Research on Practical Design Method of Single-Layer Lattice Shell Components

2013 ◽  
Vol 351-352 ◽  
pp. 775-781
Author(s):  
Fan Wang ◽  
Xiao Rong Pan

There are some limitations on the calculation about effective length factor of the single-layer lattice shell structure`s component by the current specifications. That`s why Euler formula is commonly used to anti-push the effective length in engineering design. In traditional design, one or few components were used to calculate the effective length factor, and the single biggest value is assigned to all components for design. Owing to the coarse method, values of some components` effective length are too large or too small. This paper improved the traditional design method, and used excel in formula programming to calculate effective length factors of all components. Then all factors are assigned to all components for designing by SAP2000. At the end of the article, it explored the difference in this new design method with the traditional design method.

2014 ◽  
Vol 584-586 ◽  
pp. 1841-1844
Author(s):  
Fang Fang Yang

Super high-rise building seismic design of complex shape is very important, can not be carried out according to the traditional design method. This paper gives a design principle based on behavior, it in the engineering design and more attention. Method based on behavior on the properties of reaction structures under earthquake is evaluated. High-rise buildings must be based on the method of state to confirm that the building to meet seismic performance.


2014 ◽  
Vol 919-921 ◽  
pp. 58-63
Author(s):  
Cheng Liu ◽  
Ping Zhou Cao

Construction of denitrification system is an important environmental engineering in power industry now. Denitrification system is always set over the blower bracket, frame for denitrification needs to pass through existing structure if blower bracket works together with boiler frame. Based on the denitrification project of a power plant in north China, this paper puts forward reasonable structural arrangement of steel frame through existing structure, which is that frame for denitrification works alone and the column affected by existing structure selects solid-web column with openings. The beam supporting SCR reactor could be simplified as a beam under dead load only. Optimal design of its section in simplified model can improve design efficiency and economize the cost. The critical load of special column with bracings can be obtained by the linear elastic buckling analysis and effective-length factor can be calculated according to Euler Formula.


2019 ◽  
Vol 11 (11) ◽  
pp. 168781401988677 ◽  
Author(s):  
Liming Zhou ◽  
Jinghao Tang ◽  
Weijie Wang ◽  
Erfei Zhao ◽  
Shuhui Ren ◽  
...  

To calculate the ultimate load of the lattice boom accurately, the effective length factor and imperfection factor are introduced to the current stability factor formula. First, we propose a stability factor formula by conducting a series of tests of high-strength steel tubes under axial compression and analyzing the experimental data. Second, the effective length factor of the chord which is caused by braces is calculated on the basis of different effective length factors and stability curves. Then, the correctness of the proposed effective length factor and the stability factor formula are proved by destructive tests under three loading modes. Using the modified stability factor formula, the accuracy of ultimate load of lattice boom is enhanced. These findings will be of great value for improving the design level of lattice boom and providing a theory and test basis for the completion of the buckling design method of the high-strength steel tubes.


2021 ◽  
Vol 11 (11) ◽  
pp. 4845
Author(s):  
Mohammad Hossein Noorsalehi ◽  
Mahdi Nili-Ahmadabadi ◽  
Seyed Hossein Nasrazadani ◽  
Kyung Chun Kim

The upgraded elastic surface algorithm (UESA) is a physical inverse design method that was recently developed for a compressor cascade with double-circular-arc blades. In this method, the blade walls are modeled as elastic Timoshenko beams that smoothly deform because of the difference between the target and current pressure distributions. Nevertheless, the UESA is completely unstable for a compressor cascade with an intense normal shock, which causes a divergence due to the high pressure difference near the shock and the displacement of shock during the geometry corrections. In this study, the UESA was stabilized for the inverse design of a compressor cascade with normal shock, with no geometrical filtration. In the new version of this method, a distribution for the elastic modulus along the Timoshenko beam was chosen to increase its stiffness near the normal shock and to control the high deformations and oscillations in this region. Furthermore, to prevent surface oscillations, nodes need to be constrained to move perpendicularly to the chord line. With these modifications, the instability and oscillation were removed through the shape modification process. Two design cases were examined to evaluate the method for a transonic cascade with normal shock. The method was also capable of finding a physical pressure distribution that was nearest to the target one.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 524
Author(s):  
Junhua Xu ◽  
Shuangbao Zhang ◽  
Guofang Wu ◽  
Yingchun Gong ◽  
Haiqing Ren

With the increasing popularity of cross-laminated timber (CLT) constructions around the world, there have been attempts to produce CLT using local wood species in different countries, such as Japanese larch (Larix kaempferi (Lamb.) Carr.) in China. Thus, the need to investigate the connection performance also increases to support the design and construction of CLT buildings using local wood species. In this study, the withdrawal properties of three different types of self-tapping screws (STS), with a diameter of 6 mm, 8 mm, and 11 mm, were tested with Japanese larch CLT. The results revealed that the withdrawal strength of STS increased with increasing density and effective length, but decreased with an increasing diameter. With a density increment of 0.05 g/cm3, the withdrawal strength increased by an average of 9.4%. With an effective length increment of 24 mm, the withdrawal strength increased by an average of 1.4%. An empirical regression model was adopted to predict the withdrawal strength of Japanese larch CLT based on the results, which can be used for potential engineering design of CLT connections using STS.


Author(s):  
Yanning Yuan ◽  
Yuchen Zhao ◽  
Xiaoli Xi

Abstract A single-layer ultra-wideband (UWB) stop-band frequency selective surface (FSS) has several advantages in wireless systems, including a simple design, low debugging complexity, and an appropriate thickness. This study proposes a miniaturized UWB stop-band FSS design. The proposed FSS structure consists of a square-loop and metalized vias that are arranged on a single layer substrate; it has an excellent angle and polarization-independent characteristics. At an incident angle of 60°, the polarization response frequencies of the transverse electric and magnetic modes only shifted by 0.003 f0 and 0.007 f0, respectively. The equivalent circuit models of the square-loop and metallized vias structure are analysed and the accuracy of the calculation is evaluated by comparing the electromagnetic simulation. The 20 × 20 array constitutes an FSS reflector with a unit size of 4.2 mm × 4.2 mm (less than one-twentieth of the wavelength of 3 GHz), which realizes an UWB quasi-constant gain enhancement (in-band flatness is <0.5 dB). Finally, the simulation results were verified through sample processing and measurement; consistent results were obtained. The FSS miniaturization design method proposed in this study could be applied to the design of passband FSS (complementary structure), antennas and filters, among other applications.


2014 ◽  
Vol 716-717 ◽  
pp. 1518-1521
Author(s):  
Shu Fang ◽  
Yan Xu ◽  
Fei Dong

The manufacture of fire robot has characteristics such as different types and piece production, and flexible manufacture and cost control of the fire robot must be considered due to these characteristics. In this paper, the similarity of fire robot’s working environment was analyzed, The demand of chassis’s adaptability and the method using general technical platform were discussed with the thinking of modular design, and new series fire robots which composed of the general platform and different function modules were proposed, and the manufacture cost of traditional design method and modular design method were compared in using the activity-based costing method, and under the new design method the manufacture cost were decreased extremely.


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