Showing papers by "Faizal Mustapha published in 2012"

A framework for weighting of criteria in ranking stage of material selection process

Abstract: Material selection is an onerous process of design activities which needs to be carefully carried out in order to increase the probability of success. A lot of multi-criteria decision-making methods have been proposed in material selection, many of which require quantitative weights for the attributes. Since weights play a very significant role in the ranking results of the materials, this paper presents a framework for determining importance degree of criteria to overcome the shortcomings of this subject in material selection. Furthermore, the suggested framework covers the situation of interdependent relationship between the criteria which has not been surveyed in material selection yet. An example was considered to illustrate how this framework is conducted. On the basis of the numerical results, it can be concluded that the proposed method can soundly deal with the material selection problems.

Finite element validation on adhesive joint for composite fuselage model

Abstract: A novel fabrication miniature composite fuselage structure consisted of a woven composite laminated with an adhesively bonded butt joint under axial compression loading is numerically simulated in this research. A Finite Element Analysis (FEA) via ABAQUS/Explicit was utilized to capture the complete compressive response that predicts the crushing behaviour and its mechanical strength from initial compression loading until its final failure mode. A woven C-glass fibre/epoxy 200 g/m

A Structural Health Monitoring of a Pitch Catch Active Sensing of PZT Sensors on CFRP Panels: A Preliminary Approach

Abstract: © 2012 Aris et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A Structural Health Monitoring of a Pitch Catch Active Sensing of PZT Sensors on CFRP Panels: A Preliminary Approach

Impact Resistance of Armor Composite Made of Kevlar29 and Al2O3 Powder

Abstract: In this study, the impact behavior of a composite material made from Kevlar29 – Al2O3/ epoxy for hard body armor is considered The present experimental method focused on the behavior of the ballistic limit, energy absorption, and final velocity of flat cylindrical and conical projectiles The results indicated that the maximum ballistic limit at impact velocity is 400 ±7 m/s for an 18 mm target thickness Experimental results showed that the best ballistic performance was achieved with composite materials made of Kevlar29 – Al2O3/epoxy The results concerning the initial and final velocities showed good agreement compared with the Ipson and Recht equation

Computational Simulation for Static and Dynamic Load of Rectangular Plate in Elastic Region for Analysis of Impact Resilient Structure

Abstract: Impact resilient structures are of great interest in many engineering applications varying from civil, land vehicle, aircraft and space structures, to mention a few examples. To design such structure, one has to resort fundamental principles and take into account progress in analytical and computational approaches as well as in material science and technology. With such perspective, the first objective of this work is to develop a computational algorithm to analyze flat plate as a generic structure subjected to impact loading for numerical simulation and parametric study without considering the surface impact effect. The analysis is carried out from first principles for static and dynamic analysis; the latter is based on dynamic response analysis in the elastic region. The second objective is to utilize the computational algorithm for direct numerical simulation, and as a parallel scheme, commercial off-the shelf numerical code is utilized for parametric study, optimization and synthesis. Through such analysis and numerical simulation, effort is devoted to arrive at optimum configuration in terms of loading, structural dimensions, and material properties, among others. The codes developed are validated for generic cases. Further simulations are carried out using commercial codes for some sample applications to explore impact resilient structural characteristics in the elastic region.

Investigation of axial crushing behaviour of a composite fuselage model using the cohesive elements

Abstract: Finite element analysis (FEA) on a new fabrication miniature composite fuselage structure under axial compression loading is presented. ABAQUS/Explicitsimulationisemployedtopredictthecrushingbehaviourandmechanicalstrengthfromtheinitialcompressionloadingtothefinal failuremode.AwovenC-glassfiber/epoxy200g/m 2 compositelaminated withorthotropicelasticmaterialpropertiesisusedforthefuselagemodel. This proposed model is established to observethe crushing load and collapsemodes under anaxialcompressionimpact.Adhesively bonded joint progressionis generated using the technique of cohesiveelement. Various anglesofthelaminaaredeliberatedintheanalysistoacquireandimagine theeffectoftheangleoforientation.Compositelaminaanglesareexaminedandvalidatedusing FEAmodelling as a numericalparametricstudy. TheresultsshowthatthefiniteelementanalysisusingABAQUS/Explicit canreproducesatisfactorilytheload-deflectionresponse.Itcanbeconcluded that special cases of antisymmetriclamination are found to have the strongestresistanceto theappliedload.

