Spatial Grid Structures Research Articles

Shape and Cross-Section Optimization of Spatial Grid Structures Using Genetic Algorithm

The optimization of the structures is difficult because the variables have different physical property or different quantitative attribute. The shape and cross-section optimization of spatial grid structures is performed by an improved genetic algorithm. The constraint conditions are composed of the structural deformation, the stability of the compressive members, the slender ratios, and etc. The treatment of the constraint conditions and the optimization function gives an unconstrained analytic function by adopting Lagrange multipliers. The method enhances the running efficiency of the genetic algorithm. The programme for structural optimization containing the mixed codes of continuous real variables, discontinuous real variables, and integer variables is coded by using MATLAB Toolbox functions for genetic algorithm. The analysis of examples shows that the programme is reliable, and the convergence of the algorithm is fast as well.

A new experimental technique on the tubular joints of spatial grid structures

A new experimental technique was developed on the plate-inserted welded tubular joints of spatial grid structures. In the experimental technique, a microcomputer controlling instrument of moire intervention (MCIMI) was adopted. A test was designed on the plate-inserted welded tubular joints of spatial grid structures to show the effectiveness of the MCIMI technique. Both traditional electrical measuring technique and MCIMI technique were employed in the test. The test results showed that the MCIMI technique was feasible in the case of the complicated tests on steel structures. The MCIMI technique not only implemented the limitation of traditional electrical measuring technique, but also improved the accuracy of the test. According to the test results, we further examined the plate-inserted welded tubular joints in the cable-stayed spatial grids of the Binhai International Convention & Exhibition in Tianjin, China. The analysis showed the joints are safely designed with adequate conservatism. The research provided a new application of MCIMI in the field of large-scale structure engineering.

Application of 3d Time Domain Method for Seismic Soil-Structure Interaction Analysis of Spatial Grid Structure

This paper proposes a direct three-dimensional (3D) numerical method in time domain for seismic soil-structure interaction (SSI) analysis of spatial grid structure. First, a finite element model including soil, foundation and typical spatial grid structure is developed. Then, the precisions of equivalent viscous-spring artificial boundary element (VSABE) and size effect of site soil region are discussed. Finally, under different site types, time history analyses for models with or without considering SSI effect are implemented respectively under horizontal seismic excitation. The results show that VSABE has the same precision as infinite element boundary and plane size of truncated soil region can be five times of structure plane size for SSI analysis of spatial grid structure. Moreover, except for hard site, it is shown that horizontal acceleration and displacement of spatial grid roof increases substantially when SSI effect is considered. Therefore, it is suggested that SSI influence should be taken into account in engineering design of spatial grid structure.

Optimal Design of Spatial Grid Structure Using Group Search Optimization

An economic and safety design proposal of the spatial grid structure is very difficult to find according to traditional design method.The group search optimization and its improved algorithm are applied in optimization design of a spatial grid structure in this paper. In this paper the finite element model of the spatial grid structure is firstly built through the platform of ANSYS. Then based on the parameterized programme language ADPL of ANSYS ,the group search optimization (GSO) and the quick group search optimization(QGSO ) are compiled ,the optimization analysis of the spatial grid structure are carried out. Finally, the optimization results and the optimization one from ANSYS are compared. It show that the optimization methods hereinbefore are feasible and the design proposals of them are better than the one of ANSYS.

Numerical Simulation of Progressive Collapse and Study of Resisting Progressive Collapse of Spatial Grid Structures Based on ANSYS/LS-DYNA

In this paper, different destruction forms of spatial grid structure are analyzed based on LS-DYNA. The key members of structure are studied and the collapsing processes of spatial grid structure caused by different failure members are simulated numerically. By comparing the results of numerical analysis, divisional design method is proposed based on the alternate path method (AP method). The divisional design method can improve resistance to progressive collapse obviously and is of certain reference value for engineering.

Regulation of technological properties in polyorganosiloxanes

The processes of the formation of a spatial-grid structure in polymethylsiloxane hardening are studied. The modification of oligodimethylsiloxane using organoelemental compounds of various natures and structures is found to regulate the rate and depth of hardening processes and to improve the complex of properties of final products.

Analysis of the Structure Style Selection for Ocean Engineering Floating Structure

Use finite element analysis software ABAQUS to analyze the bearing capacity, strength and wave attenuation performance of very large ocean engineering floating structure based on spatial grid structure, and analyze selected ocean engineering floating structures with different geometrical dimensions. The ocean engineering floating grid structure attenuates wave effectively, whose bearing capacity and strength are high. In the static loads and wave forces analysis, with the dip angle α of belly poles increasing, the maximum stresses decrease, and the bearing capacity lowers; with the height h of the pyramid larger, the maximum stresses and the bearing capacity increase; with the od D of the poles and sphere joints subjoining, the maximum stresses change in concave shape in the whole, and the bearing capacity increases in turn; with the wall thickness t1 of the poles increasing, the maximum stresses under static loads become smaller, but under wave forces the maximum stresses change in concave shape, the bearing capacity declines. The bearing capacity, strength and wave attenuation performance of the structure are influenced by it’s geometrical dimension regularly, and so will affect the project implementation in a practical way.

The optimisation method of the elastic-plastic spatial grid structures

The low boundary of load carrying capacity of the elastic-plastic spatial grid structures depend on numerous values and their variability assumed in designing process. Analysed influence all this values in searching for optimal variant of the structure lead to too great problem even taking into consideration actual computational power we have in disposal. Therefore one can take only a few values which have greatest influence on the optimal choice. In optimal analysis of the elastic-plastic spatial grid structures the previously proposed method with subsequent modification (Karczewski 1980), (Karczewski, Barszcz and Donten 1996), (Karczewski and Donten 2001) as well as computer program which was worked out by Donten K. to make possible practical utilisation this method was employed. The paper deal with evaluation of influence dimensions of particular values for choice of optimal variant of the structure. One among this values is distribution of the struts in the structure.