scholarly journals Evolution of temperature stresses in the Gadolin problem of assembling a two-layer elastoplastic pipe

2020 ◽  
pp. 20-31
Author(s):  
A. A Burenin ◽  
A. V Tkacheva
Keyword(s):  
Plastic Flow ◽  
Thermal Stresses ◽  
Piecewise Linear ◽  
Classical Case ◽  
Pipe Material ◽  
Uniform Heating ◽  
Temperature Stresses ◽  
The Moment ◽  
Uneven Heating ◽  
Outer Pipe

The work aims at solving the problem of the theory of unsteady thermal stresses simulating the assembling of the two-layer elastoplastic pipe using the shrink fit (Gadolin problem). The plastic flow condition is taken in the form of a piecewise linear condition of maximum reduced stresses (the Ishlinsky - Ivlev condition) with a parabolic yield point depending on temperature. It is shown that when solving the mechanical part of a disconnected problem of the theory of temperature stresses, the calculations of reversible and irreversible deformations and stresses can be carried out numerically, i.e. analytically without resorting to approximate calculation procedures and, therefore, without discretizing the computational domains. We present a diagram of the emergence and disappearance of plastic flow regions under the assembly conditions and its subsequent cooling. With a different choice of problem parameters, some plastic regions may not appear. However, it is impossible to obtain other areas of plastic flow by changing the geometry of the problem, properties of assembly materials, and the level of heating. This is the adequacy of the calculations. Only those plastic areas that are shown in the diagram appear and disappear. In contrast to the classical case of uniform heating of the outer pipe, this article deals with a widely used case of an uneven heating of the outer pipe from the inner surface. In this case, irreversible deformations are calculated, and then taken into account, which originated in the pipe material before the moment of landing. A comparison of the distribution of residual stresses obtained during the uniform and non-uniform heating of the outer pipe is given. As a result, the interference with the uniform heating exceeds the interference formed with the non-uniform heating of the pipe.

scholarly journals Automated system for design and calculation of heating devices for hot die forging

2021 ◽  
Vol 2131 (5) ◽  
pp. 052013
Author(s):  
E Galsanova ◽  
A Greshilov ◽  
Ya Kalinin ◽  
A Yakovlev
Keyword(s):  
Thermal Stresses ◽  
Ease Of Use ◽  
Automated System ◽  
Temperature Stresses ◽  
Heating Uniformity ◽  
Design Systems ◽  
Uneven Heating ◽  
Maximum Heating ◽  
Hot Die Forging ◽  
Selection Of

Abstract Methods of mathematical modeling, basic technologies and methods of modeling in various design systems of the stamping process are considered. The canonical equations of temperature stresses are obtained, which make it possible to obtain a picture of the temperature distribution over the workpiece area during heating. A mathematical model has been developed for a thin metal strip during heating; thermal stresses arising in it due to uneven heating have been described. Numerical modeling has been carried out on the basisof field data, which will allow verification of the automated environment for the selection of functional and design schemes and the calculation of the parameters of heating devices in hot volumetric stamping of workpieces in terms of speed, energy efficiency, heating quality: accuracy of achieving specified temperatures and maximum heating uniformity. By areas, ease of use and readjustment, resource, reliability and maintainability. The proposed system will include the following CAD elements: databases and rules for operating with them, calculation modules, modules for selecting and matching options.

The Analyses and Calculation for Thermal Stresses of SBR Modified Asphalt Pavement

2011 ◽  
Vol 243-249 ◽  
pp. 4112-4118
Author(s):  
Min Jiang Zhang ◽  
Gang Chen ◽  
Li Xia Hou ◽  
Li Ping Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stresses ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
The Finite Element Method ◽  
Temperature Stresses ◽  
Modified Asphalt ◽  
Temperature Performance

Based on the viscoelasticity theory and the data of creep test, Burgers model was established, which was used to study the viscoelastic property of SBR asphalt mixtures, and the viscoelastic constitutive relation was obtained. Using the finite element method, the temperature stresses field was calculated under the environmental conditions and the thermal stresses of SBR modified asphalt pavement was given at the last part of this paper. The study indicated that SBR modified asphalt mixtures have the advantage over common asphalt mixture in low-temperature performance.

