scholarly journals Metrology Data-Based Simulation of Freeform Optics

2018 ◽  
Vol 8 (12) ◽  
pp. 2338 ◽  
Author(s):  
Ingo Sieber ◽  
Allen Yi ◽  
Ulrich Gengenbach
Keyword(s):  
Performance Prediction ◽  
Simulation Analysis ◽  
Measurement Data ◽  
Surface Measurement ◽  
Measurement Tool ◽  
Freeform Surfaces ◽  
Microinjection Molding ◽  
Surface Data ◽  
Freeform Optics ◽  
Accurate Performance

This paper describes the approach to use measurement data to enhance the simulation model for designing freeform optics. Design for manufacturing of freeform optics is still challenging, since the classical tolerancing procedures cannot be applied. In the case of spherical optics manufacturing, tolerances are more or less isotropic, and this relationship is lost in case of freeform surfaces. Hence, an accurate performance prediction of the manufactured optics cannot be made. To make the modeling approach as accurate as possible, integration of measured surface data of fabricated freeform optics in the modeling environment is proposed. This approach enables performance prediction of the real manufactured freeform surfaces as well as optimization of the manufacturing process. In our case study this approach is used on the design of an Alvarez-optics manufactured using a microinjection molding (µIM) process. The parameters of the µIM process are optimized on the basis of simulation analysis resulting in optics, with a performance very close to the nominal design. Measurement of the freeform surfaces is conducted using a tactile surface measurement tool.

scholarly journals Data-Driven Intelligent 3D Surface Measurement in Smart Manufacturing: Review and Outlook

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Yuhang Yang ◽  
Zhiqiao Dong ◽  
Yuquan Meng ◽  
Chenhui Shao
Keyword(s):  
High Resolution ◽  
High Performance ◽  
Sampling Design ◽  
Three Dimensional ◽  
Measurement Data ◽  
Data Driven ◽  
Surface Measurement ◽  
Smart Manufacturing ◽  
Future Research ◽  
3D Surface

High-fidelity characterization and effective monitoring of spatial and spatiotemporal processes are crucial for high-performance quality control of many manufacturing processes and systems in the era of smart manufacturing. Although the recent development in measurement technologies has made it possible to acquire high-resolution three-dimensional (3D) surface measurement data, it is generally expensive and time-consuming to use such technologies in real-world production settings. Data-driven approaches that stem from statistics and machine learning can potentially enable intelligent, cost-effective surface measurement and thus allow manufacturers to use high-resolution surface data for better decision-making without introducing substantial production cost induced by data acquisition. Among these methods, spatial and spatiotemporal interpolation techniques can draw inferences about unmeasured locations on a surface using the measurement of other locations, thus decreasing the measurement cost and time. However, interpolation methods are very sensitive to the availability of measurement data, and their performances largely depend on the measurement scheme or the sampling design, i.e., how to allocate measurement efforts. As such, sampling design is considered to be another important field that enables intelligent surface measurement. This paper reviews and summarizes the state-of-the-art research in interpolation and sampling design for surface measurement in varied manufacturing applications. Research gaps and future research directions are also identified and can serve as a fundamental guideline to industrial practitioners and researchers for future studies in these areas.

scholarly journals Influence of Lawns on the Summer Thermal Environment and Microclimate of Heritage Sites: A Case Study of Fuling Mausoleum, China

2020 ◽  
Author(s):  
Xiaoyu Wang ◽  
Peng Liu ◽  
Gongwen Xu
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Thermal Environment ◽  
Measurement Data ◽  
Ground Temperature ◽  
Rapid Urbanization ◽  
Actual Measurement ◽  
Heritage Sites ◽  
Human Thermal Comfort ◽  
The Impact

Abstract The thermal environment and microclimate of heritage sites has been severely impacted by rapid urbanization. This study collected various meteorological measurement data as a reference for computational fluid dynamics (CFD) simulation settings. Then CFD was applied to simulate the impact of lawns on the thermal environment and microclimate of Fuling Mausoleum. We found that lawns and soil can cool the air through evaporation, and thus have a specific cooling effect on the bricked ground. After lawns were planted, the bricked ground temperature decreased by 1.56–17.54°C than that before lawns were planted at 14:00, a decrease of 2.68%–24.20%. Under normal circumstances, when the wind speed or relative humidity increased, the ground temperature dropped. Greenbelt vegetation can adjust the microclimate and human thermal comfort indicators. The consistency of the difference between the actual measurement and the CFD simulation results shows that CFD simulation can thus accurately reflect the internal temperature field distribution if the selection of simulation parameters is reasonable. Theoretical calculation and analysis, experimental measurement research, and modern computer simulation analysis methods applied together constitute a complete system for studying modern physical environmental problems and can provide reliable and economic results.

