Simulation Study of the Workspace of the Parallel Machine Tool

A new three dimensional simulation method is introduced to study the workspace of a 6 PSS (P denotes a prismatic kinematic pair, S denotes a spherical kinematic pair) parallel machine tool. This algorithm adopts the method of numerical analysis to investigate the boundary points in a series of sections which form the surface of the workspace. That is, to study such points that have the largest polar radius on a certain section in a system of polar coordinates according to conditions of constraint. The constraint conditions considered in the article include the maximum and minimum displacements of each dieblock, the maximum and minimum angles of oscillation in each hinge. By converting the constraint inequalities into constraint equations, the largest polar radius corresponding to every constraint condition can be evaluated and the minimum one is used to decide the boundary point. This algorithm greatly simplifies the computational process and can be used to analyze any section of the workspace. It provides a theoretical basis for the structural design of such a machine tool.

Interactions between the fluid and an isolation tool in a pipe:laboratory experiments and numerical simulation

A remote-control tether-less isolation tool is a mechanical device that is normally used in pipelines to block the flow at a given position by transforming a blocking module. In this study, the interactions between the fluid and the plug module of the isolation tool were investigated. Simulations of the plug process and particle image velocimetry measurements were performed to study the flow characteristics. Numerical solutions for the continuity, momentum, and energy equations were obtained by using commercial software based on finite-volume techniques. Box–Behnken design was applied, and response surface methodology（RSM）-based CFD simulation analysis was conducted. The dynamic model in the plug process was built by RSM and used to evaluate the influences of the main mechanical parameters on the pressure during the plug process. The diameter of the isolation tool and the diameter of the plug module have strong influences on the process, and the length of the isolation tool has only a little influence on the plug process.

Numerical simulation of freezing effect and tool change of shield machine with a frozen cutterhead

A shield machine with freezing function is proposed in order to realize tool change operation at atmospheric pressure. Furthermore, the transformation project of freezing cutterhead and tool change maintenance method are put forward. Taking the shield construction of Huanxi Power Tunnel as an example, a numerical analysis of the freezing cutter head of the project was carried out. The results show that when the brine temperature is-25 °C, after 30 d of freezing, the thickness of the frozen wall can reach 0.67 m and the average temperature drops to-9.9 °C. When the brine temperature is-30 °C, after 50 d of freezing, the thickness of the frozen wall can reach 1.01 m and the average temperature drops to-12.4 °C. If the thickness of the frozen wall is 0.5 m and the average temperature is-10 °C, as the design index of the frozen wall, the brine temperature should be lower than-28 °C to meet the excavation requirements in 30 d. Analyzing the frozen wall stress under 0.5 m thickness and-10 °C average temperature condition, the tensile safety factor and compressive safety factor are both greater than 2 at the most dangerous position, which can meet the tool change requirements for shield construction.

Experimental Investigation and Numerical Simulation on Interfacial Carbon Diffusion of Diamond Tool and Ferrous Metals

We numerically simulated and experimentally studied the interfacialcarbon diffusion between diamond tooland workpiece materials.A diffusion modelwith respect to carbon atoms of diamond toolpenetrating into chips and machined surface was established.The numericalsimulation results of the diffusion process revealthat the distribution laws of carbon atoms concentration have a close relationship with the diffusion distance,the diffusion time,and the originalcarbon concentration of the work material.In addition,diamond face cutting tests of die steels with different carbon content are conducted at different depth of cuts and feed rates to verify the previous simulation results.The micro-morphology of the chips is detected by scanning electron microscopy.Energy dispersive X-ray analysis was proposed to investigate the change in carbon content of the chips surface.The experimentalresults of this work are of benefit to a better understanding on the diffusion wear mechanism in single crystaldiamond cutting of ferrous metals.Moreover,the experimentalresults show that the diffusion wear of diamond could be reduced markedly by applying ultrasonic vibration to the cutting toolcompared with conventionalturning.

THEORETICAL PREDICTION OF TOOL-CHIP CONTACT LENGTH IN ORTHOGONAL METAL MACHINING BY COMPUTER SIMULATION

A method for determination of tool-chip contact length is theoreticallypresented in orthogonal metal machining. By using computer simulation and based on the analyses ofthe elastro-plastic deformation with lagrangian finite element method in the deformation zone, theaccumulated representative length of the low layer, the tool-chip contact length of the chipcontacting the tool rake are calculated, experimental studies are also carried out with 0.2 percentcarbon steel. It is shown that the tool-chip contact lengths obtained from computer simulation havea good agreement with those of measured values.

