236 research outputs found
First ply failure analysis of composite plates / Jamaluddin Mahmud, Valliyapan D. Natarajan and Isfanizam Ismail
Get PDFThis paper is aimed to simulate the failure of selected fiber reinforced composite plates under transverse loading. A mathematical model and computational model are presented for the aJ1alysis.Higher Order Shear Deformation plate theory is utilized to predict the deformation of the plat.es. A failure criterion with the existence of coupling terms to determine the mode of failure for compositeplat.es is employed to predict. the failure. The uniqueness of this criterion compared to all other existing criteria is that it. includes the coupling terms, which relate the interaction between the longitudinal stress and the transverse stresses. As a consequence, it allows the interaction between the fiber properties aJ1d the matrix properties in terms of the strength of the material, which other failure criteria have neglected. Variation of material properties through thickness is used and accommodated by a discrete layer approach. A program based on a finite element method is developed using Fotran-90 to determine the lamina stresses. These stresses are then used in the present. failure model to determine the First Ply Failure. Finally, the First Ply results for various composite plates are analyzed. The results obtained with current failure criterion are also compared with the results obtained with existing failure criteria. The stresses distribution obtained have proved that the present finite-element program could determine lamina and inter-lamina stresses accurately when compared to the exact solutions. The results of the failure analysis have shown that the present failure models could offer a better prediction of failure for any composite laminate
The effect of skin orientation on biomechanical properties / Nor Fazli Adull Manan and Jamaluddin Mahmud
Get PDFSkin technology has become a world interest recently and further investigations could improve the current application of skin and leather. Aligning to this, a biomechanical analysis of animal skin is carried out, where the sheepskins are investigated thoroughly using uniaxial tensile tests. The main aim of this study is to compare the biomechanical properties of sheepskin in means of hair effect and orientation layout between horizontal and vertical orientation. The testing specimens are taken from the fresh slaughtered Boer sheepskin and they are prepared into four categories; horizontal (unshaved), horizontal (shaved), vertical (unshaved) and vertical (shaved) according to ASTM International Standard test method for tensile strength of leather (D2209). As a result, the characterisation techniques show that the Ogden s coefficient, μ and Ogden s exponent, α, are 0.369 (MPa) and 7.604 respectively for horizontal (unshaved). However, μ and a for horizontal (shaved) are 0.512 (MPa) and 8.930. In contrast, the value of μ and a for vertical (unshaved) are 0.444 (MPa) and 9.928 and for vertical (shaved) are 0.539 (MPa) and 10.617. This study has contributed to the knowledge of biomechanics especially biomechanical properties of sheepskin. This could be useful for future investigation and analysis of softtissues, hyperelastic modeling and animal dermatology
Optimization of truss structures based on member dispositions / Associate Prof. Dr. Wahyu Kuntjoro and Jamaluddin Mahmud
Get PDFA design is optimum if a certain design objective function is minimum (or maximum), and still meets its design requirements. Truss structures can be optimized by deleting members which do not contribute significantly or at all to load carrying capacity. Through conventional member size optimization, non performer members can be identified, and then removed. Strength and displacement were formulated as the design constraints while the weight of structure was formulated as the objective function. The Linear Extended Interior Penalty Function was employed to optimize the structure. Finite Element Analysis, together with an approximation procedure were used to obtain the truss structural responses. This paper describes the development of truss optimization through members deletion. Three-bar and six-bar truss structures were used as case studies. Results showed that the truss disposition could be optimized using members deletion strategy
Investigating The Shear Behaviour of Hard Points on Honeycomb Sandwich Panels / Nazarrudin Abdullah Ramdzam and Jamaluddin Mahmud
