Correlation of Theoretical and Photothermoelastic Results on Thermal Stresses in Idealized Wing Structures

1960 ◽  
Vol 27 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Herbert Tramposch ◽  
George Gerard
Keyword(s):  
Thermal Stress ◽  
Thermal Behavior ◽  
Experimental Evaluation ◽  
High Speed ◽  
Thermal Stresses ◽  
Initial Conditions ◽  
Temperature Distributions ◽  
Wing Structures ◽  
Simplifying Assumptions ◽  
Transient Thermal

After a rather complete exploratory program described in previous papers, the photothermoelastic method was applied to the experimental evaluation of thermal-stress theories. The new technique was correlated with several theories which analyzed the transient thermal stresses in idealized wing structures of high-speed aircraft. Various theories were investigated which represented the same idealized wing models and differed from each other only in the simplifying assumptions regarding the temperature distributions in skin and webs. The theories were evaluated by duplicating the boundary and initial conditions on plastic models and then by correlating the theories with the observed fringe orders in nondimensional form. A significant general conclusion was reached after correlating the available theories and experimental results. Owing to simplifying assumptions concerning the thermal behavior in the flanges, thermal stresses predicted by the available theories are all higher than the experimental observation. In some cases the discrepancy is as great as 30 per cent.

Analysis of the Thermal Stress and Strain on Arrigo Fiammingo’s Artistic Window in the Cathedral of Perugia

2001 ◽  
Vol 123 (6) ◽  
pp. 1173-1180 ◽  
Author(s):  
Cinzia Buratti
Keyword(s):  
Thermal Stress ◽  
Thermal Stresses ◽  
Actual State ◽  
Stress And Strain ◽  
Work Of Art ◽  
Temperature Distributions ◽  
Software Program ◽  
Thermal Stress And Strain

Thermal stress can damage fragile materials such as glass. It is a worrisome problem if the glass is a work of art, such as the polychromatic window of Arrigo Fiammingo (1565), in the Cathedral of Perugia, the topic of this paper. The window surface, irradiated by sunlight, suffers different thermal stresses, according to the color of the glass elements. In the present paper a calculation of stresses and strains on the window is carried out, for different temperature distributions due to sunlight, by using the ANSYS 5.3 software program. Results are compared with the actual state of the fissures on the window.

scholarly journals Hybrid Simulation of Solar-Wind-Like Turbulence

Solar Physics ◽  
2019 ◽  
Vol 294 (11) ◽  
Author(s):  
D. Aaron Roberts ◽  
Leon Ofman
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
High Speed ◽  
Radial Flow ◽  
Initial Conditions ◽  
Thermal Fluctuations ◽  
Flow Speed ◽  
Initial State ◽  
Simplifying Assumptions ◽  
The Magnetic Field

Abstract We present 2.5D hybrid simulations of the spectral and thermodynamic evolution of an initial state of magnetic field and plasma variables that in many ways represents solar wind fluctuations. In accordance with Helios near-Sun high-speed stream observations, we start with Alfvénic fluctuations along a mean magnetic field in which the fluctuations in the magnitude of the magnetic field are minimized. Since fluctuations in the radial flow speed are the dominant free energy in the observed fluctuations, we include a field-aligned $v_{\|}(k_{\perp })$v∥(k⊥) with an $k^{ -1}$k−1 spectrum of velocity fluctuations to drive the turbulent evolution. The flow rapidly distorts the Alfvénic fluctuations, yielding spectra (determined by spacecraft-like cuts) transverse to the field that become comparable to the $k_{\|}$k∥ fluctuations, as in spacecraft observations. The initial near constancy of the magnetic field is lost during the evolution; we show this also takes place observationally. We find some evolution in the anisotropy of the thermal fluctuations, consistent with expectations based on Helios data. We present 2D spectra of the fluctuations, showing the evolution of the power spectrum and cross-helicity. Despite simplifying assumptions, many aspects of simulations and observations agree. The greatly faster evolution in the simulations is at least in part due to the small scales being simulated, but also to the non-equilibrium initial conditions and the relatively low overall Alfvénicity of the initial fluctuations.

