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SAPAVE: an improved semi-analytical FE program for dynamic viscoelastic analysis of asphalt pavement

INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING 2022年第9期23卷 3024-3035页

作者： Shen, Kairen Wang, Hao Zhang, Hanyu Tong, Jusheng Chen, Xianhua Southeast Univ Sch Transportat Nanjing Peoples R China Rutgers State Univ Dept Civil & Environm Engn Piscataway NJ USA

Analyzing dynamic viscoelastic responses induced by moving loads is a significant issue for pavement design and performance evaluation. Developing three-dimensional FE models in commercial software is an effective method, but the time-consuming disadvantage prevents it from extensive engineering applications. In this paper, an improved semi-analytical FE model was proposed to overcome this drawback. Besides, modified artificial boundaries were applied to minimise the interference of reflected waves generated by model edges. Further, a program named SAPAVE has been developed in matlab to achieve the modeling procedure, of which accuracy and efficiency were verified by comparing with the three-dimensional FE model in ABAQUS. The computing cost of SAPAVE was only one-sixth of ABAQUS, while SAPAVE can roughly achieve the function of ABAQUS for simple pavement modeling. The response considering the asphalt layer as viscoelastic was quite different from the linear elastic in the comparative study. The viscoelastic analysis seems to be closer to the field situation. Besides, the impact of vehicle speed was studied to examine the application ability of SAPAVE, and the results were generally consistent with existing researches. Overall, this study indicates that SAPAVE is an efficient and accurate tool for mechanical analysis of asphalt pavement.

关键词： Asphalt pavement viscoelastic mechanics dynamic response semi-Analytical finite element method matlab programming

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Discrete sizing optimization of stepped cylindrical silo using PSO method and implicit dynamic FE analysis

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ENGINEERING WITH COMPUTERS 2021年第2期37卷 1015-1047页

作者： Tian, Zhongke Jiao, Dongmei Qingdao Univ Sci & Technol Coll Elect Engn Qingdao 266061 Shandong Peoples R China

Considering the size discreteness of commercially available metal plates and the intrinsic buckling strength vulnerability of slender silo, this paper proposed a methodology, which integrated the nonlinear implicit dynamic Finite Element Method (FEM), Particle Swarm Optimization (PSO) algorithm and matlab programming, to optimize the wall-thickness layout for stepped thin-walled cylindrical silo, with the objective of minimizing silo mass while ensuring its structural stability. Taking into account both practicality and reliability, silo discharge loads were amplified 1.6 times to try to reflect the comprehensive effectiveness of negative and positive factors on slender silo buckling strength. When evaluating the fitness of PSO method, nonlinear implicit dynamic FEM results, such as kinetic energy history data plots, total energy history data plots, etc., were used to intuitively determine whether silo buckled or not. In essence, the optimal wall-thickness layout problem of a stepped silo is an NP-hard combinational optimization problem. The discrete thicknesses of rolled metal plates set an unavoidable constraint on stepped silo size optimization, which implies that there are only a few specific thickness values could be selected. In addition, the data of plate width are also discrete and one width value might correspond to several thickness data. For reasons for saving the potential cutting costs, the heights of most silo segments should be an integral multiple of the corresponding plate width value as far as possible, while the overall height of the silo should be kept still. To realize this goal, numerical processing techniques, such as generating a random number from a uniformly distributed set of discrete positive integers, linear normalization and linear interpolation, etc., were applied in this study.

