scholarly journals Seismic Analysis of AP1000 Nuclear Island Structure by Using the Finite Element Software ANSYS

2017 ◽  
Vol 20 (K2) ◽  
pp. 14-23
Author(s):  
Kien Dinh Nguyen ◽  
Dong Lam Vu
Keyword(s):  
Finite Element ◽  
Seismic Analysis ◽  
Element Model ◽  
Relative Displacement ◽  
Maximum Displacement ◽  
Acceleration Time ◽  
Island Structure ◽  
Finite Element Software ◽  
Acceleration Time Histories ◽  
Time Histories

Seismic analysis of AP1000 nuclear island structure by using the commercial finite element software ANSYS is presented. Using the ANSYS Workbench, a sophisticated threedimensional finite element model of the structure is created and employed in the analysis. Dynamic response of the structure to both the one-directional and three-directional acceleration time histories are considered in the analysis. The time histories for the relative displacement, velocity and absolute acceleration of the structure are obtained for various earthquakes, including American El Centro, Japanese Kobe and Vietnamese Dien Bien earthquakes. The numerical results show that the dynamic characteristics obtained by using one-directional and thee-directional acceleration time histories are different, and the three three-directional acceleration time histories should be employed in the seismic analysis. The result also reveals that the nuclear island is safer in Dien Bien earthquake that it is in El Centro and Kobe earthquakes. The distribution of the von Mises stresses of the structure according to the maximum displacement at the top point is also examined and highlighted.

Validation of FMVSS201 Featureless Headform Finite Element Model for Rotational Acceleration

2001 ◽  
Author(s):  
Saeed D. Barbat
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Fe Model ◽  
Rotational Acceleration ◽  
Acceleration Time ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Drop Tests ◽  
Constitutive Parameters

Abstract This paper demonstrates an application of the nine linear accelerometer scheme, proposed by (Padgaonkar et al., 1975), to the development and validation of a finite element model of a deformable featureless headform for rotational accelerations. Steps and procedures involved in the development and calibration of the model are also described. A set of tri-axial accelerometers was mounted at the headform center of gravity, C.G., which is located at the origin of the local coordinate axes of the headform. Three bi-axial accelerometers were also mounted at the front, left, and top of the headform’s aluminum skull and on the local coordinate axes of the physical headform. Nine linear accelerations were measured at the headform in drop tests against a rigid plate at impact speeds of 2.68, 4.0, 5.36, and 6.71 m/s (6, 9, 12, and 15 mph). The rotational accelerations of the headform were then calculated from the nine linear acceleration measurements. In the finite element (FE) model of the featureless deformable headform, a visco-elastic material law, available in the non-linear dynamic explicit code PAM-CRASH, was used to simulate the vinyl skin response during impact. The constitutive parameters of the headform’s skin material were calibrated through comparison of the headform drop simulations at various impact speeds with the corresponding tests. Headform responses, such as, resultant acceleration time histories at the headform C.G. and the rotational acceleration time histories obtained from the FE predictions of the headform responses during the drop tests simulations correlated very well with those obtained from experiments. Validation of the headform model for rotational accelerations provided higher level of confidence in the prediction capability of the model when used for interior head impact simulations with vehicle upper interior as specified by the Federal Motor Vehicle Safety Standard FMVSS 201.

scholarly journals Dynamic behaviour of nuclear island structure of AP1000 under El Centro and Dien Bien earthquakes

2021 ◽  
Vol 7 (4) ◽  
pp. 34-41
Author(s):  
Lam Dong Vu Lam ◽  
Ngoc Dong Pham ◽  
Dinh Kien Nguyen ◽  
Dai Minh Nguyen ◽  
Tien Thinh Do
Keyword(s):  
Finite Element ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Nuclear Power ◽  
Seismic Analysis ◽  
Element Model ◽  
Island Structure ◽  
Finite Element Software

AP1000 is a nuclear power plant developed by Westinghouse based on an advanced passive safety feature, and it is one of selected technologies for Ninh Thuan 2 Nuclear Power Plant. The dynamic behavior of the plant under earthquakes is the most concerned in design and construction of the plant. This paper presents a seismic analysis of the AP1000 nuclear island structure by using the computational finite element software ANSYS. A 3D finite element model for the structure is developed and its dynamic response, including the time histories for displacements, velocities andaccelerations, deformed configurations and von Mises stresses of the structure are obtained for America El Centro (6.9 Richter) and Vietnam Dien Bien (5.3 Richter) earthquakes. A comparison on the dynamic response of the structure under the two earthquakes is given, and the dynamic behavior of the structure under the earthquakes is discussed.

