scholarly journals A structural analysis in seismic archaeology: the walls of Noto and the 1693 earthquake

1995 ◽  
Vol 38 (5-6) ◽  
Author(s):  
E. Guidoboni ◽  
P. Riva ◽  
V. Petrini ◽  
A. Madini Moretti ◽  
G. Lombardini
Keyword(s):  
Finite Element ◽  
Research Programme ◽  
Historical Earthquakes ◽  
Quality Standard ◽  
Seismic Effects ◽  
Ground Acceleration ◽  
Element Analysis ◽  
Second Development ◽  
High Quality Standard ◽  
The One

A crucial problenl for seismic archeology is how to recognize seismic effects and how to date them. On an experimental basis. we proposed that the problem be reversed, and that we begin at the other end: i.e. by analyzing already known seismic effects on ancient structures, testified by written sources. to be able to .calibrate>> the types or possible observations and any subsequent elaborations. The choice of the walls of Noto was suggested by the fact that Noto was abandoned following the earthquake of l693 (I,= XI MCS. Me 7.5) which had already been studied in depth as part of an ING research programme (1988-92). Moreover, just after recent research, this event proved to be reconstructed with a high quality standard. Photogrammetric measurements were made on several parts of the town walls to plot a numerical model aimed at ascertaining specific aspects of the earthquake damage. An estimate of the ground acceleration during the earthquake has been attempted via non-linear finite-element analyses of a building located by the main city gate. The analyses show that. in order to obtain the building vault collapse, a ground acceleration of 0.5 to 0.7 g had to be reached during the earthquake. This result, typical of a strong earthquake such as the one of 1693, proves that an approach based on finite element analysis and a sound engineering judgment Inay be systematically applied to historical earthquake sites to obtain some estimates of ground acceleration in historical earthquakes. On the whole, this work aimed at starting up the second development phase of the great event of 1693 of which the macroseismic erfects are known. In the meantime, some possibilities of tackling structural analyses in seismic archaeology are being explored.

scholarly journals A three - dimensional finite element study on the stress distribution pattern of two prosthetic abutments for external hexagon implants

2013 ◽  
Vol 07 (04) ◽  
pp. 484-491 ◽  
Author(s):  
Wagner Moreira ◽  
Caio Hermann ◽  
Jucélio Tomás Pereira ◽  
Jean Anacleto Balbinoti ◽  
Rodrigo Tiossi
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
3D Fea ◽  
The One ◽  
Von Mises ◽  
Three Dimensional Finite Element

ABSTRACT Objective: The purpose of this study was to evaluate the mechanical behavior of two different straight prosthetic abutments (one- and two-piece) for external hex butt-joint connection implants using three-dimensional finite element analysis (3D-FEA). Materials and Methods: Two 3D-FEA models were designed, one for the two-piece prosthetic abutment (2 mm in height, two-piece mini-conical abutment, Neodent) and another one for the one-piece abutment (2 mm in height, Slim Fit one-piece mini-conical abutment, Neodent), with their corresponding screws and implants (Titamax Ti, 3.75 diameter by 13 mm in length, Neodent). The model simulated the single restoration of a lower premolar using data from a computerized tomography of a mandible. The preload (20 N) after torque application for installation of the abutment and an occlusal loading were simulated. The occlusal load was simulated using average physiological bite force and direction (114.6 N in the axial direction, 17.1 N in the lingual direction and 23.4 N toward the mesial at an angle of 75° to the occlusal plan). Results: The regions with the highest von Mises stress results were at the bottom of the initial two threads of both prosthetic abutments that were tested. The one-piece prosthetic abutment presented a more homogeneous behavior of stress distribution when compared with the two-piece abutment. Conclusions: Under the simulated chewing loads, the von Mises stresses for both tested prosthetic-abutments were within the tensile strength values of the materials analyzed which thus supports the clinical use of both prosthetic abutments.

