Non-linear normal modes of a simply supported beam: continuous system and finite-element models

2004 ◽  
Vol 82 (31-32) ◽  
pp. 2683-2691 ◽  
Author(s):  
Carlos E.N. Mazzilli ◽  
Mário E.S. Soares ◽  
Odulpho G.P. Baracho Neto
Keyword(s):  
Finite Element ◽  
Normal Modes ◽  
Continuous System ◽  
Finite Element Models ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Non Linear

Evaluation of non-linear normal modes for finite-element models

2002 ◽  
Vol 80 (11) ◽  
pp. 957-965 ◽  
Author(s):  
C.E.N. Mazzilli ◽  
O.G.P. Baracho Neto
Keyword(s):  
Finite Element ◽  
Normal Modes ◽  
Finite Element Models ◽  
Non Linear

Reduction of finite-element models of planar frames using non-linear normal modes

2001 ◽  
Vol 38 (10-13) ◽  
pp. 1993-2008 ◽  
Author(s):  
C.E.N. Mazzilli ◽  
M.E.S. Soares ◽  
O.G.P. Baracho Neto
Keyword(s):  
Finite Element ◽  
Normal Modes ◽  
Finite Element Models ◽  
Planar Frames ◽  
Non Linear

Study on Flexibility of Intracranial Vascular Stents Based on the Finite Element Method

2018 ◽  
Vol 35 (4) ◽  
pp. 465-474 ◽  
Author(s):  
L. Liu ◽  
H. Jiang ◽  
Y. Dong ◽  
L. Quan ◽  
Y. Tong
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cantilever Beam ◽  
Beam Model ◽  
The Finite Element Method ◽  
Simply Supported Beam ◽  
Bending Deformation ◽  
Vascular Stents ◽  
Simply Supported ◽  
Loading Method

ABSTRACTFlexibility is a particularly important biomechanical property for intracranial vascular stents. To study the flexibility of stent, the following work was carried out by using the finite element method: Four mechanical models were adopted to simulate the bending deformation of stents, and comparative studies were conducted about the distinction between cantilever beam and simply supported beam, as well as the distinction between moment-loading method and displacement-loading method. A complete process as implanting a stent including compressing, expanding and bending was also simulated, for analyzing the effects of compressing and expanding deformation on stent flexibility. At the same time, the effects of the arrangement and the number of bridges on stent flexibility were researched. The results show that: 1. A same flexibility index was obtained from cantilever beam model and simply supported beam model; displacement-loading method is better than moment-loading for simulating the bending deformation of stents. 2. The flexibility of stent with compressing and expanding deformation is lower than that in the initial form. 3. Crossly arranging the neighboring bridges in axial direction, can effectively improve the stent flexibility and reduce the flexibility difference in various bending directions; the bridge number, has proportional non-linear correlation with the stent rigidity as well as the maximum moment required for bending the stent.

Two non-linear finite element models developed for the assessment of failure of masonry arches

2008 ◽  
Vol 336 (1-2) ◽  
pp. 42-53 ◽  
Author(s):  
Michele Betti ◽  
Georgios A. Drosopoulos ◽  
Georgios E. Stavroulakis
Keyword(s):  
Finite Element ◽  
Finite Element Models ◽  
Masonry Arches ◽  
Linear Finite Element ◽  
Non Linear

scholarly journals Nonlinear Pounding Analysis of Multispan and Simply Supported Beam Bridges Subjected to Strong Ground Motions

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Hong-Yu Jia ◽  
Xian-Lin Lan ◽  
Nan Luo ◽  
Jian Yang ◽  
Shi-Xiong Zheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Parameter Analysis ◽  
Cross Sectional ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Finite Element Software ◽  
Impact Element ◽  
Bearing Stiffness ◽  
The Impact ◽  
Gap Width