The Effects of Severe Thermal and Pressure Transients on the Survival of Internally Coated Tubes

2010 ◽  
Author(s):  
J. T. Harris ◽  
A. E. Segall ◽  
R. Carter
Keyword(s):  
Finite Element ◽  
Thermal Stresses ◽  
Elastic Analysis ◽  
Uniform Heating ◽  
Temperature Dependent ◽  
Pressure Function ◽  
Stress States ◽  
Transient Thermal ◽  
Hoop Stresses ◽  
Over Time

The effects of severe thermal and pressure transient pulses on the interior of coated tubes have been analyzed using finite-element methods. For the modeling, an axisymmetric mesh was developed and used to assess the transient, thermal- and stress-states and the propensity for fracture related damage. For all calculations, temperature dependent thermophysical and elastic properties were used during the analysis. The model also utilized uniform heating and pressure across the ID surface imposed via convective coefficients and a piece-wise linear pressure function over time. Results for the strictly elastic analysis indicated that both had a significant influence on the maximum circumferential (hoop) stresses and temperatures and that the compressive thermal-stresses help to offset any tensile components generated by the internal pressure on the ID. Preliminary calculations also investigated the influence of these factors when a crack was introduced at the interface of the coating and substrate.

Finite-Element Simulations and Probabilistic Fracture Assessments of the Response of Alternate Rifling Geometries

2007 ◽  
Author(s):  
A. E. Segall ◽  
R. Carter
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Thermal Stresses ◽  
Rotational Symmetry ◽  
Element Model ◽  
Time Dependent ◽  
Uniform Heating ◽  
Thermal Pressure ◽  
Single Firing ◽  
Hoop Stresses

A 3-D finite-element model was used to simulate the severe and localized thermal/pressure transients and the resulting stresses experienced by a rifled ceramic-barrel with a steel outer-liner; the focus of the simulations was on the influence of non-traditional rifling geometries on the thermoelastic- and pressure-stresses generated during a single firing event. In order to minimize computational requirements, a twisted segment of the barrel length based on rotational symmetry was used. Using this simplification, the model utilized uniform heating and pressure across the ID surface via a time-dependent convective coefficient and pressure generated by the propellant gasses. Results indicated that the unique rifling geometries had only a limited influence on the maximum circumferential (hoop) stresses and temperatures when compared with more traditional rifling configurations because of the compressive thermal stresses developed at the heated (and rifled) surface.

scholarly journals Propagation of Thermal Stresses in an Infinite Medium

1959 ◽  
Vol 11 (4) ◽  
pp. 237-244 ◽  
Author(s):  
F. J. Lockett ◽  
I. N. Sneddon
Keyword(s):  
Thermal Stresses ◽  
Infinite Medium ◽  
Nonuniform Distribution ◽  
The Body ◽  
Heat Sources ◽  
Dynamic Stresses ◽  
Elastic Bodies ◽  
State Of Stress ◽  
Body Forces ◽  
Uneven Heating

In the full linear theory of thermoelasticity there is a coupling between the thermal and the purely mechanical effects so that not only does a nonuniform distribution of temperature in the solid produce a state of stress but dynamical body forces or applied surface tractions produce variations in temperature throughout the body. In a recent paper (Eason and Sneddon, (2)) an account was given of the calculation of the dynamic stresses produced in elastic bodies, both infinite and semi-infinite, by uneven heating. In this paper we shall consider the propagation of thermal stresses in an infinite medium when, in addition to heat sources, there are present body forces which vary with the time.

