scholarly journals Investigation on Single Tube CFST Arch Models by Modeling Structural Stressing State Based on NSF Method

2019 ◽  
Vol 9 (23) ◽  
pp. 5006 ◽  
Author(s):  
Yang ◽  
Wang ◽  
Shi ◽  
Sun ◽  
Zheng ◽  
...  
Keyword(s):  
Failure Load ◽  
Stress Fields ◽  
Accurate Estimation ◽  
Behavioral Characteristics ◽  
Arch Model ◽  
Structural Failure ◽  
Arch Models ◽  
Single Tube ◽  
Internal Forces ◽  
Strain Stress

This paper investigated the behavioral characteristics of two single tube concrete-filled steel tube (CFST) arch models under different loads. Applying the numerical shape function (NSF) method, the limited strain data of arch models were interpolated to obtain more detailed strain information at unmeasured points. By numerically modeling and characterizing the structural stressing state of arches, these interpolated strains were calculated as the normalized strain energy density (SED) sum to plot the corresponding characteristic curves. Utilizing the Mann-Kendall (M-K) criterion, the qualitative characteristic load was detected from the curve and was referred to as the failure load, updating the existing definition of structural failure. Then, from the perspective of experimental strains, strain/stress fields, and stressing state submodes of internal forces obtained based on the NSF method, the working behavioral characteristics of each respective CFST arch model under loads were embodied in detail. The mutation features were distinguished from the development trend of strain/stress fields or distribution patterns of internal forces to verify the rationality of the updated failure load. Consequently, the NSF method can have a reasonable interpolation on the limited experimental data. By modeling structural stressing state, it can conduct an accurate estimation of the structural failure load and provide a reference for the future design of arch bridges.

Research Data Analysis Using EViews

2019 ◽  
pp. 292-324
Author(s):  
Erginbay Uğurlu
Keyword(s):  
Autocorrelation Function ◽  
Academic Writing ◽  
Unit Root Test ◽  
Garch Models ◽  
Arch Model ◽  
Arch Models ◽  
Arch Effect ◽  
Lm Test ◽  
Partial Autocorrelation Function ◽  
Stock Indexes

The aim of this chapter is to provide a detailed empirical example of autoregressive conditional heteroskedasticity (ARCH) model and selected generalized ARCH models. Before the ARCH/GARCH models are estimated, several calculations and tests should be done. The mean model is determined using the autocorrelation function and partial autocorrelation function and also the unit root test. The existence of ARCH effect is tested using ARCH-LM test. After these steps are done, then ARCH/GARCH models can be estimated. All these theoretical aspects are applied to Sofia Stock Indexes (SOFIX) using EViews 9 software package. The windows and output of EViews are presented. To show the output's academic writing format researchers' outputs are presented in a table.

scholarly journals A Two-Regime Markov-Switching GARCH Active Trading Algorithm for Coffee, Cocoa, and Sugar Futures

Mathematics ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 1001 ◽  
Author(s):  
Oscar V. De la Torre-Torres ◽  
Dora Aguilasocho-Montoya ◽  
María de la Cruz del Río-Rama
Keyword(s):  
Markov Switching ◽  
Garch Models ◽  
Arch Model ◽  
Conditional Heteroscedasticity ◽  
Arch Models ◽  
Trading Decisions ◽  
Portfolio Managers ◽  
Autoregressive Conditional Heteroscedasticity ◽  
Potential Use ◽  
The U.S

In the present paper we tested the use of Markov-switching Generalized AutoRegressive Conditional Heteroscedasticity (MS-GARCH) models and their not generalized (MS-ARCH) version. This, for active trading decisions in the coffee, cocoa, and sugar future markets. With weekly data from 7 January 2000 to 3 April 2020, we simulated the performance that a futures’ trader would have had, had she used the next trading algorithm: To invest in the security if the probability of being in a distress regime is less or equal to 50% or to invest in the U.S. three-month Treasury bill otherwise. Our results suggest that the use of t-student Markov Switching Component ARCH Model (MS-ARCH) models is appropriate for active trading in the cocoa futures and the Gaussian MS-GARCH is appropriate for sugar. For the specific case of the coffee market, we did not find evidence in favor of the use of MS-GARCH models. This is so by the fact that the trading algorithm led to inaccurate trading signs. Our results are of potential use for futures’ position traders or portfolio managers who want a quantitative trading algorithm for active trading in these commodity futures.

