On the Thermal Effects in a Warp Beam (A Wound-Yarn-Package)

1978 ◽  
Vol 100 (1) ◽  
pp. 8-12
Author(s):  
S. K. Batra ◽  
D. S. Lee ◽  
S. Backer
Keyword(s):  
Stress Field ◽  
Thermal Effects ◽  
Temperature Effects ◽  
Continuum Model ◽  
Prolonged Storage ◽  
New Model ◽  
Cylindrically Anisotropic

The development of the stress field in a cylindrically-wound-yarn-package with side flanges (warp beams), during winding, can be predicted [6] using Beddoe’s [4] cylindrically anisotropic continuum model. This model is extended to account for the temperature effects observed during prolonged storage of the beams. The results predicted by the new model compare well with the experimental observations.

On the Stress Analysis of Cylindrically Wound Packages: The Case of a Warp Beam

1976 ◽  
Vol 46 (6) ◽  
pp. 453-459 ◽  
Author(s):  
Subhash K. Batra ◽  
Danny S. Lee ◽  
Stanley Backer
Keyword(s):  
Experimental Data ◽  
Boundary Value Problem ◽  
Thermal Effects ◽  
The State ◽  
Polymeric Films ◽  
Prolonged Storage ◽  
Anisotropic Models ◽  
State Of Stress ◽  
Anisotropy Parameters ◽  
Cylindrically Anisotropic

The state of stress in a warp beam is investigated through continuum (isotropic and anisotropic) models. Beddoe's [2] model (cylindrically anisotropic) is found to give an acceptable description. The anisotropy parameters are estimated by comparing the calculated results with the experimental data. Influence of prolonged storage at higher temperatures (up to 130°F) on the barrel pressure and flange thrust are discussed. An auxiliary (boundary value) problem is formulated to account for these thermal effects; its solution gives results which are comparable to those observed experimentally. Means of estimating the mechanical and thermomechanical parameters of the system are discussed in some detail. The analyses can be adapted to model the state of stress in the cylindrically wound packaging of sheet-like material such as paper and polymeric films.

scholarly journals UNDERSTANDING TEMPERATURE EFFECTS ON FRICTION AT TOOL – CFRP WORKPIECE INTERFACE USING OPEN-LOOP FRICTION TESTING

2021 ◽  
Vol 2021 (3) ◽  
pp. 4605-4611
Author(s):  
S. Ashworth ◽  
◽  
K. Kerrigan ◽  
Keyword(s):  
Tool Wear ◽  
Thermal Effects ◽  
Temperature Effects ◽  
Open Loop ◽  
Friction Testing ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Cutting Processes ◽  
Coated Carbide

Cutting processes of carbon fibre reinforced polymer (CFRP) material generate significant energy in the form of heat which can be detrimental to final surface and sub-surface quality. By artificially changing the temperature of the workpiece to simulate cutting temperatures, thermal effects on friction metrics can be understood. Feed rate and CFRP pre-heating for macro and nanoscale open loop pin on plate friction testing has been completed for two aerospace grade CFRP materials with steel, carbide and coated carbide pins to give an insight to fundamental tool wear that occurs in CFRP machining.

A thermomechanical model for saturated soil at small and large strains

2015 ◽  
Vol 52 (8) ◽  
pp. 1101-1110 ◽  
Author(s):  
C. Zhou ◽  
C.W.W. Ng
Keyword(s):  
Thermal Effects ◽  
Stress Path ◽  
Saturated Soil ◽  
Shear Behaviour ◽  
Large Strains ◽  
Bounding Surface ◽  
Thermomechanical Model ◽  
New Model ◽  
Small Strains ◽  
Thermomechanical Behaviour

Many elastoplastic models have been developed for simulating thermomechanical behaviour of saturated soil. Although the yield surface of these models shrinks with temperature, its shape is always assumed to be independent of temperature. This simplification may induce errors in predicting thermal effects on shear behaviour. Furthermore, existing models tend to focus on thermomechanical behaviour at large strains. Behaviour such as the degradation of the shear modulus with strain at small strains (<1%) is often ignored. To address these issues, a new thermomechanical model is developed using the bounding surface plasticity theory. Both the size and shape of the bounding surface are allowed to change with temperature. The new model is able to predict elastoplastic response of saturated soil at small strains, even when stress path is within the bounding surface. Using this new model, thermomechanical behaviour of four different soils having different overconsolidation ratios is simulated. Comparisons between measured and computed results reveal that the new model is able to capture many vital aspects of thermomechanical behaviour, including volume changes during heating and cooling, and thermal effects on drained and undrained shear behaviour. In particular, it predicts a gradual degradation of the shear modulus at small strains. By incorporating thermal effects on the shape of the bounding surface, the modelling of thermomechanical behaviour, especially the effective stress path during undrained shearing, is improved.