Thermal Field Analysis of Matrix Heating System on Thermoforming Machine

2013 ◽  
Vol 664 ◽  
pp. 853-858
Author(s):  
Chun Hui Situ ◽  
Qing Qing Luo ◽  
Tao Mei ◽  
Jiang Zhuang
Keyword(s):  
Temperature Distribution ◽  
Food Packaging ◽  
Thermal Field ◽  
Heating System ◽  
Field Analysis ◽  
Heating Zone ◽  
The Finite Element Method ◽  
Uniform Heating ◽  
Linear Distribution ◽  
Uneven Heating

Thermoforming machine plays a very important role in industrial production, food packaging and other industries. In traditional thermoforming machine, highest temperature often appears in the center of the heating zone, and gradually reduces from the middle to both sides. It results in uneven heating, reducing the rate of finished products and a waste of resources. According to the finite element method, this article established the thermal field model of matrix heating system in thermoforming machine and simulated the temperature distribution of plastic in heating system under the conditions of “uniform heating” and “non-uniform heating” separately. It found that under the condition of “non-uniform heating”, the temperature distribution appeared uniform. The temperature of main region to be heated appeared approximately linear distribution, with the variation range of less than 5 °C, resulted in better effect than that under the condition of “uniform heating”

scholarly journals THE CONCENTRATION OF THERMAL STRESSES IN METAL MATERIALS AND CONSTRUCTION UNDER LOCAL HEATING

2020 ◽  
pp. 72-77
Author(s):  
V. Deryushev ◽  
M. Zayceva ◽  
D. Evseev ◽  
E. Kosenko
Keyword(s):  
Thermal Stresses ◽  
Local Heating ◽  
Temperature Stresses ◽  
Heating Spot ◽  
Cold Zone ◽  
Thin Walled Structures ◽  
Energy Flows ◽  
Metal Materials ◽  
Thin Walled ◽  
Elastic Characteristics

significant thermal stresses arising in thin-walled metal materials and structures loaded with tensile stresses can lead either to their complete destruction or to the appearance of discontinuity zones in them. The equations for calculation of temperature stresses in flat thin-walled structures at their localized thermal heating caused by the action of concentrated energy flows are analyzed. As an example, a thin-walled stretched plate subjected to strong local heating in a circular spot is considered. The developed model takes into account the change of elastic characteristics under strong local heating and the change in the thickness of the material in the heating spot. As an example, the diagram of the distribution of tangential stresses for a stretched plate in the area of a circular heating spot is given. Thus, the results of the study show that there is a rupture and concentration of stresses along the contour of the heating spot from the cold zone.

KAJIAN PENGARUH PENGGUNAAN SEMEN EKSPOS SEBAGAI FINISHING DINDING INTERIOR TERHADAP PSIKOLOGIS PENGGUNA RUANG

AKSEN ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 43-51
Author(s):  
I Gede Made Gani Rakandenu ◽  
Dyah Kusuma Wardhani
Keyword(s):  
Industrial Design ◽  
Residential Buildings ◽  
Commercial Buildings ◽  
Pipe Material ◽  
Color Palette ◽  
Great Demand ◽  
Interior Wall ◽  
The Moment ◽  
Design Style

The use of exposed cement materials as wall finishing lately is in great demand and is becoming a designtrend at the moment. Many property buildings ranging from commercial buildings such as cafes, restaurants,to hotels to residential buildings such as houses, apartments and condos use exposed cement as one ofthe interior wall finishing. Exposed cement as wall finishing is usually associated with industrial designstyles. In Indonesia, exposed cement is applied as finishing material after bricks. Using exposed cementas wall finish that nowadays has been trending in architecture and interior applicants gives a differentambience of space, home or building yet still economically acceptable. The using of exposed cement aswall finish are close to the using of industrial style. As known, industrial style is an interior architecturedesign style that adopting industries elements such as the using of metal, bricks and pipe material thenbe exposed on purpose. Industrial style has color palette such as black and greyish. Therefore the usingof exposed cement as wall finish often used in industrial design style. However with the popular use ofexposed cement as wall finish does not mean that it can freely acceptable in all situations, because it canaffect the comfort of the room user.

