Rubber Plastometer with Uniform Rate of Shear—Shearing-Cone Plastometer

1946 ◽  
Vol 19 (3) ◽  
pp. 822-831 ◽  
Author(s):  
G. H. Piper ◽  
J. R. Scott
Keyword(s):  
Plastic Flow ◽  
Mechanical Design ◽  
Plastic Material ◽  
Edge Zone ◽  
Uniform Rate ◽  
Wide Range

Abstract A new shearing-cone plastometer, suitable for investigating the plastic-flow relations of highly viscous materials over a wide range of stress, is described. A mushroom-shaped rotor, having upper and lower surfaces of conical type, is rotated in the plastic material contained in a cylindrical mould. With this type of shearing surface the rate of shear is uniform throughout the material, except for a small edge zone, thus overcoming some disadvantages of previous plastometers. The mechanical design is based on the Mooney shearing-disk plastometer except that provision is made for a wide range of speeds of rotation.

Magnetomechanical Instabilities in Elastic-Plastic Cylinders, Part II: Plastic Response

1996 ◽  
Vol 63 (3) ◽  
pp. 742-749 ◽  
Author(s):  
D. L. Littlefield
Keyword(s):  
Electric Current ◽  
Plastic Flow ◽  
Plastic Material ◽  
Yield Criterion ◽  
Confining Pressure ◽  
Constitutive Law ◽  
Linear Perturbation ◽  
Uniform Motion ◽  
Elastic Plastic ◽  
Wide Range

The analysis of elastic instabilities in metal cylinders when subjected to electromagnetic fields (Littlefield, 1996a) is extended in this work to include elastic-plastic flow. The cylinder is assumed to be infinitely long and perfectly conducting. The Prandtl-Reuss elastic-plastic material model is the assumed constitutive law, with the von Mises yield criterion employed to limit the effective stress. An axial electric current, assumed to be conducting along the surface of the cylinder, generates a confining pressure, causing plastic flow that is initially assumed to be uniform throughout the cross section. The propagation of small axisymmetric disturbances to this uniform motion is studied by applying linear perturbation theory. Solutions to these equations exhibit a wide range of instability modes, as was the case for the purely elastic results, and the frequency of the oscillating disturbances appears to be suppressed by electromagnetic effects. However, in contrast to the elastic result, no threshold magnetic field exists, and distending instabilities are possible for all levels of electric current. Physical mechanisms resulting in these distinctions are suggested.

Theory and Application of the Parallel-Plate Plastimeter. Part 2

1935 ◽  
Vol 8 (4) ◽  
pp. 587-596 ◽  
Author(s):  
J. R. Scott
Keyword(s):  
Plastic Flow ◽  
Parallel Plate ◽  
Plastic Material ◽  
Compressive Load ◽  
Flow Equation ◽  
Simple Type ◽  
Plastic Properties ◽  
Further Development ◽  
Rubber Stock ◽  
Existing Data

Abstract In Part I (loc. cit.) the behavior of a plastic material in the parallel-plate (Williams) plastimeter was studied, and an expression was deduced showing how the rate of decrease in thickness of the sample during compression depends on the volume of the sample, its plastic properties, the compressive load, and the thickness itself. Subsequently, observations were published which showed that the basic principle adopted in this study was incorrect in certain particulars. Peek (loc. cit.), using these observations as a basis, deduced a new expression for the rate of decrease in thickness, though this is too complex for convenient practical use, except in an approximate simplified form. It has now been shown that the expression deduced in Part I, in spite of the inaccurate basis used, is sufficiently near to the truth to render substantially correct the conclusions there stated concerning the plastic properties of unvulcanized rubber stocks. By adopting the more accurate basis used by Peek, moreover, expressions for the rate of decrease in thickness can be deduced for materials showing more complex types of plastic flow than that considered in Part I or by Peek; this had proved impossible by the method previously used. The expression obtained by Peek for the simple type of plastic flow, as well as those now deduced for the more complex types, can be expressed in a form that furnishes a simple and rapid method of examining and analyzing experimental results. As a result of the work described in this paper, it is thus possible to determine, from results obtained with the parallel-plate plastimeter, whether or not a material such as unvulcanized rubber stock exhibits any of the types of plastic flow represented in the general form by Equation 1, and, if so, to find the values of the plastic constants of the material. The procedure is similar to that described in Part I, and consists simply in comparing, by superposition, a set of standard curves drawn on transparent paper with the curve plotted from experimental data. This further development of the method of studying plastic properties by means of the parallel-plate plastimeter should greatly increase its utility as an instrument of research. It has not yet been possible to apply the new method to a systematic study of rubber stocks, but from an examination of existing data it appears that these stocks, tested at 90° C., agree approximately with various forms of the generalized plastic flow equation already referred to.