关键词： Stepped silo Discrete sizing optimization Buckling Finite element method Nonlinear implicit dynamic analysis Particle swarm optimization matlab programming

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Software development for prediction of the weld bead in CMT and pulsed-MAG processes

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INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 2013年第1-4期64卷 171-178页

作者： Meco, Sonia Pardal, Goncalo Eder, Alexander Quintino, L. IST UTL Inst Super Tecn P-1200 Lisbon Portugal Fronius Int GmbH A-4600 Wels Thalheim Austria

Prediction of weld bead shapes prior to welding has been a challenge for researchers in recent years. The assurance of a weld shape with adequate penetration and dilution, good wetting angles and no undercuts leads to less repairing and reworking and thus, lower cost and time consumed. CMT is a variant of MIG/MAG welding process recently introduced in the market. Software control for bead-shape prediction helps the user to get familiar with this modern technology. In the present paper, two approaches were undertaken for software development. These were applied to CMT and pulsed-MAG welding and the results were compared. The graphical interface was built to help the user choose the welding parameters and get the representation of the weld bead profile. The two approaches used to predict the weld bead profiles are neural networks and interpolation method. The data entries for the two different methods are: welding process (CMT and MAG-pulsed), plate thickness, travel speed and wire feed speed. The output data is the complete welding profile defined by X and Y coordinates of the points on the welding profile. The neural networks were trained with different numbers of neurons, multiple layers and different networks, and welding data bases with different structures were used, in order to find the best fitting neural network. The final results for each method were checked against real profiles and it was concluded that the neural network method was more flexible and the accuracy of each methods was nearly the same.

关键词： Welding CMT(cold metal transfer) MIG/MAG (metal inert/active gas) Pulsed matlab programming Neural networks Interpolation

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Acoustic tomography system for online monitoring of temperature fields

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2017年第5期11卷 623-630页

作者： Yan, Hua Ma, Zhao Zhou, Ying Gang Shenyang Univ Technol Sch Informat Sci & Engn Shenyang 110870 Liaoning Peoples R China

For online monitoring of complex temperature distributions, an acoustic tomography system based on sound travel-time measurement is developed. For coping with the reverberation phenomenon in actual measurement, an anti-reflection interference measurement method for sound travel-time is proposed based on cross-correlation and peak recognition. In view of the fact the pixel number provided by commonly used reconstruction algorithms, such as least-squares methods, is very limited, radial basis function approximation and regularisation technique are used, which leads to the pixel number of the reconstruction image increasing dramatically. Mixed programming with LabVIEW and matlab is used. Queue structure is adopted to make data acquiring program and data processing program parallel. Test results show that the system can run normally as designed. The measurement values of sound travel-time acquired by the proposed method are stable even in strong reflection interference. Test results show that the system can run normally as designed. The measurement values of sound travel-time acquired by the proposed method are stable even in strong reflection interference. The temperature fields reconstructed are coincided with actual fields, and correctly reflect the temperature changes in the measured area with the heater number, heater location and heating time.

关键词： temperature measurement acoustic tomography temperature distribution acoustic variables measurement time measurement reverberation acoustic wave interference acoustic correlation least squares approximations approximation theory image recognition image reconstruction virtual instrumentation mathematics computing data acquisition acoustic tomography system complex temperature distribution monitoring sound traveltime measurement reverberation phenomenon antireflection interference measurement method cross-correlation peak recognition image reconstruction algorithm least-square method radial basis function approximation regularisation technique LabVIEW programming data processing program data acquiring program queue structure matlab programming

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Dynamic elastic analysis of flexible pavements under moving vehicles: a semi-analytical finite element treatment

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ROAD MATERIALS AND PAVEMENT DESIGN 2022年第6期23卷 1440-1450页

作者： Shen, Kairen Zhang, Hanyu Tong, Jusheng Wang, Hao Chen, Xianhua Southeast Univ Sch Transportat Nanjing Peoples R China Rutgers State Univ Dept Civil & Environm Engn New Brunswick NJ USA

Semi-analytical finite element method has great advantages in computational efficiency compared with three-dimensional, because it only requires a two-dimensional mesh in the cross-section by incorporating the Fourier series along the third dimension. This study utilised the method to analyse pavement responses induced by moving vehicles. Combined with the structural property of pavement, the method is improved in terms of meshing and boundary conditions based on existing research. Using the Fourier series to represent loading functions along the driving direction, the load motion can be expressed as the translation of trigonometric functions. Spring element is applied at bottom to simulate the soil support, and viscous element is applied at vertical boundary to control the interference of reflected wave. The whole algorithm was realised by matlab programming. This algorithm was first used to analyse a layered structure under a rectangular load. Its accuracy and efficiency were verified by comparing it with a three-dimensional finite element model in ABAQUS. Then this algorithm was utilised to simulate a test road under a moving truck. The material assembly used the parameters calibrated by several nondestructive tests. Analysis results were compared with the field monitor of sensors for verification. This study also has some reference value about applying semi-analytical finite element method in pavement engineering.

