Orthogonal Analysis on Responses Indexes of Asphalt Pavement

2013 ◽  
Vol 361-363 ◽  
pp. 1523-1526
Author(s):  
Ya Li Ye ◽  
Chuan Yi Zhuang ◽  
Jie Yang ◽  
Yan Zhou
Keyword(s):  
Sensitivity Analysis ◽  
Asphalt Pavement ◽  
Compressive Strain ◽  
Maximum Shear Stress ◽  
Three Dimensional ◽  
Material Design ◽  
Structure Design ◽  
Accurate Analysis ◽  
Orthogonal Analysis ◽  
The Impact

The asphalt layer thickness, base thickness, the modulus of the asphalt layer, base modulus and subgrade modulus are selected as the responses indexes of asphalt. The level of each factor corresponding parameters and test results table are established by orthogonal analysis for four-level table of five factors. This paper took the Shell Designing Software BISAR 3.0 as calculation tool to get the three-dimensional response results of the different kinds of asphalt pavement. Based on results, the course bottom tensile strain of the asphalt layer, subgrade compressive strain and maximum shear stress of asphalt pavement are analyzed by intuitive analysis, variance analysis, and sensitivity analysis. It is found that the sensitivity analysis is a more accurate analysis of the factors of the factor in the level of assessment indicators. Response to the degree of influence of various factors on the pavement mechanics, pavement structure design and material design should be selected according to road type of damage specifications. In accordance with the sensitivity analysis of the impact of factors based on balanced other design specifications.

scholarly journals Temperature Adaptability of Asphalt Pavement to High Temperatures and Significant Temperature Differences

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Xueying Zhao ◽  
Aiqin Shen ◽  
Baofu Ma
Keyword(s):  
Asphalt Pavement ◽  
Maximum Shear Stress ◽  
Structure Design ◽  
Temperature Fields ◽  
Asphalt Pavements ◽  
Fe Model ◽  
Tire Pressure ◽  
Significant Temperature ◽  
Pavement Structure ◽  
Temperature Adaptability

Temperature adaptability of asphalt pavements is very important, due to their potential influence on pavement structure design, particularly in areas that experience significant temperature differences. In this paper, a finite element (FE) model was developed, and Turpan-Xiaocao Lake Highway in southern Xinjiang was taken as a case study engineering, which tends to experience this adverse environmental condition (temperature difference: 25.5°C; July 14, 2008). In this model, the generalized Kelvin model and the Burgers model were used. The time-dependent tire pressure was considered. To guide pavement structure design and control pavement distresses in this area, seven alternative pavement structures were selected to simulate and analyze pavement temperature fields and the mechanical responses. It was observed that the influence of air temperature had the greatest impact on Str-1, possibly due to the thinnest asphalt course. Moreover, when rutting depth, maximum shear stress of the asphalt course, deflection on the pavement surface, and compressive strains at the subgrade top surface were taken as the evaluation indices, the adaptability of asphalt pavements using compound base courses had obvious advantage due to their strong absorption and reflection of load impact. The adaptability of seven structures analyzed in this paper decreased in the following order: Str-5 > Str-6 > Str-4 > Str-2 > Str-m > Str-1 > Str-3. In addition, it broke the traditional view that asphalt pavement with a flexible base had the poor ability on rutting resistance. Besides, it also suggests that when the thickness of asphalt courses was equivalent, increasing the thickness of chemical-treated base courses would help with the deformation resistance, and vice versa.

scholarly journals Modeling and Analysis of Piston using Various Piston Crown Geometries

2020 ◽  
Vol 9 (5) ◽  
pp. 1004-1012
Keyword(s):  
Thermal Analysis ◽  
Maximum Shear Stress ◽  
Three Dimensional ◽  
Thermal Loads ◽  
Ic Engine ◽  
Modeling And Analysis ◽  
Engine Piston ◽  
Piston Crown ◽  
Stress Maximum ◽  
The Impact

Piston is the essential part of an IC engine and due to increase in manufacturing of automobiles of various types based on performance and power, the piston of an IC engine is under significant stress which causes wear of the piston. Piston is under mechanical and thermal loads due to combustion of the fuel and generation of high pressure gases. To reduce the damage incurred on an IC piston by the combustion of fuel the crown geometry of the piston can be modified. This reduces the wear incurred on an IC engine piston and increases the life of the IC engine piston. To understand the impact of mechanical loads on the piston static structural analysis has to be performed and to understand the impact of thermal loads, thermal analysis has to be performed. In this paper we have modeled three dimensional pistons with four different crown geometries using CATIA and performed static structural and thermal analysis in ANSYS to find total deformation, equivalent (von-misses) stress, maximum shear stress, temperature and heat flux. So we can find the best crown geometry for the manufacturing of IC engine piston.

