scholarly journals A Novel Modeling Method in Metal Strip Leveling Based on a Roll-Strip Unit

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Guodong Yi ◽  
Zili Wang ◽  
Zhouyu Hu
Keyword(s):  
Influence Factor ◽  
Bending Moment ◽  
Static Friction ◽  
Longitudinal Direction ◽  
Metal Strip ◽  
Equivalent Model ◽  
Normal Operation ◽  
Linear Distribution ◽  
Plastic Extension ◽  
Force Relationship

In the metal strip-multiroll leveling process, the action behavior of each roll is different. However, modeling each roll individually will result in redundancy which is not conducive to the modeling of the entire leveling process. To overcome this problem, a roll-strip unit (RSU) model is proposed to uniformly describe the behavior of each roll during the leveling process. The RSU and its equivalent model are defined on the basis of analyzing the force relationship between the roll and the strip. According to the linear distribution of the bending moment in the longitudinal direction of the strip, the position of the zero bending moment, that is, the virtual fulcrum, is obtained to determine the interval of the RSU. A plastic deformation function is established to describe the influence of plastic extension on the tension and velocity of the strip. The fitting of the deformation curve of the strip is optimized by the tension influence factor and the zero curvature moment. The static friction condition between the roll and the strip which ensures the normal operation of the RSU is given. The AMESim model of the RSU is established to lay the foundation for the dynamic modeling of the multiroll leveler.

scholarly journals Effect of Combined Stresses on Fiber- Epoxy Composite Curved Pipe

2018 ◽  
Vol 26 (7) ◽  
pp. 58-71
Author(s):  
Fadhel Abbas Abdullah ◽  
Omar Emad Shukry
Keyword(s):  
Internal Pressure ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Fiber Composite ◽  
Bending Moment ◽  
Longitudinal Direction ◽  
Curve Pipe ◽  
Curved Pipe ◽  
Composite Curve ◽  
Composite Pipes

The aim of this research is to study the behavior of fiber epoxy composite curve pipe under internal pressure and bending moment. The specimens made from woven roving (Mat) fiber glass pipes and epoxy composite with 50% volume fraction are used to manufacturing curved pipe. The experimental work included manufacturing pipe specimens by vacuum bag technique. Pipe specimens were having 100mm inner diameter, 450 mm length of curvature center line of curve pipe with (43 degree) and two wall thickness are 4 and 3 mm. The test rig was designed and performed to study the effect of internal pressure and bending moment on the composite pipes. Also, the tensile test of the samples was done. The analytical expression solution has been accomplished to determine the strain, stress, for hoop and longitudinal direction. It is evident that the hoop stress for woven roving fiber composite pipe was more than longitudinal stress by almost (14%). The maximum internal pressure in the case of internal pressure only was more than compared to the combined internal pressure with bending moment by almost (115%). The most dangerous region is found in the inner arc of the curved pipe (intrude) area.

Strength Limit of Thimble Tube With Material Plasticity Under Bending Moment and Axial Compression Force

2018 ◽  
Author(s):  
Hisashi Koike ◽  
Masaji Mori ◽  
Daisuke Fujiwara ◽  
Takashi Shimomura
Keyword(s):  
Fuel Assembly ◽  
Seismic Event ◽  
Plastic Material ◽  
Bending Moment ◽  
Normal Operation ◽  
Beam Model ◽  
Allowable Limit ◽  
Perfectly Plastic ◽  
Asme Code ◽  
Elastic Perfectly Plastic

