Experimental and Numerical Study on Torsional Behavior of Precast Concrete Screw Pile Body

2012 ◽  
Vol 188 ◽  
pp. 137-143
Author(s):  
Xin Li ◽  
Li Liang
Keyword(s):  
Numerical Study ◽  
Precast Concrete ◽  
Unit Length ◽  
Numerical Test ◽  
Element Model ◽  
Concrete Cover ◽  
Design Parameters ◽  
Screw Pile ◽  
Concrete Pile ◽  
Torsional Behavior

Precast concrete screw pile is a new kind of pile foundation. Because the pile bears very large torsion in construction, the torsional properties of pile body including cracking torsion, ultimate torsion and torsional deformation were studied in this paper in order to improve the anti-torsional ability of precast concrete screw pile. Experimental method and numerical method are used to research the torsional behavior of precast concrete pile body. Experimental and numerical results of cracking torsion, ultimate torsion and relationship between torsion and angle of twist per unit length of different specimens are obtained. In addition, five factors of strength level of concrete, degree of prestress, distance of spiral hoop, concrete cover and diameter of spiral hoop influencing on torsional behavior of precast concrete pile body are researched by orthogonal numerical test. The rational finite element model and solution method are concluded for calculating the torsional behavior of concrete pile. Moreover, the rational pile type and design parameters of precast concrete screw pile are obtained.

scholarly journals Research on character of screw pile group composite foundation used in high-speed railway

2019 ◽  
Vol 265 ◽  
pp. 05010
Author(s):  
Maocai Zhao ◽  
Lu Zhang
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Pile Group ◽  
Element Model ◽  
Composite Foundation ◽  
Design Parameters ◽  
High Speed Railway ◽  
Screw Pile ◽  
Side Resistance ◽  
Pile Length

As a result of rapid development of a high-speed railway and infrastructure in China in recent years, the subgrade deformation and settlement control standards put forward more stringent requirements. Based on ABAQUS 6.14, established finite element model of screw pile group composite foundation. Then obtained the settlement, axial force distribution and pile side resistance distribution of center pile of pile group. Next design parameters sensitive analysis was made, such as pile length, pile spacing and so on, in order to obtain a reasonable design pile parameters by analysis of mechanical behavior.

Effect of Tumor Variables and Sensor Design on the Measured Stiffness Distribution of Tumor-Embedded Tissues: A Numerical Study

2016 ◽  
Author(s):  
Yichao Yang ◽  
Zhili Hao
Keyword(s):  
Indentation Depth ◽  
Numerical Study ◽  
Tactile Sensor ◽  
Element Model ◽  
Design Parameters ◽  
Sensor Design ◽  
Tissue Stiffness ◽  
Tumor Identification ◽  
Tissue Region ◽  
Stiffness Distribution

This paper reports on a numerical study on how the measured stiffness distribution of a tumor-embedded tissue via a two-dimensional (2D) tactile sensor varies with the tumor variables (i.e., elasticity, size and depth) and the sensor design parameters. The sensor entails a polydimethylsiloxane (PDMS) microstructure embedded with a 3×3 sensing-plate/transducer array sitting on a Pyrex substrate. Pressing the sensor against a tissue region with a pre-defined indentation depth pattern, the tissue stiffness distribution is extracted from the measured slopes of the deflections of the 3×3 sensing-plate array versus the indentation depth. A finite element model (FEM) of the tissue-sensor interaction, which includes the Pyrex substrate, the microstructure, and a tumor-embedded tissue, is created using COMSOL Multiphysics. The tumor variables and the sensor design parameters are varied in the model to examine how the measured tissue stiffness distribution is affected by them. Based on the numerical results, the relation of the measured tissue stiffness distribution to the tumor variables and sensor design parameters is obtained, shedding insight on establishing a threshold on the stiffness contrast for tumor identification.

scholarly journals Influence of Temperature on the Longitudinal Cracking in Multipurpose Precast Concrete Sleepers Prior to Their Installation

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2731
Author(s):  
Jesús Donaire-Ávila ◽  
Antonio Montañés-López ◽  
Fernando Suárez
Keyword(s):  
Precast Concrete ◽  
Crack Opening ◽  
Longitudinal Crack ◽  
Element Model ◽  
Design Parameters ◽  
Thermal Variation ◽  
Concrete Aggregates ◽  
Longitudinal Cracking ◽  
Non Linear ◽  
Influence Of Temperature On

Prestressed monoblock railway sleepers are concrete elements with almost no reinforcement apart from the prestressing wires, which makes them very sensitive to any stress variation that can induce tensile stresses. In recent years, severe longitudinal cracking has been observed in a number of sleepers in hot regions of Spain, even before these elements were put in service. This work studies the problem while considering the thermal variation as the main factor affecting this cracking phenomenon. A non-linear static load-step analysis is applied on a non-linear finite element model to reproduce the problem and, after its experimental validation, the influence of three design parameters of the sleepers are studied: the nature of concrete aggregates, the dowel thickness, and the dowel material. The results show that all these three parameters may have significant influence on the problem, with the dowel material being the most important parameter. When the dowels are made of a material with a high elastic modulus and a high thermal expansion coefficient, the crack opening induced by a realistic thermal variation can reach significant values and result in longitudinal crack propagation. The changes of humidity are not considered in this study because they are beyond the scope of this work.