scholarly journals Improved Performance Prediction of Marine Propeller: Numerical Investigation and Experimental Verification

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Yue Tan ◽  
Jing Li ◽  
Yuan Li ◽  
Chunbao Liu
Keyword(s):  
Experimental Data ◽  
Performance Prediction ◽  
Outer Boundary ◽  
Tangential Velocity ◽  
Marine Propeller ◽  
Computational Performance ◽  
Accurate Performance ◽  
Improved Performance ◽  
Experimental Values ◽  
Good Agreement

An approach was presented to improve the performance prediction of marine propeller through computational fluid dynamics (CFD). After a series of computations were conducted, it was found that the passage in the former study was too narrow, resulting in the unnecessary radial outer boundary effects. Hence, in this study, a fatter passage model was employed to avoid unnecessary effects, in which the diameter was the same as the length from the propeller to the downstream outlet and the diameter was larger than the previous study. The diameter and length of the passage were 5D and 8D, respectively. The propeller DTMB P5168 was used to evaluate the fat passage model. During simulation, the classical RANS model (standard k-ε) and the Multiple Reference Frame (MRF) approach were employed after accounting for other factors. The computational performance results were compared with the experimental values, which showed that they were in good agreement. The maximum errors of Kt and Kq were less than 5% and 3% on different advance coefficients J except 1.51, respectively, and that of η was less than 2.62%. Hence the new model obtains more accurate performance prediction compared with published literatures. The circumferentially averaged velocity components were also compared with the experimental results. The axial and tangential velocity components were also in good agreement with the experimental data. Specifically, the errors of the axial and tangential velocity components were less than 3%, when the r/R was not less than 3.4. When the J value was larger, the variation trends of radial velocity were consistent with the experimental data. In conclusion, the fat passage model proposed here was applicable to obtain the highly accurate predicted results.

Surface Variation Modeling by Fusing Surface Measurement Data With Multiple Manufacturing Process Variables

2016 ◽  
Author(s):  
Jie Ren ◽  
Hui Wang
Keyword(s):  
High Precision ◽  
Spatial Data ◽  
Measurement Data ◽  
Cost Effective ◽  
Surface Shape ◽  
Surface Measurement ◽  
Process Variables ◽  
Process Information ◽  
Surface Variation ◽  
Sampled Measurements

Controlling surface shape variations plays a key role in high-precision manufacturing. Most manufacturing plants rely on a number of multi-resolution measurements on manufactured surfaces to evaluate surface shapes and resultant quality. Conventional research on surface shape modeling focused on interpolation and extrapolation of spatial data using sampled measurements based on presumed spatial relationship over entire surface locations. However, the prediction accuracy is heavily restricted by the density of sampled measurements, preventing cost-effective evaluation of surface shape in high precision. New opportunities emerge for cost-effective high-precision surface manufacturing when the industry begins to extensively collect in-plant process information. This paper explores the opportunity by investigating strategies for fusing surface measurement data with multiple process variables. The fusion is achieved by characterizing the relationships between surface height and process variables using (1) linear regression based co-Kriging and (2) fuzzy if-then rules as well as considering spatial correlations. Under (3) Bayesian sequential updating frameworks, a generic surface variation model is updated sequentially using different process information. Case studies are conducted for comparisons and demonstrate the advantages of the fuzzy inference based spatial model.

scholarly journals Feeding head of relative rotary based on EDEM+FLUENT

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878482
Author(s):  
Sun Xiaoxia ◽  
Meng Wenjun ◽  
Yuan Yuan
Keyword(s):  
Simulation Analysis ◽  
Three Dimensional ◽  
Dynamics Analysis ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Surface Data ◽  
Fluent Simulation ◽  
Physical Prototype ◽  
Work Mechanism ◽  
Curve Equation

This article takes an efficient feeding head as the research object to study its work mechanism and perform dynamics analysis of the materials in the feeding head. In addition, this article obtains the physical prototype of a three-dimensional model and the feeding surface equation through the surface data of the feeding head and investigates different unfold lines of the feeding surface. In addition, this article recommends a curve equation of the feeding head under different friction coefficients through EDEM + FLUENT simulation analysis and conducts a research on transport and feeding quantity to deduce the equation for the transport quantity of the feeding head. Finally, the verity of the preceding curve equation and transport quantity is confirmed, which has important guiding significance for the feeding head design.