UK Research Programme on Residual Stresses: Progress to Date

2007 ◽  
Author(s):  
S. K. Bate ◽  
A. P. Warren ◽  
C. T. Watson ◽  
P. Hurrell ◽  
J. A. Francis
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Research Programme ◽  
Assessment Procedure ◽  
Engineering Structures ◽  
Element Analysis ◽  
Simplifying Assumptions ◽  
Modelling Techniques

A long-term UK research programme on residual stresses was launched in 2004. It involves Rolls-Royce plc and Serco Assurance, and is supported by UK industry and academia. The programme is aimed at progressing the understanding of weld residual stresses and the implementation of finite element simulation and residual stress measurement for assessing the integrity of engineering structures. Following on from this, the intention is then to develop improved guidance on residual stress modelling techniques. In the first two years finite element activities have addressed heat source representation, simplified modelling (e.g. 2D v 3D, bead lumping), material hardening models, high temperature behaviour and phase transformations. It is recognized that simplifying assumptions have to be made in order to reduce the computational run-time and modelling complexity, especially for multi-pass welds. The effects of these assumptions on the determined stresses have been considered by carrying out finite element analyses of welded mock-ups. The welded mock-ups have been developed to provide measured residual stress data which are necessary to validate the modelling techniques that have been developed. These activities have been used to support the development of guidelines on the use finite element analysis to predict residual stresses in welded components. These guidelines will be incorporated in the next issue of the British Energy R6 defect assessment procedure.

Three-dimensional analyses of two high-speed trains crossing on a bridge

2003 ◽  
Vol 217 (2) ◽  
pp. 99-110
Author(s):  
H-T Lin ◽  
S-H Ju
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
High Speed ◽  
Three Dimensional ◽  
Dynamic Effect ◽  
Response Ratio ◽  
Element Analysis ◽  
Dynamic Finite Element Analysis ◽  
High Speed Trains ◽  
The One

This paper investigates the dynamic characteristics of the three-dimensional vehicle-bridge system when two high-speed trains are crossing on a bridge. Multispan bridges with slender piers and simply supported beams were used in the dynamic finite element analysis. A response ratio (RR) was defined in this study to represent the ratio of the vehicle-bridge interaction of two-way trains to that of a one-way train. The finite element results indicate that this ratio increases significantly when two-way trains run near the same speed, and the maximum value is approximately equal to or smaller than two for the vertical dynamic response. This means that the maximum dynamic response of the two-way trains is at most twice that of the one-way train. When the two-way train speeds are sufficiently different, the response ratio approaches one on average, which means that the dynamic effect of the two-way train is similar to that of the one-way train. Finite element results also indicate that the averaged response ratio in the three global directions is about 1.65 when the two-way trains run at the same speed.

scholarly journals Evaluation of Useful Biomechanical Parameters On Scoliosis Using Finite Element Method

2020 ◽  
Vol 7 (2) ◽  
pp. 71-80
Author(s):  
Midiya Khademi ◽  
Ali Nikoo
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Cobb Angle ◽  
Vertebral Column ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Spine Model ◽  
Patient Model ◽  
The One ◽  
External Forces

Background: Scoliosis is a deformity of the vertebral column, and shape-changing and deformation of the spine are some critical factors that can cause this abnormality. This condition causes some problems like deflection of the spine in the coronal plane toward medial or lateral. Cobb angle is a measurement for the investigation of the severity of this condition. There are several effective therapies suggested for the reduction of the Cobb angle for patients who has this abnormality. It has suggested that before applying external forces to correct this condition, biomechanical evaluation of this deformity, can be useful during diagnosis. Methods: The purpose of this study is the evaluation of Cobb angle correction using external forces. For this aim first, the dimensional data of the patient’s vertebrae are extracted from CT-scan images using Mimics software, and the vertebral column modeled in Catia software for finite element analysis (FEA). Afterward, the model was imported into Abaqus software to evaluate the effect of forces on the spine model. The study was done by assuming two cases for the spine, one-piece (without a nucleus) and two-piece (with a nucleus) intervertebral disc. Results: After studying the results of this simulation, it concluded that after applying gravity force to these two cases, the percentage of Cobb angle’s reduction was about 0.05 for a two-piece disc and about -0.18 for the one-piece disc. Therefore, the two-piece disc assumption was better for analyzing this parameter. The results of maximum displacement and von misses stress show that the two-piece disc is accurate. Conclusion: In order to investigate which analysis is appropriate to be selected, choosing a twopiece intervertebral disc model is superlative. Whether our goal is only to examine the stress which is present in the patient model, choosing a one-piece disc is a more optimal duo to take much less time.