NUMERICAL STUDY ON DEFORMATION CHARACTERISTICS OF FIBRE REINFORCED LOAD TRANSFER PLATFORM AND COLUMNS SUPPORTED EMBANKMENTS

2020 ◽  
Author(s):  
Cong Dang ◽  
Liet Dang ◽  
Hadi Khabbaz ◽  
Daichao Sheng
Keyword(s):  
Shear Strength ◽  
Load Transfer ◽  
Numerical Study ◽  
Deformation Modulus ◽  
Element Model ◽  
Strength Properties ◽  
Design Parameters ◽  
Published Data ◽  
Ground Modification ◽  
Modification Technique

In this investigation, a ground modification technique utilising fibre-reinforced-load-transfer-platform (FRLTP) and column-supported (CS) embankment constructed on multilayered soft soils is proposed and investigated. After validating the proposed model with published data in the literature, numerical analysis was firstly conducted on the two-dimensional finite element model of a CS embankment without or with FRLTP to examine the influence of the FRLTP inclusion into the CS embankment system. Secondly, an extensive parametric study was performed to further investigate the effects of the FRLTP essential parameters including platform thickness, shear strength and tensile strength properties, and deformation modulus on the embankment performance during the construction and post-construction stages. Additionally, the influence of the embankment design parameters such as column spacing, column length and diameter was also examined. The numerical results reveal that the FRLTP inclusion can be effective in enhancing the CS embankment behaviour. It is also found that when increasing the platform thickness, the shear strength properties of FRLTP plays a significant role in improving the overall performance of a column-embankment with FRLTP.

scholarly journals Numerical Study and Optimization of a Novel Piezoelectric Transducer for a Round-Window Stimulating Type Middle-Ear Implant

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 40 ◽  
Author(s):  
Houguang Liu ◽  
Hehe Wang ◽  
Zhushi Rao ◽  
Jianhua Yang ◽  
Shanguo Yang
Keyword(s):  
Middle Ear ◽  
Piezoelectric Transducer ◽  
Numerical Study ◽  
Round Window ◽  
Low Frequency ◽  
Element Model ◽  
Design Parameters ◽  
Middle Ear Implant ◽  
Middle Ear Implants ◽  
Human Ear

Round window (RW) stimulation is a new application of middle ear implants for treating hearing loss, especially for those with middle ear disease. However, most reports on it are based on the use of the floating mass transducer (FMT), which was not originally designed for round window stimulation. The mismatch of the FMT’s diameter and the round window membrane’s diameter and the uncontrollable preload of the transducer, leads to a high variability in its clinical outcomes. Accordingly, a new piezoelectric transducer for the round-window-stimulating-type middle ear implant is proposed in this paper. The transducer consists of a piezoelectric stack, a flextensional amplifier, a coupling rod, a salver, a plate, a titanium housing and a supporting spring. Based on a constructed coupling finite element model of the human ear and the transducer, the influences of the transducer design parameters on its performance were analyzed. The optimal structure of the supporting spring, which determines the transducer’s resonance frequency, was ascertained. The results demonstrate that our designed transducer generates better output than the FMT, especially at low frequency. Besides this, the power consumption of the transducer was significantly decreased compared with a recently reported RW-stimulating piezoelectric transducer.

scholarly journals Numerical Modelling of Reinforced Concrete Slender Walls Subjected to Coupled Axial Tension–Flexure

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Element Model ◽  
Lateral Loading ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
High Rise ◽  
Ultimate Deformation ◽  
Axial Tension ◽  
Plastic Hinge Length

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.

scholarly journals Influence of Patching on the Shear Failure of Reinforced Concrete Beam without Stirrup

2021 ◽  
Vol 6 (7) ◽  
pp. 97
Author(s):  
Stefanus Adi Kristiawan ◽  
Halwan Alfisa Saifullah ◽  
Agus Supriyadi
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Numerical Study ◽  
Unsaturated Polyester ◽  
Reinforced Concrete Beam ◽  
Concrete Cover ◽  
Shear Capacity ◽  
Rc Beam ◽  
Shear Span ◽  
Shear Cracking

