scholarly journals Volume optimization of end-clamped arches

2020 ◽  
Author(s):  
Alessandra Fiore
Keyword(s):  
Objective Function ◽  
Second Step ◽  
Structural System ◽  
Shape Parameters ◽  
Construction Costs ◽  
Force Method ◽  
Kinematic Behaviour ◽  
Material Volume ◽  
Optimal Material ◽  
Arch Shape

Even if arch arised as structural system more than two thousand years ago, this structural typology is still not widely diffused and is mainly adopted when large spans have to be covered. The structural efficiency of arches primarily depends on optimal material exploitation, i.e. minimization of internal stress eccentricity that reduces structural material volume and weight. An efficient structure, under these terms, implies simple and light scaffolding, so contributing in minimizing construction costs. Although very abundant knowledge and literature on arches, there is still scope for design optimization. This study is framed within this context and deals with the structural analysis of end-clamped plane circular arches under uniformly distributed vertical load and self weight. In the first step, the analytical solution of arch static and kinematic behaviour is derived by the force method. In the second step, the arch shape is optimized, by assuming the arch volume, and thus the weight, as objective function. Finally minima of the objective function (i.e. optimal geometric shape parameters) are computed and charted in order to be used for practical purposes.

scholarly journals Accounting for the Inhomogeneity of Deformation in Identification of Microstructure Evolution Model / Niejednorodność Odkształcenia W I Dentyfikacji Modelu Rozwoju Mikrostruktury

2015 ◽  
Vol 60 (4) ◽  
pp. 3087-3094 ◽  
Author(s):  
D. Szeliga ◽  
R. Kuziak ◽  
R. Kopp ◽  
G. Smyk ◽  
M. Pietrzyk
Keyword(s):  
Objective Function ◽  
Compression Test ◽  
Microstructure Evolution ◽  
Evolution Model ◽  
Second Step ◽  
Compression Tests ◽  
Force Measurements ◽  
Microstructural Parameters ◽  
Inverse Approach ◽  
Optimized Model

The paper deals with the problem of identification of microstructure evolution model on the basis of two-step compression test. Classical interpretation of this test assumes uniform fields of strains, stresses and temperatures in the deformation zone and calculates the coefficients in the model on the basis of force measurements in the second step. In the present paper the inverse approach was applied. Finite element (FE) simulations of the compression test were performed and local values of microstructural parameters were determined accounting for the inhomogeneity of deformation. Objective function was formulated as the Euclid norm for the error between measured and calculated forces for various interpass times. Coefficients in the microstructure evolution model were determined by searching for the minimum of the objective function. Optimized model was validated in simulations of plane strain compression tests.

A Model for Assessing the Shape of Solder Joints in the Presence of PCB and Package Warpage

2005 ◽  
Vol 128 (3) ◽  
pp. 184-191 ◽  
Author(s):  
Mahidhar Rayasam ◽  
Terrace B. Thompson ◽  
Ganesh Subbarayan ◽  
C. Gurumurthy ◽  
J. R. Wilcox
Keyword(s):  
Solder Joints ◽  
Equilibrium Configuration ◽  
Circuit Board ◽  
Second Step ◽  
Computationally Efficient ◽  
Test Vehicle ◽  
Step Procedure ◽  
Solder Volume ◽  
Restoring Forces ◽  
Material Volume

Our goals in this paper are to develop and demonstrate a computationally efficient methodology for assessing the effect of circuit board warpage, component warpage, and solder volume variation on the shape of the solder joints in area array packages. The effect of warpage is analyzed using a two-step procedure in the present paper. In the first step, the restoring forces and moments (in the molten state of solder droplet) that result from a given solder joint height, solder material volume, pad diameter, and pad inclination are predicted using the surface tension theory. In the second step of the analysis, the forces and moments at individual solder joints caused by varying solder heights and pad tilts are combined to predict the equilibrium configuration of the package. A program written in the MATHEMATICA® environment was developed to implement the above-described methodology. The developed procedure was validated on an experimental test vehicle with nine solder joints. The heights of solder joints computed by the program matched the experimentally measured heights to within ±5% error. Further, the general capabilities of the modeling procedure are demonstrated by assuming complex combinations of package and PCB warpage.