Multidisciplinary Design Optimization of the Composite Cooling Structure for Nickel-based Alloy Turbine Blade

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaoru Qian ◽  
Peigang Yan ◽  
Wanjin Han
Keyword(s):  
Shear Stress ◽  
Flow Field ◽  
Turbine Blade ◽  
Maximum Shear Stress ◽  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Structure Design ◽  
Von Mises Stress ◽  
Von Mises

Abstract A designed method, multidisciplinary coupling computation and multiobjective optimization, has been established for the composite cooling structure of heavy gas turbine blade manufactured with a directionally solidified Ni-based superalloy. The method combines the one-dimensional fluid network gas-thermal coupling computation, three-dimensional flow field coupled with solid stress field, and anisotropic stress calculation based on finite deformation crystal slip. The temperature, flow field, Von-Mises stress and maximum resolved shear stress of the blade before and after optimization were analyzed. The results show that the optimized blade has lower maximum blade temperature, a more uniform temperature distribution, a lower flow resistance of the coolant channel at the leading edge than that of the original blade. The maximum Von-Mises stress of the optimized blade increases by 10.05 % more than the original blade. The maximum shear stress on the suction side and the pressure surface of the optimized blade are improved and slightly deteriorated compared with that of the original blade, respectively. The corresponding relationship of the maximum shear stress distribution with the local temperature gradient reveals further space for the improvement of the composite cooling structure. This paper has a particular guiding significance for the cooling structure design of the turbine blade.

scholarly journals Influence of Modulus of Base Layer on The Strain Distribution for Asphalt Pavement

2021 ◽  
Vol 16 (4) ◽  
pp. 126-152
Author(s):  
Kang Yao ◽  
Xin Jiang ◽  
Jin Jiang ◽  
Zhonghao Yang ◽  
Yanjun Qiu
Keyword(s):  
Strain Distribution ◽  
Tensile Strain ◽  
Asphalt Pavement ◽  
Compressive Strain ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Element Model ◽  
Neutral Axis ◽  
Base Layer ◽  
Maximum Tensile Strain

In order to investigate the influence of modulus of the base layer on the strain distribution for asphalt pavement, the modulus ratio of the base layer and the AC layer (Rm) is introduced as a controlled variable when keeping modulus of the AC layer as a constant in this paper. Then, a three-layered pavement structure is selected as an analytical model, which consists of an AC layer with the constant modulus and a base layer with the variable modulus covering the subgrade. A three dimensional (3D) finite element model was established to estimate the strains along the horizontal and vertical direction in the AC layer under different Rm. The results show that Rm will change the distribution of the horizontal strains along the depth in the AC layer; the increase of Rm could reduce the maximum tensile strain in the AC layer, but its effect is limited; the maximum tensile strain in the AC layer does not necessarily occur at the bottom, but gradually rises to the middle with the increase of Rm. Rm could significantly decline the bottom strain in the AC layer, and there is a certain difference between the bottom and the maximum strain when Rm is greater than or equal to one, which will enlarge with increasing Rm. Rm could change the depth of the neutral axis in the AC layer, and the second neutral axis will appear at the bottom of the AC layer under a sufficiently large Rm. The average vertical compressive strain in the AC layer will significantly enlarge with the increase of Rm.

Three-dimensional swimming robotic fish with slide-block structure: design and realization

Robotica ◽  
2013 ◽  
Vol 32 (5) ◽  
pp. 823-834
Author(s):  
Yongnan Jia ◽  
Long Wang
Keyword(s):  
Mechanical Design ◽  
Block Structure ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Structure Design ◽  
Robotic Fish ◽  
Experimental Results ◽  
Design Parameters ◽  
Slide Block ◽  
The Impact

SUMMARYThis paper focuses on the mechanism design of a slide-block structure and its application on a biomimetic modular robotic fish for three-dimensional swimming. First, as a barycenter-adjustor, the slide-block structure is integrated into a mechanical design of a robotic fish, which is constructed by a control module, a driving module, and a fan-shaped caudal fin. The three-dimensional locomotion of robotic fish is decomposed into two-dimensional locomotion in horizontal plane and ascent–descent locomotion in vertical plane. Both the kinematics of the horizontal swim and the dynamics of the ascent–descent swim are analyzed by the curve fitting method. Finally, experimental results validate the three-dimensional swimming capability of the robotic fish. Furthermore, the impact of two design parameters on the swimming capability of the robotic fish is discussed by the experimental method. The experimental results confirm that the robotic fish with one driving module and a fan-shaped low-aspect-ratio caudal foil can produce higher propulsive speed than other parameter combinations.