The thimble tube, which is made of Zircaly-4, is one of the main components of a PWR fuel assembly. The thimble tube has an important role as a structural member of the skeleton. Another role of the thimble tube is to guide a rod cluster control assembly (RCCA) for insertion during the reactor operation, and the function has to be assured not only in normal operation but in a seismic event. In a horizontal seismic event, the fuel assembly vibrates laterally, which gives bending moment to the thimble tube. In addition, axial compressive force acts on the thimble tube in a vertical seismic event. The integrity of the thimble tube has to be maintained while this force and moment act. Mitsubishi has confirmed by the elastic stress analysis that the stress of the thimble tube is lower than the limit value requested for the seismic event. The stress evaluation method is based on the ASME code. The ASME code also describes the limit analysis which is available when the predicted stress is beyond elastic region of the material. In the analysis, the material is assumed to be elastic-perfectly plastic, and the maximum load that the structure can carry is calculated. For the reason mentioned above, the allowable limit of the thimble tube should be determined as a function between the force and the moment. We are planning to examine the allowable limit experimentally. As a step before testing, an analytical approach for the limit is discussed in this paper. Firstly, the allowable limit is calculated by a beam model assuming elastic-perfectly plastic material, based on the ASME code. Secondly, a 3D model analysis with elastic-plastic material is performed to predict the practical strength. Based on the comparison with the analysis using elastic-perfectly plastic material, ASME based limit is considerably conservative compared with the one with the actual stress-strain curve. Conversely, this means there is enough room to rationalize the allowable limit. As the future work, the experiment will be conducted to obtain the practical limit of the thimble tube and to verify the analysis results.

EFFECTS OF THE INITIAL DEFLECTION SHAPE ON THE MOMENT AMPLIFICATION FACTOR OF BEAM-COLUMNS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Haruna Utsunomiya ◽  
Masayuki Haraguchi ◽  
Masae Kido ◽  
Keigo Tsuda
Keyword(s):  
Amplification Factor ◽  
Slenderness Ratio ◽  
Compressive Force ◽  
Bending Moment ◽  
Load Ratio ◽  
Longitudinal Direction ◽  
Initial Deflection ◽  
Axial Compressive Force ◽  
Beam Columns ◽  
The Moment

In the design of slender steel beam-columns, the moment amplification factor is used to estimate the maximum moment along with the longitudinal direction. While formulas for evaluating the factor have been presented on the basis of elastic or elastic-plastic analysis, the initial deflection of the column is not considered. The effect that the initial deflection on the strength and behavior of the column has been shown only when the initial deflection shape is half sine wave. This paper discusses the effect of the initial deflection shape on the value of the moment amplification factor by performing the analytical work. The analytical model is the hinged-end beam-column subjected to constant axial compressive force and end moments. First of all, the equilibrium differential equation which governs the problem is solved and the formula for calculating the bending moment is presented. In the parametric study, magnitude of initial deflection, initial deflection shape, axial load ratio, slenderness ratio and end moment ratio are selected as the parameters. In this paper, we discuss the effects of the amount of the initial deflection and the initial deflection shape.

Modeling the Effect of Surface Roughness on the Adhesion, Contact and Friction in Micro-Electro-Mechanical Systems (MEMS) Interfaces

2003 ◽  
Author(s):  
Noureddine Tayebi ◽  
Andreas A. Polycarpou
Keyword(s):  
Surface Texturing ◽  
Static Friction ◽  
Normal Operation ◽  
Root Mean Square Roughness ◽  
Adhesion Forces ◽  
Sensors And Actuators ◽  
Micro Electro Mechanical Systems ◽  
Friction Forces ◽  
Normal Forces ◽  
Adhesion Contact

It has been experimentally shown that surface texturing (roughening) decreases the effect of intermolecular adhesion forces that are significant in MEMS applications. These forces can hinder normal operation of sensors and actuators as well as micro-engines where they might increase friction, which could be catastrophic. In this paper, a model that predicts the effects of roughness, asymmetry, and flatness on the adhesion, contact, and friction forces in MEMS interfaces is presented. The three key parameters used to characterize the roughness the asymmetry and the flatness of a surface topography are the root-mean-square roughness (RMS), skewness and kurtosis, respectively. It is predicted that surfaces with high RMS, high kurtosis and positive skewness exhibit lower adhesion and static friction coefficient, even at extremely low external normal forces.

scholarly journals Principles of Automated Data Processing of Mandelstam – Brillouin Backscatter Characteristics for Evaluating the State of Optical Fibers

T-Comm ◽  
2020 ◽  
Vol 14 (8) ◽  
pp. 47-52
Author(s):  
Igor V. Bogachkov ◽  
Keyword(s):  
Optical Fibers ◽  
Light Guide ◽  
Functional Dependence ◽  
Single Mode ◽  
Longitudinal Direction ◽  
The State ◽  
Normal Operation ◽  
Fiber Types ◽  
Operational Parameters ◽  
Acoustic Modes

