Finite element method for solving asphalt mixture problem

2019 ◽  
Vol 10 (4) ◽  
pp. 569-579
Author(s):  
Wang Lijun ◽  
Li Qingbo
Keyword(s):  
Finite Element ◽  
Uniaxial Compression ◽  
Asphalt Mixture ◽  
Element Model ◽  
True Stress ◽  
Bending Test ◽  
Uniaxial Compression Test ◽  
Content Type ◽  
Freeze Thaw ◽  
Material Resources

Purpose Asphalt mixture is widely used in road engineering, and its performance research is particularly important. But the study of asphalt mixture performance needs a lot of tests, such as bending test, splitting test and so on. It also needs a lot of time and material resources. The purpose of this paper is to obtain test results through finite element numerical simulation, and show that this saves a lot of manpower and material resources. Design/methodology/approach The mechanical parameters of the material are obtained through uniaxial compression tests. The true stress and plastic strain are calculated according to nominal stress and nominal strain. A constitutive model is established. Then a finite element model of asphalt mixture is established. The numerical simulation and performance study of asphalt mixture bending test is carried out. At the same time, according to the above method, the asphalt mixture is subjected to freeze-thaw cycles and ultraviolet aging, and the mechanical parameters are obtained by a uniaxial compression test. A numerical model is established to simulate the bending characteristics of asphalt mixture after freeze-thaw cycles and ultraviolet aging. Findings A uniaxial compression test of the asphalt mixture is conducted to obtain nominal stress and nominal strain. The true stress and plastic strain are calculated and the elastic modulus is established with Poisson’s ratio as the elastic part, and the true stress and plastic strain as the plastic part. The model is constructed, the finite element model is established and the bending test is numerically simulated. The verified trend is consistent, and the method is feasible. According to the above method, the concrete is subjected to freeze-thaw cycle and ultraviolet aging, and the finite element model is established by using uniaxial compression test to obtain parameters. The bending test is simulated and the verification method is feasible. With the increase of the number of freeze-thaw cycles and the increase of UV aging time, the maximum bending strain of SBS modified asphalt mixture and matrix asphalt mixture is decreased .The low-temperature performance of SBS modified asphalt mixture is better than that of matrix asphalt mixture. Originality/value A method of simulating asphalt mixture test by finite element method numerical simulation is established. By using this method, the performance of asphalt mixture is studied, which saves a lot of manpower and material resources. At the same time, this method can be used to study the characteristics of asphalt mixture under complex conditions.

scholarly journals Numerical Simulation of Static Stress-Strain Relationship and Failure Mode for Freeze-Thaw Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xiaolin Yang ◽  
Genhui Wang ◽  
Hongzhao Li ◽  
Jiang Fan
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Uniaxial Compression ◽  
Strain Curve ◽  
Stress And Strain ◽  
Uniaxial Compression Test ◽  
Stress Strain ◽  
Element Analysis ◽  
Freeze Thaw ◽  
Thaw Cycle

To analyze the causes of failure of cubic concrete test specimens under quasistatic axial compression, microtests and finite element numerical simulation of C40 cubic concrete test specimens were conducted without the freeze-thaw cycle and with 50 freeze-thaw cycles. Based on the analysis of the microstructure of concrete, the variation law of the full curve of stress and strain was analyzed by the uniaxial compression test and the splitting tensile test of concrete. The results show that freeze-thaw damage is mainly caused by the cyclic reciprocating stress of the micropore structure inside the concrete. The peak stress of concrete uniaxial compression and splitting tensile strength gradually decrease with the number of freeze-thaw cycles; the full stress-strain curve tends to shift downward and to the right. Finite element analysis shows that under the quasistatic uniaxial compression loading condition, the stress and strain fields in the test specimens are symmetrically distributed but nonuniform. The plastic deformation of the concrete weakens the nonuniformity of the stress distribution and is closer to the experimental failure morphology.

