scholarly journals Influence of Disc Specimen Configuration on Its Three-Dimensional Dynamic Stress Balance

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Sheng Zhang ◽  
Bingxin Yu ◽  
Xiaojun Li ◽  
Longfei Wang ◽  
Xulong Zhang
Keyword(s):  
Dynamic Stress ◽  
Three Dimensional ◽  
Time History ◽  
Brazilian Disc ◽  
Disc Specimen ◽  
Loading Mode ◽  
Dimensional Finite Element ◽  
History Of ◽  
Three Dimensional Finite Element ◽  
Semicircular Bending

In order to investigate the dynamic stress balance of different configurations of rock specimens, three-dimensional finite element models of SHPB were established. Five types of configuration disc specimens with a diameter of 75 mm and a thickness of 30 mm were impacted at a speed of 5 m/s using a special-shaped bullet. The propagation laws of stress wave on the contact surface of the specimen-bar and the inside of the specimen were analyzed, and the time history of the stress balance factors at different positions of the specimen was obtained. The results show that the amplitudes of the transmitted waves corresponding to the five types of disc specimens with different configurations have obvious differences, and the stress propagation in the specimen has three-dimensional characteristics. According to the ease of achieving stress balance, the five configuration specimens are ordered by notched semicircular bending disc, flattened Brazilian disc, cracked straight-through flattened Brazilian disc, Brazilian disc, and cracked straight-through Brazilian disc specimen. Among them, only the first three configurations of the specimen reached the stress balance. The dynamic stress balance is affected by the disc loading mode, end contact conditions, the presence of prefabricated cracks, and disc thickness. In addition, as the disc loading end is a processed platform, it is beneficial to achieve stress balance. Prefabricated cracks are not conducive to achieving stress balance. The loading method of the notched semicircular bending disc is more conducive to achieving stress balance. This research has a certain guiding significance for selecting suitable specimen configuration and research methods to carry out rock dynamic fracture experiments.

Static and vibration characteristics of thin-walled box beams: An experimental investigation

2017 ◽  
Vol 20 (10) ◽  
pp. 1540-1559 ◽  
Author(s):  
Kiana Kashefi ◽  
Abdul Hamid Sheikh ◽  
Michael C Griffith ◽  
MS Mohamed Ali ◽  
Kazuo Tateishi
Keyword(s):  
Three Dimensional ◽  
Time History ◽  
Displacement Transducer ◽  
Vibration Characteristics ◽  
Element Analysis ◽  
Linear Variable Displacement Transducer ◽  
Dimensional Finite Element ◽  
Box Beams ◽  
Thin Walled ◽  
Three Dimensional Finite Element

Static and vibration characteristics of thin-walled straight and curved box beams were investigated experimentally. Three different beam configurations were considered for the tests: one straight and two curved box beams. The load was applied at the centroid of the box section for the straight and one curved beam specimens. However, for the other curved specimen, the load was applied eccentrically to investigate its behavior under the additional torsion induced by the eccentricity. Displacements and strains were obtained using linear variable displacement transducer, one-directional and rosette strain gages. The specimens were excited using an impact at their free ends. The time history of strains was obtained to calculate natural frequencies and damping ratios. The experiment results were compared with those obtained from three-dimensional finite element analysis for all cases. The results obtained from implementing tests on the straight specimen were also used to validate an efficient numerical method recently developed by the authors.

Fire Durations of Concern for a Modern Legal Weight Truck Cask

2006 ◽  
Author(s):  
Neelima Mallidi ◽  
Miles Greiner ◽  
Venkata V. R. Venigalla
Keyword(s):  
Thermal Protection ◽  
Three Dimensional ◽  
Time History ◽  
Element Analysis ◽  
Pressurized Water ◽  
Dimensional Finite Element ◽  
Term Creep ◽  
Three Dimensional Finite Element ◽  
The Impact ◽  
Containment Integrity

The response of a truck package designed to transport four pressurized water reactor fuel assemblies to a simplified radiation fire model is simulated for a range of fire durations using three-dimensional finite element analysis. A model is developed to determine the cumulative seal degradation from its temperature versus time history. This model is used to determine the minimum fire duration that causes the seal to lose containment integrity. The fire durations that cause the maximum cladding temperature to reach its long term creep deformation and burst rupture temperatures are determined and found to be longer than the duration that cause the seal to lose containment integrity. These simulations are repeated for package models without the compliant regions of the impact limiters, and for a package with the impact limiter completely removed. These simulations quantify the level of thermal protection the impact limiters provide to the seals and cladding during simulated fires.

On Predicting Softening Effects in Hard Turned Surfaces—Part II: Finite Element Modeling and Verification

2004 ◽  
Vol 127 (3) ◽  
pp. 484-491 ◽  
Author(s):  
Jing Shi ◽  
C. Richard Liu
Keyword(s):  
Finite Element ◽  
Thermal History ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Hardness Measurement ◽  
Fe Model ◽  
Dimensional Finite Element ◽  
History Of ◽  
Three Dimensional Finite Element

A material softening model based on thermal activation energy has been successfully established through tempering experiments in the first part of this study. To apply the model to predicting material softening in hard turned surfaces, the thermal history of work material is needed. In this part, a three-dimensional finite element (FE) model of machining hardened 52100 steel is constructed, and coupled thermal-stress analysis is performed to obtain the material thermal history. Then the material softening model uses the computed thermal history as input to predict the material hardness profiles along the depth into the machined surfaces. Overall, the prediction precisely catches the trend of hardness change along depth and agrees reasonably well with the hardness measurement. What’s more, the sensitivity of material softening to cutting parameters is investigated both quantitatively and qualitatively. Within the investigation range, it is observed that the increase of tool flank wear and feed rate produces severe material softening and a deeper softened layer, while the increase of cutting speed causes significant softening to the surface material but hardly changes the softened depth.