To investigate the nonlinear impact effect of multispan simply supported beam bridges under strong earthquakes, firstly, the dynamic motion equation, the algorithm of its solution, and some pounding modelling methods are presented and the finite element model of a considered multispan simply supported railway beam bridge is established in the nonlinear finite element software of SAP2000 in which the primary nonlinear characteristics of the bearing and the impact element are considered herein. Secondly, the natural vibration characteristic of the considered railway bridge is analyzed to prepare for the subsequent parameter analysis. Finally, the influence of three nonlinear parameters, i.e., stiffness of impact element, separation gap width of expansion joint, and bearing stiffness, on impact responses of bridge structures is studied. The results show that the first several modes of multispan simply supported beam bridges are mainly longitudinal and vertical vibrations. Under longitudinal seismic excitations, the large longitudinal displacement response is induced possibly and results in the collision or even unseating of superstructures at the expansion joints and abutments. The influence of separation gap width between adjacent decks on the pounding effect of bridges is greater than that of collision stiffness originated from the pounding modelling element. The impact force and pounding number run up to the maximum conditional on the collision stiffness of 9.9 × 109 (N/m) and the separation gap width of 0.14 (m). The bearing stiffness affects significantly the displacement of the pier top and the cross-sectional internal force at the bottom of piers but has little effect on the collision force and number.

scholarly journals Seismic Assessment in a Historical Masonry Minaret by Linear and Non-linear Seismic Analyses

2020 ◽  
Author(s):  
Emin Hökelekli ◽  
Ali Demir ◽  
Emre Ercan ◽  
Halil Nohutçu ◽  
Abdurrahman Karabulut
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Properties ◽  
Ground Motions ◽  
Element Model ◽  
Operational Modal Analysis ◽  
Finite Element Models ◽  
Non Linear ◽  
Concrete Damage ◽  
Historical Masonry

Operational Modal Analysis (OMA) method is frequently used in order to determine dynamical properties of historical masonry structures. In this study, damage pattern of historical Alaca minaret which is selected as application is investigated under different ground motions by updating finite element models (FEM) depending on operational modal analysis test. Initial Finite element model was prepared in ABAQUS V10 program and numerical dynamic characteristics of minaret were determined. In addition, experimental dynamic properties of minaret were provided by operational modal analysis. Initial numerical model of brick masonry structure was calibrated via OMA method. Then, linear and non-linear seismic analyses of calibrated FEM of historical minaret were performed by using different earthquakes acceleration records that occurred in Turkey. Concrete Damage Plasticity model was taken into account in non-linear seismic analyses. As a result of the analyses, it is concluded that the stresses obtained with linear analyses aren’t as realistic as the non-linear analyses results and the earthquakes can cause some damages in the minaret.  

Non-linear 3D Evaluation of Different Oral Implant-Abutment Connections

2012 ◽  
Vol 91 (12) ◽  
pp. 1184-1189 ◽  
Author(s):  
P. Streckbein ◽  
R.G. Streckbein ◽  
J.F. Wilbrand ◽  
C.Y. Malik ◽  
H. Schaaf ◽  
...  
Keyword(s):  
Finite Element ◽  
Cone Angle ◽  
Three Dimensional ◽  
Bone Strain ◽  
Finite Element Models ◽  
Implant Abutment ◽  
Non Linear ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Micro-gaps and osseous overload in the implant-abutment connection are the most common causes of peri-implant bone resorption and implant failure. These undesirable events can be visualized on standardized three-dimensional finite element models and by radiographic methods. The present study investigated the influence of 7 available implant systems (Ankylos, Astra, Bego, Brånemark, Camlog, Straumann, and Xive) with different implant-abutment connections on bone overload and the appearance of micro-gaps in vitro. The individual geometries of the implants were transferred to three-dimensional finite element models. In a non-linear analysis considering the pre-loading of the occlusion screw, friction between the implant and abutment, the influence of the cone angle on bone strain, and the appearance of micro-gaps were determined. Increased bone strains were correlated with small (< 15°) cone angles. Conical implant-abutment connections efficiently avoided micro-gaps but had a negative effect on peri-implant bone strain. Bone strain was reduced in implants with greater wall thickness (Ankylos) or a smaller cone angle (Bego). The results of our in silico study provide a solid basis for the reduction of peri-implant bone strain and micro-gaps in the implant-abutment connection to improve long-term stability.

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