scholarly journals Analytical model of liner with previous loads

2019 ◽  
pp. 99-106
Author(s):  
Dmytriv, V. ◽  
Dmytriv, I. ◽  
Krasnytsia, B.
Keyword(s):  
Cylindrical Shell ◽  
Analytical Model ◽  
Modulus Of Elasticity ◽  
Mechanical Characteristics ◽  
Structural Parameters ◽  
Vacuum Pressure ◽  
Central Angle ◽  
Radial Plane ◽  
Working Length ◽  
Preliminary Tension

Purpose. Development analytical model of the liner, taking into account its previous tension, structural and technological parameters and physical-mechanical characteristics of the rubber material, for modeling its deformations in the radial, longitudinal and circular planes. Methods. Analytical, mathematical modeling. Results. On the basis of the equilibrium equations for a cylindrical shell, taking into account the isotropy of the medium and the without momentary stress state, the spatial of forces and the preliminary tension of the liner, a system of analytic equations is developed that enables modelling of the deformations of the liner, which is the factor of its closure. The analytical dependences of the deformation of the liner in the longitudinal, circular and radial planes, depending on its structural parameters and physical and mechanical characteristics of the material, are developed. Parameters for deformation simulation are: R – radius of liner, Е – modulus of elasticity, h – thickness of liner, рн – vacuum pressure, l – the length of the active part of liner, ν – Poisson's coefficient for rubber, Fн force of tension of liner. Depending on the central angle in the radial plane of the section, the shape of the deformation of the liner is simulated along its entire working length. Conclusions. The obtained dependences allow simulating the deformation of the liner in the longitudinal, circular and radial planes, depending on its structural parameters and physical-mechanical characteristics of the material. The developed analytical dependences take into account the preliminary tension of the liner, the vacuum pressure and makes it possible to model, depending on the central angle in the radial plane of the cross-section of rubber. The use of developed analytical dependencies makes it possible to substantiate the basic parameters that influence the technological process of milk yield cows Keywords: liner, vacuum pressure, modulus of elasticity, radial deformation, coordinate system, tension of rubber, the cylindrical shell, the isotropic medium.

scholarly journals Dynamic model of closure the liner

2020 ◽  
pp. 114-122
Author(s):  
I. V. Dmytriv I. V.
Keyword(s):  
Cylindrical Shell ◽  
Modulus Of Elasticity ◽  
Mechanical Characteristics ◽  
Vacuum Pressure ◽  
Design Parameters ◽  
Radial Deformation ◽  
Central Angle ◽  
Radial Plane ◽  
Working Length ◽  
Physical And Mechanical Characteristics

Annotation Purpose. Develop analytical dependences for modeling the speed and dynamics of deformation of liner depending on its design parameters and physical and mechanical characteristics, taking into account the technological parameters of the process. Methods. Based on the system of geometric equilibrium equations for a cylindrical shell, taking into account the isotropy of the medium and the momentless stress state, the spatial action of forces and pre-tension of the liner, developed analytical equations that allow modeling the dynamics of deformation of liner in time, which allows to determine the time constant of the system “liner – milking cup”. Results. Analytical dependences of the dynamics of deformation of liner in time in the radial plane and the rate of deformation depending on its design parameters and physical and mechanical characteristics of the material are developed. Parameters for deformation simulation are: R – radius of liner, Е – modulus of elasticity, ρ – the density of the rubber material, h – thickness of liner, рн – vacuum pressure, l – the length of the active part of liner, ν – Poisson's coefficient for rubber, Fн – force of tension of liner. Depending on the central angle in the radial plane of the section, the shape of the deformation of the liner is modeled along its entire working length during the closing and opening stroke. Conclusions. The obtained dependences allow to model the dynamics of deformation of liner in the radial plane depending on its design parameters and physical and mechanical characteristics of the material. The developed analytical dependences take into account the pre-tension of the liner, vacuum pressure and allows modeling depending on the central angle in the radial plane of the rubber section. The use of the developed analytical dependences makes it possible to substantiate the main parameters that affect the process of closing and opening of the liner. The characteristic of the deformation in the cross section of the largest deformation is that the tension of the liner does not affect the deformation characteristic. This is due to the isotropy property of the cylindrical shell and the elastic isotropic properties. Keywords: liner, vacuum pressure, modulus of elasticity, radial deformation, coordinate system, tension of rubber, the cylindrical shell, the isotropic medium.