Comparative Moisture Performance of Wood/Wood-Based Claddings Predicted by Four Hygrothermal Simulation Tools

A number of hygrothermal(HAM)numerical simulation packages are available,either wholly or partially dedicated to heat,air and moisture transfer simulations of building materials and wall assemblies.The objective of this work was to compare the HAM responses and moisture performance of western red cedar and composite wood claddings of a wood frame wall as predicted by four HAM simulation tools:DELPHIN,WUFI,hygIRC,and COMSOL.Three Canadian cities having different climates were selected for simulation:Ottawa(ON),Vancouver(BC)and Calgary(AB).In each city,simulations were run for two years as selected from a historical climate data set based on the moisture index(MI).The wall orientation receiving the most wind-driven rain for the two years was selected for simulations.Material properties were taken from the National Research Council(NRC)material property database.Cladding temperature and relative humidity(RH)values as well as the moisture accumulated in the entire structure were compared amongst the results obtained from the four tools.The mold growth index on the cladding surface was used as a basis for comparing the moisture performance.

Quenching Simulation of PM Coated Tools

HIP cladding is a powder metallurgical coating technique used in the production of wear parts and tools. In many cases the composite components consist of carbide-free hot-work steel as base material and wear resistant carbide-rich PM cold-work steel as coating material. To ensure operativeness a heat treatment matched to the substrate and coating material is required. Dissimilar phase transformation behaviour and different thermal expansion coefficients of layer and substrate entail inner stresses affecting the transformation kinetics in turn. In order to get a deeper insight into these effects Finite Element simulation tools are used. On the one hand, the transient heat conduction problem of the quenching process has to be solved. Non-linear boundary conditions and phase transformation of both, substrate and layer are considered. On the other hand, the mechanical response is calculated. The overall aim of the investigation is an improvement of common heat treatment techniques used for HIP cladded wear parts.

Simulation Laboratory and Critical Appraisal of Development Tool

In order to carry out the different network question meaning the research to like the protocol interaction,the network dynamics' function,the measurable quantity waits for it is the necessary delivery is including.Thus,the network simulation may use in showing or quite interesting network performance and so on.Part two aim is provides the type of development tool,including consider such as cost,ease to use and limitations of software packages.The report is to meets the system specification requirement immediately the available component.

Modeling Abrasion Forces in a Pneumatically Powered Grinding Tool Using Compressible Large Eddy Simulation

This paper describes the design of a new kind of miniature abrading sphere, which is magnetically mounted inside a spherical gap and set in rotation pneumatically with air. Large eddy simulation is performed in conjunction with the compressible Smagorinsky model. Minimal temperature variation allows for the assumption of adiabatic walls. Fluid-solid interaction is modeled using the law of the wall for compressible turbulent flow. A parametric study is done to determine optimal geometric layout while taking physical restrictions into account. The resulting optimal configuration is then examined in detail in order to determine demands to be met by the computerized control of the magnetic bearing as well as to quantify the force available to the abrasion process. Finally, a mathematical relation is given that determines available abrasion force depending on standard volumetric flow rate and rotation frequency. The findings presented here provide a basis for further development of smaller versions of the tool.

基于Solidworks Simulation的工装压板有限元分析及优化设计

针对弹簧工装在传统设计制造中存在的重量大、结构笨重、加工成本高等问题,采用Solidworks软件对其关键部件工装压板进行优化设计。利用Solidworks软件对工装压板进行参数化建模及装配,并利用Simulation模块对工装压板装配体进行静力学分析。在有限元分析的基础上,采用评估优化算例进行优化设计,优化结果表明工装压板质量减轻了10.5%,形变减小了1~2μm,性能结构更加合理,可提高工作效率,降低工人劳动强度。

THREE-DIMENSIONAL FINITE-ELEMENT SIMULATION OF STRETCHING TECHNOLOGICAL PARAMETERS b_t/h AND b_b/h OF HEAVY FORGINGS

A thee-dimensional finite-element simulation of stretching technological parameters of heavy forgings is performed by using ANSYS program. The law of internal stress distribution with different bt/h (tool width ratio) and different bb/h (blank width ratio) is studied. Consequently,the critical tool width ratio( bt/h )cr and blank width ratio( bb/ h )cr leading no bi-axial tension are obtained. It lays a credible foundation for designing reasonable stretching technology.

Simulation Analysis of Surface Roughness for Milling Process

Surface roughness is one of the most important evaluation indexes in machine cutting. In order to analyze how the tool path affects the roughness of the surface after milling, series of simulations are implemented in MasterCAM. We set up the same processing conditions with same parameters such as speed, material and feed rate etc. in these simulations, but different processing paths are used. We choose three paths: the parallel milling along the X-Y axis direction, the parallel milling along the Z-X or Z-Y axis direction and the streamline processing in the simulations. At the same time, end miller, arc miller and ball miller are respectively selected in the software. So there are totally 9 simulations of the milling process that are performed. Then the experimental cutting processes are performed correspondingly and the surface roughness and the accuracy are measured. The results show that the milling effect of the arc is better and the waste is minimal in the parallel milling along the Z-X or Z-Y axis direction with the end mills.

