Rozaina Ismail

Magnetorheological Elastomers: A Review

This present paper reviews on the material compositions of Magnetorheological elastomer (MRE) as presented by researchers. As the article review, this paper much focuses on the selection of the material in the MRE ingredients. MRE has been known as a new kind of smart material over past decades. MREs offer innovative solutions for various applications in the engineering field since the rheological properties of MREs can be controlled by an external magnetic field. The characteristic responses of MRE are influenced by many factors such its elastomer matrix, the size, distribution, composition, percentage volume of filler particles and so on.

Influence of Different Fillers on the Tensile Properties of 50/50 NR/NBR Blend

This paper reviews the relationship of the effect of different fillers used in the natural and nitrile rubber compounds on the tensile properties. The use of fillers in the rubber compounds is well known in order to modify and improve their properties. Thus, four different grades of carbon black and non-carbon black fillers were used to achieve the aim of the study. A comparison between carbon black and calcium carbonate system leads to further scientific findings for the understanding of the tensile properties of filled rubber compounds. The tensile properties of the five samples were investigated by using a Tensile Instron Machine. Five test pieces were tested for every sample at a stretching rate of 500 mm/min at standard laboratory temperature. Then, median values of the five test pieces of each sample were calculated. As the conclusion, different types of fillers results to different properties of the elastomers. Carbon black fillers can be proved to have better tensile properties compared to non-carbon black fillers. The best filler with the highest tensile properties was N220 with 23.63 MPa and elongation at break at 638.63 %.

An Evaluation of High-Rise Concrete Building Performance Under Low Intensity Earthquake Effects

The paper presents an evaluation of high rise building in Kedah which subjected to low intensity earthquakes effects. The earthquake study is relevant even though Malaysia is outside the earthquake region but still had experienced and did suffered from major cases in the past like Tsunami. Engineers should concern and consider the loading for reinforced concrete building due to earthquake in Malaysia’s building design procedure. The study addresses on the earthquake study due to performance of critical frame reinforced concrete building. The Quarters Tentera Laut Diraja Malaysia (TLDM) Langkawi, Kedah was chosen as a main model for this study. The building was analyzed using Finite Element Modelling (FEM) under different types of analyses using IDARC 2D depend on variety of earthquake intensities from Time History Analysis (THA) considering low to medium earthquake intensities. The yield point at beam-column connections was analyzed to determine the damage index and damage level of the building. The building performed the early yielding point at 3.115 s for beam element at intensity 0.20 g. Based on result, the critical frame 2A/F–B of the building can stand an earthquake happen with intensity up to 0.20 g. There is no structural damage but some non-structural damage is expected in the non-linear analysis of modal frames which indicates that the building was categorized in the light damage level.

Evaluation of Medium-Rise Reinforced Concrete Building Performance under Low Intensity Earthquake Effect

The paper presents an evaluation of medium-rise reinforced concrete building in Johor which is subjected to low intensity earthquake effects. Even-though Malaysia is outside the earthquake region, the country had experienced and did suffer from major cases due earthquake in the past like tsunami. Engineers should concern and consider the loading for reinforced concrete building due to earthquake in the building design procedure. The study addresses the performance of critical frame reinforced concrete building when subjected to earthquake motion. The building of Marlborough College Malaysia chooses as model. The building was analyzed using Finite Element Modelling (FEM) using IDARC (2D) with respect to various earthquake intensities obtained from Time History Analysis (THA) data. The yield point at the beam-column connections was analyzed to determine the damage index and damage level of the building subjected to the various earthquake intensities. The building performed the early yielding point at 4.2650 sec for beam element at the intensity of 0.15g. Based on the results, it was found that the critical frame of Condominium Marlborough College Malaysia can stand an earthquake occurrence with intensity up to 0.20g. There is no structural damage some non-structural damage is expected in the non-linear analysis of modal frames. The building was also categorized as the one in the light damage level.

Seismic Damage Analysis of Reinforced Concrete Frame of Public Buildings in Ipoh Subjected to Acheh Earthquake Event

This study addresses the vulnerability of public buildings in Malaysia subjected to earthquakes from Sumatra and Philippines. A case study that has been conducted on medium-rise reinforced concrete buildings which are mostly categorized as moment resisting frames. Block K (Federal Reserve Unit), Islamic Complex, and Police Quarters were chosen as main models for this study. The building was analyzed using Finite Element Modeling (FEM) under variety of earthquake intensities from Time History Analysis (THA) considering low to medium earthquake intensities. The yield point at beam-column connections was analyzed to determine the damage index and damage level of the building. The performance of critical frame reinforced concrete building when subjected to earthquake motion (Near source: Acheh) was addressed. The buildings evaluated were subjected to low-intensity earthquakes. There are different damage levels that affect the frames when different intensities are applied by looking at structural and non-structural damage. The level of the damage state (minor, moderate, major, collapse levels) has been defined as well. As a result, the high-rise building developed plastic hinge due to the earthquake intensity of 0.05 g and have damage indexes in the range 0.050 (light damage level) to 1.0 (collapse). A greater damage index means that the members yield earlier and the plastic rotation is larger and vice versa. As for the result, the damage to columns is light, the damage level of most columns is “medium destruction,” and the performance of the high-performance concrete is satisfactory.

