Shape and force control of cable structures with minimal actuators and actuation

2021 ◽  
pp. 095605992110458
Author(s):  
Najmadeen Mohammed Saeed ◽  
Ahmed Aulla Hamed Manguri ◽  
Abubakr Mustafa Adabar
Keyword(s):  
Force Control ◽  
Current Approach ◽  
Effective Parameters ◽  
Cable Structures ◽  
Stress Control ◽  
Force Method ◽  
Upper Limit ◽  
Current Technique ◽  
Shape Adjustment ◽  
Prestressed Cable

Shape adjustment and stress control can be considered as one of the effective parameters in prestressed cable structures since such structures are widely constructed nowadays due to their characteristics. The assembly errors and applied loads hugely affect the cables’ nodal positions and stress due to their delicacy. The former could disturb the shape, which affects the appearance and the function of the structure. In contrast, the latter may increase the stress in some cables above the upper limit or induce slack in some others. Accordingly, a technique has been proposed that combined fmincon optimization that relies on four different algorithms with a controlling approach based on the force method. The presented method aims to minimize the total amount of actuation and miniaturize the number of actuators. The targets of previously confirmed techniques can be obtained with less actuation and fewer actuators by using the current technique. Based on the verified examples, the advantage of the current approach over the quoted methods is up to 55% and 37% in terms of the number of actuators and the total amount of actuation, respectively.

scholarly journals An Approximate Linear Analysis of Structures Utilizing Incremental Loading of Force Method

2020 ◽  
Vol 4 (6) ◽  
pp. 37-44
Author(s):  
Najmadeen Mohammed Saeed ◽  
Ahmed Aulla Manguri
Keyword(s):  
Simple Technique ◽  
Geometrical Property ◽  
Current Approach ◽  
Geometrically Nonlinear ◽  
Force Method ◽  
Internal Forces ◽  
Small Change ◽  
Nodal Displacements ◽  
Good Agreement ◽  
Incremental Loading

A relatively simple technique has been introduced in this paper. The approach is based on the Linear Force Method (FM) with discretion of the applied loads to the subsequence steps and updating coordinates in each iteration to have new geometrical property. The accuracy of the technique depends on the size of the discretion which depends on the number of iterations. A small change in the configuration could hugely affect the displacement and internal forces in geometrically nonlinear structures, that’s why the current approach is vital. The proposed technique is validated with other techniques of nonlinear analysis of the structures with a very good agreement in both terms of external nodal displacements and internal bar forces.

scholarly journals An Approximate Linear Analysis of Structures Utilizing Incremental Loading of Force Method

2020 ◽  
Vol 4 (6) ◽  
pp. 37-44
Author(s):  
Najmadeen Mohammed Saeed ◽  
Ahmed Aulla Manguri
Keyword(s):  
Simple Technique ◽  
Geometrical Property ◽  
Current Approach ◽  
Geometrically Nonlinear ◽  
Force Method ◽  
Internal Forces ◽  
Small Change ◽  
Nodal Displacements ◽  
Good Agreement ◽  
Incremental Loading

A relatively simple technique has been introduced in this paper. The approach is based on the Linear Force Method (FM) with discretion of the applied loads to the subsequence steps and updating coordinates in each iteration to have new geometrical property. The accuracy of the technique depends on the size of the discretion which depends on the number of iterations. A small change in the configuration could hugely affect the displacement and internal forces in geometrically nonlinear structures, that’s why the current approach is vital. The proposed technique is validated with other techniques of nonlinear analysis of the structures with a very good agreement in both terms of external nodal displacements and internal bar forces.

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

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