scholarly journals Transient Thermoelastic Analysis of Pressurized Rotating Disks Subjected to Arbitrary Boundary and Initial Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Mohammad Zamani Nejad ◽  
Azam Afshin
Keyword(s):  
Thermal Stresses ◽  
Initial Conditions ◽  
Exact Analytical Solution ◽  
Separation Of Variables ◽  
Outer Radius ◽  
Rotating Disks ◽  
Arbitrary Boundary ◽  
Inner Radius ◽  
Transient Thermal

This paper focuses on exact analytical solution of transient thermoelastic behaviors of rotating pressurized disks subjected to arbitrary boundary and initial conditions. The pressure, inner radius, and outer radius are considered constant. The basic thermoelasticity theory under generalized assumptions is used to solve the thermoelastic problem. Using the method of the separation of variables, the relations of temperature and transient thermal stresses in the radial direction are obtained. In the case study, the disk is considered under heat flux. Some useful discussions and numerical examples are presented. The analytical results were compared with those of the finite element method and good agreement was found. The relations obtained in this paper can be applied to any arbitrary boundary and initial conditions.

A Three-Dimensional Treatment of Transient Thermal Stresses in a Circular Cylinder Due to an Arbitrary Heat Supply

1978 ◽  
Vol 45 (4) ◽  
pp. 817-821 ◽  
Author(s):  
Y. Takeuti ◽  
N. Noda
Keyword(s):  
Thermal Stress ◽  
Circular Cylinder ◽  
Cylindrical Surface ◽  
Heat Supply ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Numerical Results ◽  
Stress Problem ◽  
Transient Thermal Stress ◽  
Transient Thermal

We deal with a transient thermal stress problem in an infinitely long circular cylinder due to a nonuniform heat supply in circumferential and longitudinal directions on its cylindrical surface. The analysis is developed using the Boussinesq-Papkovich functions. Numerical results are given for several forms of heat supply.

Numerical Investigation of High Speed Combustion and its Impact on Thermal Structure

2014 ◽  
Author(s):  
Litao Zhang ◽  
Lili Zheng ◽  
Lingyun Hou
Keyword(s):  
Heat Flux ◽  
Thermal Stress ◽  
High Speed ◽  
Thermal Stresses ◽  
Numerical Study ◽  
Thermal Structure ◽  
Great Influence ◽  
Leading Edge ◽  
Reacting Flow ◽  
Fuel Flow

This paper presents numerical study of high-speed combustion and its relationship with thermal stress distribution on a cavity combustion chamber. First, a physical model is established to describe high speed compressible turbulent reacting flow as well as thermal transport in combustor structure. It is then applied to a model combustor with two-staged fuel injections to examine the effects of fuel flow rate and inflow conditions on the heat flux intensity and thermal stress distributions across the thickness of the combustor wall. The result shows that the injection method of the first stage has a great influence on the flow field near the second one, and it affects combustion and heat release distribution inside the combustor. The intensity of heat flux passing through the combustor wall changes along the downstream of the flow, and large thermal stresses are generated in the vicinity of the injector, the leading edge and the trailing edge of the cavity.

On an Axisymmetric Coupled Thermal Stress Problem in a Finite Circular Cylinder

1983 ◽  
Vol 50 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Y. Takeuti ◽  
R. Ishida ◽  
Y. Tanigawa
Keyword(s):  
Thermal Stress ◽  
Circular Cylinder ◽  
Thermal Stresses ◽  
Coupling Effect ◽  
Three Dimensions ◽  
Thermomechanical Coupling ◽  
Coupling Term ◽  
Wide Range ◽  
A New Technique ◽  
Transient Thermal

This paper presents a general treatment of the transient thermal stresses of a finite circular cylinder with consideration of the thermomechanical coupling effect using a new technique. The method used is quite useful for the solution of a wide range of transient thermal stress problems in two or three dimensions. From numerical results, we can find that there is a clear effect on the thermal stress distribution when the coupling term is taken into account.

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