых размеров конструкции. Ограничения такой задачи должны формироваться на основе общих требований CSR. В тексте приведено описание нормативных требований и основные их особенности. Кратко описаны возможные варианты постановки задачи и соображения о программной реализации её решения. The paper deals with principal considerations of double-hull oil tankers primary supporting members (PSM) structural design, which meets the requirements of Common Structural Rules (CSR). The algorithms of structural design procedure for different typical arrangements of tankers are considered in the paper. The study shows main features of structural design process that lead to complexity of functional relations. As CSR requirements consist of prescriptive requirements and direct analysis requirements (that usually means finite element analysis) the suggested algorithms include both of these stages. The text explains the need of statistical data of existing designs collecting. Such data includes ratios between required and actual web depths, scantlings of brackets, ratios between moments of inertia of PSM and some others. This data can be used in structural design process and form the limitations of design parameters. As shear forces and bending moments in primary supporting members depend on ratios of its bending stiffness and relation between design parameters are rather complicated it is appropriate to use mathematical programming models, which present a decision support instrument. There are many ways of formulation and implementation of structural design task, and the paper gives general considerations about it. The brief review of previous contributions on this subject is also given.

Design of SBR systems for nutrient removal from wastewaters subject to seasonal fluctuations

2002 ◽  
Vol 46 (8) ◽  
pp. 91-98 ◽  
Author(s):  
N. Artan ◽  
D. Orhon ◽  
R. Tasli
Keyword(s):  
Design Procedure ◽  
Design Parameters ◽  
Seasonal Fluctuations ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Fundamental Relationship ◽  
Recycle Ratio ◽  
Biological Nitrogen ◽  
P Removal

Designing SBR systems for simultaneous biological nitrogen and phosphorus removal is evaluated and defined for wastewaters from small coastal areas subject to seasonal fluctuations in quantity and quality. A design procedure is developed using basic process stoichiometry and significant operating parameters. A stepwise approach was utilized to secure full nitrification, available nitrate limitation for denitrification, a mixed phase with enough anaerobic fraction for P removal. A fundamental relationship between the effective sludge age, the recycle ratio and the cycle time was developed and used for the determination of physical design parameters.

scholarly journals Rationality Analysis of High-rise Building Structure Calculation un- der SATWE Procedure

1970 ◽  
Vol 1 (1) ◽  
Author(s):  
Fan Guiqing
Keyword(s):  
Structural Design ◽  
Structural Model ◽  
Design Procedure ◽  
Design Parameters ◽  
Land Resources ◽  
High Rise ◽  
Structural Problems ◽  
Seismic Force ◽  
Structural Calculation ◽  
Capital Construction

In recent years, with the increasing shortage of land resources in our country, in or der to make full use of limited land resources, the development of construction industry is developing towards high-rise and super-high-rise buildings.This is based on the use of structural design and structural calculation of building structures with the higher requirement. For structural designers, the structural model is determined reasonably, the structural design procedure is used correctly, the design parameters and seismic force parameters are accurately input, the results are correctly analyzed and the structural calculation model is adjusted according to the calcu- lated results. Repeated adjustments in order to design safe high-rise buildings, so that the capital construction investmenthas been rationally used. In this paper, how to use the SATWE program developed by China Academy of Building Science to study the structural calculation and structural problems, how to analyze the calculation results and use the calculated results to reflect the problem and then adjust the structural model and other issues to study.

Sorption of Se (IV) from aqueous solutions with subsequent determination by X-ray fluorescence analysis

2020 ◽  
Vol 86 (10) ◽  
pp. 5-9
Author(s):  
D. G. Filatova ◽  
A. A. Arkhipenko ◽  
M. A. Statkus ◽  
V. V. Es’kina ◽  
V. B. Baranovskaya ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Fluorescence Analysis ◽  
Standard Samples ◽  
Phase Contact Time ◽  
Sorbent Phase ◽  
X Ray ◽  
Fundamental Parameters ◽  
Inductively Coupled ◽  
Subsequent Determination

An approach to sorptive separation of Se (IV) from solutions on a novel S,N-containing sorbent with subsequent determination of the analyte in the sorbent phase by micro-x-ray fluorescence method is presented. The sorbent copolymethylenesulfide-N-alkyl-methylenamine (CMA) was synthesized using «snake in the cage» procedure and proven to be stable in acid solutions. Conditions for quantitative extraction of Se (IV) were determined: sorption in 5 M HCl or 0.05 M HNO3 solutions when heated to 60°C, phase contact time being 1 h. The residual selenium content in the solution was determined by inductively coupled plasma mass spectrometry (ICP-MS) using 82Se isotope. The absence of selenium losses is proved and the mechanism of sorption interaction under specified conditions is proposed. The method of micro-x-ray fluorescence analysis (micro-RFA) with mapping revealed a uniform distribution of selenium on the sorbent surface. The possibility of determining selenium in the sorbent phase by micro-RFA is shown. When comparing the obtained results with the results of calculations by the method of fundamental parameters, it is shown the necessity of using standard samples of sorbates to obtain correct results of RFA determination of selenium in the sorbent phase.

EXPERIMENTAL STUDIES OF REINFORCED CONCRETE STRUCTURES WITH CROSS-SHAPED SPATIAL CRACK UNDER TORSION WITH BENDING

2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Determination ◽  
Calculation Method ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Experimental Scheme

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.

Sign in / Sign up

Export Citation Format

Share Document