Ionic Conductivity in Uniaxial Micro Strain/Stress Fields of Yttria-Stabilized Zirconia

2011 ◽  
Vol 50 (5R) ◽  
pp. 055803 ◽  
Author(s):  
Kazuhisa Sato ◽  
Ken Suzuki ◽  
Ryo Narumi ◽  
Keiji Yashiro ◽  
Toshiyuki Hashida ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Yttria Stabilized Zirconia ◽  
Stress Fields ◽  
Stabilized Zirconia ◽  
Strain Stress

scholarly journals Reliability-Based Ultimate Limit State Design of Micropiles in Ontario Soils

2021 ◽  
Author(s):  
Alexandre P. R. P. Almeida
Keyword(s):  
Bond Strength ◽  
Failure Load ◽  
Limit State ◽  
Accurate Estimation ◽  
Ultimate Limit State ◽  
Resistance Factors ◽  
Ground Conditions ◽  
Load Tests ◽  
Ultimate Limit State Design ◽  
Ultimate Limit

The design practice of micropiles in Ontario soils under the ultimate limit state was improved through both statistical and reliability analyses of a database of 40 micropile load tests. Micropile design is extremely dependent on engineering experience and judgement due to the lack of an accurate estimation of the bond strength. The FHWA manual of micropiles only provides wide ranges of bond strength in different ground conditions. Micropile load tests were conducted by Keller Foundations Ltd and collected for this study. From a statistical analysis, Fuller and Hoy’s method was selected as the best method to estimate the failure load from non-failed tests. Adjusted parameters were given to predict the bond strength of micropiles. A method was proposed to estimate the contributions from the cased length and the tip to the total resistance. In the end, a reliability analysis was conducted and the resistance factors were recalibrated.

scholarly journals Stressing State Analysis on a Single Tube CFST Arch Under Spatial Loads

2019 ◽  
Vol 9 (23) ◽  
pp. 5039
Author(s):  
Kangkang Yang ◽  
Jian Yuan ◽  
Jun Shi ◽  
Kaikai Zheng ◽  
Jiyang Shen
Keyword(s):  
Strain Energy Density ◽  
Strain Energy ◽  
Characteristic Curve ◽  
Arch Model ◽  
Average Strain ◽  
Bending Strain ◽  
Strain Data ◽  
Internal Forces ◽  
Arch Structures ◽  
Behavior Characteristics

This paper analyzes the stressing state characteristics of a concrete-filled steel tubular (CFST) arch model under spatial loads, using the method of modeling structural stressing state and the thin plate simulating interpolation (TSI) method. Firstly, the parameter-generalized strain energy density (GSED) is applied to model the stressing state of the arch. Then, the normalized GSED sum at each load plots the characteristic curve. The characteristic loads P (66 kN) and Q (85 kN) in the curve are distinguished by the Mann–Kendall (M–K) criterion. To characterize structural axial and bending stressing states, the parameters of the sectional average strain and generalized bending strain are proposed as stressing state submodes. Finally, the TSI method is used to interpolate strain data for deep analysis of internal forces. By modeling the structural stressing state, the working behavior characteristics of arch structures are greatly revealed in a particular view and the results could provide a reference for the development of bridge design.

scholarly journals Reliability-Based Ultimate Limit State Design of Micropiles in Ontario Soils

2021 ◽  
Author(s):  
Alexandre P. R. P. Almeida
Keyword(s):  
Bond Strength ◽  
Failure Load ◽  
Limit State ◽  
Accurate Estimation ◽  
Ultimate Limit State ◽  
Resistance Factors ◽  
Ground Conditions ◽  
Load Tests ◽  
Ultimate Limit State Design ◽  
Ultimate Limit

The design practice of micropiles in Ontario soils under the ultimate limit state was improved through both statistical and reliability analyses of a database of 40 micropile load tests. Micropile design is extremely dependent on engineering experience and judgement due to the lack of an accurate estimation of the bond strength. The FHWA manual of micropiles only provides wide ranges of bond strength in different ground conditions. Micropile load tests were conducted by Keller Foundations Ltd and collected for this study. From a statistical analysis, Fuller and Hoy’s method was selected as the best method to estimate the failure load from non-failed tests. Adjusted parameters were given to predict the bond strength of micropiles. A method was proposed to estimate the contributions from the cased length and the tip to the total resistance. In the end, a reliability analysis was conducted and the resistance factors were recalibrated.

