scholarly journals Failure Time of Loaded Wooden Beams During Fire

1983 ◽  
Vol 1 (4) ◽  
pp. 297-303 ◽  
Author(s):  
M.H. Do ◽  
G.S. Springer
Keyword(s):  
Cross Section ◽  
Elevated Temperatures ◽  
Failure Time ◽  
Rectangular Cross Section ◽  
Full Scale ◽  
National Bureau ◽  
Southern Pine ◽  
Simply Supported ◽  
Failure Times

A model is presented for predicting the failure time of loaded wooden beams of rectangular cross-section exposed to elevated temperatures or to fire. Failure times calculated by the model were compared to failure times measured in this study using 19.05 mm x 19.05 mm simply supported southern pine beams, and to failure times measured by the National Bureau of Standards during the fire of a full scale room. Reasonable agreements were found between the calculated failure times and the data.

Some Operating Characteristics of the Supersonic Axi-Symmetric Parallel Diffuser

1965 ◽  
Vol 7 (1) ◽  
pp. 15-22 ◽  
Author(s):  
P. J. Baker ◽  
B. W. Martin
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Static Pressure ◽  
Elevated Temperatures ◽  
Rectangular Cross Section ◽  
Pressure Ratio ◽  
Oblique Shock ◽  
Operating Characteristics ◽  
Single Shock ◽  
Shock System

This paper extends the investigation of the supersonic parallel diffuser previously reported by Martin and Baker (I)‡ and Baker (2) to cover the case of the axi-symmetric cross-section. The flow patterns and the wall static pressure distributions appear broadly to correspond to those which occur in the parallel diffuser of rectangular cross-section. But the axi-symmetric diffuser is found to have a wider operating range (in terms of overall blowing pressure ratio) before the single shock gives way to an oblique shock system, and this permits higher optimum recovery of static pressure. In the axi-symmetric configuration, only very short lengths of duct are necessary to achieve full static pressure recovery in both the single shock and the oblique shock regimes. The use of short diffusers would lessen the cooling problems of large-scale jet engine test facilities, in which exhaust jets must be recompressed at elevated temperatures.

Effect of Bimodularity on the Stress State of a Variable Cross-Section Reinforced Beam

2019 ◽  
Vol 974 ◽  
pp. 646-652
Author(s):  
Aleksey N. Beskopylny ◽  
Elena Kadomtseva ◽  
Vadim Poltavskii ◽  
Mikhail Lukianenko
Keyword(s):  
Stress State ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Neutral Line ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Reinforcing Bars ◽  
Tensile Stresses ◽  
Simply Supported ◽  
Compressive Stresses

The article is dedicated to the effect of different modulus of the material on the stress state of a beam of the variable rectangular cross section. The height of the beam varies linearly along its length. Formulas for calculating the maximum compressive and tensile stresses and determining the neutral line are obtained. The maximum tensile and compressive stresses are determined for the clamped and simply supported beams. The dependence of the maximum normal stress on the number of reinforcing bars located in the stretched zones is numerically investigated. The stress state of the beam is compared with and without consideration of the bimodularity of the material for simply supported and cantilever beams. It is shown that taking into account the bimodularity of the material significantly affects the maximum tensile and compressive stresses. The magnitude of the tensile stresses is increased by 30%; the magnitude of the compressive stresses is reduced by 21%. As a bimodular material, fibro foam concrete is considered in work.

scholarly journals The improved buckling theory for the column beyond the elastic limit

2020 ◽  
Vol 17 (3) ◽  
pp. 87-93
Author(s):  
L. M. Kagan-Rosenzweig ◽  
Keyword(s):  
Cross Section ◽  
Elastic Limit ◽  
Rectangular Cross Section ◽  
Critical Force ◽  
Tangent Modulus ◽  
Force Level ◽  
Small Disturbance ◽  
Simply Supported ◽  
Monotonic Increase ◽  
The Moment

The article considers a new effect, namely, spontaneous bending (due to the vanishingly small disturbance) of an inelastic column when it is centrally compressed by a force that is less than critical. Earlier, no attention was paid to this effect. The problem is discussed on the example of a simply supported column of rectangular cross section. At a certain level of the force applied to the column curved due to spontaneous bending, the force increment causes the moment increment of an indefinite value. This force level is considered to be the critical one. Its calculation, which does not take into account the non-monotonic increase in stresses during the column deformation, gives the critical force exactly equal to the tangent modulus one.

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