Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : impact

Study the Effect of Coupling Agents (Polyvinyl alcohol) and (Lignin) on Mechanical Properties for Polymer Composite Materials

Balkees Mohammed Diaa

Engineering and Technology Journal, 2016, Volume 34, Issue 2, Pages 26-34

In this research study the mechanical properties of (Impact, Hardness and Surface roughness) for PMCs materials that used for (Load-bearing structure, Sandwich panels , radio controlled vehicles, sporting goods …etc.), the PMCs materials made from epoxy resin (Polyp rime-EP) type as matrix and a random glass fiber (E-type) as a reinforcementwith volume fraction (20%) by Hand-Lay up process after addition of coupling agent (Polyvinylalcohol (PVA)) with percent of (0.5%) for first sample and addition of coupling agent (Lignin (Lg)) with percent of (0.5%)for second sample but third sample was polymer composite material without addition of coupling agent for comparing with others, and we noticed an enhancement in mechanical properties for polymer composite material after addition of coupling agent. Either when immersion the three samples in solutions, first solution was water (H2O) and the second solution nitric acid (HNO3) diluted with concentration (0.1N), for seven weeks to each solution, mechanical properties were tested for samples every week, showed decreasing in values of mechanical properties, the polymer composite materials that contains coupling agents expressed more resistance than polymer composite material untreated with coupling agent. And the material that contains coupling agent after immersion in water showed much higher resistance to mechanical properties than immersion in diluted nitric acid.

Simulation of Behavior of Plate on Elastic Foundation under Impact Load by the Finite Element Method

Mohammed Y. Fattah; Mohammed J. Hamood; Sura Amoori Abbas

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 44-58

Transient response and vibrations of an elastic plate resting on sandy soil are presented. Plates are commonly used structural elements and are subjected to wide variety of static and dynamic loads. Such studies are of particular interest in analytical investigations related to structural foundation on soil media. The influence of impact induced high strain-rates within the structure, which causes property changes in all used materials, has to be regarded according to experimental results.
The main objective of the present paper, using the finite element approach through ANSYS program is the simulation of the dynamic response of the foundation under impact load. As a case study, previous experimental work included application of a dynamic load generated by dropping a steel ball (38.1 mm in diameter, 2.22 N in weight) from a height of 609.6 mm onto an aluminum target plate (203.2 mm in diameter, 12.7 mm thick) placed on top of a sand medium. The impact load is defined as a product of the loading magnitude and a time varying function which is assumed to be a Hanning's function for a monopeak, smooth-shaped curve. The problem is discretised by using four types of elements; Solid 45 to model the soil, Shell 63 to model the aluminum plate and Target 170 and Contact 174 are used to model the contact between the plate and soil. Shell 63 (elastic shell) has both bending and membrane capabilities.
It is noticed that the finite element analysis agrees well with the experimental results throughout the entire range of behavior, and the difference in the ultimate displacement is about 6.2%. It can be concluded that ANSYS program is well suited for impact analyses of soil and structural dynamics problems in the non-linear range.

Effect of Boundary Conditions on Impact Resistance of Concrete Slabs

Eyad K. Sayhood; Nisreen S.Mohammed; Sabah K. Muslih

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 841-860

A theoretical analysis based on the numerical solution of the slab impact integral equation is carried out to determine the impact force and deflection time histories, the strain energy absorbed by the slabs and the maximum bending moment.
Effect of slab boundary conditions on impact response of slab is also discussed. The theoretical results obtained in the present analysis are compared with experimental and theoretical works previously done. A good agreement is found between theoretical and experimental results. This indicates that the impact resistance of relatively large slabs may be predicted by using the theoretical approach based on equation of undamped slab vibration. All the derivations required to predict the effect of boundary conditions are performed for both forced and free vibrations. For the same falling mass and the same applied kinetic energy (height of drop) for all cases, the maximum central deflection and the maximum impact force are affected by the boundary conditions of the slabs

Mechanical Properties and Dynamic Response of Lightweight Reinforced Concrete Beam

AzizI brahimAbdulla; a A. Ali; Alya; Ahmed Adnan Ghanee

Engineering and Technology Journal, 2012, Volume 30, Issue 2, Pages 293-311

The study is conducted to perform two goals: The first geal is to produce a
lightweight concrete using major components which are locally available with
some standard admixtures.Many mixtures are prepared using many ratios of
superplasticizer (SP) and silica fume (SF) admixtures to yield a lightweight
aggregate concrete, the effects of using different ratios of these admixtures on unit
weight, compressive strength and flexural strength are studied individually and
accumulatively. The secondis to study the dynamic specifications of normal and
lightweight reinforced concrete beams.
The results showed that the increasing in dosage of superplasticizer (SP) for
(LWAC) increases the density of (LWAC), and the increasing in dosage of silica
fume (SF) decreases the density of (LWAC). The experimental impact tests for
R.C. beams shows that the lightweight R.C. beams have a better response under
impact loading with respect to the maximum dynamic deflection (2.955mm for
normal weight beam and 1.58mm for lightweight beam). Also,Impact force
transferred to supports reactions of lightweight beams is smaller within 45% than
the impact force transferred to reaction of normal weight concrete under the same
impact load, and the time to reach 90% damping equal to 1.223 sec and 1.6 sec for
lightweight and normalweight R.C. beams respectively. Also, the reinforced
concrete beams are tested under repeated impact load up to failure. The tests
showed that the no. of blows to cause first crack for lightweight concrete beams
more than twice of this for normalweight concrete beams.

Impact Resistance of Lightweight Chopped Worn-Out Tires Concrete

Zaid M. K. Al-Azzawi; Dhafir T. F. Al-Khameesi

Engineering and Technology Journal, 2010, Volume 28, Issue 16, Pages 5200-5212

This study summarizes results of an experimental investigation of the
impact resistance of 12 lightweight concrete slabs made from incorporating chopped worn-out tires (Ch.W.T.) into the mixes as a partial replacement of the sand in mortar mixes, and as partial replacement for both sand and gravel for concrete mixes; volumetrically.
The main variables were; the partial replacement ratio (PRR) and the shape of the falling mass (striker). Data were obtained pertaining to compressive strength, static and dynamic modulus of elasticity, and modulus of rupture. In addition, the crack pattern under impact loading was studied to provide insight into the internal behavior and failure mechanism of lightweight Ch.W.T. concrete slabs. Results of this work indicate that incorporating Ch.W.T. into mortar and concrete mixes succeeded in reducing its unit weight from 17.9% to 26.2% according to type of mix and partial replacement ratio. In contrast, the ultimate
impact resistance, expressed in the number of blows required for complete separation of the specimen, increased from 91% to 186% for mortar mixes depending on the partial replacement ratio and the type of falling mass; and did not decreased significantly for concrete mixes.

Dynamic Failure Mode And Impact Energy Absorption of Filament-Wound Square Cross-Section Composite Tubes

Mohammad Abdul Hassan Whaib; Hussain J. Al-Alkawi

Engineering and Technology Journal, 2010, Volume 28, Issue 14, Pages 4874-4889

In the present work simulation of impact response using LS-DYNA explicit
finite element code is described to investigate the crash behavior and energy absorption characteristics of square glass fiber reinforced plastic tubes, subjected to impact load. Filament-wound tubes with two layers [+45º, -45º] were fabricated and tested. The experimental crushing characteristics data are compared with the obtained numerical results, showing good agreement. The effect of geometrical parameters, winding angle and the failure mode on the energy absorption
characteristics are also investigated.