For early diagnostics of the state of optical fibers (OFs) located in the laid optical cables (OCs), it is necessary to identify potentially unreliable sections of the S in advance, which over time can lead to the destruction of fibers and disrupt the normal operation of fiber-optic communication lines (FOCLs). For diagnosis and forecasting of the state of the OFs that are in the laid OCs, Brillouin optical pulse reflectometers (BOTDR) are used, in which the back-reflected signal of the spontaneous Mandelstam – Brillouin scattering (MBS) is analyzed. In the process of obtaining a trace of the distribution of the Mandelshtam – Brillouin backscatter spectrum (MBBS) along the OF, the Brillouin frequency shift (BFS) is determined. After this, a graphs of the distribution of strain along the light-guide is constructed. A classification of varieties of single-mode optical fibers based on analysis of the MBS characteristics is discussed in this paper. It is shown how by the characteristics of the frequency profiles of the MBBS, one can determine the type of fiber and also evaluate the change in the strain and BFS. The MBBS profile come under influence by the functional dependence of the distribution of acoustic modes in the OF, their longitudinal direction. Both of them depend on the structure of the OF layers, as well as on the types and concentration of various alloying additives of the core OF. For single-mode OFs, when describing the MBS process, it is necessary to take into account the spatial distribution and interaction of the main optical and several acoustic modes. After uploading the data file from the BOTDR, it is necessary to process the information in order to determine the BFS and the strain along the light-guide. This process can be automatized, if a database has been formed. When a new Brillouin reflectogram appears, the MBBS profile from it must be compared with templates from the generated database. To classify the fiber types, it is necessary to evaluate the degree of matching of the explored MBBS profile with all the database templates. To assess the degree of coincidence of the considered MBBS profiles, needs to be defined the overall part of the frequency band for analysis. The programs for the automated processing of the Brillouin reflectograms data are presented. Based on the analysis of Brillouin reflectograms, it is possible to identify a factor that had a predominant influence on the characteristics of the MBS signal in the explored sections of single-mode optical fibers. As a result of the program's work, a template is output that, according to the program's estimates according to the algorithm described above, has the best match with the downloaded image. To increase the accuracy of assessing the similarity of the explored profiles, it is also recommended to carry out calculations according to the above-described algorithm when aligning not only the maximum levels, but also combine the graphs along the frequency axis. It is clear that during the overlay the frequencies of the "peaks" (BFS), there will be a very strong coincidence of the patterns, and the type of the OFs will be determined correctly, while at some temperatures a good degree of similarity with another pattern could be obtained. The obtained estimate of the BFS allows one to determine the degree of the OF strain. The identification of the MBBS profile and other characteristics of the MBS allows you to create a database various types of the OFs and different manufacturers, which can be used to classify the type of the OFs. The results presented in this exploratory development show how based on the analysis of BOTDR reflectograms, it is possible to automatically determine the type of the OF in OC, to identify a factor that has a predominant effect on the frequency response and strain in the explored sections of the OFs in FOCL, which can improve the efficiency of predicting the operational parameters of the physical channels of optical telecommunication systems.

scholarly journals Reliability of Buried Pipes in Heterogeneous Soil Subjected to Seismic Loads

2021 ◽  
Vol 11 (1) ◽  
pp. 6708-6713
Author(s):  
H. Benzeguir ◽  
S. M. Elachachi ◽  
D. Nedjar ◽  
M. Bensafi
Keyword(s):  
Structural Reliability ◽  
Limit State ◽  
Bending Moment ◽  
Longitudinal Direction ◽  
Point Of View ◽  
Ultimate Limit State ◽  
Buried Pipe ◽  
Limit States ◽  
Ground Acceleration ◽  
Buried Pipes

Dysfunctions and failures of buried pipe networks, like sewer networks, are studied in this paper from the point of view of structural reliability and heterogeneity of geotechnical conditions in the longitudinal direction. Combined soil spatial variability and Peak Ground Acceleration (PGA) induce stresses and displacements. A model has been developed within the frame of geostatistics and a mechanical description of the soil–structure interaction of a set of buried pipes with connections resting on the soil by a two-parameter model (Pasternak model). Structural reliability analysis is performed considering two limit states: Serviceability Limit State (SLS), related to large "counter slope" in a given pipe, and Ultimate Limit State (ULS), corresponding to bending moment.