Three-Dimensional Seismic Analysis on Reactor Structure

2010 ◽  
Author(s):  
Naibin Jiang ◽  
Feng-gang Zang ◽  
Li-min Zhang ◽  
Chuan-yong Zhang
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Earthquake Excitation ◽  
Finite Element Software ◽  
Reactor Structure ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The seismic analysis on reactor structure was performed with a new generation of finite element software. The amount of freedom degree of the model was more than twenty millions. The typical responses to operational basis earthquake excitation were given. They are larger than those with two-dimensional simplified finite element method, and the reasons of this phenomenon were analyzed. The feasibility of seismic analysis on large-scale three-dimensional finite element model under existing hardware condition was demonstrated, so some technological reserves for dynamic analysis on complicated equipments or systems in nuclear engineering are provided.

Development of Target Power Spectral Density Functions Compatible With Design Response Spectra

2015 ◽  
Author(s):  
Jinsuo R. Nie ◽  
Jim Xu ◽  
Joseph I. Braverman
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Seismic Analysis ◽  
General Procedure ◽  
Response Spectra ◽  
Acceleration Time ◽  
Power Spectral ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Spectral Shapes

For seismic analysis of nuclear structures, synthetic acceleration time histories are often required and are generated to envelop design response spectra following the U.S. Nuclear Regulatory Commission, Standard Review Plan (SRP) Section 3.7.1. It has been recognized that without an additional check of the power spectral density (PSD) functions, spectral matching alone may not ensure that synthetic acceleration time histories have adequate power over the frequency range of interest. The SRP Section 3.7.1 Appendix A provides a target PSD function for the Regulatory Guide 1.60 horizontal spectral shape. For other spectral shapes, additional guidance on developing the target PSD functions compatible with the design spectra is desired. This paper presents a general procedure for the development of target PSD functions for any practical design response spectral shapes, which has been incorporated into the recent SRP 3.7.1, Revision 4.

Displacement and Vibration Behavior of Reinforced Concrete Cantilever

2013 ◽  
Vol 848 ◽  
pp. 100-103
Author(s):  
Xin Yan Wu ◽  
An Ping Lou
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Vibration Frequency ◽  
Element Model ◽  
Reinforced Concrete Structure ◽  
Maximum Displacement ◽  
Analysis And Design ◽  
First Order ◽  
Finite Element Software ◽  
Cantilever Length

In this paper, finite element model (FEM) of a reinforced concrete structure cantilevered slab was established in non-linear finite element software ABAQUS. Influence of cantilever length and tensile reinforcement on the structural displacement and vibration frequency was calculated. The results show that the vibration frequency of the first order and maximum displacement will various with the diameter of the reinforced cantilever slab and the length of the cantilevered slab. This paper will offer the references to the analysis and design of the cantilever slab.

scholarly journals Seismic Assessment of Footbridges under Spatial Variation of Earthquake Ground Motion (SVEGM): Experimental Testing and Finite Element Analyses

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1227 ◽  
Author(s):  
Izabela Joanna Drygala ◽  
Joanna Maria Dulinska ◽  
Maria Anna Polak
Keyword(s):  
Finite Element ◽  
Spectral Density ◽  
Earthquake Ground Motion ◽  
Density Functions ◽  
Acceleration Time ◽  
Kinematic Excitation ◽  
Acceleration Time Histories ◽  
Dynamic Analyses ◽  
Time Histories ◽  
Spectral Density Functions

In this paper, the seismic assessments of two footbridges, i.e., a single-span steel frame footbridge and a three-span cable-stayed structure, to the spatial variation of earthquake ground motion (SVEGM) are presented. A model of nonuniform kinematic excitation was used for the dynamic analyses of the footbridges. The influence of SVEGM on the dynamic performance of structures was assessed on both experimental and numerical ways. The comprehensive tests were planned and carried out on both structures. The investigation was divided into two parts: in situ experiment and numerical analyses. The first experimental part served for the validation of both the finite element (FE) modal models of structures and the theoretical model of nonuniform excitation as well as the appropriateness of the FE procedures used for dynamic analyses. First, the modal properties were validated. The differences between the numerical and the experimental natural frequencies, obtained using the operational modal analysis, were less than 10%. The comparison of the experimental and numerical mode shapes also proved a good agreement since the modal assurance criterion values were satisfactory for both structures. Secondly, nonuniform kinematic excitation was experimentally imposed using vibroseis tests. The apparent wave velocities, evaluated from the cross-correlation functions of the acceleration-time histories registered at two consecutive structures supports, equaled 203 and 214 m/s for both structures, respectively. Also, the coherence functions proved the similarity of the signals, especially for the frequency range 5 to 15 Hz. Then, artificial kinematic excitation was generated on the basis of the adopted model of nonuniform excitation. The obtained power spectral density functions of acceleration-time histories registered at all supports as well as the cross-spectral density functions between registered and artificial acceleration-time histories confirmed the strong similarity of the measured and artificial signals. Finally, the experimental and numerical assessments of the footbridges performance under the known dynamic excitation generated by the vibroseis were carried out. The FE models and procedures were positively validated by linking full-scale tests and numerical calculations. In the numerical part of the research, seismic analyses of the footbridges were conducted. The dynamic responses of structures to a representative seismic shock were calculated. Both the uniform and nonuniform models of excitation were applied to demonstrate and quantify the influence of SVEGM on the seismic assessment of footbridges. It occurred that SVEGM may generate non-conservative results in comparison with classic uniform seismic excitation. For the stiff steel frame footbridge the maximum dynamic response was obtained for the model of nonuniform excitation with the lowest wave velocity. Especially zones located closely to stiff frame nodes were significantly more disturbed. For the flexible cable-stayed footbridge, in case of nonuniform excitation, the dynamic response was enhanced only at the points located in the extreme spans and in the midspan closely to the pillars.