A Finite Element Analysis for an Iron Ore Pellet Compression Test

2017 ◽  
Vol 899 ◽  
pp. 474-477
Author(s):  
Maria Carolina dos Santos Freitas ◽  
Flavia de Paula Vitoretti ◽  
Jorge Franklin Mansur Rodrigues Filho ◽  
Viviane Lima Silva ◽  
Jose Adilson de Castro ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Mechanical Behavior ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Iron Ore ◽  
Element Model ◽  
Uniaxial Compression Test ◽  
Iron Ore Pellets ◽  
Ore Pellets

The increasing global demand for iron ore pellets has made the pelletizing companies to step up their investments. The mechanical strength of the pellets, as well as its wear resistance are important factors to characterize the mechanical behavior. These properties are influenced by the type and nature of the ore or concentrate, the additives and the subsequent heat treatment used. This paper develops a numerical finite element model in order to characterize the mechanical behavior of iron ore pellets. The main objective of this study was to establish a valid finite element model that is able to simulate the mechanical behavior of iron ore pellets. The uniaxial compression test was made to evaluate the mechanical properties of the pellets. Furthermore, modeling and simulations are done using the software ABAQUS CAE® for uniaxial compression using the material properties obtained by the test. Lastly, in order to validate the model, the experimental data is crossed with the simulation results to discuss its correlation and particularities.

Investigation on the shaft voltage generation of large synchronous turboalternators

2020 ◽  
Vol 39 (5) ◽  
pp. 1145-1156
Author(s):  
Kevin Darques ◽  
Abdelmounaïm Tounzi ◽  
Yvonnick Le-menach ◽  
Karim Beddek
Keyword(s):  
Finite Element ◽  
Design Methodology ◽  
Short Circuit ◽  
Element Model ◽  
Stator Winding ◽  
Content Type ◽  
Voltage Generation ◽  
The Impact ◽  
Investigation Process ◽  
Circulating Currents

Purpose This paper aims to go deeper on the analysis of the shaft voltage of large turbogenerators. The main interest of this study is the investigation process developed. Design/methodology/approach The analysis of the shaft voltage because of several defects is based on a two-dimensional (2D) finite element modeling. This 2D finite element model is used to determine the shaft voltage because of eccentricities or rotor short-circuit. Findings Dynamic eccentricities and rotor short circuit do not have an inherent impact on the shaft voltage. Circulating currents in the stator winding because of defects impact the shaft voltage. Originality/value The original value of this paper is the investigation process developed. This study proposes to quantify the impact of a smooth stator and then to explore the contribution of the real stator winding on the shaft voltage.

Analysis on sealing performance of VL seals based on mixed lubrication theory

2019 ◽  
Vol 71 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Shixian Xu ◽  
Zhengtao Su ◽  
Jian Wu
Keyword(s):  
Finite Element ◽  
Film Thickness ◽  
Finite Element Model ◽  
Friction Factor ◽  
Contact Pressure ◽  
Element Model ◽  
Mixed Lubrication ◽  
Content Type ◽  
Deformation Mechanics ◽  
The Finite Element Model

Purpose This paper aims to research the influence of pressure, friction factors, roughness and actuating speed to the mixed lubrication models of outstroke and instroke. Design/methodology/approach Mixed lubrication model is solved by finite volume method, which consists of coupled fluid mechanics, deformation mechanics and contact mechanics analyses. The influence of friction factor on the finite element model is also considered. Then, contact pressure, film thickness, friction and leakage have been studied. Findings It was found that the amount of leakage is sensitive to the film thickness. The larger the film thickness is, the greater the influence received from the friction factor, however, the effect of oil film on the friction is negligible. The friction is determined mainly by the contact pressure. The trend of friction and leakage influenced by actuating velocity and roughness is also obtained. Originality/value The influence of friction factor on the finite element model is considered. This can make the calculation more accurate.

