Engineering and Technology Journal

This paper represents experimental and numerical study the behavior of the rubberized steel frame connections. One single-bay, one-story without elastic buckling are cyclically tested. The experimental specimens are simulated and analyzed by the ABAQUS program. Four specimens of steel plane portal frame are investigated under horizontal reversed cyclic loads. The specimen connections are developed by using different diameters of composite steel bolts/rubber instead of conventional steel bolts to connect the beams with columns. The yield and ultimate strength, ductility, envelope curves, and damping ratio of these specimens are analyzed and compared. The finite element method is used to establish and verify the results of the laboratory test. The results of the experimental and numerical tests gave a large load-carrying capacity, reduction in the stresses, excellent ductility and energy dissipation capacity, and remarkably improved damping ratio.

One of the main requirements of the truck tire sidewall are flexing resistance, tensile strength and tear resistance, as well as resistance to weather conditions experienced by tires during use, which include exposure to sunlight and ultraviolet radiation. Therefore, the requirements and changing circumstances led to develop the design parts of tires, and sidewall is more susceptible to these conditions, where it will be studying the properties of truck tire sidewall produced by Al- Dewaniya Tires Factory- Iraq, according to the specifications designed by Italian Perilli Co. since about 20 years ago, which prompted to development the mechanical and physical properties of those components.
The present work aim to design stocks with high specifications, through the study of the impact of the substantial material (rubber) in truck tire sidewall recipe. Natural rubber, Standard Vietnam Rubber (SVR5) and synthetic rubber, Styrene-Butadiene-Rubber(SBR1502),also the introduction of a new type of synthetic rubber is Poly Butadiene (BRcis), filled with carbon black (N550) as a reinforcement agent with fixed loading percentage (51pphr),as well as other components such as accelerators, anti-oxidants, anti-ozonants and vulcanizing agent. Through laboratory testing found that stocks containing (NR/SBR/BRcis) blending with (40/60/-), (40/50/10) and (40/40/20) as a percentage loading has given good results in many tests including tensile, tear, compression, hardness and fatigue crack growth resistance.

In this paper the finite element methodis used as a numerical techniqueto
investigatethe three-dimensional elastomeric materials (rubber or rubber-like
materials) under finite, or large, strains analysis.The non-linear element equations for
the displacement and pressure field parameters are formulated using the minimized
variational approach. Essentially, approximate solutions for the displacement and
pressure field parameters are obtained from the solutions of the two corresponding
sets of non-linear simultaneous equations via the nonlinear Newton-Raphson iterative
procedure. The basic iterative solution procedure convergence is further improved via
breaking the applied load down into load incrementwith optimized incremental steps.
Additionally,a complete finite element formulation is reported and detailed in this
work,and the mathematical complexities conjoined with such kinds of analysis are
simplified as possible.
Solving some numerical examples and comparing the results with that obtained
from some available results and ANSYS 12.0 showed that the current formulation of
the finite element methods is correctand the resulted program is capable for solving
incompressible elastomeric materials under finite strain. The formulation used for the
finite element derivations for large strain analysis gave satisfactory results as
compared with that of available results.

This paper is concerned with determining material parameters for
incompressible isotropic hyperelastic strain–energy functions. A systematic
procedure analysis is implemented based on the use of least squares optimization
method for fitting incompressible isotropic hyperelastic constitutive laws to
experimental data from the classical experiments of Treloar [3] on natural rubber.
Two phenomenological constitutive models are used to fit the experimental data
of natural rubber, these are Mooney-Rivlin and Ogden models. The material
parameters using Mooney-Rivlin are obtained using the linear least squares
method, while for Ogden model the material coefficients are nonlinear,
consequently the nonlinear least squares approach has been used. In this work the
nonlinear least squares method with trusted region TD have been used using
MATLAB Ver. 7 to find these coefficients. The comparison shows that the present
mathematical formulations are correct and valid for modeling rubbery materials.
Also it was found that Mooney-Rivlin model is suitable when the deformation is
not to exceed 100%, while Ogden model is more appropriate when deformation
exceed 100%. In addition, as the degree of non-linearity in material behaviour
increases more material coefficients are required.