Thermal Effects on Far-Field Distributed Acoustic Strain-Rate Sensors

2021 ◽  
Author(s):  
Smith Edward Leggett ◽  
Ding Zhu ◽  
Alfred Daniel Hill
Keyword(s):  
Phase Shift ◽  
Temperature Gradient ◽  
Strain Rate ◽  
Hydraulic Fracture ◽  
Thermal Effects ◽  
Temperature Effects ◽  
Fiber Optic ◽  
Displacement Discontinuity ◽  
Observation Well ◽  
Optical Phase

Abstract Fiber-optic cables cemented outside of the casing of an unconventional well measure cross-well strain changes during fracturing of neighboring wells with low-frequency distributed acoustic sensing (LF-DAS). As a hydraulic fracture intersects an observation well instrumented with fiber-optic cables, fracture fluid injected at ambient temperatures can cool a section of the sensing fiber. Often, LF-DAS and distributed temperature sensing (DTS) cables are run in tandem, enabling the detection of such cooling events. The increasing use of LF-DAS for characterizing unconventional hydraulic fracture completions demands an investigation of the effects of temperature on the measured strain response by LF-DAS. Researchers have demonstrated that LF-DAS can be used to extract the temporal derivative of temperature for use as a differential-temperature-gradient sensor. However, differential-temperature-gradient sensing is predicated on the ability to filter strain components out of the optical signal. In this work, beginning with an equation for optical phase shift of LF-DAS signals, a model relating strain, temperature, and optical phase shift is explicitly developed. The formula provides insights into the relative strength of strain and temperature effects on the phase shift. The uncertainty in the strain-rate measurements due to thermal effects is estimated. The relationship can also be used to quantify uncertainties in differential-temperature-gradient sensors due to strain perturbations. Additionally, a workflow is presented to simulate the LF-DAS response accounting for both strain and temperature effects. Hydraulic fracture geometries are generated with a 3D fracture simulator for a multi-stage unconventional completion. The fracture width distributions are imported by a displacement discontinuity method program to compute the strain-rates along an observation well. An analytic model is used to approximate the temperature in the fracture. Using the derived formulae for optical phase shift, the model outputs are then used to compute the LF-DAS response at a fiber-optic cable, enabling the generation of waterfall plots including both strain and thermal effects. The model results suggest that before, during, and immediately following a fracture intersecting a well instrumented with fiber, the strain on the fiber drives the LF-DAS signal. However, at later times, as completion fluid cools the observation well, the temperature component of the LF-DAS signal can equal or exceed the strain component. The modeled results are compared to a published field case in an attempt to enhance interpretation of LF-DAS waterfall plots. Finally, we propose a sensing configuration in order to identify the events when "wet fractures" (fractures with fluids) intersect the observation well.

The Stress Field in a Cylindrically Anisotropic Body Under Two-Dimensional Surface Tractions

1972 ◽  
Vol 39 (3) ◽  
pp. 791-796 ◽  
Author(s):  
N. J. Pagano
Keyword(s):  
Stress Field ◽  
Composite Structures ◽  
Elastic Stress ◽  
Anisotropic Body ◽  
Circular Cylinders ◽  
Important Class ◽  
Two Dimensional ◽  
Direct Extension ◽  
Cylindrically Anisotropic ◽  
Dimensional Surface

In this work, a general solution for the elastic stress field in a cylindrically anisotropic body, the hollow circular cylinder, under surface tractions which do not vary along the generator and which can be expressed in the form of a Fourier series, is presented. The form of the solution is sufficiently general to permit direct extension to an important class of composite structures, namely, laminated circular cylinders. Some of the peculiar effects of anisotropy are illustrated by the solution of a specific boundary-value problem—a circular hole in a large plate under tension.

scholarly journals Enhancement of methodology for protection of structures in contradiction of thermal effects

2021 ◽  
Vol 264 ◽  
pp. 02033
Author(s):  
Еlena Rojkova ◽  
Nodira Ruzieva ◽  
Zuxritdin Ergashev
Keyword(s):  
Heat Conduction ◽  
Anisotropic Material ◽  
Thermal Effects ◽  
Temperature Effects ◽  
Heat Conduction Equation ◽  
Operator Method ◽  
Variable Coefficients ◽  
Conduction Equation ◽  
One Dimensional ◽  
Unsteady Heat Conduction

The research paper is devoted to protection of structures against heat and temperature effects. The necessity of improving the calculation of multilayered fence structures is shown. The solution of a one-dimensional unsteady heat conduction equation with constant and variable coefficients allowing to use of inhomogeneous and anisotropic materials as the fence material is given. An example of the solution of a fence made of inhomogeneous and anisotropic material is given. Solution of heat conduction equation is obtained by the recurrence-operator method. The solution of one-dimensional unsteady heat conduction equation with variable coefficients is obtained using the recurrence-operator method. The possibility of using the solution of the equation for multilayered inhomogeneous anisotropic fence materials is indicated.

Solvent-dependent singlet oxygen lifetimes: temperature effects implicate tunneling and charge-transfer interactions

2016 ◽  
Vol 18 (33) ◽  
pp. 22946-22961 ◽  
Author(s):  
Mikkel Bregnhøj ◽  
Michael Westberg ◽  
Frank Jensen ◽  
Peter R. Ogilby
Keyword(s):  
Charge Transfer ◽  
Singlet Oxygen ◽  
Temperature Effects ◽  
New Model

A new model for an old problem: a barrier to account for temperature effects on singlet oxygen lifetimes.

scholarly journals The Burgers Equation for a New Continuum Model with Consideration of Driver’s Forecast Effect

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Lei Yu ◽  
Bingchang Zhou
Keyword(s):  
Continuum Model ◽  
Burgers Equation ◽  
Density Wave ◽  
Reductive Perturbation Method ◽  
Stable Region ◽  
Local Cluster ◽  
New Model ◽  
Stop And Go ◽  
The Stability ◽  
Positive Effect

A new continuum model with consideration of driver’s forecast effect is obtained to study the density wave problem and the stop-and-go phenomena. The stability condition of the new model is derived by using linear analysis. The triangular shock wave, one type of density wave, which is determined by Burgers equation in the stable region, is discussed in great detail with reductive perturbation method. The local cluster appears when we perform the numerical simulations for the new model. It also proves that the driver’s forecast effect has the positive effect of reducing the local cluster.

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