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Adah, E. I.
Department of Civil and Environmental Engineering, University of Calabar, Calabar, Nigeria.
Onyelowe, K. C.
Department of Civil Engineering, Michael Okpara University of Agriculture, Umudike, Nigeria
Okorie, A. U.
Department of Civil Engineering, Bayero University, Kano, Nigeria
Ukpata, J. O.
Department of Civil Engineering, University of Cross River State, Calabar, Nigeria
Adah, P. U.
Department of Mechanical Engineering, University of Calabar, Nigeria.
ABSTRACT
The study is aimed at
formulating an improved yield criterion or allowable stress equation for the
analysis of rectangular plates based on the maximum principal stress theory of
yield. The theory was stated mathematically and the new formulation was carried
out by modifying the equation to obtain a new general allowable stress equation
in terms of yield stress and stress factor. The polynomial shape profiles for
twelve plate types were evaluated to obtain the n-value equations for each
plate type which were substituted into the newly formulated general stress
factor equation to obtain the specific stress factor equations for each plate
type. Numerical application was carried out using structural steel as the plate
material and the values of the stress factor for each plate type were obtained.
With these values, the applied stress for each plate type was determined. From
the values of the stress factors obtained, it was observed that all the values
were less than unity, with the least and highest values as 0.61 and 0.91
respectively, which resulted in allowable stress values ranging from 275MPa to
412MPa, greater than the yield stress of 250MPa. This of course reveals the
limitation of this yield theory in its original form. To prevent failure, a
correction multiplier factor was introduced to the stress factor to obtain a
safety factor which reduces the allowable stress to a maximum of 245MPa, which
is below the yield stress, thereby ensuring safety. The yield strength served
as the control for safety with which the obtained values are compared. Hence,
creating a new improved and adequate allowable stress equation, which is easily
applicable by analysts and designers of plate structures to use in predicting
stress and preventing failure of structures. This will save time and improve
lives.
Keywords: Yield Criterion, Maximum Principal Strain, Rectangular Plates, Allowable stress, Stress Factor
https://doi.org/10.33922/j.ujet_v10i2_6
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Published
Wednesday, August 21, 2024
Issue
Vol. 10 No. 2, December 2024
Article Section
GENERAL
The contents of the articles are the sole opinion of the author(s) and not of UJET.
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