Simulation logging experiment and interpretation model of array production logging measurements in a horizontal well

The distributions of local velocity and local phase holdup along the radial direction of pipes are complicated because of gravity differentiation,and the distribution of fluid velocity fi eld changes along the gravity direction in horizontal wells.Therefore,measuring the mixture flow and water holdup is difficult,resulting in poor interpretation accuracy of the production logging output profile.In this paper,oil–water two-phase flow dynamic simulation logging experiments in horizontal oil–water two-phase fl ow simulation wells were conducted using the Multiple Array Production Suite,which comprises a capacitance array tool(CAT)and a spinner array tool(SAT),and then the response characteristics of SAT and CAT in diff erent fl ow rates and water cut production conditions were studied.According to the response characteristics of CAT in diff erent water holdup ranges,interpolation imaging along the wellbore section determines the water holdup distribution,and then,the oil–water two-phase velocity fi eld in the fl ow section was reconstructed on the basis of the fl ow section water holdup distribution and the logging value of SAT and combined with the rheological equation of viscous fl uid,and the calculation method of the oil–water partial phase fl ow rate in the fl ow section was proposed.This new approach was applied in the experiment data calculations,and the results are basically consistent with the experimental data.The total fl ow rate and water holdup from the calculation are in agreement with the set values in the experiment,suggesting that the method has high accuracy.

PVLab, a Powerful, Innovative Software Package for the Simulation of Photovoltaic Systems

This paper describes a new, highly modular, simulation tool named ＂PVLab＂ and developed by the GREMAN laboratory. It is designed to assist the designer in the sizing ofPV （photovoltaic） installations. The programming structure and physical models implemented within this tool are described, and several case studies are proposed to highlight its relevance. The predicted yearly electrical energy production of grid-connected PV plants is discussed. In particular, the predicted performance of such plants is compared with that given by the PVsyst software. PVLab has a high level of flexibility, allowing its physical models and databases （e.g., meteorological data） to be modified according to the user＇s needs. This is made possible through the use of expertise applied to all of the computing steps, and to the MATLAB development environment. The user＇s ability to control the source code itself will allow much greater progress to be made in the field of renewable energy applications than with PVsyst, which is currently the commercial reference.

Technology Provides Better Document Search Results on Slovak Legislation Webpage as Result of a Simulation of Webpage Performance Parameters

This article acquaints the public with the insights gained from conducting document searches in the Slovak public administration information system,when supported by knowledge of its management.Additionally,it discusses the advantages of simulating performance parameters and comparing the obtained results with the real parameters of the eZbierka(eCollection)legislation webpage.This comparison was based upon simulated results,obtained through the Gatling simulation tool,versus those obtained from measuring the properties of the public administration legislation webpage.Both sets of data(simulated and real),were generated via the the document search technologies in place on the eZbierka legislation webpage.The webpage provides users with binding laws and bylaws available in an electronically signed PDF file format.It is free open source.In order to simulate the accessing of documents on the webpage,the Gatling simulation tool was used.This tool simulated the activity,performed in the background of the information system,as a user attempted to read the data via the steps mentioned in the scenario.The settings of the simulated environment corresponded as much as possible to the hardware parameters and network infrastructure properties used for the operation of the respective information system.Based on this data,through load changing,we determined the number of users,the response time to queries,and their number;these parameters define the throughput of the server of the legislation webpage.The required parameter determination and performance of search technology operations are confirmed by a suitable hardware design and the webpage property parameter settings.We used the data from the eZbierka legislation webpage from its operational period of January 2016 to January 2019 for comparison,and analysed the relevant data to determine the parameter values of the legislation webpage of the slov-lex information system.The basic elements of the design solution include the technology used,the technology for searching the legislative documents with support of a searching tool,and a graphic database interface.By comparing the results,their dependencies,and proportionality,it is possible to ascertain the proper determination and appropriate applied search technology for selection of documents.Further,the graphic interface of the real web database was confirmed.

Virtual simulation experiment of the design and manufacture of a beer bottle-defect detection system