PERFORMANCE PREDICTION OF WIND PROPULSION SYSTEMS USING 3D CFD AND ROUTE SIMULATION

2019 ◽  
Author(s):  
A Persson ◽  
D.-Q. Li ◽  
F Olsson ◽  
S Werner ◽  
U Dhomé
Keyword(s):  
Performance Prediction ◽  
New Technology ◽  
Vortex Formation ◽  
Propulsion Systems ◽  
Cfd Simulations ◽  
Energy Saving Potential ◽  
Reasonable Cost ◽  
Accurate Performance ◽  
3D Effects ◽  
Ship Performance

Accurate performance prediction is necessary when designing/optimising wind propulsion systems (WPS). An independent, trustworthy prediction of the energy-saving potential is also needed to support the ship owner’s decision to invest in new technology. By using weather statistics along with a mathematical model of ship performance, route simulations can estimate the time and power required for transit of a route. Such simulations are commonly used today to optimise the design and operation of conventional ships. The introduction of WPS poses additional challenges for route simulations. WPS performance must be predicted at all points along the route, with wind of differing velocity and direction. The apparent wind will vary vertically (twist), due to the interaction between the ship velocity and the atmospheric boundary layer. Also, many proposed concepts use multiple WPS, introducing additional complexity, such as independent spin ratios/ sheeting angles. 3D CFD simulations capture the complex physics, including vortex formation and interaction effects, providing accurate performance prediction and an understanding of the flow. However, 3D CFD is costly, and it would not be possible to simulate all conditions at a reasonable cost. We present simplified approaches to modelling of WPS, using a limited number of CFD simulations, either in 2D or 3D, which are then extrapolated such that 3D effects are represented, and all conditions covered. The methodology is demonstrated on rotor sails and wing sails.

Pre-Grouting Treatment and Flow Numerical Simulation for the Landslide Area of Dalian Metro

2011 ◽  
Vol 71-78 ◽  
pp. 2787-2791
Author(s):  
Shu Ai Jiang ◽  
An Nan Jiang
Keyword(s):  
Water Surface ◽  
Simulation Analysis ◽  
General Trend ◽  
Measurement Data ◽  
Surface Displacement ◽  
Element Model ◽  
Landslide Area ◽  
Software Simulation ◽  
Simulation Results ◽  
Observation Wells

The study discusses the simulation analysis based on the modflow software. Generalize body site, zone and boundary conditions of simulation, make a finite element model based on the geology of the Collapse of Lot 110 , Dalian Metro. Determine the accuracy of the simulation results based on the comparison between the test and the field measurement data. And then predict the flow of groundwater and the penetration. Base on the software simulation of the surface displacement and field observation wells pumping records, to calculate the water surface elevation and the elevation, the general trend of measuring is same and the values are ​​consistent. Prove the necessity of the injection that is used in the accident.

scholarly journals Review on the Surface Heat Transfer Coefficients of Radiant Systems

2019 ◽  
Vol 111 ◽  
pp. 01075 ◽  
Author(s):  
Jun Shinoda ◽  
Ongun B. Kazanci ◽  
Shin-ichi Tanabe ◽  
Bjarne W. Olesen
Keyword(s):  
Heat Transfer ◽  
Heated Surface ◽  
Measurement Data ◽  
Radiant Heat ◽  
Surface Measurement ◽  
Radiant Heat Transfer ◽  
Extensive Literature ◽  
Prediction Errors ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Heat transfer coefficients are often used to describe the thermal behaviour of radiant systems and how it transfers heat between the cooled/heated surface and the room. In addition to current standards, numerous studies have been conducted to obtain the heat transfer coefficients through experiments and simulations. However, inconsistency is evident in the values or expressions suggested. Thus, this study investigated possible sources of discrepancy through an extensive literature review on articles and standards that focused on the heat transfer coefficients at the cooled/heated surface. Measurement data provided by different authors were extracted to compare both the amount of heat transfer and the actual heat transfer coefficients. Consequently, suggested values and expressions were used to predict the measurement data in other articles to examine their accuracy. Comparison of the results showed that the radiant heat transfer coefficients had a consistent value throughout the literature and had prediction error within ±20%. However, larger deviations and prediction errors were seen in the total and convective heat transfer. It was suggested that some of the sources of error may have been the calculation procedure of each heat transfer mechanism, choice of reference temperature and its measurement height/position, and room dimensions.

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