scholarly journals Design of Cruciform Specimens for Biaxial testing of Composites

1992 ◽  
Vol 1 (5) ◽  
pp. 096369359200100
Author(s):  
J L D Runkle ◽  
A B Doucet
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Gage Section ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Biaxial Testing ◽  
Element Analysis ◽  
Cruciform Specimen ◽  
The One ◽  
Specimen Shape

Orthotropic finite element analysis was used to design a cruciform specimen for use in biaxial testing of fiber reinforced composites. Several notch designs were investigated and the optimal specimen shape was chosen as the one in which failure would more likely occur in the gage section rather than across the cruciform arms.

Study on Structural Analysis for One-Cylinder Vertical Engine Assembly by FEA Method

2014 ◽  
Vol 496-500 ◽  
pp. 597-600
Author(s):  
Yong Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Analysis ◽  
Design Process ◽  
Design Approach ◽  
Maximum Pressure ◽  
Structural Components ◽  
Element Analysis ◽  
The One

In this paper, a simulation driven design approach was employed for the design process of the structural components of the one-cylinder vertical Engine. Finite element analysis (FEA) of the one-cylinder vertical engine assembly has been completed for assembly and maximum pressure loads using FEA software.

variety of span lengths, widths, number of grlders and slab thickness were analyzed. For two 50 ft. spans with seven girders (slab aspect ratio of 0.12) the value of D in the S/D formula varies between 6.1 and 7.96 for midspan center girder depending on the slab to girder stiffness ratio. This is in lieu of the 5.5 specified in AASHTO Standard Specification. Perhaps more representative are results for a 100 ft., two span continuous bridge with five girders spaced at 9 ft, where D varies between 8.4 and 10.8. Another Interesting result in Walker's report is regarding the structural idealization of the bridge. It has been found that the simple grid model can represent the essential behavior of the bridge as the more exact models do. The grid model was constructed such that the transverse beams represent the equivalent slab and diaphragms (if present) and the longitudinal beams represent the longitudinal composite girders. The fact that the grid model gives good representation of the essential behavior of the bridge can not be generalized. The grid model has certain limitations, however it gives a better representation of the bridge behavior than does a simple two-value S/D rule. A simple micro computer implementation of a grid model is seen by Walker as a better method than the S/D formula to predict lateral load distribution. Recently Hays, Sessions and Berry (8), have demonstrated that the effect of span length, which is neglected in AASHTO can be considerable. They found that AASHTO results are slightly unconservative for short spans and quite conservative for longer spans. Furthermore they compared the results of a finite element analysis with field test results and concluded that the comparison showed generally good agreement. A wide range of load distribution methods are available in the technical literature (9-17). These methods range from empirical methods, as the one recommended by AASHTO and described above, to sophisticated computer-based solution techniques which take into consideration the three-dimensional response of the bridge. The computer methods utilize a wide rang of structural idealization. Some use a simple equivalent anisotropic plate or grid work while others use sophisticated finite element models that consider detailed aspects of the interaction between the components of the bridge superstructure. The parameters which influence the load distribution most are; the number of girders and their spacing, the span length, and the girder moment of Inertia and slab thickness.