Vulnerability of High-Rise Buildings in Kuala Lumpur Subjected to Acheh Earthquake Event

The earthquake study is relevant even though Malaysia is outside the earthquake region but still had experienced and did suffer from major cases in the past like tsunami. Engineers should concern about and consider the loading for reinforced concrete building due to earthquake in Malaysia’s building design procedure. The study addresses the earthquake study due to performance of critical frame reinforced concrete building which were subjected to low-intensity earthquakes effects. Building of Ampang Jaya Municipal Council (MPAJ), Employees’ Provident Fund (KWSP), Block F (Public Work Department, JKR), and Department of Survey and Mapping Malaysia (JUPEM) were chosen as main models for this study. The building was analyzed using Finite Element Modeling (FEM) under different types of analyses using IDARC2D depend on variety of earthquake intensities from Time History Analysis (THA) considering low to medium earthquake intensities. The yield point at beam-column connections was analyzed to determine the damage index and the damage level of the building. The buildings analyzed, which were subjected to the Acheh earthquake ground motion, developed plastic hinge due to the earthquake intensity of 0.012 g for all buildings except building of Employees’ Provident Fund (KWSP) which developed plastic hinge due to the earthquake intensity of 0.05 g and had damage indexes in the range 0.00 (no damage) to 1.0 (collapse). A greater damage index means that the members yield earlier and the plastic rotation is larger and vice versa. As for the result, the damage to columns is light, the damage level of most columns is “medium destruction,” and the performance of the high-performance concrete is satisfactory. While the damage in the beams is much serious, the distribution of the damage index reflects the seismic design principle of “strong column, weak beam.”

Dynamic mechanical behavior magnetorheological nanocomposites containing CNTs: A review

Carbon nanotubes (CNTs) based polymer composites have variety of engineering applications due to their excellent mechanical, electrical, chemical, magnetic, etc. properties. This paper is an attempt to present a coherent yet concise review of as many of these publications as possible on the mechanical aspect of the Magnetorheological Elastomer (MRE) composites with the addition of multi-walled carbon nanotubes (CNTs). The dynamic mechanical response of the MR nanocomposites to applied magnetic fields has been investigated through dynamic mechanical analysis. It is found that a small amount of carbon nanotubes can effectively improve the mechanical performance of conventional MR elastomers. In summary, multi-walled carbon nanotubes reinforced magnetorheological composite has been developed to take advantage of both the smart MR technology and outstanding properties of carbon nanotubes. Furthermore review is also carried out on the capability of carbon nanotubes to impart the stiffness and damping performan...

A Review of Magnetorheological Elastomers: Characterization Properties for Seismic Protection

Magnetorheological (MR) materials are belong to the group of smart materials that can be significantly altered in a controlled under the influence of an external stimulant which by changing their viscolesatic properties due to stress, pH level, moisture content, electric fields or in the case of MREs, magnetic fields. The MREs are interesting materials especially for the active stiffness and vibration control of structural systems. As a controllable stiffness element, MREs can offer innovative engineering solutions to various engineering challenges. Recently, they are being considered as new enabling components in active control systems, such as adaptive tuned vibration absorber and improving seismic protection base-isolated structures. The characteristic response will be influenced by many factors including; the elastomer matrix, the size, distribution, composition and percentage volume of the ferromagnetic particles, and whether the ferromagnetic particles are aligned in chains or randomly dispersed. A review is presented in this paper of the characteristic properties of magnetorheological elastomers and how these properties are affected by varying magnetic fields and the indicated compositional parameters. Besides describing the fundamental behavior of MREs, various applications of MREs for seismic protection are discussed and compared.

Magnetorheological Elastomer Performances with the Presence of Carbon Black

This paper deals with the isotropic magnetorheological elastomers (MRE) samples which compounded in the absence of magnetic field. Two types of MRE composites with and without the addition of carbon black were fabricated. The mechanical properties through tensile test were obtained by using an Instron Tensile Machine. Morphological characterization test of these MRE samples was conducted by using a scanning electron microscopic (SEM). From the experimental study, it can be concluded that, the addition of carbon black in MRE increases tensile strength, decreases the elongation of the break and also cure time. Thus, this study demonstrated that carbon black has a significant improvement on the mechanical properties of MRE. This method of fabrication of MRE is useful for the further research on rubber bearing application.

Seismic Site Classification of JKR Bridge at Sungai Sepang Using Multichannel Analysis of Surface Wave (MASW)

In seismic engineering, the dynamic property of the soil is one of the most important aspects in ground response analysis. Dynamic property is significantly affected by local soil deposits. Shear wave velocity (V s) of soil is one of the main parameters in determining the amplification factor on ground surface. This study aims to determine the shear wave velocity profile of the bridge at Sungai Sepang by using multichannel analysis of surface wave (MASW) method. All the acquired raw data from the MASW field test were analyzed and it can be summarized to three major steps: First, filter the wiggle plot to the analyzable range of frequency of Rayleigh wave; second, develop the dispersion curves of Rayleigh wave phase velocity and; third, inversion of dispersion curve to obtain the V s profiles. The filter and the development of dispersion curve processes were carried out by using Pickwin softwis (SeisImager/SW). Results show that the soil for bridge at Sungai Sepang is having a very low V s30, which is 143.3 and 137.2 m/s, respectively. The soils are classified as Class E which can be considered soft soil according to Uniform Building Code (UBC). Based on the N-SPT value by using empirical formula, the value of V s30 ranges from 101.22 to 151.87 m/s by using different empirical formula. It can be concluded that the value of V s30 for bridge by using MASW is accepted since the value is near to the value of numerical equation from N-SPT value based on borehole data at Sungai Sepang site.