Fatigue Life Calculation of the in-Service Dented Pipeline

2011 ◽  
Vol 467-469 ◽  
pp. 1327-1332 ◽  
Author(s):  
Wu Ying ◽  
Peng Zhang ◽  
Wu Liu

Dent is one of the important factors affecting pipeline fatigue life, and it will greatly reduce the fatigue life of the pipeline in service. Based on a large number of foreign dented pipeline fatigue test results and fatigue life model, for the typical dent defect, using finite element method, various parameters are changed and finite element models are obtained under different conditions. According to many calculation results, a key ratio of peak period stress and pipeline pressure variation are obtained, which are substituted to the fatigue life model and the example are calculated.

2011 ◽  
Vol 55-57 ◽  
pp. 1659-1664 ◽  
Author(s):  
Wu Ying ◽  
Peng Zhang

Dent is one of the important factors affecting pipeline fatigue life, and it will greatly reduce the fatigue life of the pipeline in service. And the peak cycle stress on the dented pipeline is the key parameter to calculate pipeline fatigue life. For typical II type dent in the pipeline, the finite element models are established under different circumstances. A large number of the calculation results are sorted, inducted, drew. On this basis, the results are analysed by univariate and multivariate. Non-linear regression analysis was utilized to fit the results by matlab, some specific expressions of the relationship between the dented pipeline peak cycle stresses and the dent depth, diameter and thickness of pipeline, and the dent longitudinal length are obtained after much calculation and analog.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2978
Author(s):  
Zhi-Min Liu ◽  
Xue-Jin Huo ◽  
Guang-Ming Wang ◽  
Wen-Yu Ji

Compared with straight steel–concrete composite beams, curved composite beams exhibit more complicated mechanical behaviors under combined bending and torsion coupling. There are much fewer experimental studies on curved composite beams than those of straight composite beams. This study aimed to investigate the combined bending and torsion behavior of curved composite beams. This paper presents static loading tests of the full elastoplastic process of three curved composite box beams with various central angles and shear connection degrees. The test results showed that the specimens exhibited notable bending and torsion coupling force characteristics under static loading. The curvature and interface shear connection degree significantly affected the force behavior of the curved composite box beams. The specimens with weak shear connection degrees showed obvious interfacial longitudinal slip and transverse slip. Constraint distortion and torsion behavior caused the strain of the inner side of the structure to be higher than the strain of the outer side. The strain of the steel beam webs was approximately linear. In addition, fine finite element models of three curved composite box beams were established. The correctness and applicability of the finite element models were verified by comparing the test results and numerical calculation results for the load–displacement curve, load–rotational angle curve, load–interface slip curve, and cross-sectional strain distribution. Finite element modeling can be used as a reliable numerical tool for the large-scale parameter analysis of the elastic–plastic mechanical behavior of curved composite box beams.


2017 ◽  
Vol 11 (1) ◽  
pp. 244-257 ◽  
Author(s):  
Xingyou Yao

Background: Cold-formed steel structural sections used in the walls of residential buildings and agricultural facilities are commonly C-shaped sections with web holes. These holes located in the web of sections can alter the elastic stiffness and the ultimate strength of a structural member. The objective of this paper is to study the buckling mode and load-carrying capacity of cold-formed thin-walled steel column with slotted web holes. Methods: Compression tests were conducted on 26 intermediate length columns with and without holes. The tested compressive members included four different kinds of holes. For each specimen, a shell finite element Eigen-buckling analysis and nonlinear analysis were also conducted. The influence of the slotted web hole on local and distortional buckling response had also been studied. The comparison on ultimate strength between test results and calculated results using Chinese cold-formed steel specification GB50018-2002, North American cold-formed steel specification AISI S100-2016, and nonlinear Finite Element method was made. Result: Test results showed that the distortional buckling occurred for intermediate columns with slotted holes and the ultimate strength of columns with holes was less than that of columns without holes. The ultimate strength of columns decreased with the increase in transverse width of hole in the cross-section of member. The Finite element analysis results showed that the web holes could influence on the elastic buckling stress of columns. The shell finite element could be used to model the buckling modes and analysis the ultimate strength of members with slotted web holes. The calculated ultimate strength shows that results predicted with AISI S100-2016 and analyzed using finite element method are close to test results. The calculated results using Chinese code are higher than the test results because Chinese code has no provision to calculate the ultimate strength of members with slotted web holes. Conclusion: The calculated method for cold-formed thin-walled steel columns with slotted web holes are proposed based on effective width method in Chinese code. The results calculated using the proposed method show good agreement with test results and can be used in engineering design for some specific cold-formed steel columns with slotted web holes studied in this paper.


2017 ◽  
Vol 54 (1) ◽  
pp. 180-179 ◽  
Author(s):  
Raul Cormos ◽  
Horia Petrescu ◽  
Anton Hadar ◽  
Gorge Mihail Adir ◽  
Horia Gheorghiu

The main purpose of this paper is the study the behavior of four multilayered composite material configurations subjected to different levels of low velocity impacts, in the linear elastc domain of the materials, using experimental testing and finite element simulation. The experimental results obtained after testing, are used to validate the finite element models of the four composite multilayered honeycomb structures, which makes possible the study, using only the finite element method, of these composite materials for a give application.