A condition structural index (CSI) using principal component analysis (PCA) for normal, damage and repair conditions of CFRP laminate

Abstract: The paper deals with data reduction technique by using the principle component analysis (PCA) applied to the carbon fiber reinforced plastic (CFRP) panels for structural health monitoring study. Two CFRP panels were subjected to damage and repair coincide with typical aircraft structural repair manual (SRM). Data was taken at normal/ undamaged, damaged and repaired condition by placing PZT smart sensors at predetermined distanced across the damaged and repaired structure. A time-based data response was captured for post analysis during the interrogation on the structure at each condition. The raw data was captured in a Lamb wave form and only the interested intervals were selected by using Morlet wavelet analysis to evaluate the Condition Structural Index (CI) and Amplitude Based Assessment (ABA) for each conditions. The results were evaluated by using the PCA technique in order to distinguish the characteristic of the normal, damage and repair conditions. The results showed that in all cases considered, it was possible to distinguish the conditions of normal, damaged and repaired states with promising accuracy and repeatability of the data.

A Comparative Study of an Aircraft Radome Closed Mold through Vacuum Infusion Technique

Abstract: In this paper, manufacturing process of aircraft radome via closed mold with vacuum infusion process is presented. Closed mold is needed to get smooth inner and outer surface. The radome mold was formed from the original part of the aircraft Duke 60 Beachcraft. The closed mold is made from fiber glass/polyester composite via hand lay-up technique. Tooling grade vinyl ester gel coat is applied on the mold to produce fine smooth surface and protection. Later, the radome part is fabricated with vacuum infusion and the consistency of thickness is achieved.

Implementation of Extreme Low Power Micro-Controller for a Wireless Structural Health Monitoring (SHM) System

Abstract: This paper presents the newly improved design of wireless sensor technology for Structural Health Monitoring (SHM) system or continuous monitoring for Non Destructive Testing (NDT). Numerous researches have indulged in designing wireless sensor networks where the reliability and the capability to do rapid assessment on the aeronautical, mechanical and civil structure are concerned. A lot of challenges associated with the design have been discussed including on power consumption by the device with regards the operation nature over period of times vs. energy sources. This research project explores the implementation of Nano Watt XLPTM technology microcontroller from Microchip and applicable smart PZT sensors or the newly refined technique in (NDT) that utilise ultrasonic guided waveform response to detect structural defects. The developed SHM system provide low power wireless nodes to perform automatic data collection and analysis with possibilities to integrate with green energy sources more effectively thus reducing the cost of maintenance and increase the reliability of the system.

Equilibrium and non-equilibrium models of the power markets

Abstract: The competition trend within the electricity segment has motivated the research community efforts and directed them towards investigations of deregulation of the electricity markets. This underlines significant research needs to insure providing appropriate design and functioning, as well as analysis support models that would fit to recent electricity market settings. Thus, this work focuses on facets of the deregulated electricity markets and on modeling the power market. It aims primarily at identifying, classifying and characterizing the quite bewildering multiplicity of the methods available in the specialized literature on the topic. This study offers review of the most appropriate works related to electricity market models, like the equilibrium and non-equilibrium models, and some other related areas of research, like optimization as an exogenic variable or firm decisions function. The agent and Cournot based supply function has non-equilibrium and equilibrium simulation models under the conditions of both imperfect and perfect competition. Lastly, it characterizes the approaches most suitable for implementing different types of market analysis and planning studies in the electricity sector for new setting. Key words: Electricity market deregulation, equilibrium and non-equilibrium market models, market behavior.

