Application of Modified Consistent Mode Imperfection Method in Stability Analysis of Single-Layer Reticulated Shells

2013 ◽  
Vol 477-478 ◽  
pp. 744-748 ◽  
Author(s):  
Sheng He ◽  
Jian Cai ◽  
Qi Qi Liu

Based on the probability reliability theory, this paper proposes a modified consistent mode imperfection method, which fits the integral stability analysis of single-layer reticulated shells with the initial geometric imperfections. Nearly 1000 elasto-plastic load-deflection overall processes of four different rise-to-span ratio for Kiewitt-8 single-layer reticulated shells are analyzed by using the random imperfection mode method, the consistent mode imperfection method and the modified consistent mode imperfection method respectively. The study shows that the random imperfection mode method can assess the influence of initial geometric imperfections on structure stability more scientifically, but the calculation is quite large. By using the consistent mode imperfection method, the buckling load is not sure to be the most unfavorable, and the degree of reliability couldnt be ensured effectively. The modified consistent mode imperfection method can gain the buckling load which meets the requirement of probability reliability with less calculation. It can also assess the stability performance of single-layer reticulated shell structure more reasonably and safely.

2011 ◽  
Vol 243-249 ◽  
pp. 7001-7004 ◽  
Author(s):  
Ling Ling Wang ◽  
Yu Zhen Chang

The paper proposed a new system of spatial structure: steel- concrete composite ribbed shell, and briefly compared the three analysis methods considering the initial imperfections of structures: the random imperfection mode method, the consistent imperfection mode method and the improved random imperfection mode method. By using of the consistent imperfection mode method and nonlinear finite element analysis software ANSYS, we analyzed a composite steel-concrete ribbed shell with the span of 40m and span ratio f/L=1/4, which is simply supported at its surrounding and is subjected to uniform loading along it’s whole span. The critical load and instability regions of this shell are presented. The results show that with the increasing of the initial imperfections, the value of critical load decreased from 27% to 36%; the trend of load-displacement curve and the location of structural instability regions remain unchanged, only the shape of instability regions will change. This indicted that the effect of the initial imperfections within composite ribbed shell is far less than its influence to the single-layer shell. The steel-concrete composed ribbed shell is not sensitive to the initial geometric imperfections and shows a strong post-buckling performance.


2012 ◽  
Vol 170-173 ◽  
pp. 2592-2596
Author(s):  
Shu Tang Liu ◽  
Qi Liang Long ◽  
Long Wang

Stability is an important measurement index of reticulated shell structure to security and reliability. Considering the temperature change, using structural buckling analysis in ANSYS, the stability of reticulated shell structure was invested. Analysis shows that stability of reticulated shell structure affected by temperature change impact; as the temperature goes down, the safety factor (stability coefficient) continually decrease. The conclusion showed that: 1) reticulated shell construction is suitable in summer; 2) Insulated curing of shell should be paid attention in cold season, and which will be useful on design, construction and use of structure.


2014 ◽  
Vol 931-932 ◽  
pp. 525-528
Author(s):  
Sanguan Vongchavalitkul

There are differences in each countrys design code for concrete elastic modulus that cause uncertainty in stability analysis of critical buckling load column. This paper investigates the impact of uncertainty on concrete elastic modulus for designing of critical buckling load of building column. The statistical data on materials and applied load being collected in Thailand are used together with an investigation on the uncertainty of the concrete elastic modulus in the design code from 8 countries. Finally the Monte Carlo simulation is used to find out the stability index in term of reliability index. The results show that the uncertainty of the concrete elastic modulus plays an important role in stability analysis and should be considered in the design.


2012 ◽  
Vol 226-228 ◽  
pp. 1185-1189
Author(s):  
Jian Kang ◽  
Xiang Yu Liu

Radiant cable suspendome based on single-layer lattice shell is proposed in this paper whose cable-strut system is like that of Radiant Beam String Structure, the purpose of this paper is to do stability analysis of the structure.The linear buckling analysis of the hybrid structure and the single-layer lattice shell who has the same geometry parameters is carried out, we can preliminarily understand the stability of the hybrid structure. At the same time, nonlinear buckling analysis is carried out to study the stability of the hybrid structure under different rise-span ratios, different prestress level and half-span load. The results show that the introduction of prestressed cables greatly improve the structure's stability and reduce the structure sensitivity to original geometrical imperfection.


2005 ◽  
Vol 20 (2) ◽  
pp. 115-124 ◽  
Author(s):  
Zhi-Hua Chen ◽  
Yang Li

As a kind of hybrid space structures, the suspendome system increases the stiffness and improves the stability of the original dome system by the appropriate use of prestressing cables. Based on the engineering application of suspendome in Tianbao Center (completed in China, 2002), the present paper concentrates on the stability performance of the suspendome with a span of 35.4m using different structural parameters, including the rise-span ratio, magnitude and level settings of initial prestressing in cables, connection rigidity and boundary support condition. Stability performances including buckling mode, critical loads and sensitivity to initial geometric imperfection are studied in detail, and contrast analyses with the corresponding singly-layer shells are carried out to study the superiorities of the suspendome over the single-layer shell. Some valuable conclusions are drawn for practical design.


2014 ◽  
Vol 1078 ◽  
pp. 220-223
Author(s):  
Wen Bin Shi

ANSYS14.0 structural analysis software is used in order to make a ring rib-reticulated shell for the overall stability analysis. Considering the geometric nonlinear analysis and initial geometric imperfections influence , obtain a key node of the load - displacement curve and assess the ultimate strength of the structure. The results showed that: the structure meets the "Space grid rules" for monolayer shells stability requirements. And it is found that load distribution form and initial geometry defect has a great deal whit bearing capacity of single-layer lattice shell stability by comparison.


2013 ◽  
Vol 788 ◽  
pp. 598-601
Author(s):  
Jun Qiang Wu ◽  
Yu Cui

This single-layer spherical reticulated shell has the advantages of reasonable stress,beautiful appearance ,fast construction,is widely applied in practical engineering. Through the static stability analysis of three kinds of single-layer spherical lattice shell structure using ansys, we get them in the uniform deformation under static load, the modal, buckling load. The results show that: The Kiewitt latticed shells displacement is small, structure is stable, better than SchwedLer and lianfang.


Author(s):  
Gaik A. Manuylov ◽  
Sergey B. Kositsyn ◽  
Irina E. Grudtsyna

The aim of the work is to research the precritical and postcritical equilibrium of the stiffened plates subjected aliquant critical loads. Methods. The finiteelement complex MSC PATRAN - NASTRAN was used in the paper. To simulate the plates, flat four-node elements were used. Calculations taking into account geometric nonlinearity were carried out. The material of the shells was considered absolutely elastic. Results. A technique has been developed to study the stability of reinforced longitudinally compressed plates; the critical forces of the stiffened plates of various thicknesses had been calculated. Graphs of deflections dependences on the value of the compressive load had been constructed. The influence of initial geometric imperfections on the value of the critical loads for stiffened plates has been investigated.


1995 ◽  
Vol 117 (2) ◽  
pp. 162-169 ◽  
Author(s):  
C. Sun ◽  
W. J. D. Shaw ◽  
A. M. Vinogradov

The stability of a ring confined by a rigid boundary, subjected to circumferential end loads, is investigated both theoretically and experimentally. The effect of initial geometric imperfections on the buckling load is determined by assuming an initial deflection configuration as a simple sine form and the critical condition was derived from equilibrium analysis. An experimental approach was designed to verify the analytical results. Comparison with other theoretical results are also made.


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