scholarly journals Analytical Model for Deflections of Bonded Posttensioned Concrete Slabs

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Min Sook Kim ◽  
Joowon Kang ◽  
Young Hak Lee

This paper presents a finite element analysis approach to evaluate the flexural behavior of posttensioned two-way slabs depending on the tendon layout. A finite element model was established based on layered and degenerated shell elements. Nonlinearities of the materials are considered using the stress-strain relationships for concrete, reinforcing steel, and prestressing tendons. Flexural testing of the posttensioned two-way slabs was conducted to validate the developed analytical process. Comparing the analytical results with the experimental results in terms of deflections, it showed generally good agreements. Also a parametric study was performed to investigate the effects of different types of tendon layout.

2013 ◽  
Vol 405-408 ◽  
pp. 3222-3228
Author(s):  
Rong Gang Yin ◽  
Zhi Guo Li ◽  
Hong Xiang She ◽  
Jian Hai Zhang

In order to improve the modeling efficiency for finite element analysis pre-processing, a parametric modeling method of underground powerhouse for finite element analysis is proposed. By inputting the basic geometric parameters, different types of underground powerhouse models are built by using this method. The basic ideas, basic principle and the process of this parametric modeling are presented. And the parametric modeling procedure is coded by using VC++, interactive interface and display window are designed by using MFC and OpenGL. Finite element model of Houziyan underground powerhouse which is built by using the procedure proves that this method greatly improves the efficiency and precision of modeling.


2015 ◽  
Vol 730 ◽  
pp. 101-104
Author(s):  
Nan Huang ◽  
Hui Li ◽  
Ping Fei Xu

The flexural behavior of reinforced concrete beams strengthened by CFRP is analyzed by using the way which connected tests with finite element simulation.First,through the test to get the load data of one unstrengthened and one strengthened reinforced concrete beam.Then,the finite element model is carried out based on Ansys finite element analysis software.The reinforced beam carrying capacity is improved based on the test data and finite element calculation results.Steel bars stress change curve, CFRP stress curve and the load displacement curves are in good agreement with experimental results.


2008 ◽  
Vol 131 (1) ◽  
Author(s):  
C. F. Qian ◽  
H. J. Yu ◽  
L. Yao

In order to investigate the possibility of numerical simulation for whole structures of heat exchangers, two finite element analysis models have been established for the fixed tubesheet structure composed of tubesheet, cylindrical shell, and tubes using different types of elements. Stresses and deformations produced by pressure load or thermal load are calculated, and the axial strain at the middle area of the cylindrical shell is experimentally measured. By comparing the numerical results with experimental measurements, it is found that both finite element analysis models can give satisfactory results. Considering the difficulties in modeling heat exchangers, beam and shell elements are recommended.


2016 ◽  
Vol 27 (3) ◽  
pp. 284-291 ◽  
Author(s):  
Diego José Stringhini ◽  
Ricardo Sommerfeld ◽  
Lucas Caetano Uetanabaro ◽  
Denise Piotto Leonardi ◽  
Melissa Rodrigues Araújo ◽  
...  

Abstract The aim of this study was to evaluate the stress and dislodgement resistance by finite element analysis of different types of fixation in mandibular orthognathic surgery. A 3D solid finite element model of a hemi-mandible was obtained. A bilateral sagittal split osteotomy was simulated and the distal segment was advanced 5 mm forward. After the adjustment and superimposing of segments, 9 different types of osteosynthesis with 2.0 miniplates and screws were simulated: A, one 4-hole conventional straight miniplate; B, one 4-hole locking straight miniplate; C, one 4-hole conventional miniplate and one bicortical screw; D, one 4-hole locking miniplate and 1 bicortical screws; E, one 6-hole conventional straight miniplate; F, one 6-hole locking miniplate; G, two 4-hole conventional straight miniplates; H, two 4-hole locking straight miniplates; and I, 3 bicortical screws in an inverted-L pattern. In each model, forces simulating the masticatory muscles were applied. The values of stress in the plates and screws were checked. The dislodgement resistance was checked at the proximal segment since the distal segment was stable because of the screen at the occlusal tooth. The regions with the lowest and highest displacement were measured. The offset between the osteotomized segments was verified by millimeter intervals. Inverted-L with bicortical screws was the model that had the lowest dislodgment and the model with the lowest tension was the one with two conventional plates. The results suggest that the tension was better distributed in the locking miniplates, but the locking screws presented higher concentration of tension.


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.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.


2011 ◽  
Vol 346 ◽  
pp. 379-384
Author(s):  
Shu Bo Xu ◽  
Yang Xi ◽  
Cai Nian Jing ◽  
Ke Ke Sun

The use of finite element theory and modal analysis theory, the structure of the machine static and dynamic performance analysis and prediction using optimal design method for optimization, the new machine to improve job performance, improve processing accuracy, shorten the development cycle and enhance the competitiveness of products is very important. Selected for three-dimensional CAD modeling software-UG NX4.0 and finite element analysis software-ANSYS to set up the structure of the beam finite element model, and then post on the overall structure of the static and dynamic characteristic analysis, on the basis of optimized static and dynamic performance is more superior double wall structure of the beam. And by changing the wall thickness and the thickness of the inner wall, as well as the reinforcement plate thickness overall sensitivity analysis shows that changes in these three parameters on the dynamic characteristics of post impact. Application of topology optimization methods, determine the optimal structure of the beam ultimately.


Author(s):  
Luiz T. Souza ◽  
David W. Murray

The paper presents results for finite element analysis of full-sized girth-welded specimens of line pipe and compares these results with the behavior exhibited by test specimens subjected to constant axial force, internal pressure and monotonically increasing curvatures. Recommendations for the ‘best’ type of analytical finite element model are given. Comparisons between the behavior predicted analytically and the observed behavior of the experimental test specimens are made. The mechanism of wrinkling is explained and the evolution of the deformed configurations for different wrinkling modes is examined. It is concluded that the analytical tools now available are sufficiently reliable to predict the behavior of pipe in a manner that was not previously possible and that this should create a new era for the design and assessment of pipelines if the technology is properly exploited by industry.


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