Time Series Analysis Using ARCH Models: A Case Analysis of Australian Stock Index

2017 ◽  
Vol 3 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Prabhat Mittal
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Stochastic Processes ◽  
Stock Price ◽  
Stock Exchange ◽  
Case Analysis ◽  
Stock Index ◽  
Arch Model ◽  
Arch Models ◽  
New Class

Australian All Ordinaries Stock Index has been in the headline since 1997 for its tear jerking effect on the stock exchange. Present work attempts to develop a realistic time-series model to explain the behavior of the stock price data during 2 January 1997 to 29 December 2006 collected from www.yahoofinance.com. To begin with residual analysis reveals that assumption of constant one period ahead forecast variance does not hold true. Accordingly, a new class of stochastic processes, called Autoregressive Conditional Heteroscedastic (ARCH) is studied. To this end, Computer programs on Ms-Excel have been used to fit the ARCH model.

scholarly journals Mechanical Behavior of Tunnel Lining with Cracks at Different Positions

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 194 ◽  
Author(s):  
Jie Su ◽  
Yinming Jie ◽  
Xiaokai Niu ◽  
Chang Liu ◽  
Xuan Liu
Keyword(s):  
Carrying Capacity ◽  
Three Dimensional ◽  
Side Wall ◽  
Internal Force ◽  
Structural Failure ◽  
Three Dimensional Model ◽  
Lining Structure ◽  
Internal Forces ◽  
Stress And Deformation ◽  
Longitudinal Cracks

Cracks in the lining significantly reduce the safety of a tunnel during operation. It is urgent to figure out the influence of cracks on tunnel carrying capacity. In this paper, three-dimensional model tests were conducted to investigate deformation, internal force, and deterioration laws of the lining with prefabricated cracks at different positions. The main conclusions were obtained as follows: (1) The carrying capacity of the lining structure with prefabricated cracks was reduced, and the deformation of the lining structure increased. The penetration of the vault crown crack accelerated the damage of the lining structure, and structural failure occurred when the crack went through at the left arch spring. (2) The internal force of the lining was greatly affected by the positions of prefabricated cracks. The internal forces of the lining structure decreased with the existence of prefabricated cracks. Whether or not there were prefabricated cracks, tension cracks appeared in the inside fiber of the vault and inverted arch. (3) The deformation of the lining structure with the existence of prefabricated cracks increased. When the prefabricated crack was located at the vault, the deformation was the largest, followed by the arch spring, side wall, and arch shoulder. (4) The analysis shows that prefabricated cracks at the vault are the most damaging under stress and deformation of the lining structure, so longitudinal cracks at the vault should be strengthened.

scholarly journals Shear Bands Topology in the Deformed Bulk Metallic Glasses

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 374 ◽  
Author(s):  
Mikhail Seleznev ◽  
Alexei Vinogradov
Keyword(s):  
Shear Bands ◽  
Experimental Studies ◽  
Stress Fields ◽  
Propagation Path ◽  
Mode Iii ◽  
Out Of Plane ◽  
Dislocation Type ◽  
External Stresses ◽  
Strain Stress ◽  
Linear Propagation

Recent experimental studies revealed the presence of Volterra dislocation-type long-range elastic strain/stress field around a shear band (SB) terminated in a bulk metallic glass (BMG). The corollary from this finding is that shear bands can interact with these stress fields. In other words, the mutual behaviour of SBs should be affected by their stress fields superimposed with the external stresses. In order to verify this suggestion, the topography of the regions surrounding SBs terminated in the BMGs was carefully analysed. The surfaces of several BMGs, deformed by compression and indentation, were investigated with a high spatial resolution by means of scanning white-light interferometry (SWLI). Along with the evidence for the interaction between SBs, different scenarios of the SB propagation have been observed. Specifically, the SB path deviation, mutual blocking, and deflection of SBs were revealed along with the significant differences between the topologies of the mode II (in-plane) and mode III (out of plane) SBs. While the type II shear manifests a linear propagation path and a monotonically increasing shear offset, the type III shear is associated with a curved, segmented path and a non-monotonically varying shear offset. The systematic application of the “classic” elastic Volterra’s theory of dislocations to the behaviour of SBs in BMGs provides new insight into the widely reported experimental phenomena concerning the SB morphology, which is further detailed in the present work.

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