Utilisation d'éléments structuraux en aluminium dans les ponts routiers : Étude économique et structurale

2001 ◽  
Vol 28 (6) ◽  
pp. 1029-1040 ◽  
Author(s):  
Carol Roy ◽  
Denis Beaulieu ◽  
Josée Bastien
Keyword(s):  
Cost Analysis ◽  
Bridge Deck ◽  
Concrete Slab ◽  
Second Step ◽  
Structural System ◽  
Analysis Study ◽  
Simple Repair ◽  
Potential Use ◽  
Economic Standpoint ◽  
Made In

The study presented in this paper is part of a project aiming at evaluating the potential use of aluminum in structures. The types of intervention could range from a simple repair or a reinforcement involving structural aluminum, the replacement of a used bridge deck by an aluminum deck, to the construction of a new bridge made in full or in part of aluminum. It is this latter type of intervention that justified a research project, the results of which are presented in this article. The first step involves identifying the most advantageous type of aluminum structural system from a structural standpoint as well as an economic standpoint. This step includes the analysis and partial design of 40 girder- or truss-type road bridges, spanning 15 and 35 m, supporting either an active concrete slab or an aluminum deck. These studies have shown that bridges built using a Pratt-type truss and an active concrete slab provided the best results. It is also shown that some calculation criteria, such as vibration, deflection, and fatigue criteria limited the extensive use of aluminum in bridges. In the second step, nine bridges are more comprehensively analysed and designed, based on the standards used in North America, and three are fully designed, including the connexions, in order to realize a cost analysis study that is as accurate as possible. Special attention is given to vibration and fatigue problems as well as to the details related to connexions calculation. The study concludes that the development of an aluminum-only medium span road bridge system is a non-viable project in the short to mid term from a structural standpoint as well as an economic standpoint, and it makes recommendations on the use of aluminum decks and on the continuation of the work.Key words: aluminum, analysis, bridges, connexions, design, fatigue, standards, vibration.[Journal translation]

Topology Optimization on the Material Distribution of Track Segment for Heavy Machinery

2011 ◽  
Vol 346 ◽  
pp. 460-470
Author(s):  
Yong Li ◽  
Guo Qiang Wang ◽  
Zhen Hua Yan
Keyword(s):  
Topology Optimization ◽  
Variable Density ◽  
Material Distribution ◽  
Distribution Law ◽  
Track Segment ◽  
Heavy Machinery ◽  
Maximum Stiffness ◽  
Material Volume ◽  
Optimal Material ◽  
Optimal Area

To achieve the rational shape and structure of large or super-large track segment, this paper investigated the optimal material distribution law of the track segment with topology optimization by variable density method. In this method the element density of the optimal area is the design variable, the maximum stiffness between the track segment and the terrain is the object, and the material volume per centum of the optimal area is the constraint. In this study, we obtained the topology optimal results of a track segment for a certain heavy-machinery by OPTISTRUCT software. The paper also presented the transitional geometrical distribution law of the optimal material from solid state to hollow state at the same constraint of the material volume percentum and at the different terrain stiffness. Finally, the optimal shape was put into application.

scholarly journals Layout Selection for an Optimal Sewer Network Design Based on Land Topography, Streets Network Topology, and Inflows

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2491
Author(s):  
Juan Saldarriaga ◽  
Jesús Zambrano ◽  
Juana Herrán ◽  
Pedro L. Iglesias-Rey
Keyword(s):  
Network Design ◽  
Objective Function ◽  
Network Topology ◽  
Drainage System ◽  
Mixed Integer ◽  
Integer Programming Problem ◽  
Construction Costs ◽  
Sewer Network ◽  
Hydraulic Design ◽  
Design Cost

This paper proposes a methodology for the layout selection of an urban drainage system as an extension to the methodology for an optimal sewer network design proposed by Duque, Duque, Aguilar, & Saldarriaga. The layout selection approach proposed in this paper uses an objective function that takes into account all input data in the problem, such as: land topography, street network topology, and inflow to each manhole. Once the layout is selected, the network is optimally designed using dynamic programming. The problem of layout selection is solved as a mixed-integer programming problem and is divided into two steps. The first step tries to define an initial layout using the network topology and land topography as a criterion. This allows for an initial hydraulic design and an approximation of the sewer network’s construction costs. The second step uses the data obtained in the previous process to establish an approximation of the construction costs of each arc that can be part of the layout. This is in order to minimize the objective function of the layout selection problem so that the hydraulic design cost is also minimized. The methodology was successfully tested on three case studies: the Chicó sewer network proposed by Duque et al. and two sewer network benchmarks from the literature.