关键词： Semi-analytical finite element method pavement modeling matlab programming dynamic response field monitor

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Automated estimation of leaf area index from grapevine canopies using cover photography, video and computational analysis methods

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AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH 2014年第3期20卷 465-473页

作者： Fuentes, S. Poblete-Echeverria, C. Ortega-Farias, S. Tyerman, S. De Bei, R. Univ Adelaide Plant Res Ctr Glen Osmond SA 5064 Australia Univ Talca Res & Extens Ctr Irrigat & Agroclimatol CITRA Talca Chile

Background and AimsMonitoring of canopy vigour is an important tool in vineyard management to obtain balanced vines (vegetative vs reproductive organs). Leaf area index is the main parameter representing canopy vigour. Our aim was to test an automated computational method to obtain leaf area index and canopy vigour parameters from grapevines with digital photography and video analysis using matlab programming techniques for rapid data uptake and gap size analysis. Methods and ResultsThe proposed method was tested against allometry at a Chilean experimental site planted with cv. Merlot. A temporal and spatial assessment of the method was also tested in a drought and drought/recovery experiment with cv. Chardonnay in the Riverland, South Australia. These data were geo-referenced and compared to the normalised difference vegetation index extracted from the WorldView-2 satellite images at a 2m(2) per pixel resolution. ConclusionsThe maximum leaf area index data obtained with cover digital photography and video analysis are an accurate, cost-effective and easy-to-use method to estimate spatial and temporal canopy LAI and structure when compared to standard measurements (allometry and plant canopy analyser). Significance of the StudyThis study has demonstrated that the method proposed is an accurate and inexpensive tool for application in experiments and by the industry to monitor spatio-temporal distribution of vigour.

关键词： canopy cover digital image analysis matlab programming porosity satellite imagery

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A novel analysis of grapevine berry tissue demonstrates a variety-dependent correlation between tissue vitality and berry shrivel

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AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH 2010年第2期16卷 327-336页

作者： Fuentes, S. Sullivan, W. Tilbrook, J. Tyerman, S. Univ Adelaide Sch Agr Food & Wine Adelaide SA 5064 Australia

Background and Aims: For Vitis vinifera L. berries late in ripening, varietal differences have been found in tissue vitality and water relations linked to berry shrivel. Berry shrivel impacts on quality attributes. Here we quantified berry tissue vitality and shrivel across a broader range of varieties. Methods and Results: Berries from 22 varieties (similar degrees Brix at harvest maturity) were sectioned longitudinally at the centre and stained to measure tissue vitality and morphology. An analysis tool using matlab (R) R2008a (The Mathworks, Inc, Natick, MA, USA) quantified vitality and morphology, from which a shrivel index was developed. There was a correlation between shrivel and vitality across all varieties, such that greater vitality was associated with less shrivel. Similar within-variety correlations occurred for some varieties. Three clusters were identified across the varieties that reflected different degrees of tissue vitality and shrivel. Patterns of tissue vitality within the berry were also identified that appeared to differentiate between white and red winegrape varieties. Conclusion: Tissue vitality and shrivel indices separated varieties into distinct clusters that indicates mechanistic differences in the way cell vitality in the mesocarp is linked to berry water relations. Significance of the Study: Cell death before harvest may impact on berry quality. Tools to identify the onset of cell death and shrivel may allow more refined measures of quality and maturity assessment.