Study of Orientation Control for a Wheeled Jumping Robot in the Flight Phase of Motion

2019 ◽  
Vol 20 (4) ◽  
pp. 236-243 ◽  
Author(s):  
S. F. Jatsun ◽  
L. Yu. Vorochaeva ◽  
S. I. Savin
Keyword(s):  
Control System ◽  
Piecewise Linear ◽  
The Body ◽  
Linear Functions ◽  
Piecewise Linear Functions ◽  
Supporting Surface ◽  
Flight Phase ◽  
Angular Velocities ◽  
Jumping Robot ◽  
The Moment

The work studies the flight phase (a part of jumping motion) of a jumping robot. The robot consists of the body with wheeled base and a jump booster module installed in the body. The jump booster module allows the robot to accelerate in a given direction up to a predetermined speed, allowing to control the velocity of the robot at the moment when it breaks contact with the supporting surface. The goal of this study is to develop a control system for the robot’s wheels, allowing to use their inertial properties to control the robot orientation at the moment of landing. This is achieved by controlling the wheels’ orientation throughout the duration of the motion. The goal of controlling the orientation of the robot at the moment of landing is to be able to land on all four wheels and avoid tipping over. The paper studies the supporting surfaces (from which the robot jumps and to which the robot lands) described by piecewise linear functions, including a horizontal and slopped linear sub-functions. In this work, four types of supporting surfaces were distinguished, which the distinction based on the slope of the mentioned about sub-function. Another varying parameter is the point where two sub-functions connect. For the purpose of this study a kinematic and dynamic model of the robot were developed, and a control system design was proposed. The proposed control system includes a trajectory planner that allows to plan the robot’s motion resulting in the desired orientation of the robot’s body at the moment of landing. This problem was formulated as an optimization problem. Simulation results showed the dependencies between the three supporting surface parameters (two angles describing linear sub-functions and the point where the sub-functions intersect) and the duration of the robot flight, the achieved velocities of the robot’s wheels and required motor torques. The influence of those parameters on the maximal and minimal values of the wheels’ angular velocities achieved during the flight were demonstrated. This could be used in designing this type of robots, in particular it could help to set specifications for the robot’s wheel motors.

Loading History Effects for Deep-Water S-Lay of Pipelines

2004 ◽  
Vol 126 (2) ◽  
pp. 156-163 ◽  
Author(s):  
Heedo D. Yun ◽  
Ralf R. Peek ◽  
Paul R. Paslay ◽  
Frans F. Kopp
Keyword(s):  
Deep Water ◽  
Numerical Solutions ◽  
Pipe Material ◽  
Loading History ◽  
Material Models ◽  
Plastic Deformations ◽  
History Effects ◽  
Departure Angle ◽  
Numerical Finite Element ◽  
The Moment

For economic reasons S-Lay is often preferred to J-Lay. However in very deep water S-Lay requires a high curvature of the stinger to achieve the required close-to-vertical departure angle (or a large, low curvature stinger). Choosing the high curvature stinger can lead to plastic deformations of the pipe. The high top tension increases the plastic deformations in two ways: firstly it adds an overall tensile component to the strains, thereby increasing the strains at the 12 o’clock position. Secondly, it increases the strain concentrations, which arise due to discontinuous support of the pipe on the stinger. Typically, the pipe is guided over a series of roller beds. The high top tension tends to straighten the spans between the rollerbeds. To accommodate this (so that the pipe can still follow the stinger), higher curvatures occur at the roller beds. Analytical and numerical solutions are provided to quantify this effect. The analytical solution is fully developed for an arbitrary pipe material models, provided that: (i) the moment-curvature relation for the pipe under tension is known, and (ii) no cyclic plastic ratchetting occurs due to repeated bending of the pipe over the roller beds and straightening in the spans between roller beds. Agreement between the analytical and numerical (finite element) results is excellent. Proper loading history must be used in the numerical simulation, otherwise the level of strain concentration can be overpredicted.

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