Technology and Evaluation of Urban Rail Transportation Dispatch

2014 ◽  
Vol 621 ◽  
pp. 734-739
Author(s):  
Qing Yang ◽  
Xiao Hua Luo ◽  
Dong Liang ◽  
Xin Qiu
Keyword(s):  
Objective Function ◽  
Urban Transportation ◽  
Urban Rail Transit ◽  
Rail Transit ◽  
Rail Transportation ◽  
Basic Design ◽  
Full Line ◽  
Site Location ◽  
Construction Costs ◽  
Urban Rail

In order to ease the tense situation of Chinese urban transportation, many cities carry on the planning, design, reporting, and construction of urban rail transit project; it has formed an urban rail transit boom and continued so far. This study was focused on distributive control theory of urban rail transportation, including summarized principle urban rail transit site, concubines dispatched a group of principles, summed up the basic design of the site line primaries. Through methods calculate the distance of the site Manhattan, quantitatively analysis the site traffic for the site location; adjust distribution to provide a reference, which dispatched a group of full line of urban rail transit lines. Site covering a large amount of and line total construction costs are lower, and that the line units' lower construction costs, the superiority of design as the objective function, the amount of site coverage and line total construction costs. This study has positive implications for improving urban rail design, to promote the sound development of urban rail transportation.

scholarly journals Direct Displacement Control of Deformed Double Layer Dome

2020 ◽  
Vol 4 (6) ◽  
Author(s):  
Najmadeen Mohammed Saeed ◽  
Shna Jabar Abdulkarim ◽  
Hawkar Ali Haji
Keyword(s):  
Double Layer ◽  
Direct Method ◽  
Space Structures ◽  
Structural System ◽  
Structural Shape ◽  
Force Method ◽  
Concert Halls ◽  
Shape Restoration ◽  
Service Conditions ◽  
Shape Adjustment

Space structures such as double layer dome is light and active structural system that used for various structural application, for instance structural covers large areas such as exhibition halls, stadium and concert halls. They are aesthetically pleasing in appearance as well as the architectural requirement, in which tolerances of structural shape under changing service conditions are very significant, which high appearance accuracy is requested in some applications. Due to many reasons such as loading, these type of structures may suffer from a noticeable deflection, which leads to a significant potential undesired appearance of the shape. In this situation, the displacements may need to be reduced or eliminated. In this study, by applying the shape adjustment technique that its scheme is depend on the linear force method, shape restoration is performed to the double layer dome model in three different cases corresponding to the directions of loadings were considered. The improvement of controlling nodal displacement can be achieved through using a rather simple and direct method, due to calculating necessary length of actuators by applying a single formulation. It is found that if the number of provided actuators are satisfactory, controlling of all the displaced joints could be performed by a very small percentage of discrepancy, even if the controlled joints connection is not direct with the adjustable members. The technique of shape adjustment is very efficient for double layer dome model, and it can roughly eliminate the displacement of definite joints (Exterior joints only) by simply changing the length of certain bars by eo amount

scholarly journals Direct Displacement Control of Deformed Double Layer Dome

2020 ◽  
Vol 4 (6) ◽  
pp. 1-14
Author(s):  
Najmadeen Mohammed Saeed ◽  
Shna Jabar Abdulkarim ◽  
Hawkar Ali Haji
Keyword(s):  
Double Layer ◽  
Direct Method ◽  
Space Structures ◽  
Structural System ◽  
Structural Shape ◽  
Force Method ◽  
Concert Halls ◽  
Shape Restoration ◽  
Service Conditions ◽  
Shape Adjustment