关键词： berry shrivel cell vitality grapevine varieties image analysis matlab programming mesocarp vitality

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Evaluation of Hybrid Teaching Mode of College Mathematics in Applied Universities based on Fuzzy Comprehensive Evaluation Model 22

Evaluation of Hybrid Teaching Mode of College Mathematics in...

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3rd International Conference on Education Development and Studies (ICEDS)

作者： Wu, Yanhong Liu, Jianfeng Wang, Kui Shandong Huayu Univ Technol Fdn Dept Dezhou Shandong Peoples R China

ISBN: (纸本)9781450396271

With the help of computer technology, this paper establishes a comprehensive evaluation model and uses computer software to program it. Hybrid teaching mode is an optimization of the traditional teaching mode, which can ensure that students can learn comprehensively and deeply. College mathematics in application-oriented universities plays a very important basic role in the construction of learning knowledge, and plays a key role in the cultivation of students' innovation consciousness, scientific accomplishment, logical thinking ability and calculation ability, which can't be replaced by other professional courses. In recent years, college mathematics curriculum has been committed to the reform of hybrid teaching mode. In order to evaluate this kind of teaching mode, this paper constructs the comprehensive evaluation system of college mathematics hybrid teaching mode, and establishes the fuzzy comprehensive evaluation model based on analytic hierarchy process to evaluate it, and finally obtains the evaluation result. The evaluation results can guide teachers to discuss and solve the problems existing in the teaching model.

关键词： college mathematics mixed teaching mode comprehensive evaluation system matlab programming

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The Design and Kinematic Simulation of the Return System in Ball Screw Pairs Used in Special Circumstance

The Design and Kinematic Simulation of the Return System in ...

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2nd International Conference on Industrial Design and Mechanics Power (ICIDMP 2013)

作者： Zhao Guoping Fan Yuanxun Yang Feng Li Liyi Harbin Inst Technol Sch Elect Engn Harbin 150001 Peoples R China Nanjing Univ Sci & Technol Sch Mech Engn Nanjing 210094 Peoples R China

ISBN: (纸本)9783037858967

Base on analyzing the design demand of the return system in the ball screws, combining the sine curve and the quintic parabola curve, this paper introduces a new type of curve for steel balls used in heavy load bearings. By computing and programming in matlab, this paper gets the sine-quintic parabola curve and conducts the kinematic simulation based on it. The results show that the balls can get in and out of the return system continuously and cause low impulse force on the return system. The highest impulse force happens when the balls access the return system. All this results can contribute for the later design and research of the internal circulation return system. The internal circulation is widely used in the ball screw pairs under aerospace systems with a compact structure. In this circumstance, the ball screw pairs are in motion in short time and overload, so the return system is a key part in the whole system. Whether the return system is designed logically and manufactured well directly determines the reliability of the ball screw pairs, and its failure will cause serious results.

关键词： return system curve for the steel balls matlab programming kinematic simulation

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An experimental UWB module-based sensing and communication system

An experimental UWB module-based sensing and communication s...

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2nd International Workshop on Ultrawideband and Ultrashort Impulse Signals

作者： Sostanovsky, DL Boryssenko, AO Ratio Private Co Kiev Ukraine

ISBN: (纸本)0780386736

An experimental UWB system is developed, designed, prototyped and tested to support a number of multitask sensing and telecommunication applications in the 0.1-3.0 GHz band, viz. subsurface radar or GPR, intrusion sensor, "trough-wall seeing" scanner, indoor comm. & geolocation and so on. As such, a set of hardware modules has to be created that can be combined/assembled in a particular fashion/architecture for each specific mission including functioning with receiving and transmitting UWB arrays (a part of our ongoing R&D efforts). The basic system components involve: (1) transmitter (Tx), (2) receiver (Rx), (4) antennas, (5) control unit, (6) digitizer and comp interface. As well, controlling and processing software is an inherent part of each such system that has to be configured for each specific operational task.

关键词： ultra-wide band transmitter receiver antenna software radar through-wall-seeing matlab programming data acquisition change detector

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