Stress Analysis of Pseudo-Plastic Flow Between Rotating Cylinders

2011 ◽  
Author(s):  
Nariman Ashrafi ◽  
Habib Karimi Haghighi
Keyword(s):  
Dynamical System ◽  
Stress Analysis ◽  
Plastic Flow ◽  
Galerkin Projection ◽  
Narrow Gap ◽  
Rotating Cylinders ◽  
Flow Parameters ◽  
Wide Range ◽  
Stress Components ◽  
Mathematica Software

Stress analysis of Pseudo-Plastic flow between rotating cylinders is studied in the narrow gap limit. The Galerkin projection method is used to derive dynamical system from the conservation of mass and momentum equations. Flow parameters were obtained using IMSL and also verified by Mathematica Software. Stresses are computed in a wide range of the Pseudo-Plastic effects. Azimuthal stress was found to be far greater than other stress components. All stress components increased as Pseudo-Plasticity decreased. Furthermore, complete stress and viscosity maps are presented for different scenarios in the flow regime.

scholarly journals A New 4500-HP Gas Turbine for Pipeline Industrial Service

1970 ◽  
Author(s):  
R. R. Oliver ◽  
F. Fraschetti
Keyword(s):  
Gas Turbine ◽  
Mechanical Design ◽  
Maximum Efficiency ◽  
Heavy Duty ◽  
Cooperative Effort ◽  
Package Design ◽  
Wide Range ◽  
Industrial Service ◽  
Design Options ◽  
Regenerative Cycle

This paper describes the performance and mechanical design of a 4500-hp, two shaft heavy duty simple or regenerative cycle gas turbine. This machine resulted from an international cooperative effort of the joint authors’ respective companies. Initially planned for gas pipelines and process applications, a line of load compressors has been integrated into the single package design. Options include indoor or outdoor models and geared or direct mechanical output for applications not served by the integral compressor models. A variable area load turbine nozzle assures maximum efficiency over a wide range of load, speed, and amibient conditions.

Mechanical Design and Testing of a 2.5 MW sCO2 Compressor Loop

2021 ◽  
Author(s):  
Stefan D. Cich ◽  
J. Jeffrey Moore ◽  
Chris Kulhanek ◽  
Meera Day Towler ◽  
Jason Mortzheim
Keyword(s):  
High Efficiency ◽  
Mechanical Design ◽  
Guide Vane ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Design Changes ◽  
Wide Range ◽  
Inlet Conditions ◽  
Design And Testing

Abstract An enabling technology for a successful deployment of the sCO2 close-loop recompression Brayton cycle is the development of a compressor that can maintain high efficiency for a wide range of inlet conditions due to large variation in properties of CO2 operating near its dome. One solution is to develop an internal actuated variable Inlet Guide Vane (IGV) system that can maintain high efficiency in the main and re-compressor with varying inlet temperature. A compressor for this system has recently been manufactured and tested at various operating conditions to determine its compression efficiency. This compressor was developed with funding from the US DOE Apollo program and industry partners. This paper will focus on the design and testing of the main compressor operating near the CO2 dome. It will look at design challenges that went into some of the decisions for rotor and case construction and how that can affect the mechanical and aerodynamic performance of the compressor. This paper will also go into results from testing at the various operating conditions and how the change in density of CO2 affected rotordynamics and overall performance of the machine. Results will be compared to expected performance and how design changes were implanted to properly counter challenges during testing.

