Research on Functional Similarity and Structural Similarity of Mechanical Components

2014 ◽  
Vol 541-542 ◽  
pp. 603-607
Author(s):  
Jie Yin ◽  
Ai Lun Wang
Keyword(s):  
Experimental Model ◽  
Model Test ◽  
Similarity Theory ◽  
Structural Similarity ◽  
Black Box ◽  
Functional Similarity ◽  
Similarity Criteria ◽  
Test Design ◽  
Mechanical Components ◽  
Set Up

The similarity theory is in essence a method based on equation expression. In the application, the model is regarded to be similar to the prototype only if the similarity theorem can be met. But different physical objects have the same equation expression, so the model is always not similar to the prototype. To solve this problem, a new method which studies the similarity of mechanical components from the perspective of function and structure is put forward in this paper, based on the similarity theory and the ‘black box’ concept. The functional similarity criteria and structural similarity criteria derived from this method can accurately describe the similar properties of mechanical components under different similar requirements and can be used to set up the experimental model. Finally, a series of basic mechanical components are taken for example to verify the feasibility and superiority of this method. The method put forward in this paper can be applied to model test design and engineering test, etc. under different similar requirements.

Model Experimental Study of SCR Reactor Flow Optimization in 1000MW Coal-Fired Boiler

2014 ◽  
Vol 955-959 ◽  
pp. 2177-2181
Author(s):  
Wen Yan Li ◽  
Shi Yong Wang ◽  
Xiao Ming Wang
Keyword(s):  
Flow Field ◽  
Experimental Model ◽  
Model Test ◽  
Flue Gas ◽  
Gas Flow ◽  
Similarity Theory ◽  
Cold Model ◽  
Power Plant Boiler ◽  
Design Requirements ◽  
Plant Boiler

The structure and arrangement of flue and deflector modules have significant influences on flue gas flow field and distribution of NH3 concentration in a SCR reactor. Numerical calculations about distributions of velocity, NH3 concentration and flow resistance in the deNOx reactor of a 1000MW power plant boiler with CFD have provided the optimal combination of layout scheme of guide plates. A1:15 experimental model of the reactor was constructed based on the principles of similarity theory, and cold model test was carried out with air substituting for flue gas, and CO for NH3.The consequences of model test and numerical modeling were basically similar and met the design requirements. Moreover, deposition characteristics of the experimental model was studied with fly ash from coal-fired boiler, which demonstrated that deposition was not severe under both 50% and 100% boiler full load. The model experiments indicated that the optimum program could achieve purpose of the flow field optimization.

On the Deduction and the Application of Dynamic Similarity Criteria of Steel Structure under Large Deformation Condition

2012 ◽  
Vol 512-515 ◽  
pp. 1957-1960 ◽  
Author(s):  
Yuan Li
Keyword(s):  
Large Deformation ◽  
Model Test ◽  
Similarity Theory ◽  
Steel Structure ◽  
Similarity Criteria ◽  
Matrix Analysis ◽  
Scale Model ◽  
Deformation Condition ◽  
Dynamic Similarity ◽  
Similarity Relations

Dynamic similarity criteria for large deformation of huge steel structure were derived according to Dimensional Matrix Analysis of the Buckingham Pi theorem and the similarity relations that must be satisfied by the physical quantities of model and prototype in huge steel structure model test are obtained. The 1/50 scale model of TC power is designed and made based on the similarity theory and the dynamic experiment is done. The calculation data with similarity theory are in agreement with that of experiment. So the model test can substitute for prototype test when they satisfy the similarity relations. A new way to solve dynamic analysis problem of huge steel structure is explored.