Space structures such as double layer dome is light and active structural system that used for various structural application, for instance structural covers large areas such as exhibition halls, stadium and concert halls. They are aesthetically pleasing in appearance as well as the architectural requirement, in which tolerances of structural shape under changing service conditions are very significant, which high appearance accuracy is requested in some applications. Due to many reasons such as loading, these type of structures may suffer from a noticeable deflection, which leads to a significant potential undesired appearance of the shape. In this situation, the displacements may need to be reduced or eliminated. In this study, by applying the shape adjustment technique that its scheme is depend on the linear force method, shape restoration is performed to the double layer dome model in three different cases corresponding to the directions of loadings were considered. The improvement of controlling nodal displacement can be achieved through using a rather simple and direct method, due to calculating necessary length of actuators by applying a single formulation. It is found that if the number of provided actuators are satisfactory, controlling of all the displaced joints could be performed by a very small percentage of discrepancy, even if the controlled joints connection is not direct with the adjustable members. The technique of shape adjustment is very efficient for double layer dome model, and it can roughly eliminate the displacement of definite joints (Exterior joints only) by simply changing the length of certain bars by eo amount

scholarly journals Three-Step Parameters Tuning Model for Time-Constrained Genetic Algorithms

2016 ◽  
Vol 10 (10) ◽  
pp. 118
Author(s):  
Saleem Ramadan ◽  
Mahmoud Barghash
Keyword(s):  
Genetic Algorithms ◽  
Objective Function ◽  
Multiple Regression ◽  
Execution Time ◽  
Optimization Method ◽  
Second Step ◽  
Deterministic Optimization ◽  
Parameters Tuning ◽  
Constraint Model ◽  
Step Parameters

In this paper a three-step parameters tuning model for time-constrained Genetic Algorithms (GAs) was presented. The first step involved modeling the objective function using multiple regression model where the fitness value was the response variable and the GA parameters were the regressors. The second step involved constraint modeling using the objective function found in the first step and using the upper and lower limits of the GA parameters along with an upper limit on the execution time as constraints. The third step involved optimizing the constraint model found in the second step using a suitable deterministic optimization method to determine the optimal GA parameters taking into consideration four aspects that affect the GA performance. These aspects were: the problem under consideration, the GA parameters used, the execution time, and the power of the computer used.The validation of this model was demonstrated using two capacitated lot sizing problems. The model was able to predict the fitness values and the optimal parameters of the GA for these problems to a high degree of precision. Moreover, the results showed that tuning the GA parameters using multiple regression along with a suitable deterministic optimization method was an effective and robust method that enhanced the performance of the GA. The statistical analysis showed that in order to do a proper tuning for a certain GA, the designer of the GA must take into consideration not only the type of problem but also the size of the problem, the allowable execution time, and the hardware used in executing the GA. Furthermore, the results agreed with the "No Free Lunch" theorem.

Theoretical Analysis of Equivalent Elastic Modulus of Corrugated Paperboard

2012 ◽  
Vol 200 ◽  
pp. 243-248
Author(s):  
Jin Rong Wang ◽  
Xin Guang Lv ◽  
Shi Qing Huang ◽  
Yu Mei Wu ◽  
Qiong Chen
Keyword(s):  
Elastic Modulus ◽  
Sandwich Structure ◽  
Uniform Pressure ◽  
Shape Parameters ◽  
Pressure Force ◽  
Shape Coefficient ◽  
Composite Sandwich ◽  
Force Method ◽  
Out Of Plane ◽  
The Relationship

A new mathematical method is developed for the calculation of equivalent elastic modulus of UV-type corrugated paperboard. The model is assumed to be composite sandwich structure and to endure the out-of-plane uniform pressure. Force method is used for the derivation of the formula. The influence of the corrugated medium structure on the flat compression strength of corrugated paperboard is investigated as well. The equivalent elastic moduluses of two different sizes of three-layer UV corrugated paperboard are calculated according to the derived formula. The relationship between the thickness and the shape parameters with the flat compressive strength is discussed. The introduction of shape coefficient into this formula can help to optimize the corrugated sandwich structure and its cushioning pads.

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