Design and optimization of actuator for multi-joint soft rehabilitation glove

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xinjie Wang ◽  
Yan Cheng ◽  
Huadong Zheng ◽  
Yihao Li ◽  
Caidong Wang
Keyword(s):  
Constitutive Model ◽  
Element Model ◽  
Longitudinal Section ◽  
Bending Test ◽  
Hand Rehabilitation ◽  
Content Type ◽  
Design And Optimization ◽  
Soft Actuator ◽  
New Type ◽  
Soft Actuators

Purpose Currently, rehabilitation medical care is expensive, requires a large number of rehabilitation therapist and which can only limit in the fixed location. In addition, there is a lack of research on the structure optimization and theoretical analysis of soft actuators for hand rehabilitation. In view of the problems above, this paper aims to propose a cheap, portable, wearable soft multiple joints rehabilitation glove. Design/methodology/approach First, this paper determined the hyperelastic constitutive model by material tensile test. Second, the soft actuator’s internal longitudinal section shape was optimized through the comparison of three diverse chamber structures. Meanwhile, the motion model of the soft actuator is established by the finite element model analysis method. Then, this paper established the constitutive model of the soft actuator according to the torque equilibrium equation and analyzed the relationship between the soft actuator’s bending angle and the input air pressure. This paper has verified that the theoretical model is correct through the soft actuator bending test. Finally, rehabilitation gloves were manufactured according to the model and the rehabilitation performance and grasping ability of gloves were verified through experiments. Findings The optimization results show that the internal semicircular cavity has better performance. Then, the actuator performance is better after adding the external arc structure and optimizing the physical dimension. The experimental results show that the trajectory of the actuator conforms to the mathematical model and rehabilitation gloves can meet the needs of rehabilitation treatment. Practical implications Rehabilitation gloves made of actuators can help patients with hand dysfunction in daily rehabilitation training. Then, it can also assist patients with some fine and complicated hand movements. Originality/value This paper proposes a new type of soft rehabilitation glove, which is composed of new soft actuators and adapting pieces. The new actuator is small enough to be fitted to the knuckle of the glove to move each joint of the finger.

A rapid stress calculation method for short flexspline harmonic drive

2019 ◽  
Vol 36 (6) ◽  
pp. 1852-1867 ◽  
Author(s):  
Shuang Wang ◽  
Gedong Jiang ◽  
Xuesong Mei ◽  
Chuang Zou ◽  
Xian Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Calculation Method ◽  
Circumferential Stress ◽  
Element Model ◽  
Analytical Relationship ◽  
Analysis Method ◽  
Content Type ◽  
Stress Calculation ◽  
Mechanics Analysis ◽  
Rapid Calculation

Purpose Because of the compact structure, short flexspline (FS) harmonic drive (HD) is increasingly used. The stress calculation of FS is very important in design and optimization of HD system. This paper aims to study the stress calculation methods for short FS, based on mechanics analysis and finite element method (FEM). Design/methodology/approach A rapid stress calculation method, based on mechanics analysis, is proposed for the short FS of HD. To verify the stress calculation precision of short FS, a complete finite element model of HD is established. The results of stress and deformation of short FS in different lengths are solved by FEM. Findings Through the rapid calculation method, the analytical relationship between circumferential stress and length of cylinder was obtained. And the circumferential stress has proportional relation with the reciprocal of squared length. The FEM results verified that the rapid stress calculation method could obtain accurate results. Research limitations/implications The rapid mechanics analysis method is practiced to evaluate the strength of FS at the design stage of HD. And the complete model of HD could contribute to improving the accuracy of FEM results. Originality/value The rapid calculation method is developed based on mechanics analysis method of cylinder and equivalent additional bending moment model, through which the analytical relationship between circumferential stress and length of cylinder was obtained. The complete three-dimensional finite element model of HD takes the stiffness of bearing into consideration, which can be used in the numerical simulation in the future work to improve the accuracy.

Analysis of stress intensity factor for fatigue crack using bootstrap S-version finite element model

2020 ◽  
Vol 11 (4) ◽  
pp. 579-589
Author(s):  
Muhamad Husnain Mohd Noh ◽  
Mohd Akramin Mohd Romlay ◽  
Chuan Zun Liang ◽  
Mohd Shamil Shaari ◽  
Akiyuki Takahashi
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Finite Element Model ◽  
Simulation Analysis ◽  
Element Model ◽  
Bootstrap Resampling ◽  
Confidence Bounds ◽  
Content Type ◽  
Resampling Method ◽  
The Mean