Development and Verification of Modeling Practice for CFD Decay Calculations to Obtain Roll Damping of FPSO

2021 ◽  
Author(s):  
Arjen Koop ◽  
Pierre Crepier ◽  
Sebastien Loubeyre ◽  
Corentin Dobral ◽  
Kai Yu ◽  
...  
Keyword(s):  
Model Test ◽  
Test Results ◽  
Cfd Modelling ◽  
Roll Damping ◽  
Natural Period ◽  
Computational Mesh ◽  
Safety Studies ◽  
Offshore Industry ◽  
Decay Tests ◽  
Set Up

Abstract Estimates for roll damping are important input parameters for simulation studies on vessels operating at sea, e.g. FPSO mooring in waves, wind and current, workability and operability investigations, Dynamic Position studies, ship-to-ship operations and safety studies of vessels. To accurately predict the motions of vessels this quantity should be determined with confidence in the values. Traditionally, model experiments in water basins using so-called decay tests are carried out to determine the roll damping. With recent advancements in CFD modelling, the offshore industry has started using CFD as an alternative tool to compute the roll damping of FPSO’s. In order to help adopt CFD as a widely accepted tool, there is a need to develop confidence in CFD predictions. Therefore, a practical CFD modelling practice is developed within the Reproducible CFD JIP for roll decay CFD simulations. The Modelling Practice describes the geometry modelling, computational mesh, model set-up and post-processing for these type of CFD calculations. This modelling practice is verified and validated by three independent verifiers against available model test data. This paper provides an overview of the developed modelling practice and the calculated CFD results from the verifiers. The CFD modelling practice is benchmarked against available model test results for a tanker-shaped FPSO. By following this modelling practice, the CFD predictions for the equivalent linear damping coefficient and natural period of the roll motions are within 10% for all verifiers and within 10% from the model test results. Therefore, we conclude that when following the developed modelling practice for roll decay simulations, reliable, accurate and reproducible results can be obtained for the roll damping of tanker-shaped FPSOs.

scholarly journals Similarity Analysis between Scale Model and Prototype of Large Vibrating Screen

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Zerong Zhang ◽  
Yongyan Wang ◽  
Zhimin Fan
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Similarity Theory ◽  
Similarity Criteria ◽  
Scale Model ◽  
Mode Shapes ◽  
Dynamic Stresses ◽  
Operating Condition ◽  
Vibrating Screen ◽  
Scale Down

In order to predict the physical characteristics of the large vibrating screen from its scale-down model, the similarity ratios of the frequency response functions, mode shapes, and dynamic stresses between the prototype and the scale model screen are built according to the similarity theory. The natural frequencies and modal shapes are extracted from the frequency response function by means of modal tests, in which the relative error of the natural frequencies is less than 9% and the modal shapes are consistent between the prototype and the model. The operating condition parameters including dynamic stress, displacement, velocity, and acceleration were also measured and conform to the similarity criteria. The results show that the inherent and operating condition parameters of the large vibrating screen can be obtained from the scale-down model conveniently, which provides an effective method for structural optimization and substructure coupling analysis of the large vibrating screen.

Assessing the Structural and Functional Similarity of Insulin Glargine Biosimilars

2021 ◽  
pp. 193229682110584
Author(s):  
Gayatri Vishwakarma ◽  
Neh Nupur ◽  
Anurag S. Rathore
Keyword(s):  
Insulin Glargine ◽  
Structural Similarity ◽  
Statistical Correlation ◽  
Functional Similarity ◽  
Spectroscopic Techniques ◽  
Vitro Assay ◽  
Innovator Product ◽  
Stress Studies ◽  
Related Substances

Background: A biosimilar product is expected to exhibit similar safety, efficacy, and quality as that of the approved reference product. Only a few reports of thorough evaluation of the quality of insulin glargine biosimilars are available in literature. Here, we examine the structural and functional similarity of biosimilars of insulin glargine, the first basal long-acting insulin analogue with respect to its innovator product (Lantus® from Sanofi Aventis). Methods: Structural similarity was established using mass spectrometry, chromatographic, and spectroscopic techniques. Stability was compared by performing accelerated thermal stress studies. Functional similarity was established via in vitro assay. Results: Biosimilar 4 exhibited greater content of high molecular weight species (HMWs) (0.80%) and related substances (RS) (0.45±0.06%) vs others (HMWs of 0.04% and RS of 0.17%). Biosimilars 1 and 3 exhibited higher rate of impurity generation (0.78% and 0.73% per week, respectively), as compared with other drug products (0.02% to 0.43% per week). Furthermore, %aggregation at 14 days was found to statistically correlate ( R2= 0.99, root mean square error (RMSE) = 0.095) with %aggregation at 0 day (linearly) and the number of months from expiry (nonlinearly), highlighting the overpowering impact of the latter. Conclusions: While an overall structural and functional similarity was observed across insulin glargine biosimilars with respect to the innovator product, low amounts of product-related variants were seen in some biosimilars and these impact product stability. The %aggregation at 14 days exhibits statistical correlation with %aggregation at 0 day and the number of months from expiry. The order of biosimilarity was denoted as Lantus®>Biosimilar 2>Biosimilar 4>Biosimilar 1>Biosimilar 3.