Background Machine learning-based beer bottle-defect detection is a complex technology that runs automatically;however,it consumes considerable memory,is expensive,and poses a certain danger when training novice operators.Moreover,some topics are difficult to learn from experimental lectures,such as digital image processing and computer vision.However,virtual simulation experiments have been widely used to good effect within education.A virtual simulation of the design and manufacture of a beer bottle-defect detection system will not only help the students to increase their image-processing knowledge,but also improve their ability to solve complex engineering problems and design complex systems.Methods The hardware models for the experiment(camera,light source,conveyor belt,power supply,manipulator,and computer)were built using the 3DS MAX modeling and animation software.The Unreal Engine 4(UE4)game engine was utilized to build a virtual design room,design the interactive operations,and simulate the system operation.Results The results showed that the virtual-simulation system received much better experimental feedback,which facilitated the design and manufacture of a beer bottle-defect detection system.The specialized functions of the functional modules in the detection system,including a basic experimental operation menu,power switch,image shooting,image processing,and manipulator grasping,allowed students(or virtual designers)to easily build a detection system by retrieving basic models from the model library,and creating the beer-bottle transportation,image shooting,image processing,defect detection,and defective-product removal.The virtual simulation experiment was completed with image processing as the main body.Conclusions By mainly focusing on bottle mouth defect detection,the detection system dedicates more attention to the user and the task.With more detailed tasks available,the virtual system will eventually yield much better results as a training tool for image processing education.In addition,a novel visual perception-thinking pedagogical framework enables better comprehension than the traditional lecture-tutorial style.

Application of Spatially Distributed Calibrated Hydrological Model in Evapotranspiration Simulation of Three Gorges Reservoir Area of China:A Case Study in the Madu River Basin

Evapotranspiration(ET)is the key to the water cycle process and an important factor for studying near-surface water and heat balance.Accurately estimating ET is significant for hydrology,meteorology,ecology,agriculture,etc..This paper simulates ET in the Madu River Basin of Three Gorges Reservoir Area of China during 2009-2018 based on the Soil and Water Assessment Tool(SWAT)model,which was calibrated and validated using the MODIS(Moderate-resolution Imaging Spectroradiometer)/Terra Net ET 8-Day L4 Global 500 m SIN Grid(MOD16A2)dataset and measured ET.Two calibration strategies(lumped calibration(LC)and spatially distributed calibration(SDC))were used.The basin was divided into 34 sub-basins,and the coefficient of determination(R^(2))and NashSutcliffe efficiency coefficient(NSE)of each sub-basin were greater than 0.6 in both the calibration and validation periods.The R2 and NSE were higher in the validation period than those in the calibration period.Compared with the measured ET,the accuracy of the model on the daily scale is:R^(2)=0.704 and NSE=0.759(SDC results).The model simulation accuracy of LC and SDC for the sub-basin scale was R^(2)=0.857,R^(2)=0.862(monthly)and R^(2)=0.227,R^(2)=0.404(annually),respectively;for the whole basin scale was R^(2)=0.902,R^(2)=0.900(monthly)and R^(2)=0.507 and R^(2)=0.519(annually),respectively.The model performed acceptably,and SDC performed the best,indicating that remote sensing data can be used for SWAT model calibration.During 2009-2018,ET generally increased in the Madu River Basin(SDC results,7.21 mm/yr),with a multiyear average value of 734.37 mm/yr.The annual ET change rate for the sub-basin was relatively low upstream and downstream.The linear correlation analysis between ET and meteorological factors shows that on the monthly scale,precipitation,solar radiation and daily maximum and minimum temperature were significantly correlated with ET;annually,solar radiation and wind speed had a moderate correlation with ET.The correlation between maximum temperature and ET is best on the monthly scale(Pearson correlation coefficient R=0.945),which may means that the increasing ET originating from increasing temperature(global warming).However,the sub-basins near Shennongjia Nature Reserve that are in upstream have a negative ET change rate,which means that ET decreases in these sub-basins,indicating that the’Evaporation Paradox’exists in these sub-basins.This study explored the potential of remote-sensing-based ET data for hydrological model calibration and provides a decision-making reference for water resource management in the Madu River Basin.

Simulation-Based Analysis and Intuitive Visualization of the Cutting Edge Load in Micromilling of Hardened Steel

The precise micromanufacturing of complex dies with small structures for sheet-bulk metal forming is a challenge due to the high hardness of the materials to be machined. Experiments have shown that micromilling of these difficult-to-machine materials is possible despite of their high hardness. Nevertheless, the higher wear of the tools plays a decisive role. When implementing the machining task as five-axis process, it is possible to control the wear distribution by tilting the milling tools. In this paper, a simulation system is presented which determines the loads acting on the cut- ting edge with regard to different criteria, e.g., the machined material or the effective impulse. Based on this knowledge, it is possible to design the milling process to minimize the tool wear and thereby to increase the lifetime of the milling tools. In order to show the applicability of the simulation system, test workpieces were machined and the experimental results are compared to the simulation data.

Analytical Solution and Numerical Simulation of Real-Time Dispersion Monitoring Using Tone Subcarrier

A method for online dispersion monitoring by adding a single in-band subcarrier tone isintroduced.According to the theoretical analysis,the dispersion monitor and measurement range aredetermined by the specific frequency of the subcarrier tone.By using simulation tools,figures aboutrelationship between power of subcarrier tone and transmission distance in ideal condition are shown.