Modal Properties of a Cantilevered Laminated Woven Composite Plate as Affected by Stacking Sequence and Fiber Orientation: An Experimental Study

Abstract: The use of laminated composites in aircraft structures is not totally new. However, the idea of using woven fiber glass as reinforcement in primary structural members is not widely addressed as compared to unidirectional fibers. In an effort to characterize the dynamic behavior of a woven laminated composite subject to dynamic loads, modal testing is performed experimentally on a cantilevered laminated woven glass fiber/epoxy composite flat plate which resembles an aircraft wing with aspect ratio of 5. To that end, the effect of stacking sequence and fiber orientation of the laminated composite plate on the modal properties is assessed. 6-layer laminated composite configurations with various stacking sequence and fiber orientation are fabricated so as to generate variable stiffness plates. The modal test employs the single roving hammer technique to obtain the frequency response of the plate and the results of the first five modes against the fiber orientation and stacking sequence are analyzed.

Damage Classification in CFRP Laminates Using Principal Component Analysis (PCA) Approach

Abstract: Signal processing is an important element used for identifying damage in any SHM-related application The method here is used to extract features from the use of different types of sensors, of which there are many The responses from the sensors are also interpreted to classify the location and severity of the damage This paper describes the signal processing approaches used for detecting the impact locations and monitoring the responses of impact damage Further explanations are also given on the most widely-used software tools for damage detection and identification implemented throughout this research work A brief introduction to these signal processing tools, together with some previous work related to impact damage detection, are presented and discussed in this paper

Geometric Non-Linear Analysis of Composite Laminated Plates Using Higher Order Finite Strip Element

Abstract: A finite strip method for geometric non-linear static analysis based on the tangential stiffness matrix has been developed using the new concept of polynomial finite strip elements, with Reissner (higher order shear deformable element) plate-bending theory for composite plates. A finite strip analysis programming package, which is capable of performing non-linear analysis for composite flat panels, has also been developed with Reissner plate bending element. Good agreement with the finite element results has been observed through various test cases, confirming the accuracy and reliability of the new developed finite strip method.

Empirical stiffness matrix derivation for an elastic substructure

Abstract: The paper presents the study on the three-dimensional empirical derivations of the static stiffness matrix derivation of a sheet metal substructure based on the basic principles of the finite element method. An experimental procedure and techniques are developed to extract the stiffness coefficients of a 6 by 6 submatrix for a sheet tube made of mild steel ASTM A-500 SHS. The submatrix obtained from this experiment is then included in the finite element software NASTRAN as a new element. Comparison of results between the experimental and the finite element analysis is carried out via a test case to validate the method employed. Excellent agreement with the experimental results has been observed which confirms the accuracy of the approached employed

Damage Identification and Classification in CFRP Laminates – A SEM Based Study

Abstract: There are two main factors that need to be considered as important parameters that affect the response of a structure: kinetic energy (E=1/2mv^2 ) and potential energy (E=mgh). For instance, if one has a large mass but with lower height, the amount of damage produced on the structure may not be the same as if one has a smaller mass with a higher dropping height although the potential energies will be the same. Therefore, before performing tests on the structures, the selection for the appropriate test apparatus and test procedures must be made carefully to ensure that the test conditions are similar to the actual impact conditions. In this present work, a study was conducted to fully understand the damage progression and growth, not only should the impacted surface be evaluated, but also the cross sectional defects on the impacted area must be accurately identified and examined. In this current work, the impacted test specimens will be observed at different magnifications to distinguish the types of failure mechanisms using Scanning Electron Microscopy (SEM). To perform this, the impacted specimens will be examined by two different approaches: surface defects and cross-sectional defects. This allows the failure mechanism to be observed more precisely.