On the Crack Quasi-Static Growth

2019 ◽  
Vol 827 ◽  
pp. 312-317
Author(s):  
Vitalijs Pavelko
Keyword(s):  
Fracture Toughness ◽  
Crack Growth ◽  
Plastic Material ◽  
Small Scale ◽  
Invariant Equation ◽  
Practical Applications ◽  
Wide Range ◽  
Scale Yielding ◽  
Elastic Plastic Material ◽  
Principal Assumption

The theoretical model of quasi-static crack growth in the elastic-plastic material under load variation in a wide range. Small-scale yielding is principal assumption and main restriction of proposed theory. The model of crack growth provides for continues and interrelated both the crack propagation and plastic deformation development. The nonlinear first-order differential equation describes the quasi-static process of crack growth. In dimensionless form this equation invariant in respect to geometrical configuration and material. The critical size of the plastic zone is proposed as the characteristics of material resistance which is directly connected with the fracture toughness, but more convenient in practical applications of invariant equation. The demonstration of solution is performed for the double cantilever beam that widely used as the standard (DCB) sample for measurement of the mode-I interlaminar fracture toughness. he short analysis of some properties of solution of the invariant equation and its application is done.

Undergraduate Project in Compressor Rig Design, Fabrication, and Testing for Complete Engineering Training

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Huu Duc Vo ◽  
Jean-Yves Trépanier
Keyword(s):  
Data Acquisition ◽  
Engineering Students ◽  
Mechanical Design ◽  
Plastic Material ◽  
Second Phase ◽  
Engineering Programs ◽  
Undergraduate Engineering ◽  
Compressor Aerodynamics ◽  
The Rich ◽  
Two Phases

An ambitious project in propulsion was introduced as part of the final-year integrator project offerings of the mechanical and aerospace engineering programs at École Polytechnique de Montréal in 2011–2012. It has been running successfully for the past three academic years. The project consists in the design, fabrication, and placement into service of a functional instrumented multistage compressor test rig, including the compressor, for research in compressor aerodynamics. A team of 15–17 senior-year undergraduate engineering students is given a set of design and performance specifications and measurement requirements, an electric motor and drive, a data acquisition system, and some measurement probes. They must complete the project in two semesters with a budget on the order of Can$15,000. The compressor is made from rapid prototyping to keep production cost and time reasonable. However, the required rotation speed of 7200 rpm stretches the limits of the plastic material and presents the same structural challenges as industrial compressors running at higher speeds. The students are split into subteams according to the required disciplines, namely, compressor aerodynamics, general aerodynamics, structures, dynamics, mechanical design and integration, instrumentation, and project management. For the initial phase, which covers the first two months, the students receive short seminars from experts in academia and industry in each discipline and use the knowledge from fundamental engineering courses to analytically model the different components to come up with a preliminary design. In the second phase, covering three to six, the students are trained at commercial simulation tools and use them for detailed analysis to refine and finalize the design. In each of the first two phases, the students present their work in design reviews with a jury made up of engineers from industry and supervising professors. During the final phase, the compressor is built and tested with data acquisition and motor control programs written by the students. Finally, the students present their results with comparison of measured performance with numerical and analytical predictions from the first two phases and hand over their compressor rig with design and test reports as well as a user manual and an assembly/maintenance manual. This complete project allows the students to put into practice virtually all the courses of their undergraduate engineering curriculum while giving them an extensive taste of the rich and intellectually challenging environment of gas turbine and turbomachinery engineering.

An Autonomous Docking Mechanism for Vertical Lift Unmanned Aircraft

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
John Papayanopoulos ◽  
Kevin Webb ◽  
Jonathan Rogers
Keyword(s):  
Measurement Errors ◽  
Closed Loop ◽  
Mechanical Design ◽  
Tracking System ◽  
Unmanned Aircraft ◽  
Wide Range ◽  
Air Vehicle ◽  
Docking Mechanism ◽  
Infrared Tracking ◽  
Autonomous Docking