Mechanical and thermal behaviors of ultra-high molecular weight polyethylene triaxial braids: the influence of structural parameters

2018 ◽  
Vol 89 (16) ◽  
pp. 3362-3373 ◽  
Author(s):  
Shenglei Xiao ◽  
Charles Lanceron ◽  
Peng Wang ◽  
Damien Soulat ◽  
Hang Gao
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Mechanical Characteristics ◽  
Structural Parameters ◽  
Tensile Tests ◽  
Tensile Behavior ◽  
Experimental Database ◽  
Strength And Deformation ◽  
Braiding Angle ◽  
Ultra High Molecular Weight

Recently, triaxial braids made from ultra-high molecular weight polyethylene (UHMWPE) have been recognized as one of the most popular composite reinforcements in the aerospace and defense fields. To further explore the mechanical characteristics of this material, a detailed experimental study on tensile behavior is reported in this paper. The triaxial braids show a “double-peak” phenomenon in tensile strength and deformation, caused by axial yarns and the in-plane shearing of bias yarns. The evolution of the braiding angle, measured during these tensile tests, is discussed according to the braiding parameters (initial braiding angle, number of axial yarns). Using the high conductivity properties of the UHMWPE material, the temperature caused by inter-yarn friction during tensile tests is also studied. This temperature is related to the evolution of the braiding angle. The temperature increases with the increasing number of axial yarns and decreases with increasing braiding angle. This study provides an experimental database on the influence of braiding parameters on the tensile behavior of triaxial braids.

scholarly journals An Evaluation of Active Noise Control in a Cylindrical Shell

1989 ◽  
Vol 111 (3) ◽  
pp. 337-342 ◽  
Author(s):  
R. J. Silcox ◽  
H. C. Lester ◽  
S. B. Abler
Keyword(s):  
Cylindrical Shell ◽  
Analytical Model ◽  
Noise Control ◽  
Active Noise Control ◽  
Effective Control ◽  
Elastic Cylindrical Shell ◽  
Noise Sources ◽  
Active Noise ◽  
Fixed Array ◽  
Forced Responses

This paper examines the physical mechanisms governing the use of active noise control in an extended volume of a cylindrical shell. Measured data were compared with computed results from a previously derived analytical model based on infinite shell theory. For both the analytical model and experiment, the radiation of external monopoles is coupled to the internal acoustic field through the radial displacement of the thin, elastic, cylindrical shell. An active noise control system was implemented inside the cylinder using a fixed array of discrete monopole sources, all of which lie in the plane of the exterior noise sources. Good agreement between measurement and prediction was obtained for both internal pressure response and overall noise reduction. Attenuations in the source plane greater than 15 dB were recorded along with a uniformly quieted noise environment over an indicative length inside the experimental model. Results indicate that for forced responses with extended axial distributions, axial arrays of control sources may be required. Finally, the Nyquist criteria for the number of azimuthal control sources is shown to provide for effective control over the full cylinder cross section.

scholarly journals Electromagnetic and Mechanical Characteristics Analysis of a Flat-Type Vertical-Gap Passive Magnetic Levitation Vibration Isolator

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Baoquan Kou ◽  
Yiheng Zhou ◽  
Xiaobao Yang ◽  
Feng Xing ◽  
He Zhang
Keyword(s):  
Vibration Isolation ◽  
Mechanical Characteristics ◽  
Magnetic Levitation ◽  
Structural Parameters ◽  
Force Density ◽  
Vibration Isolator ◽  
Isolation System ◽  
Flat Type ◽  
Characteristics Analysis ◽  
Vertical Gap

In this paper, we describe a flat-type vertical-gap passive magnetic levitation vibration isolator (FVPMLVI) for active vibration isolation system (AVIS). A dual-stator scheme and a special stator magnet array are adopted in the proposed FVPMLVI, which has the effect of decreasing its natural frequency, and this enhances the vibration isolation capability of the FVPMLVI. The structure, operating principle, analytical model, and electromagnetic and mechanical characteristics of the FVPMLVI are investigated. The relationship between the force characteristics (levitation force, horizontal force, force ripple, and force density) and major structural parameters (width and thickness of stator and mover magnets) is analyzed by finite element method. The experiment result is in good agreement with the theoretical analysis.

Assessment of a Complex Aerospace Design through Optical Techniques

2014 ◽  
Vol 592-594 ◽  
pp. 1006-1010 ◽  
Author(s):  
Digendranath Swain ◽  
Jeby Philip ◽  
S. Annamala Pillai
Keyword(s):  
Cylindrical Shell ◽  
Strain Field ◽  
Experimental Techniques ◽  
Optical Techniques ◽  
Design Assessment ◽  
Strain Concentration ◽  
Radial Plane ◽  
Photoelastic Model ◽  
Individual Contributions ◽  
Notch Tip

This paper reports the design assessment carried out on a subassembly of an advanced rocket using experimental techniques. The design was very complex and critical, since a cylindrical shell had a square cutout on the axial-hoop plane interacting with a notch in the axial-radial plane. Herein, two optical techniques have been employed for assessing the interaction between the notch and the cutout, and their individual contributions to the strain-field. Initially, a photoelastic model was studied to estimate the stresses at the notch tip. Subsequently, DIC was employed for measuring strains at the notch during the ground based testing of the actual component. The outcomes of these two experiments showed that the effect of the cutout to the strain concentration was negligible due to the extra stiffness provided by other assemblies.