Modal Analysis on the Inclined Double-Column and Pre-Stress Combined Frame Structure of the 80MN Rapid Forging Hydraulic Press

2011 ◽  
Vol 317-319 ◽  
pp. 484-488
Author(s):  
Yi Gong Zhang ◽  
Hong Hong Yan ◽  
Zhi Qi Liu ◽  
Jian Li Song ◽  
Yong Tang Li
Keyword(s):  
Modal Analysis ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Noise Pollution ◽  
Hydraulic Press ◽  
Structure Design ◽  
Frame Structure ◽  
Mode Shapes ◽  
The Impact

In this paper, the first 80MN rapid forging hydraulic press in China was developed. The inclined double-column and pre-stress combined frame structure and the direct Pump-driven technologies were adopted for the first time in the design of this press. The linkage driving with the full-hydraulic orbital manipulator has been realized. A rapid forging frequency of 75~80 /min and a finishing precision of ±1mm for hot-state forgings can be obtained. The three dimensional full-contact solid model of the double-column combined frame structure of the 80 MN rapid forging hydraulic press has been set up. The modal analysis of the pre-tightened frame has been carried out with the FEM analysis software ANSYS. The first five-order inherent frequencies and the corresponding natural modes have been obtained, the mode shapes of various orders have also been analyzed in detail. It is shown from the research results that the inherent frequency of the frame is larger than the impact frequency. Therefore, resonant vibration of the structure will not occur. The analysis results will have an important significance for the understanding of the dynamic performance of the rapid forging hydraulic press, optimization of the structure design of the press and the decrease of vibration and noise pollution.

scholarly journals Analysis of Three-Dimensional Vibration Characteristics of Single-Circle Double-Track Subway Tunnel under Moving Load

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Chunquan Dai ◽  
Mengying Yang ◽  
Quanlei Wang ◽  
Tingzhi Yang ◽  
Kun Jiang
Keyword(s):  
Dynamic Response ◽  
Moving Load ◽  
Compressive Strain ◽  
Three Dimensional ◽  
Urban Rail Transit ◽  
Time Interval ◽  
Subway Tunnel ◽  
Double Line ◽  
Double Track ◽  
The Impact

With the development of urban rail transit, subway lines are becoming more and more denser, the departure time interval is short, and the probability of subway trains meeting is high. The impact of vibration caused by double-line subway meeting on the surrounding environment cannot be ignored. Taking the typical cross-section of a single-circle double-track subway tunnel as an example, a single running scenario and three typical meeting scenarios, namely, 4 s meeting, 6 s meeting, and 8 s meeting scenarios were considered, and a track-tunnel-foundation three-dimensional ABAQUS finite element model was established. The dynamic response of monitoring points at different distances between the center of the track bed and the center line of the track was analyzed. Results showed that due to the consistent load action period, the center acceleration of the track bed increases significantly during the meeting, the main frequency of vibration and the peak value of the 1/3 octave spectrum were increased by about 5 Hz, and the vibration level at the dominant frequency was increased by about 7 dB. The center displacement of the track bed and the peak compressive strain increased significantly under the 4 s meeting and 6 s meeting working scenarios; while the 8 s meeting and 4 s single running scenarios were basically the same, only the action time was doubled. The dynamic response of the 4 working scenarios decreases with the increase of distance, and the attenuation rate gradually decreases and has gradually stabilized within 15–19 m above the vault.