Improved Strake Design for Vortex Induced Motions of Spar Platforms

2005 ◽  
Author(s):  
Mehernosh Irani ◽  
Lyle Finn
Keyword(s):  
Model Test ◽  
Model Tests ◽  
Test Results ◽  
Test Program ◽  
Test Set ◽  
Test Methodology ◽  
Spar Platforms ◽  
Truss Spar ◽  
Set Up

An extensive model test program was conducted to explore the effectiveness of alternate strake designs to reduce Truss Spar VIV response. Different strake configurations were tested to minimize VIV response. The paper presents results of the model tests. The model test set-up is described, important parameters that are modeled (including hull and truss geometry, strake configuration, mass and mooring properties) and considerations of instrumentation and test methodology are discussed. The paper also describes the analysis of the test results and shows the effectiveness of new strake design. The present results are compared with VIV response of existing Truss Spars with conventional strake design.

Comparison of Wave-Induced Loads on a Near Surface Slender Body From Inviscid Flow Linear Solution and an Experimental Model Test

2018 ◽  
Author(s):  
Travis M. Turner ◽  
Joseph T. Klamo ◽  
Young W. Kwon
Keyword(s):  
Closed Form ◽  
Experimental Model ◽  
Model Test ◽  
Closed Form Solution ◽  
Small Diameter ◽  
Underwater Vehicles ◽  
Form Solution ◽  
Slender Body ◽  
Viscous Effects ◽  
Wave Induced

The wave-induced loads experienced by a fully-submerged vehicle, but operating near the surface, play an important role in the design and operation of the vehicle. For an inviscid fluid with a monochromatic wave field, the first-order loads on a slender body of revolution can be solved for analytically using the method of singularities. The solution involves an integral expression dependent on the cross-sectional geometry of the body. For the canonical shape of a circular cylinder with hemispheric end caps, the integrals can be directly evaluated piecewise and a closed-form solution determined. This allows the rapid and easy calculation of wave-induced loads in any simple wave environment and at any operating depth. However, the use of potential flow ignores any viscous effects and effects due to changes to the wave as it passes over the vehicle. These effects may be important for smaller man-portable unmanned underwater vehicles. To determine the usefulness of this closed-form solution for small diameter bodies, an experimental model test was conducted to measure the loads where both potential and viscous effects are present. Experiments were performed for various wavelengths, at two model depths, and for one wave height while measuring the drag and vertical force along with the pitch moment on a 4.5 inch diameter model. These experimental loads are then compared to predicted loads from the analytic solution to assess their accuracy. This allows the determination of the importance of viscous effects and passing wave modification for wave-induced loads of small diameter underwater vehicles.

scholarly journals Radial Joints Behavior of a Precast Asymmetric Underpass Induced by Long-Term Loads of Ground Vehicles

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zhiyi Jin ◽  
Taiyue Qi ◽  
Xiao Liang ◽  
Bo Lei ◽  
Yangyang Yu ◽  
...  
Keyword(s):  
Transient Response ◽  
Model Test ◽  
Similarity Theory ◽  
Rapid Development ◽  
Design Stage ◽  
Physical Model Test ◽  
Scaled Model ◽  
Joint Opening ◽  
Assembly Technology

