Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Nonlinear


Nonlinear Finite Element Analysis of High Strength Fiber Reinforced Concrete Beams

Zinah A. Abdul Hussein

Engineering and Technology Journal, 2020, Volume 38, Issue 9, Pages 1293-1304
DOI: 10.30684/etj.v38i9A.1840

This research work presents a nonlinear finite element investigation on the behavior of high strength fiber reinforced concrete beams. This investigation is carried out in order to get a better understanding of their behavior throughout the entire loading history. The three- dimensional 20-node brick elements are used to model the concrete, while the reinforcing bars are modeled as axial members embedded within the concrete brick elements. The compressive behavior of concrete is simulated by an elastic-plastic work-hardening model followed by a perfectly plastic response, which terminate at the onset of crushing. In tension, a fixed smeared crack model has been used.

Assessment of nonlinear optical properties of polyurethane/MgO nanocomposites

Marzieh Nadafan; Rasoul Malekfar; Zahra Dehghani; Mohammad Allahabadi

Engineering and Technology Journal, 2015, Volume 33, Issue 7, Pages 1175-1178

The third-order optical nonlinearities of polyurethane open cell (PUOC)/MgOnanocomposites, dissolved in dimethylformamide are characterized by Z-scan technique with continuous-wave (CW) Nd:YAG laser at its second harmonic frequency of 532 nm with TEM00 Gaussian profile. The synthesized samples are also characterized by scanning electron microscopy imaging. The nonlinear refractive indices and nonlinear absorption coefficients of the synthesized samples are obtained in the order of 10-8 cm2/W with negative sign and 10-5 cm2/W, respectively. The origin of optical nonlinearity in this case may be attributed due to the presence of strong saturable absorption effect. All the results suggest that the nonlinear coefficients of the synthesized samples can be controlled by the nanoparticles contents into PUOC. Furthermore, the results show that PUOC/MgO may be helpful candidate for the application in nonlinear optical field in the visible region.

Nonlinear Finite Element Analysis for Punching Shear Resistance of Steel Fibers High Strength Reinforced Concrete Slabs

Eyad K. Sayhood; Samer P. Yaakoub; Hussien Fadhil Hussien

Engineering and Technology Journal, 2014, Volume 32, Issue 6, Pages 1411-1432

This study is devoted to investigate the punching shear resistance of high strength reinforced concrete slabs with steel fibers by using the well-known (P3DNFEA), a non-linear finite element program for three-dimensional analysis of reinforced concrete structure.
Nine high strength reinforced concrete slabs with steel fibers and one without steel fibers, have been analyzed in the present study. The finite element solutions are compared with the available experimental data. In general, accepted agreement between the numerical results and the experimental results has been obtained.
Parametric studies have been carried out to investigate the effect of concrete compressive strength, steel fiber content, amount of steel rebars, slab depth and column dimensions on the behavior and ultimate strength of reinforced
concrete slabs.
The numerical analysis indicated that the increase in the concrete compressive strength (f'c) from 40 to 80 MPa has led to an increase in the strength by 69% and 84% for slabs without and with 0.5% steel fibers respectively. The numerical analysis indicated that by using 2.0% steel fibers, the ultimate capacity is increased by 81.7%, compared to a slab without fibers.
Also, the finite element solution revealed that increasing the longitudinal reinforcement ratio in the slab from 1% to 2% led to an increase in the ultimate shear strength of about 57%.

Nonlinear Finite Element Analysis of RPC Beams Failing in Shear

Kaiss F. Sarsam; Ihsan A.S. Al-Shaarbaf; Maha M. S. Ridha

Engineering and Technology Journal, 2011, Volume 29, Issue 11, Pages 2175-2188

Reactive powder concrete (RPC) is a new type of ultra-high strength and high ductility concrete first developed in the 1990's in France. It is recognized as a revolutionary material that provides a combination of ductility, durability, and high strength. In this research work the nonlinear f ini t e element investigation on the behavior of RPC
beams is presented. This investigation is carried out in order to get a better understanding of their behavior throughout the entire loading history. Also, a numerical parametric study was carried out on the RPC beams to investigate the influence of fibrous concrete compressive strength ( ) cf f ¢ , tensile reinforcement ratio ( ) w r , fiber content ( Vf ) and shear span to effective depth ratio (a/d) on the shear behavior and ultimate load capacity of these beams.
The three- dimensional 20-node brick elements are used to model the concrete, while the reinforcing bars are modeled as axial members embedded within the concrete brick elements. The compressive behavior of concrete is simulated by an elastic-plastic work-hardening model followed by a perfectly plastic response, which terminated at the onset of crushing. In tension, a fixed smeared crack model has been
used.

Nonlinear Finite Element Analysis of High Strength Lightweight Concrete Beams

Farked Kais Ibrahim

Engineering and Technology Journal, 2010, Volume 28, Issue 10, Pages 1910-1923

This research work presents a nonlinear finite element investigation on the
behavior of lightweight reinforced concrete beams. This investigation is carried
out in order to get a better understanding of their behavior throughout the entire
loading history.
The three-dimensional 20-node brick elements are used to model the
concrete, while the reinforcing bars are modeled as axial members embedded
within the concrete brick elements. The compressive behavior of concrete is
simulated by an elastic-plastic work-hardening model followed by a perfectly
plastic response, which terminated at the onset of crushing. In tension, a fixed
smeared crack model has been used .The effect of some important parameters
(ƒ'c , rw ,a/d) have been investigated to study their influence on the predicted loaddeflection
curves

An (SDARE) Based Treatment Scheduling For Enhancing Immune Response to (HIV)

Yasir Khudhair Abbas; Raed I. Al-Ajeel

Engineering and Technology Journal, 2009, Volume 27, Issue 4, Pages 675-690

In this paper, the problem of designing dynamic multidrug therapies scheduling to
medicate the Human Immunodeficiency Virus (HIV) type 1 infection is described. The
control approach used for this purpose is the “State Dependent Algebraic Riccati
Equation”, (SDARE), which is one of the highly promising and rapidly emerging
methodologies for designing nonlinear feedback controllers. A nonlinear dynamical
model which consists of six states, where the interaction of the (HIV) particles with the
immune system of a human being, and the Highly Active Antiretrovirus Therapy
(HAART) as Control Inputs are described, and employed to design the dynamical
multidrug therapies.
The (SDARE) approach is applied to the (HIV) mathematical model to design a
suboptimal tracking controller to drive the states of the (HIV) model to a stationary state
in which the immune system of the (HIV) patient can be bolstered enough against the
virus in a way to lead to long-term control of the (HIV) by the immune System of (HIV)
patient by itself after discontinuation of therapy.

Nonlinear Finite Element Analysis of High Strength Fiber Reinforced Concrete Corbels

Maha Mohammed Saeed Ridha

Engineering and Technology Journal, 2008, Volume 26, Issue 1, Pages 1-15

This research work presents a nonlinear fini te element
investigation on the behavior of high strength fiber reinforced concrete
corbels. This investigation is carried out in order to get a better
understanding of their behavior throughout the entire loading history.
The three- dimensional 20-node brick elements are used to
model the concrete, while the reinforcing bars are modeled as axial
members embedded within the concrete brick elements. The
compressive behavior of concrete is simulated by an elastic-plastic
work-hardening model followed by a perfectly plastic response,
which terminate at the onset of crushing. In tension, a fixed smeared
crack model has been used.