scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

2013 ◽  
Vol 788 ◽  
pp. 606-610
Author(s):  
Qing Xiang Ji ◽  
Xin Sheng Ge

Foundation pit excavation could be affected to some extent by surrounding different kinds of building materials, building structure, foundation form and load distribution, especially in intensive buildings. In this paper, based on the large-scale finite element software ANSYS, a three-dimensional finite element model is established to analyze the consequences of these complex and uncertain factors faced with by deep excavation projects and the conclusions of the excavation affected by different foundations form of adjacent buildings are arrived at.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Chong Jiang ◽  
Jia-Li He ◽  
Lin Liu ◽  
Bo-Wen Sun

A series of three-dimensional finite element analyses were performed to study the behavior of piles in sloping ground under undrained lateral loading conditions. The analyses have been conducted for slopes with different angles and two loading directions. The obtained results show that as the slope increases, it can cause greater lateral displacement and internal force of the pile. In addition, the increase of the slope ratio will cause the position of the maximum bending moment and soil resistance zero point of the pile to move downward, further increasing the pile deflection. Furthermore, when the pile distance from slope crest B < 7D, the displacement and internal force development of the pile under toward loading is more obvious. When the pile distance from the slope crest exceeds 7D, the effect of loading direction on the pile can be neglected.


Author(s):  
Antony Kirk ◽  
Grahame Knowles ◽  
Jill Stewart ◽  
Chris Bingham

High speed drive shafts are traditionally balanced using trim balance weights applied to the shaft ends. This paper considers the development and theoretical analysis of a novel and alternative strategy of balancing long flexible coupling shafts, whereby the trim balancing weights are applied by the means of a pair of ‘Balancing Sleeve’ arms that are integrally attached to each end of the coupling shaft. The trim balance weights are intended to apply a corrective centrifugal force to the coupling shaft in order to limit shaft end reaction forces. With increasing speed, the magnitude of the corrective force also increases due to the flexibility of the balance sleeve. This thereby counteracts the increased coupling shaft unbalance resulting from its own flexibility. Additionally, it is also found that the mechanism imparts a corrective bending moment to the coupling shaft ends, which has a tendency to limit deflection. The methodology is modelled as a rotating simply supported shaft with uniform eccentricity and allows application to the problem of drivetrain balancing of sub-15MW industrial gas turbines. Results show that reaction loads can theoretically be reduced from 10,000 N to approximately zero. The bending moment applied to the shaft is also shown to reduce shaft deflection theoretically to zero. In practical applications this will be unrealistic and achievable results show deflection theoretically reduced by half. Analysis of the balance sleeve feasibility is considered through use of a three-dimensional finite element model. Further to this paper, the aim is to develop a full dynamic model of both shaft and counterbalance sleeve, with verification coming from scaled, experimental test facilities.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


2007 ◽  
Vol 129 (6) ◽  
pp. 1028-1034 ◽  
Author(s):  
Liang Wang ◽  
Sergio Felicelli

A three-dimensional finite element model was developed to predict the temperature distribution and phase transformation in deposited stainless steel 410 (SS410) during the Laser Engineered Net Shaping (LENS™) rapid fabrication process. The development of the model was carried out using the SYSWELD software package. The model calculates the evolution of temperature in the part during the fabrication of a SS410 plate. The metallurgical transformations are taken into account using the temperature-dependent material properties and the continuous cooling transformation diagram. The ferritic and martensitic transformation as well as austenitization and tempering of martensite are considered. The influence of processing parameters such as laser power and traverse speed on the phase transformation and the consequent hardness are analyzed. The potential presence of porosity due to lack of fusion is also discussed. The results show that the temperature distribution, the microstructure, and hardness in the final part depend significantly on the processing parameters.


2013 ◽  
Vol 549 ◽  
pp. 172-179 ◽  
Author(s):  
Amir Hassannejadasl ◽  
Daniel E. Green

Hydropiercing is an efficient way of piercing holes in mass produced hydroformed parts with complex geometries. By driving piercing punches radially into a hydroformed and fully pressurized tube, holes will be pierced and extruded into the tube-wall. Recent experimental studies have shown that the formability of advanced high strength steel (AHSS) tubes can be increased with the application of internal pressure. In this study, three-dimensional finite element simulations of a tube hydropiercing process of a dual phase steel (DP600) were performed in LS-DYNA, using phenomenological, micromechanical and combined damage criteria. Damage was included in the numerical analysis by applying constant equivalent plastic strain (CEPS), the Gurson-Tvergaard-Needleman (GTN), and the Extended GTN (GTN+JC) model. In order to calibrate the parameters in each model, a specialized hole-piercing fixture was designed and piercing tests were carried out on non-pressurized tube specimens. Of the various ductile fracture criteria, the results predicted with the GTN+JC model, such as the punch load-displacement, the roll-over depth, and the quality of the clearance zone correlated the best with the experimental data.


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