Abstract Unmanned aerial vehicles are increasingly being tasked to connect to payload objects or docking stations for the purposes of package transport or recharging. However, autonomous docking creates challenges in that the air vehicle must precisely position itself with respect to the dock, oftentimes in the presence of uncertain winds and measurement errors. This paper describes an autonomous docking mechanism comprising a static ring and actuated legs, coupled with an infrared tracking device for closed-loop docking maneuvers. The dock’s unique mechanical design enables precise passive positioning such that the air vehicle slides into a precise location and orientation in the dock from a wide range of entry conditions. This leads to successful docking in the presence of winds and sensor measurement errors. A closed-loop infrared tracking system is also described in which the vehicle tracks an infrared beacon located on the dock during the descent to landing. A detailed analysis is presented describing the interaction dynamics between the aircraft and the dock, and system parameters are optimized through the use of trade studies and Monte Carlo analysis with a three degree-of-freedom simulation model. Experimental results are presented demonstrating successful docking maneuvers of an autonomous air vehicle in both indoor and outdoor environments. These repeatable docking experiments verify the robustness and practical utility of the dock design for a variety of emerging applications.

scholarly journals The Bearing Stiffness Effect on In-Wheel Motors

2020 ◽  
Vol 12 (10) ◽  
pp. 4070
Author(s):  
Matej Biček ◽  
Raphaël Connes ◽  
Senad Omerović ◽  
Aydin Gündüz ◽  
Robert Kunc ◽  
...  
Keyword(s):  
Thermal Management ◽  
Electric Vehicles ◽  
Automotive Industry ◽  
Motor Performance ◽  
Mechanical Design ◽  
Critical Component ◽  
Wide Range ◽  
Bearing Stiffness ◽  
Promising Solution ◽  
Electromagnetic Performance

In-wheel motors offer a promising solution for novel drivetrain architectures of future electric vehicles that could penetrate into the automotive industry by transferring the drive directly inside the wheels. The available literature mainly deals with the optimization of electromagnetically active parts; however, the mechanical design of electromagnetically passive parts that indirectly influence motor performance also require detailed analysis and extensive validation. To meet the optimal performance of an in-wheel motor, the mechanical design requires optimization of housing elements, thermal management, mechanical tolerancing and hub bearing selection. All of the mentioned factors have an indirect influence on the electromagnetic performance of the IWM and sustainability; therefore, the following paper identifies the hub bearing as a critical component for the in-wheel motor application. Acting loads are reviewed and their effect on component deformation is studied via analytically and numerically determined stiffness as well as later validated by measurements on the component and assembly level to ensure deformation envelope and functionality within a wide range of operations.

Tensile behaviour of radiata pine with different moisture contents at elevated temperatures

Holzforschung ◽  
2012 ◽  
Vol 66 (5) ◽  
pp. 659-665 ◽  
Author(s):  
Hamish Pearson ◽  
Brian Gabbitas ◽  
Sigurdur Ormarsson
Keyword(s):  
Elevated Temperatures ◽  
Mechanical Design ◽  
Control Strategies ◽  
Radiata Pine ◽  
Tensile Behaviour ◽  
Drying Time ◽  
Moisture Contents ◽  
Wide Range ◽  
Tensile Elastic Modulus ◽  
Increasing Temperature

Abstract The aim of this study was to obtain tensile elastic modulus (EM) information for radiata pine (Pinus radiata D. Don) sapwood in tangential grain direction, over a temperature range of 70°C to 150°C for a wide range of moisture contents. Such information is scarce, probably because of difficulties with research equipment design and process control strategies to perform accurate tests. As expected, EM dramatically decreased with increasing temperature and moisture content. The results were modelled to yield a relationship between stress and strain. The results were also successfully transposed into a mastercurve based on temperature-moisture equivalence through a modified form of the Williams, Landel, and Ferry equation for amorphous polymers. This result is consistent with the view that wood is visco-plastic around the glass transition zone of the ligno-hemicellulosic matrix. It is demonstrated that moisture and temperature can play a significant role in reducing stress during drying, regardless of the drying time. Properties of wood, such as tensile elastic information at elevated temperatures, are important for mechanical design, distortion modelling and understanding the fundamental behaviour of wood in general.

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