A simplified method for calculating the stress of a large storage tank wall

Author(s):  
Z. P. Chen ◽  
Y. Y. Duan ◽  
J. M. Shen ◽  
J. L. Jiang

With consideration of the influences from the constraint reaction of tank bottom plate to each shell course, a simplified long-short shell method was proposed to calculate the stress of a large storage tank wall. The first shell course was regarded as a short cylindrical shell while all the others as long cylindrical shells, and the analytic solution equations of shell stress were achieved by theory of plates and shells. With resistance stress-strain method, a field stress test was done on a 15x104 m3 floating-roof oil tank during its water filling test, and the measured stress data are in good agreement with the calculation results obtained by this simplified calculation method for shell stress. Therefore, the simplified method can be adopted to calculate the shell stress of large storage tanks accurately.

Author(s):  
Wadie Kidess

In order to get the authorization for issuing energy performance certificates in Slovenia, the expert candidate has to attend the prescribed course and pass the exam. The simplified method for heat losses calculation that is taught at this course neglects the thermal bridges, raising concerns whether the calculation results are reliable. In this paper we have compared three methods for calculation of thermal losses for a “typical” family house. The first is the above mentioned simplified calculation using a correctional factor; the second takes into account the thermal bridges, using linear thermal transmittances obtained by numerical calculation, and the third takes into account the thermal bridges, using default values for linear thermal transmittances. Noting that the second method returns the most exact values, we have found that the first method results are too large, yet still smaller than the third method results.


Author(s):  
Fan Bu ◽  
Caifu Qian

In this paper, two finite element models are established for a super-large storage tank with or without a floating roof on the medium level. Time-history analysis with consideration of fluid-solid coupling for the deformation of tank wall and medium sloshing during or after an earthquake is performed with the emphasis on the effects of the floating roof. It is found that the upper part of tank is more sensitive to the earthquake action than the lower part. The wind girders and the reinforcing rings play a big role in limiting the radial deformation of the upper part of the tank wall. The floating roof has little effect on the tank wall deformation, but it is effective in suppressing the medium sloshing during the earthquake. After the earthquake, the radial deformation of the tank wall attenuates quickly, but the sloshing attenuation of the medium presents a slow progress and the floating roof inhibits the sloshing attenuation of the medium.


2012 ◽  
Vol 430-432 ◽  
pp. 828-833
Author(s):  
Qiu Sheng Ma ◽  
Yi Cai ◽  
Dong Xing Tian

In this paper, based on ANSYS the topology optimization design for high pressure storage tank was studied by the means of the finite element structural analysis and optimization. the finite element model for optimization design was established. The design variables influence factors and rules on the optimization results are summarized. according to the calculation results the optimal design result for tank is determined considering the manufacturing and processing. The calculation results show that the method is effective in optimization design and provide the basis to further design high pressure tank.


Author(s):  
Zhanjun Feng ◽  
Weibin Wang ◽  
Wenqiang Tong ◽  
Keyi Yuan ◽  
Zandong Han ◽  
...  

Large storage tanks for oil storage are widely used in petrochemical industry. Corrosion in the tank floor and wall is a serious threat for environmental and economic safety. Owing to their unique potential for long-range, in-plane propagation through plates, Ultrasonic Guided Waves (UGW) offer an obvious solution in the development of an on-board structural health-monitoring (SHM) system, providing assessment of structural integrity for storage tank floor and wall defect in-situ inspection. This paper presents this application by focusing on their propagation through the plate structure. Even very small mechanical discontinuity or geometry change of plate structure, e.g. corrosion defect on tank floor, will influence the propagation characteristic of the guided waves. These effects are measured as mode changes, frequency shifts or filtering, reflection and diffraction of new ultrasonic modes or overall distortion of the original ultrasonic signals. By capturing and analyzing these changes we can deduct the corrosion defect of the tank floor and wall which causes the ultrasonic signal change and interactions. The T/R transducers are required to be attached on the outer edge of the tank floor and outer surface of the tank wall. The technique is developed based on the Lamb wave transmission tomography. Starting from the dispersion curve and choosing the appropriate wave mode, the propagation of the guided waves in the tank floor and wall has been carried out through numerical simulation and the experiment has been conducted for verification using the full-size oil storage tank. The low frequency guided waves can propagate longer distance in planar and tubular structures. The later has been already used in pipeline inspection. The complexity of the application of ultrasonic guided wave in tank floor inspection lies in the object containing multiple lap joint welds along the large diameter of the tank (up to 100 m) and the complicated reconstruction of the two-dimensional defect distribution information. The main scope of the investigation was the application of the ultrasonic transmission tomography for localization of non-uniformities of inside tank floor, taking into account ultrasonic signal losses due to the loading with oil on the top and ground support at the bottom for the tank floor, and the loading with oil inside for the vertical tank wall.


Author(s):  
Kimihiro Toh ◽  
Shunsuke Maeda ◽  
Takao Yoshikawa

In order to obtain the non-linear average stress-average strain relationships (σ-ε curves) of damaged structural members under both tensile and compressive loads, the systematical calculations are performed using the non-linear FE analysis (FEA) code, LS-DYNA, and the idealized σ-ε curves of damaged structural members are estimated from FEA results. In addition, by introducing the idealized σ-ε curves of damaged structural members to the simplified calculation program, which is developed by authors and based on the Smith’s method, the residual ultimate strength of damaged hull structures is calculated. The residual ultimate strength of damaged hull structures is also calculated utilizing FEA, the calculation results by the simplified calculation program are compared with the results obtained from FE analyses so as to examine the accuracy of simplified calculation method.


2014 ◽  
Vol 1065-1069 ◽  
pp. 1358-1362
Author(s):  
Jin Sheng Han ◽  
Hao Ran Liu ◽  
Shu Ping Cong

The fire resistance of concrete filled steel tubular column is usually obtained by the numerical analysis method, which is difficult to operate and not convenient in the actual civil engineering. So it is necessary to study the simplified calculation method. A large number of numerical simulation results of the temperature distribution of the section and the bearing capacity at high temperature of the concrete filled steel tubular columns are analyzed. The influences of secondary parameters are simplified. The simplified calculation method at 150 min and 180 min for the bearing capacity at high temperature of concrete filled steel tubular columns subjected to axial compression and fire is presented on the basis of comprehensive analysis of the numerical calculation results. The calculation results can be used as the basis to judge the fire resistance. It is shown by the comparison with the experimental results that the precision of the simplified calculation method can meet the requirements of engineering application.


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