scholarly journals Effect of Fiber Reinforced Polymer Tubes Filled with Recycled Materials and Concrete on Structural Capacity of Pile Foundations

2020 ◽  
Vol 10 (5) ◽  
pp. 1554 ◽  
Author(s):  
Visar Farhangi ◽  
Moses Karakouzian
Keyword(s):  
Bending Moment ◽  
Longitudinal Direction ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bridge Foundations ◽  
Reinforced Polymer ◽  
Structural Capacity ◽  
Gfrp Composite ◽  
Lateral Strength ◽  
Composite Pile

This paper deals with analyzing the structural responses of glass-fiber-reinforced polymer (GFRP) tubes filled with recycled and concrete material for developing composite piles, as an alternative to traditional steel reinforced piles in bridge foundations. The full-scale GFRP composite piles included three structural layers, using a fiber-oriented material that was inclined longitudinally. Almost 60% of the fibers were orientated at 35° from the longitudinal direction of the pile and the rest 40 percent were oriented at 86° from the horizontal axis. The segment between the inner and outer layers was inclined 3° from the hoop direction in the tube. The behavior of the filled GFRP tubes was semi-linear and resulted in increasing the total ductility and strength of the piles. Adjusting the material’s properties, such as the EAxial, EHoop, and Poisson ratios, optimized the results. The lateral strength of the GFRP composite pile and pre-stressed piles are investigated under both axial compression and bending moment loads. Based on the conducted parametric study, the required axial and bending capacities of piles in different ranges of eccentricities can be reached using the combination of tube wall thickness and GFRP fiber percentages.

Study of Safety Influence Factor of Bridge Substructure in Loess Gulch

2012 ◽  
Vol 546-547 ◽  
pp. 89-96
Author(s):  
Jin Wei ◽  
Zhong Ju Feng ◽  
Feng Ma
Keyword(s):  
Soil Erosion ◽  
Debris Flow ◽  
Pile Foundation ◽  
Influence Factor ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Zero Point ◽  
Internal Force ◽  
Prevention Measures ◽  
The Stability

In this paper, the geology characteristics of loess gulch area were summarized. The mechanical models of the influence of landslide, debris flow and soil erosion on the safety of the pile foundation were created. The influence of the geology casualty on the safety of the pile foundation were analyzed. The analyses showed, when the pile foundation located the varied position of the loess gulch, the influence of soil erosion on the pile foundation character (acting force of pile side, free length of the pile, the first zero point position of the flexure curve, drawdown of the maximum bending moment, the increment of the lateral displacement, the drawdown of the lateral bearing capacity, the drawdown of the stability, etc.) were strikingly different. The calculation method of the pile and pier internal force was put forward under the function of landslide thrust and pressing force of debris flow. The corresponding prevention measures to different influencing factors were presented in the end.

Modeling of a Cartwheel Flexural Pivot

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Bi Shusheng ◽  
Zhao Hongzhe ◽  
Yu Jingjun
Keyword(s):  
Parametric Design ◽  
Bending Moment ◽  
Equivalent Model ◽  
Vertical Force ◽  
Element Analysis ◽  
Rotational Angle ◽  
Single Beam ◽  
Primary Motion ◽  
Center Shift ◽  
Parasitic Motion

A cartwheel flexural pivot has a small center shift as a function of loading and ease of manufacturing. This paper addresses an accurate model that includes the loading cases of a bending moment combined with both a horizontal force and a vertical force. First, a triangle flexural pivot is modeled as a single beam. Then, the model of cartwheel flexural pivot based on an equivalent model is developed by utilizing the results of the triangle pivot. The expressions for rotational displacement and center shift are derived to evaluate the primary motion and the parasitic motion; the maximum rotational angle is simply formulated to predicate the range of motion. Finally, the model is verified by finite element analysis. The relative error of the primary motion is less than 1.1% for various loading cases even if the rotational angle reaches ±20 deg, and the predicted errors for the two center shift components are less than 15.4% and 7.1%. The result shows that the model is accurate enough for designers to use for initial parametric design studies, such as for conceptual design.

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