Finite Element Analysis of the ESTELA M1 Airplane Firewall (Representative Specimen)

2011 ◽  
Author(s):  
V. Ramirez-Elias ◽  
E. Ledesma-Orozco ◽  
H. Hernandez-Moreno
Keyword(s):  
Finite Element ◽  
Federal Aviation Administration ◽  
Element Model ◽  
Maximum Load ◽  
Load Factor ◽  
Representative Specimen ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper shows the finite element simulation of a representative specimen from the firewall section in the AEROMARMI ESTELA M1 aircraft. This specimen is manufactured in glass and carbon / epoxy laminates. The specimen is subjected to a load which direction and magnitude are determined by a previous dynamic loads study [10], taking into account the maximum load factor allowed by the FAA (Federal Aviation Administration) for utilitarian aircrafts [11]. A representative specimen is manufactured with the same features of the firewall. Meanwhile a fix is built in order to introduce the load directions on the representative specimen. The relationship between load and displacement is plotted for this representative specimen, whence the maximum displacement at the specific load is obtained, afterwards it is compared with the finite element model, which is modified in its laminate thicknesses in order to decrease the deviation error; subsequently this features could be applied to perform the whole firewall analysis in a future model [10].

Metrics for the Comparison of Acceleration Time Histories

2017 ◽  
Author(s):  
Nithyagopal Goswami ◽  
Mourad Zeghal ◽  
Majid Manzari ◽  
Bruce Kutter
Keyword(s):  
Acceleration Time ◽  
Acceleration Time Histories ◽  
Time Histories

A pragmatic approach for the evaluation of depth-sensing indentation in the self-similar regime

2021 ◽  
pp. 1-24
Author(s):  
Hamidreza Mahdavi ◽  
Konstantinos Poulios ◽  
Christian F. Niordson
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Depth Sensing ◽  
Finite Element Software ◽  
Element Simulation ◽  
Unique Material ◽  
Reverse Analysis ◽  
Supplementary Material ◽  
Two Parameters ◽  
Force Displacement

Abstract This work evaluates and revisits elements from the depth-sensing indentation literature by means of carefully chosen practical indentation cases, simulated numerically and compared to experiments. The aim is to close a series of debated subjects, which constitute major sources of inaccuracies in the evaluation of depth-sensing indentation data in practice. Firstly, own examples and references from the literature are presented in order to demonstrate how crucial self-similarity detection and blunting distance compensation are, for establishing a rigorous link between experiments and simple sharp-indenter models. Moreover, it is demonstrated, once again, in terms of clear and practical examples, that no more than two parameters are necessary to achieve an excellent match between a sharp indenter finite element simulation and experimental force-displacement data. The clear conclusion is that reverse analysis methods promising to deliver a set of three unique material parameters from depth-sensing indentation cannot be reliable. Lastly, in light of the broad availability of modern finite element software, we also suggest to avoid the rigid indenter approximation, as it is shown to lead to unnecessary inaccuracies. All conclusions from the critical literature review performed lead to a new semi-analytical reverse analysis method, based on available dimensionless functions from the literature and a calibration against case specific finite element simulations. Implementations of the finite element model employed are released as supplementary material, for two major finite element software packages.

Calculating Mechanics Characteristics of Single-Walled Carbon Nanotube Materials by Finite Element Method

2017 ◽  
Vol 730 ◽  
pp. 548-553
Author(s):  
Jing Ge ◽  
Hao Jiang ◽  
Zhen Yu Sun ◽  
Guo Jun Yu ◽  
Bo Su ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Radial Direction ◽  
Element Model ◽  
Beam Element ◽  
Beam Position ◽  
Single Walled Carbon ◽  
Finite Element Software ◽  
Calculation Results ◽  
The Moment

In this paper, we establish the mechanical property analysis of Single-walled Carbon Nanotubes (SWCNTs) modified beam element model based on the molecular structural mechanics method. Then we study the mechanical properties of their radial direction characteristics using the finite element software Abaqus. The model simulated the different bending stiffness with rectangular section beam elements C-C chemical force field. When the graphene curled into arbitrary chirality of SWCNTs spatial structure, the adjacent beam position will change the moment of inertia of the section of the beam. Compared with the original beam element model and the calculation results, we found that the established model largely reduced the overestimate of the original model of mechanical properties on the radial direction of the SWCNTs. At the same time, compared with other methods available in the literature results and the experimental data, the results can be in good agreement.

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