Seismic Response Analysis on Two-Tower Isolated Structure with Enlarged Base

2012 ◽  
Vol 193-194 ◽  
pp. 753-756
Author(s):  
Ying Bo Pang
Keyword(s):  
Base Isolation ◽  
Three Dimensional ◽  
Time History ◽  
Response Analysis ◽  
Analysis Model ◽  
Seismic Shear ◽  
Tower Structure ◽  
Story Drift ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this paper, the three-dimensional finite element method has been adopted to respectively establish the base isolation of the two-tower structure with enlarged base and the story-isolated vibration analysis model. Each model has been conducted the elastic-plastic time-history analysis under the horizontal earthquakes. The results show that the dynamic characteristics of the structure have been significantly changed through the arrangement of isolation layer; the seismic responses, such as the story drift, the seismic shear and the acceleration of the structure, have been also greatly affected and the damping effect of the structure is obvious.

Post-construction settlement estimation and increased earthwork volumes calculation of high loess fill

2016 ◽  
Vol 3 (1) ◽  
pp. 43-55
Author(s):  
Cai-Hui Zhu
Keyword(s):  
Empirical Equation ◽  
Three Dimensional ◽  
Influence Factors ◽  
In Situ Tests ◽  
Construction Time ◽  
Dimensional Finite Element ◽  
History Of ◽  
Three Dimensional Finite Element ◽  
Airport Runway ◽  
Fill Depth

In this study, the post-construction settlement (PCS) area distribution of high fill was analyzed based with reference to a case history of an airport runway crossing a deep gully reclaimed by a thick fill of loess. Earthwork volumes (EV) attributed to PCS was calculated based on in-situ tests. Results showed that the uneven PCS were related to fill depth, construction time, fill rate, integrated compaction degree, and boundary conditions. An empirical equation that considers the aforementioned influence factors was established to calculate the final PCS of high fill. The surface PCS of high fill and the EV can be estimated according to the proposed empirical equation and the original site topography using the three-dimensional finite element method.

Modal Analysis and Seismic Response Evaluation on Structures of Advanced PWR

2013 ◽  
Vol 838-841 ◽  
pp. 1471-1475
Author(s):  
Guo Liang Zhou ◽  
Hui Tang
Keyword(s):  
Modal Analysis ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Structural Dynamic ◽  
Dimensional Finite Element ◽  
Nuclear Structures ◽  
Three Dimensional Finite Element ◽  
New Generation

To evaluate the earthquake resistant behavior of the nuclear island buildings of new generation PWR, in this study we formed the three dimensional finite element model of nuclear island structures ,which incluse shield building, the auxiliary building, the containment vessel, and the containment internal structures. Modal analysis was performed to to reveal the structural dynamic characteristics.And with the auumption of hard bedrock support media ,the dynamic response nanalysis of the nuclear structures under earthquake was conducted,respectively with response spectrum method and time history method.It shows that the seimic response of the strucures conform with the design level.Under the input excitations of SSE(safe shutdown earthquake) level, the iner forces and deforamtions can be well controlled in linear elasticity.

Dynamic Time History Analysis on Groundwater Hydraulic Tunnel under Three Dimensional Viscoelastic Boundary Conditions

2013 ◽  
Vol 302 ◽  
pp. 622-627
Author(s):  
Ji Yao ◽  
Liang Cao ◽  
Hui Min Wang ◽  
Li Jie Zhang ◽  
Liang Wu ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Seismic Response ◽  
Seismic Waves ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Rigid Boundary ◽  
Dimensional Finite Element ◽  
Dynamic Time ◽  
Three Dimensional Finite Element

The three dimensional finite element model of a groundwater hydraulic tunnel was eatablished in this paper by FEM software ANSYS, two seismic waves of bedrock wave and EI-centro wave in similar sites were entered, and dynamic time history method was applied to compare the seismic response of the two hydraulic tunnels which were under rigid boundary conditions and viscoelastic boundary conditions respectively. The results showed that, the dynamic response of the model under rigid boundary conditions was larger than the response under viscoelastic boundary, and the viscoelastic boundary was closer to the actual situation. Under viscoelastic boundary conditions, the smaller depth of the hydraulic tunnel, the more intensive of the seismic response.

The Analysis of Dynamic Characteristics for the Powerhouse Structure of the Riverbed-Hydroelectric Station

2012 ◽  
Vol 226-228 ◽  
pp. 1285-1288
Author(s):  
Xuan Mao Peng ◽  
Zheng Xiang Song ◽  
Lin Jiang
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Dynamic Stress ◽  
Three Dimensional ◽  
Hydroelectric Station ◽  
Element Model ◽  
Calculation Model ◽  
Dimensional Finite Element ◽  
Hanjiang River ◽  
Three Dimensional Finite Element

The paper creates a three-dimensional finite element model with the Xihe Project on the Hanjiang River as a background. The space integrated finite element method is applied to analyze the dynamic characteristics of the spatial structure of the riverbed-hydroelectric station. The aim is to calculate and analyze the free vibration characteristics of the whole structure, the dynamic displacement and the dynamic stress under the two typical conditions. The calculation model is effective to consider the interaction of the upstream dam section, the main and auxiliary powerhouse and the downstream water retaining structure, as well as the foundation. The results obtained will be a valuable reference for optimizing the dynamic characteristics of the powerhouse structure of riverbed-hydroelectric station and improving the engineering design.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

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.

Sign in / Sign up

Export Citation Format

Share Document