Nonlinear Effects on the Discontinuity Stresses in a Cylindrical Shell With a Flat Head Closure

1974 ◽  
Vol 96 (1) ◽  
pp. 44-46
Author(s):  
C. K. McDonald ◽  
R. E. McDonald
Keyword(s):  
Cylindrical Shell ◽  
Modulus Of Elasticity ◽  
Nonlinear Effect ◽  
Cylindrical Shells ◽  
Nonlinear Effects ◽  
Thin Shells ◽  
Large Displacements ◽  
Low Modulus

The effect of large displacements on the flexural edge stresses in thin cylindrical shells with flat head closures subjected to axisymmetric loads is considered. Results are presented which show that neglecting this nonlinear effect leads to nonconservative results. However, it is shown that these effects can usually be safely neglected except for very thin shells or for shells with a low modulus of elasticity. Curves are given which illustrate this effect for selected shell parameters.

scholarly journals Enhancing Solar Still Performance Using Vacuum Pump and Geothermal Energy

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 539
Author(s):  
Syed Danish ◽  
Abdelrahman El-Leathy ◽  
Mohanad Alata ◽  
Hany Al-Ansary
Keyword(s):  
Heat Exchanger ◽  
Wind Speed ◽  
Ambient Temperature ◽  
Water Temperature ◽  
Analytical Model ◽  
Vacuum Pump ◽  
Vacuum Pressure ◽  
Geothermal System ◽  
Outlet Temperature ◽  
Solar Still

Improvement in the performance of a solar still is investigated with the integration of a geothermal cooling system and a vacuum pump. Geothermal cooling is simulated to provide a cold, effective underground water temperature, which could reach 15–25 °C below ambient. Cooling is achieved by circulating water underground. As a result of this circulation, the cold fluid from the ground flows into a counter flow shell and tube heat exchanger. A vacuum pump is used to keep the solar still at a certain vacuum pressure. The sizes of the geothermal system and solar still are designed in such a way that the water outlet temperature from the ground and its flow rate are capable of condensing the entire vapor produced by the still. An analytical model was developed and then solved using the Newton–Raphson method for solving non-linear equations. A prototype was built to validate the analytical model. The results were in close agreement. A 305% increase in daily water productivity resulted from the proposed enhancements. After experimental validation, the effects of various parameters such as vacuum pressure, ambient temperature, and wind speed on the yield of geothermal solar still were examined. It was found that the increase in vacuum pressure enhanced performance, whereas the increase in wind speed had a detrimental effect on the yield of the solar still. A higher ambient temperature increased the yield of the solar still. Finally, the design of the heat exchanger for condensing the distilled water using geothermal cooling water was also investigated in terms of the increase in UA (the product of overall heat transfer coefficient and the area of heat exchanger) with inlet cooling geothermal water temperature.

Effects of structural parameters of oil groove on transmission characteristics of hydro-viscous clutch based on viscosity-temperature property of oil film

2017 ◽  
Vol 69 (5) ◽  
pp. 690-700 ◽  
Author(s):  
Fangwei Xie ◽  
Diancheng Wu ◽  
Yaowen Tong ◽  
Bing Zhang ◽  
Jie Zhu
Keyword(s):  
Contact Zone ◽  
Load Capacity ◽  
Structural Parameters ◽  
Groove Depth ◽  
Central Angle ◽  
Friction Contact ◽  
Temperature Property ◽  
Pressure Flow ◽  
Content Type ◽  
Oil Film

Purpose The purpose of this paper is to study the influence of structural parameters of oil groove (such as central angle number, depth and so on) on pressure, flow, load capacity and transmitted torque between friction pairs of hydro-viscous clutch. Design/methodology/approach According to the working process of friction pairs of hydro-viscous clutch, mathematical models of hydrodynamic load capacity and torque transmitted by the oil film were built based on viscosity-temperature property. Then analytical solutions of pressure, flow, load capacity and transmitted torque were obtained; effects of central angle of oil groove zone and friction contact zone, oil film thickness, number of oil grooves on pressure, flow, load capacity and torque were studied theoretically. Findings The research found that the central angle of oil groove zone, number of oil grooves and oil groove depth have similar effects on flow, which means that with the increase of central angle, number or depth of oil grooves, the flow also increases; pressure in friction contact zone and oil groove zone drops along radial direction, whereas its value in oil groove zone is higher. With the increase of the central angle of oil groove zone, pressure in friction contact zone and friction contact zone rises, and the load capacity increases, whereas the transmitted torque drops. Number of oil grooves has little effect on load capacity. When the oil film thickness increases, its flow increases accordingly, whereas the pressure, load capacity and transmitted torque drops. Meanwhile, the transmitted torque decreases with the increase of number of oil grooves, whereas the oil groove depth nearly has no effects on transmitted torque. Originality/value In this paper, mathematical models of hydrodynamic load capacity and torque transmitted by oil film were built based on viscosity-temperature property in the working process of hydro-viscous clutch, and their analytical solutions were obtained; effects of structural parameters of oil groove on transmission characteristics of hydro-viscous clutch based on viscosity-temperature property were revealed. The research results are of great value to the theory development of hydro-viscous drive technology, the design of high-power hydro-viscous clutch and relative control strategy.