2017 ◽  
Vol 54 (1) ◽  
pp. 111-115
Author(s):  
Anamaria Florescu ◽  
Stefan Manea ◽  
Violeta Hancu ◽  
Roxana Manu ◽  
Cornelia Florentina Biclesanu

Present study examines, by means of finite element method, the influence of cervical cavity shape on tensions distribution caused by occlusal overload of the teeth with abfraction lesion. Same force values are applied to four 3-D lower premolar finite element models, representing four different cavity shapes. An extracted lower premolar which presented an abfraction lesion has been used. The restoration was achieved by using ER adhesive systems and Giomers. The premolar was scanned and the resulting sections were processed and converted into a 3D digital format. Thus, a model of finite elements which presented a restored wedge-shaped cavity in the cervical dental area was obtained. Then, by modifying the shape and dimensions, there were created another 3 modified-shape cavities. Forces of different magnitudes (45-150N), exerted at a 45 degree angle on buccal cusp, have been applied. A wedge-shaped cavity with a short occlusal side does not show tension in the cervical region, nor in the distal angle of the restoration up to a force of 100N. So, in order to increase the retention of the abfraction restoration, changing the shape of the cavity could be the treatment of choice. Clinical relevance In order to avoid costly and unethical research, by means of FEM, different shapes of cervical cavities were easily created and conditions that influence retention of abfraction restoration were tested.


2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Alamsyah Alam ◽  
A. B. Mapangandro ◽  
Amalia Ika W ◽  
M U Pawara

Ro - Ro Ferry is equipped with a connecting door between the port and the ship. The ramp door experiences load during loading and discharging of the rolling cargo. This repetitive load may cause fatigue failure. The structure of the ramp door should withstand this load. Therefore, The ramp door should be properly designed to ensure the structural integrity of the ramp door. The purpose of this research is to analyze the maximum stress and the Fatigue life of the bow ramp door. The method used is the finite element method. The given loads are several types of vehicles that are commonly transported by the ship. The given load case is the point load working at the girder plate and between the girder plate. Based on the simulation results with the given point load, the maximum stress is identified located between the girder for the large truck case with 397.02 MPa, while the minimum stress located at the girder for sedan car with 43.93 MPa. As for the fatigue life of the bow ramp door construction. it is 1.17 ~ 398.64 years, and the load cycle is 5.35 x 104 ~ 9.05 x 106 cycle. Keywords : Bow Ramp Door; Stress; Fatigue Life; Finite Element; Ferry


2021 ◽  
Vol 4 (4) ◽  
pp. 11-31
Author(s):  
S. Koryagina

the article presents the principles and algorithms of the finite element method in solving geotechnical prob-lems taking into account seismic impacts for determining the stress-strain state of structures and slope stabil-ity, implemented in the Midas GTS NX software package. GTS NX allows you to perform calculations of various types of geotechnical problems and solve complex geotechnical problems in a single software envi-ronment. GTS NX covers the entire range of engineering and geotechnical projects, including calculations of the "base-structure" system, deep pits with various mounting options, tunnels of complex shape, consolida-tion and filtration calculations, as well as calculations for dynamic actions and stability calculations. At the same time, all types of calculations in GTS NX can be performed both in 2D and in 3D. The author does not claim to be the author of the finite element method, but he cannot do without pointing out the basic equa-tions, as this affects the definition of the boundaries of use, the formulation of algorithms for constructing calculation schemes and the analysis of calculation results.


2021 ◽  
Vol 14 (2) ◽  
pp. 54-66
Author(s):  
Svetlana Sazonova ◽  
Viktor Asminin ◽  
Alla Zvyaginceva

The sequence of application of the mixed method for calculating internal forces in statically indeterminate frames with elements of increased rigidity is given. The main system is chosen for the frame with one kinematic and one force unknown. The canonical equations of the mixed method are written, taking into account their meaning. Completed the construction of the final diagram of the bending moments and all the necessary calculations and checks. When calculating integrals, Vereshchagin's rule is applied. The solution of the problem is checked by performing the calculation using the computer program STAB12.EXE; the results of the calculations are numerically verified using the finite element method. An example of the formation of the initial data for the STAB12.EXE program and the subsequent processing of the calculation results, the rules for comparing the numerical results and the results obtained in the calculation of the frame by the mixed method are given.


Author(s):  
Sijia Wang ◽  
Tianlai Yu

Because of the low height of the prestressed short rib T-beam bridge and the poor torsion resistance of the main beam, the positive moment in the middle span of the bridge deck will increase correspondingly compared with the normal rib beam bridge. At present, there is little research on the calculation method of the bridge deck of the prestressed short rib T-beam bridge. In this paper, the space finite element method and the continuous one-way slab method are used to calculate the forces on the bridge deck, based on the space finite element method, a finite element elastic supported continuous beam method is proposed to calculate the forces on the bridge deck. By comparing the calculation results of the three methods with the test results, the reasonable calculation method of the bridge deck is studied. The results show that the spatial finite element analysis method can simulate the mechanical performance of the deck of the bridge of the prestressed short rib T-beam bridge well, the stress calculation results are consistent with the test results, and the calculation accuracy is high, which can be used in the actual engineering design; The finite element analysis method of elastic support continuous beam can also simulate the mechanical performance of the deck of the bridge of the prestressed short rib T-beam bridge. The concept of the method is clear, the calculation is convenient, and it is more suitable for the application of engineering design; The calculation results of the continuous one-way slab method are too large to be safe for design.


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