Deteriorated concrete cover, e.g., spalling or delamination, especially when it occurs at the web of a reinforced concrete (RC) beam within the shear span, can reduce the shear capacity of the beam. Patching of this deteriorated area may be the best option to recover the shear capacity of the beam affected. For this purpose, unsaturated polyester resin mortar (UPR mortar) has been formulated. This research aims to investigate the efficacy of UPR mortar in limiting the shear cracking and so restoring the shear capacity of the deteriorated RC beam. The investigation is carried out by an experimental and numerical study. Two types of beams with a size of 150 × 250 × 1000 mm were prepared. The first type of beams was assigned as a normal beam. The other was a beam with a cut off in the non-stirrup shear span, which was eventually patched with UPR mortar. Two reinforcement ratios were assigned for each type of beams. The results show that UPR mortar is effective to hamper the propagation of diagonal cracks leading to increase the shear failure load by 15–20% compared to the reference (normal) beam. The increase of shear strength with the use of UPR mortar is consistently confirmed at various reinforcement ratios.

scholarly journals Development of a Novel Damage Detection Framework for Truss Railway Bridges Using Operational Acceleration and Strain Response

Vibration ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 422-445
Author(s):  
Md Riasat Azim ◽  
Mustafa Gül
Keyword(s):  
Damage Detection ◽  
Damage Identification ◽  
Numerical Study ◽  
Damage Index ◽  
Strain Analysis ◽  
Time History ◽  
Principal Component ◽  
Element Model ◽  
Railway Bridges ◽  
Truss Bridge

Railway bridges are an integral part of any railway communication network. As more and more railway bridges are showing signs of deterioration due to various natural and artificial causes, it is becoming increasingly imperative to develop effective health monitoring strategies specifically tailored to railway bridges. This paper presents a new damage detection framework for element level damage identification, for railway truss bridges, that combines the analysis of acceleration and strain responses. For this research, operational acceleration and strain time-history responses are obtained in response to the passage of trains. The acceleration response is analyzed through a sensor-clustering-based time-series analysis method and damage features are investigated in terms of structural nodes from the truss bridge. The strain data is analyzed through principal component analysis and provides information on damage from instrumented truss elements. A new damage index is developed by formulating a strategy to combine the damage features obtained individually from both acceleration and strain analysis. The proposed method is validated through a numerical study by utilizing a finite element model of a railway truss bridge. It is shown that while both methods individually can provide information on damage location, and severity, the new framework helps to provide substantially improved damage localization and can overcome the limitations of individual analysis.

Effect of Interfacial Properties on the Mechanical Behavior of Bone-Like Materials: A Numerical Study

2017 ◽  
Vol 09 (01) ◽  
pp. 1750014 ◽  
Author(s):  
Xingguo Li ◽  
Bingbing An ◽  
Dongsheng Zhang
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Numerical Study ◽  
Element Model ◽  
Interfacial Behavior ◽  
Yield Behavior ◽  
Bonding Property ◽  
The Matrix ◽  
Bonding Properties ◽  
Superior Mechanical Properties

Interfacial behavior in the microstructure and the plastic deformation in the protein matrix influence the overall mechanical properties of biological hard tissues. A cohesive finite element model has been developed to investigate the inelastic mechanical properties of bone-like biocomposites consisting of hard mineral crystals embedded in soft biopolymer matrix. In this study, the complex interaction between plastic dissipation in the matrix and bonding properties of the interface between minerals and matrix is revealed, and the effect of such interaction on the toughening of bone-like biocomposites is identified. For the case of strong and intermediate interfaces, the toughness of biocomposites is controlled by the post yield behavior of biopolymer; the matrix with low strain hardening can undergo significant plastic deformation, thereby promoting enhanced fracture toughness of biocomposites. For the case of weak interfaces, the toughness of biocomposites is governed by the bonding property of the interface, and the post-yield behavior of biopolymer shows negligible effect on the toughness. The findings of this study help to direct the path for designing bioinspired materials with superior mechanical properties.

Numerical Study for Global Detection of Cracks Embedded in Beams

1999 ◽  
Author(s):  
S. A. Lipsey ◽  
Y. W. Kwon
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Natural Frequency ◽  
Mode Shape ◽  
Numerical Study ◽  
Element Model ◽  
Mode Shapes ◽  
Linear Effect ◽  
Modes Of Vibration ◽  
Damage Simulation

Abstract Damage reduces the flexural stiffness of a structure, thereby altering its dynamic response, specifically the natural frequency, damping values, and the mode shapes associated with each natural frequency. Considerable effort has been put into obtaining a correlation between the changes in these parameters and the location and amount of the damage in beam structures. Most numerical research employed elements with reduced beam dimensions or material properties such as modulus of elasticity to simulate damage in the beam. This approach to damage simulation neglects the non-linear effect that a crack has on the different modes of vibration and their corresponding natural frequencies. In this paper, finite element modeling techniques are utilized to directly represent an embedded crack. The results of the dynamic analysis are then compared to the results of the dynamic analysis of the reduced modulus finite element model. Different modal parameters including both mode shape displacement and mode shape curvature are investigated to determine the most sensitive indicator of damage and its location.

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