Closed-Form Analytical Solutions for Thin-Walled Cylindrical Composite Shell Structures Subjected to Axial and Bending Loads Under Temperature Environment

2015 ◽  
Author(s):  
Sthanu Mahadev ◽  
Wen S. Chan
Keyword(s):  
Cylindrical Shell ◽  
Analytical Model ◽  
Analytical Solutions ◽  
Composite Shell ◽  
Axial Stiffness ◽  
Radius Of Curvature ◽  
Stacking Sequence ◽  
Analysis Scheme ◽  
Thin Walled ◽  
Laminate Thickness

This research discourse presents the development of a holistic mathematical model that is dedicated to showcase a set of analytical expressions for predicting global stiffness (axial stiffness, bending stiffness) and a material response characterization based on ply-per-ply in-plane stress investigations relevant to open-celled multidirectional curved cylindrical shell configurations. Additionally, the analytical model is shown to present the capability to mathematically determine the location of the centroid for thin-walled, composite cylindrical shells. The resulting centroidal expression for a composite system is essentially shown to be a primary function of material properties, composite stacking sequence, fiber orientation angle and the structural geometry as opposed to metal counterparts whose centroidal point is solely governed by their geometry. Analytical stress estimates are computed for thin-walled curved cylindrical shell constructions that are subjected to typical tension and longitudinal bending type loading conditions applied at the centroid under the presence and absence of a uniformly distributed thermal loading environment. A broad parametric investigation on the in-plane ply stresses (σx,σy,τxy) are conducted via choosing three fundamental parameters namely; varying mean radius of curvature, changing laminate thickness-to-mean radius ratio and increasing laminate thickness respectively. Three preferentially tailored variabilities in ply stacking sequence are established from a [(±45° / 0°]s symmetric-balanced composite lay-up to illustrate the effects on ply stresses. An ANSYS based finite element analysis scheme is employed to numerically determine the location of centroid and further substantiate the analytically acquired centroid predictions including and excluding the effects of temperature. The centroidal point is identified and its location is progressively reported for a fully open cross-sectioned curved strip to a fully closed cylindrical composite tube configuration by examining their distribution pattern as a function of circumferential arc angle (2α). FE tool is additionally utilized to compare the analytical stiffness predictions and analyze the validity of the in-plane analytical stress estimates. Excellent agreement is achieved in comparison between analytical solutions and computationally generated FE results. The central goal of this work is to demonstrate the potential of the formulated mathematical framework in accurately predicting the key mechanical attributes that dictates the structural behavior of curved composite shell members. This analytical model is designed to serve as a robustly efficient tool towards assisting structural design engineers in quickly gaining a broad fundamental understanding on the physical characteristics and structural response of such configurations by accurately conducting simple parametric studies during preliminary design phase prior to performing complex FE analyses.

Mechanical Characteristics of Historical Beams of Picea Abies Wood: Assessment by Ultrasound

2014 ◽  
Vol 1618 ◽  
pp. 257-262
Author(s):  
Javier Ramón Sotomayor-Castellanos ◽  
José María Villaseñor-Aguilar
Keyword(s):  
Picea Abies ◽  
Moisture Content ◽  
Wood Density ◽  
Modulus Of Elasticity ◽  
Mechanical Characteristics ◽  
Structural Members ◽  
Full Size ◽  
Ultrasound Waves ◽  
Ultrasound Measurements ◽  
Speed Of Ultrasound

ABSTRACTFive historical full-size wood structural beams of Picea abies were tested with ultrasound. The speed of ultrasound, the modulus of elasticity, the moisture content and the wood density were measured for each specimen. The speed of the ultrasound waves in the radial, tangential and longitudinal directions was 1,769 m/s, 1,599 and 5,713 m/s respectively. The modulus of elasticity in the radial, tangential and longitudinal directions was 1,353 MPa, 1,069 MPa and 13,863 MPa respectively. The moisture content was on average 11.92% and the density was on average 422 kg/m3. Wood parameters such as density and orthotropic directions had influence in ultrasound measurements. In spite of local weakness in the beams, they had enough strength to be considered full structural members.

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