Analysis of the Heavy Traffic Impact on the Life of Asphalt Concrete Pavement

2014 ◽  
Vol 1030-1032 ◽  
pp. 1116-1119
Author(s):  
Pei Pei Tang ◽  
Ai Qin Shen ◽  
Meng Bo Gao
Keyword(s):  
Service Life ◽  
Asphalt Concrete ◽  
Asphalt Pavement ◽  
Heavy Traffic ◽  
Structure Design ◽  
Traffic Impact ◽  
Ultimate Failure ◽  
Asphalt Concrete Pavement ◽  
The Impact ◽  
Pavement Service Life

With China's rapid economic development, traffic and heavy-duty vehicles increased significantly. Asphalt pavement failure caused by heavy traffic is increasingly prominent.Pavement's service life was greatly reduced. On the basis of extensive research and theoretical calculation the article analyzes the impact of heavy traffic on the asphalt pavement service life from three aspects of rutting,ultimate failure and fatigue failure, provides a theoretical basis for heavy traffic asphalt pavement structure design.

scholarly journals Experimental and Numerical Models of Three-Dimensional Gravity-Driven Flow of Shear-Thinning Polymer Solutions Used in Vaginal Delivery of Microbicides

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Vitaly O. Kheyfets ◽  
Sarah L. Kieweg
Keyword(s):  
Sensitivity Analysis ◽  
Rheological Properties ◽  
Power Law ◽  
Numerical Models ◽  
Three Dimensional ◽  
Shear Thinning ◽  
Lateral Spreading ◽  
Free Surface Flows ◽  
Experimental Methodology ◽  
The Impact

HIV/AIDS is a growing global pandemic. A microbicide is a formulation of a pharmaceutical agent suspended in a delivery vehicle, and can be used by women to protect themselves against HIV infection during intercourse. We have developed a three-dimensional (3D) computational model of a shear-thinning power-law fluid spreading under the influence of gravity to represent the distribution of a microbicide gel over the vaginal epithelium. This model, accompanied by a new experimental methodology, is a step in developing a tool for optimizing a delivery vehicle's structure/function relationship for clinical application. We compare our model with experiments in order to identify critical considerations for simulating 3D free-surface flows of shear-thinning fluids. Here we found that neglecting lateral spreading, when modeling gravity-induced flow, resulted in up to 47% overestimation of the experimental axial spreading after 90 s. In contrast, the inclusion of lateral spreading in 3D computational models resulted in rms errors in axial spreading under 7%. In addition, the choice of the initial condition for shape in the numerical simulation influences the model's ability to describe early time spreading behavior. Finally, we present a parametric study and sensitivity analysis of the power-law parameters' influence on axial spreading, and to examine the impact of changing rheological properties as a result of dilution or formulation conditions. Both the shear-thinning index (n) and consistency (m) impacted the spreading length and deceleration of the moving front. The sensitivity analysis showed that gels with midrange m and n values (for the ranges in this study) would be most sensitive (over 8% changes in spreading length) to 10% changes (e.g., from dilution) in both rheological properties. This work is applicable to many industrial and geophysical thin-film flow applications of non-Newtonian fluids; in addition to biological applications in microbicide drug delivery.

scholarly journals Using Radar Reflectivity to Evaluate the Vertical Structure of Forecast Convection

2018 ◽  
Vol 57 (12) ◽  
pp. 2835-2849 ◽  
Author(s):  
Mariusz Starzec ◽  
Gretchen L. Mullendore ◽  
Paul A. Kucera
Keyword(s):  
Sensitivity Analysis ◽  
Vertical Structure ◽  
Three Dimensional ◽  
Radar Reflectivity ◽  
Convective Structure ◽  
Object Based ◽  
Convective Cells ◽  
The Impact

AbstractSeveral months of regional convection-permitting forecasts using two microphysical schemes (WSM6 and Thompson) are evaluated to determine the accuracy of the simulated convective structure and convective depth and the impact of microphysical scheme on simulated convective properties and biases. Forecasts are evaluated by using concepts from object-based approaches to compare the three-dimensional simulated reflectivity field with the reflectivity field as observed by radar. Results from analysis of both schemes reveals that forecasts generally perform well near the surface but differ considerably aloft both from observations and from each other. Forecasts are found to contain too many convective cores that are individually larger than in the observations, with at least double the number of observed convective cores reaching the midtroposphere (i.e., 4–8 km). Although the number of cores is overpredicted, WSM6 cores typically contain lower simulated reflectivity values than the observations, and the regions of highest reflectivity values do not extend far enough vertically. Conversely, Thompson cores are found to have significantly higher reflectivity values within cores, with the strongest intensities extending higher than in the observations and having magnitudes higher than any observed cores. Forecast reflectivity distributions within convective cells are found to contain more spread than in the observations. The study also assessed the uncertainty in simulated reflectivity calculations by using a second commonly utilized method to calculate simulated reflectivity. The sensitivity analysis reveals that the primary conclusions with each method are similar but the variability generated by using different simulated reflectivity calculations can be as pronounced as when using different microphysical schemes.

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