Nawal Aswan Abdul Jalil

Hybrid Composite Laminates Reinforced with Kevlar/Carbon/Glass Woven Fabrics for Ballistic Impact Testing

Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

The Effects of Stacking Sequence Layers of Hybrid Composite Materials in Energy Absorption under the High Velocity Ballistic Impact Conditions: An Experimental Investigation

In the current study, the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption, which were fabricated from Kevlar, carbon, glass fibres, and resin have been experimentally investigated at the high velocity ballistic impact conditions. All the samples have equal mass, shape, and density, nevertheless, they have different stacking sequence layers. After running the ballistic test in the same conditions, the final velocities of the bullets showed that how much energy absorbed by the samples. The energy absorption of each sample through the ballistic impact has been calculated, accordingly, the decent ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterize the material properties.

Modeling and Eigenfrequency Analysis of Sound-Structure Interaction in a Rectangular Enclosure with Finite Element Method

Vibration of structures due to external sound is one of the main causes of interior noise in cavities like automobile, aircraft, and rotorcraft, which disturb the comfort of passengers. Accurate modelling of such phenomena is required in eigenfrequency analysis and in designing an active noise control system to reduce the interior noise. In this paper, the effect of periodic noise travelling into a rectangular enclosure is investigated with finite element method (FEM) using COMSOL Multiphysics software. The periodic acoustic wave is generated by a point source outside the enclosure and propagated through the enclosure wall and excites an aluminium flexible panel clamped onto the enclosure. The behaviour of the transmission of sound into the cavity is investigated by computing the modal characteristics and the natural frequencies of the cavity. The simulation results are compared with previous analytical and experimental works for validation and an acceptable match between them were obtained.

Chaotic fractal search algorithm for global optimization with application to control design

This paper presents chaos-embedded optimization algorithms named as Chaotic Fractal Search (CFS). These algorithms are improved variance to original Stochastic Fractal Search (SFS) algorithm. The influence of two chaos maps which are Chebyshev map and Gauss/Mouse map on the convergence speed and fitness accuracy of the SFS are investigated in this study. Two well-known benchmark test functions with different dimension levels and landscapes were employed in order to evaluate the performance of proposed CFS algorithms in comparison to their predecessor algorithm. Furthermore, the proposed approach is implemented in the optimal tuning of conventional PID and PD-type fuzzy logic controllers for a twin rotor system (TRS) in hovering mode. The simulation study indicates that CFS algorithm with Gauss/Mouse chaotic map in both Diffusion and First Updating process outperforms other CFS algorithms and original SFS algorithm. In addition, PD-type fuzzy logic controller shows superiority over PID controller in twin rotor system control design.

Issues Surrounding Car Center Stack Designs in Malaysia: An Exploratory Study

Car center stack designs have evolved rapidly throughout the years. Manufacturers are working hard in keeping up with the current trends in the automotive market by offering latest technologies embedded into car center stack designs. Consistent with the current trend, Malaysian automotive manufacturers are offering advanced features in car center stacks, which includes touchscreen and navigation systems. Recently car center stacks became the highlight as it became a potential source for driver distraction. An exploratory qualitative study, involving eight regular drivers and two professional drivers were recruited for this exploratory study. A laddering interview technique was applied to reveal chains of attributes, consequences and values. Several prominent attributes related to the value of safety were “Simple Design”, “Touchscreen”, “Meter Design”, and “Multi-Function Steering”. Touchscreen systems were perceived differently by professional drivers compared with regular drivers. There is a need for further studies regarding the touchscreen system designs for Malaysian drivers.

Effects of Structural Parameters on the Dynamics of a Beam Structure with a Beam-Type Vibration Absorber

A beam-type absorber has been known as one of the dynamic vibration absorbers used to suppress excessive vibration of an engineering structure. This paper studies an absorbing beam which is attached through a visco-elastic layer on a primary beam structure. Solutions of the dynamic response are presented at the midspan of the primary and absorbing beams in simply supported edges subjected to a stationary harmonic load. The effect of structural parameters, namely, rigidity ratio, mass ratio, and damping of the layer and the structure as well as the layer stiffness on the response is investigated to reduce the vibration amplitude at the fundamental frequency of the original single primary beam. It is found that this can considerably reduce the amplitude at the corresponding troublesome frequency, but compromised situation should be noted by controlling the structural parameters. The model is also validated with measured data with reasonable agreement.

Tremor suppression for 4-DOFs biodynamic hand model using genetic algorithm

A person who has severe hand tremor will have difficulty in doing specific tasks such as eating, combing or holding any objects. Currently, there is no medication that can cure the tremor. Thus, this study proposes the active tremor control, in which an intelligent controller is applied to suppress the hand tremor. The main objective is to optimise the proportional-integral (PI) controller using genetic algorithm (GA). A linear voice coil actuator (LVCA) is applied onto a four degree of freedom (4-DOF) human hand model represented in state space. The findings of the study demonstrate that the PI controller optimised by GA gives excellent performance in reducing the tremor error. Based on the frequency evaluation, the PI controller performance was roughly around 84% in reducing the peak of simulated hand tremor. The outcomes provide an important contribution towards achieving novel methods in suppressing hand tremor model by means of intelligent control.

Identification of Corrosion on a Hollow Tube Using Vibration

Vibration based technique have so far been focused on the identification of structural damage. However, not many studies have been conducted on the corrosion identification on pipes. The objective of this paper is to identify corrosion on pipes from vibration measurements. A hollow pipe, 500 mm in length with 63.5 mm in diameter was subjected to impact loading using an impact hammer to identify the natural frequency of the tube in two conditions i) without any corrosion and ii) with an induced localized 40 mm by 40 mm corrosion at the middle of the pipe. The shift of natural frequencies of the structures under free boundary conditions was examined for each node of excitation. The results showed that there is a shift in natural frequency of the pipe, between 3 and 4 Hz near to the corrosion area. It can suggested that that the impact vibration is capable of identifying of localized corrosion on a hollow tube.

Lateral Collision with Side Airbag: A Literature Review

The paper presents a literature review of the efficacy of side passive safety in the event of lateral collision and the latest development of side airbag. According to the latest Global Status Report on Road Safety 2013, the total number of death every year due to road accident still maintained in a huge number of 1.24 million. Malaysia is one of the countries having highest estimated road traffic death rate of 25 per 100,000 populations. Moreover, 5% growth annually of fatalities rate forecasted. In general, lateral collision or side impact is the second most common vehicle crash type which takes almost 10,000 occupant deaths each year. Side airbags were introduced into vehicle firstly in 1995 in order to improve occupants injury. It is statically proven that combination of head with thorax side airbag is very effective in reducing occupants fatalities rate, however thorax only airbag is less significant. With the aid from Computer Aided Engineer (CAE) software, designer can further improve airbag design and optimize its performance in order to find the best combination of design parameter such as of area of air vent, Time-To-Fire (TTF), operating pressure of the inflator gas and many more, while design cycle time can be reduced significantly up to 40%. Nevertheless, people are afraid that side airbag deployment load may hurt children and small size female seated in Out-Of-Position (OOP). Researcher could resolve it by adopting the latest Computer Fluid Design (CFD) airbag simulation technique which have a better simulation result of OOP load, since CFD method provide more realistic airbag deployment simulations especially in the first few milliseconds which are significant in OOP test.