With the rapid development of the urbanization, many underpasses are designed and constructed in big cities to alleviate the huge traffic pressure. The construction method has been changed from traditional on-site concrete pouring technology to prefabricated assembly technology. However, this change will inevitably bring out some new problems to be studied such as the behaviour of the radial joints. In this study, the numerical simulation model of Moziqiao precast and assemble underpass with large asymmetric cross section was constructed by using the ABAQUS software to study the transient response of the underpass induced by ground surface dynamic load. Based on the similarity theory a 1/10 scaled model test was carried out to study the long-term radial joint behaviour of the underpass considering the prestress loss during the 2000 000 loading cycles. The results transient dynamic response from computed and tested was compared in terms of acceleration. The comparison showed that the transient response accelerations have good consistency. The results of the physical model test were analysed in terms of joint opening, closure, and slipping. The accumulative joint opening was closely correlated to the prestress level, and the joint opening at different prestress levels increased with the loss of the prestress. The joints closure decreased with the increase of the previous accumulative color value. The joint slipping mainly attributed to the slipping of the top segment. Both the opening and slipping of the joints at RJ 1 were larger than that of RJ3 due to the wider span of RJ1, which reflected an asymmetric effect. This study revealed the long-term accumulative behaviour of the radial joints, which convinced us that the long-term accumulative deformation of the joints should be taken into consideration during the design stage for similar projects.

Centrifuge-model test study of key hazard factors of deep toppling deformation and disaster pattern of anti-dip layered-rock slope under gravity

2020 ◽  
Author(s):  
Da Zheng ◽  
Hua Zhao
Keyword(s):  
Model Test ◽  
Rock Slope ◽  
Shear Failure ◽  
Similarity Theory ◽  
Distinct Element ◽  
Centrifuge Model Test ◽  
Centrifuge Model ◽  
Layered Rock ◽  
External Conditions ◽  
Toppling Deformation

<p>To study the toppling deformed body before construction of the dam at the Gushui hydropower station, we developed here a physical model of the slope on the basis of known local geology and of similarity theory. We simulated valley trenching by a method using prior produced block modules and three levels of excavation, and we studied key hazard factors of deep toppling deformation and the disaster pattern related to anti-dip, layered-rock slope under gravity by a five-stage centrifuge-model test and Universal Distinct Element Code numerical-simulation analysis. The results show the following: (1) The occurrence, development and destruction of deep toppling deformation of anti-dip layered rock slopes must have gone through a long geological history; the accumulation of energy and deformation is a very long process, and accelerated-deformation is closely related to changes in external conditions (such as excavation, earthquake, etc.); (2) lithologic conditions (relatively weak rock mass), structural conditions (appropriate layer thickness and dip angle), and external conditions (valley trenching or excavation of slopes) are key factors for deep toppling deformation, while the free-surface condition is the key hazard factor; (3) deep toppling deformation can lead to multilevel bending zones at different depths inside the slope after the several stages of valley trenching (multilevel excavation); the bending zone is gradually connected from the foot of the slope all the way to the top, which eventually becomes the failure boundary; and the development and connection of the bending zone may result in the overall shear failure of the slope along the bending zone; (4) for deep toppling deformation, we propose a qualitative-judgment index and quantitative-judgment indicators of the degree of toppling deformation. We derived quantitative-judgment formulas for the degree of toppling deformation and the calculation formulas were used for the maximum depth of toppling deformation, and we established a system for discrimination of destruction patterns for deep toppling deformation of anti-dip slope.</p>

scholarly journals Correction of Earth Pressure and Analysis of Deformation for Double-Row Piles in Foundation Excavation in Changchun of China

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yijun Zhou ◽  
Aijun Yao ◽  
Haobo Li ◽  
Xuan Zheng
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Large Scale ◽  
Similarity Theory ◽  
Earth Pressure ◽  
Physical Model Test ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Double Row ◽  
The Earth

In order to study the earth pressure and the deformation behavior of the double-row piles in foundation excavation, a large-scale physical model test was introduced to simulate deformation of double-row piles in foundation excavation based on the principle of similarity theory in this paper. Represented by the deep foundation pit engineering of Changchun, the strain and the displacement of the double-row piles and the earth pressure are calculated by the above-mentioned physical model test. Then a numerical simulation has been carried out to validate practicability of the physical model test. The results show that the strain and the displacement of the front-row piles are larger than the back-row piles. The earth pressure of the front-row piles appears to be “right convex,” correcting the specification of the earth pressure and putting forward the coefficient of β. The results in this paper may provide constructive reference for practical engineering.

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