PurposeFailure of the materials occurs once the stress intensity factor (SIF) overtakes the material fracture toughness. At this level, the crack will grow rapidly resulting in unstable crack growth until a complete fracture happens. The SIF calculation of the materials can be conducted by experimental, theoretical and numerical techniques. Prediction of SIF is crucial to ensure safety life from the material failure. The aim of the simulation study is to evaluate the accuracy of SIF prediction using finite element analysis.Design/methodology/approachThe bootstrap resampling method is employed in S-version finite element model (S-FEM) to generate the random variables in this simulation analysis. The SIF analysis studies are promoted by bootstrap S-version Finite Element Model (BootstrapS-FEM). Virtual crack closure-integral method (VCCM) is an important concept to compute the energy release rate and SIF. The semielliptical crack shape is applied with different crack shape aspect ratio in this simulation analysis. The BootstrapS-FEM produces the prediction of SIFs for tension model.FindingsThe mean of BootstrapS-FEM is calculated from 100 samples by the resampling method. The bounds are computed based on the lower and upper bounds of the hundred samples of BootstrapS-FEM. The prediction of SIFs is validated with Newman–Raju solution and deterministic S-FEM within 95 percent confidence bounds. All possible values of SIF estimation by BootstrapS-FEM are plotted in a graph. The mean of the BootstrapS-FEM is referred to as point estimation. The Newman–Raju solution and deterministic S-FEM values are within the 95 percent confidence bounds. Thus, the BootstrapS-FEM is considered valid for the prediction with less than 6 percent of percentage error.Originality/valueThe bootstrap resampling method is employed in S-FEM to generate the random variables in this simulation analysis.

Thermo-mechanical analysis of train wheel-rail contact using a novel finite-element model

2020 ◽  
Vol 72 (5) ◽  
pp. 687-693
Author(s):  
Liuqing Yang ◽  
Ming Hu ◽  
Deming Zhao ◽  
Jing Yang ◽  
Xun Zhou
Keyword(s):  
Finite Element ◽  
Peer Review ◽  
Frictional Heating ◽  
Element Model ◽  
Mechanical Analysis ◽  
Partial Slip ◽  
Computational Time ◽  
Fe Model ◽  
Content Type ◽  
Explicit Finite Element

Purpose The purpose of this paper is to develop a novel method for analyzing wheel-rail (W-R) contact using thermo-mechanical measurements and study the effects of heating on the characteristics of W-R contact under different creepages. Design/methodology/approach This study developed an implicit-explicit finite element (FE) model which could solve both partial slip and full sliding problems by setting different angular velocities on the wheels. Based on the model, four material types under six different creepages were simulated. Findings The results showed that frictional heating significantly affected the residual stress distribution under large creepage conditions. As creepage increased, the temperature of the wheel tread and rail head rose and the peak value was located at the trailing edge of the contact patch. Originality/value The proposed FE model could reduce computational time and thus cost to about one-third of the amount commonly found in previous literature. Compared to other studies, these results are in good agreement and offer a reasonable alternative method for analyzing W-R contact under various conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0298

Review of advances in micromechanical modeling of aggregate–aggregate interactions in asphalt mixtures

2007 ◽  
Vol 34 (2) ◽  
pp. 239-252 ◽  
Author(s):  
Zhanping You ◽  
Qingli Dai
Keyword(s):  
Finite Element ◽  
Particle Interaction ◽  
Asphalt Mixture ◽  
Complex Mixture ◽  
Element Model ◽  
Laboratory Simulation ◽  
Micromechanical Modeling ◽  
Discrete Elements ◽  
Interacting Particles ◽  
Work Done

This paper presents a comprehensive review of the work done by a number of researchers on the modeling of asphalt mixture. Included are some of the earliest models such as those with non-interacting particles (models with and without geometry specified), models with particle interaction, and some new models developed in recent years. The paper focuses on the description and comparison of the most recently developed finite element network model (FENM), a clustered discrete element model (DEM), and a micromechanical finite element model (FEM) used in micromechanical modeling of asphalt mixture. These models consider the complex mixture microstructure and aggregate–aggregate interaction. These models are demonstrated and applications of the advances are provided, where virtual laboratory simulation and laboratory tests were employed. The feasibility of nanotechnology application in asphalt mixture is also briefly discussed.Key words: micromechanical modeling, micromechanics, aggregate–aggregate interaction, finite elements, discrete elements, asphalt mixture.

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