1987 ◽  
pp. 46-46
Keyword(s):  
Finite Element ◽  
Load Distribution ◽  
Slab Thickness ◽  
Good Representation ◽  
Span Length ◽  
Element Analysis ◽  
Technical Literature ◽  
Grid Model ◽  
Bridge Superstructure ◽  
The One

scholarly journals Effects of R-Phase on Mechanical Responses of a Nickel-Titanium Endodontic Instrument: Structural Characterization and Finite Element Analysis

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Leandro de Arruda Santos ◽  
Pedro Damas Resende ◽  
Maria Guiomar de Azevedo Bahia ◽  
Vicente Tadeu Lopes Buono
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Niti Alloy ◽  
Bending Moment ◽  
Geometrical Model ◽  
Scanning Calorimetry ◽  
Element Analysis ◽  
Mechanical Responses ◽  
Angular Deflection ◽  
The One

The effects of the presence of the R-phase in a near-equiatomic NiTi alloy on the mechanical responses of an endodontic instrument were studied by using finite element analysis. The input data for the constitutive model in the simulation were obtained by tensile testing of three NiTi wires: superelastic austenite NiTi, austenite + R-phase NiTi, and fully R-phased NiTi. The wires were also characterized by X-ray diffraction and differential scanning calorimetry. A commercially available endodontic instrument was scanned using microcomputed tomography, and the resulting images were used to build the geometrical model. The numerical analyses were performed in ABAQUS using load and boundary conditions based on the ISO 3630-1 specification for the bending and torsion of endodontic instruments. The modeled instrument containing only R-phase demanded the lowest moment to be bent, followed by the one with mixed austenite + R-phase. The superelastic instrument, containing essentially austenite, required the highest bending moment. During bending, the fully R-phased instrument reached the lowest stress values; however, it also experienced the highest angular deflection when subjected to torsion. In summary, this simulation showed that NiTi endodontic instruments containing only R-phase in their microstructure would show higher flexibility without compromising their performance under torsion.

Mechanical Behavior of Hollow Steel-Concrete Composite Columns with Perforated Ribs

2011 ◽  
Vol 255-260 ◽  
pp. 619-623
Author(s):  
Yao Zeng ◽  
Chong Wu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Behavior ◽  
Bearing Capacity ◽  
The Other ◽  
Element Analysis ◽  
Composite Columns ◽  
The Finite Element Analysis ◽  
The One ◽  
Relationship Of

Two different specimens of hollow composite columns with perforated ribs, one is the column with double steel skin and the other is with single steel skin, were designed for imposing axial compression test. The tests indicated that both of the columns have a good bearing capacity and the column with double steel skin has a comparatively better bearing capacity than the one with single steel skin. Then comparisons between tests and finite element analysis (FEA) were preceded, which showed that not only the load-displacement relationship of the columns, but also a reasonable failure mode can be simulated by the finite element analysis.

Bone Response From a Dynamic Stimulus on a One-Piece and Multi-Piece Implant Abutment and Crown by Finite Element Analysis

2014 ◽  
Vol 40 (5) ◽  
pp. 525-532 ◽  
Author(s):  
Habib Hajimiragha ◽  
Mohammadreza Abolbashari ◽  
Saeed Nokar ◽  
AmirHossein Abolbashari ◽  
Mehrdad Abolbashari
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Dynamic Finite Element Analysis ◽  
Bone Response ◽  
Dynamic Stimulus ◽  
The One ◽  
Von Mises ◽  
Distribution Of Stress

The present study was done to evaluate the effects of different types of abutments on the rate and distribution of stress on the bone surrounding the implant by dynamic finite element analysis method. In this study two ITI abutment models—one-piece and multi-piece—along with fixture, bone, and superstructure have been simulated with the help of company-made models. The maximum Von Mises stress (MVMS) was observed in the distobuccal area of the cortical bone near the crest of implant in two implant models. In the multi-piece abutment, MVMS was higher than the one-piece model (27.9 MPa and 23.3 MPa, respectively). Based on the results of this study, it can be concluded that type of abutment influences the stress distribution in the area surrounding the implant during dynamic loading.

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