Get PDFHoneycomb sandwich panels which act as the main structure of UiTM solar car, namely Stingray, are exposed to the localize load due to the weight of the handling system components attached to it. Therefore, hard points were introduced to strengthen the structure. Nevertheless, studies pertaining to the shear behaviour of hard points have not been well established. Therefore, this study was aimed to investigate the shear behaviour of hard points on honeycomb sandwich panels due to variations of potting agent volume. The samples, which are panels with hard points were fabricated with variations of potting agent volume (1ml, 2ml and 3ml). Apart from that, panels with hard points made of commercial metal insert (NAS1834) were also fabricated for benchmarking purposes. Shear tests were conducted on the samples to observe the failure mode, where the procedure was based on a published work. Stress-strain diagrams were plotted to determine the Modulus of Rigidity, Gave,1ml, Gave,2ml, Gave,3ml and Gave,NAS1834 and shear strength (the maximum load which the panel could withstand). As an alternative solution, finite element analysis was performed for the same specification. Initially, the panels with hard points were modelled using SOLIDWORKS and then assembled in CATIA. A commercial finite element analysis software, HyperWorks, was used to simulate the deformation behaviour of the panels under shear, according to the conducted tests set up. The experiments results are found to produce similar curves trend to other researchers. The simulated results for shear properties were compared with all the samples from physical tests. In general, the results show that the shear strength of the panels could be increased by increasing the volume of the potting agent. The panels with hard points with 3ml of potting agent volume have the highest shear strength as compared to the other three variations. It can be concluded that the research related to the application of the hard points on the solar car is important and found to be very useful for improving the next UiTM Eco-Photon solar car
Failure analysis of fiber reinforced composite materials used in Malaysian industries / Jamaluddin Mahmud, Wahyu Kuntjoro and Aidah Jumahat
No full textThe main objective of this paper is to determine the curves bounding the actual load carrying capacity in terms of the First Ply Failure and the Last Ply Failure of composite materials used in Malaysian Industries. A mathematical model
and computational model are presented for the analysis. Higher Order Shear Deformation plate theory is employed to predict the deformation of the plate. The selected material properties through thickness is used and accommodated
by a discrete layer approach. A program based on finite element method is developed using Fortran-90 to determine the lamina stresses. These stresses are then used in the present failure model to determine the First Ply Failure
and Last Ply Failure, by progressively reducing the stiffness of the laminas. Finally, the First Ply Failure and Last Ply failure results are analysed, in terms of lower and upper bound within which the true load carrying capacity lies
Hardness, tensile and microstructure assessment of carbon/glass hybrid composite laminate / Ahmad Fuad Ab Ghani and Jamaluddin Mahmud
Get PDFHybrid composites are often made by combining the high and low modulus fibers. The high modulus fiber, such as Carbon fiber provides the stiffness and load bearing qualities, whereas the low modulus fiber, such as glass fiber makes the composite more durable and low in cost. Nevertheless, the optimum arrangement between these fibers is still under comprehensive investigation. This paper assesses the hardness, tensile and microstructure of Hybrid Composite Laminates by varying the arrangement of Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP). Hardness and Tensile Tests were carried out on seven different layup arrangements of the Carbon-Glass Hybrid Composite Laminates. Hardness tests were performed using micro hardness tester and pyramid shape indenter. Tensile Tests were performed in accordance to ASTM D3039 to determine the Modulus of Elasticity, E and Tensile Strength, UTS. In addition, the failure modes of the laminates were also observed. Microstructural analyses were carried out using Scanning Electron Microscope (SEM). In general, the results show that the hybridization effect has improved proportionately the Modulus of Elasticity of the hybrid composite laminates compared to GFRP constituents. However, it is also interesting to observe that the hybridization effect does not necessarily improves the hybrid laminate Tensile Strength, UTS due to delamination and incompatibility at the interface between CFRP the GFRP bond
PEMIKIRAN JAMALUDDIN ABDUL RAZIQ TENTANG PENYATUAN KALENDER ISLAM INTERNASIONAL DAN IMPLEMENTASINYA DI INDONESIA
No full textMankinds needs a calendar as a regulator and time divider. Especially for Muslims, the need for a calendar is very urgent because there are many Muslim worships related to time, such as the Hajj, Ramadan fasting and other purposes. There are two systems of calendars based on the circulation times of heavenly bodies. First, the Christian calendar is a dating system based on the average circulation of the Earth around the Sun (Solar System). Second, the Hijri Calendar is a calendar based on the average circulation of the moon around the Earth (Lunar System). The criteria clearly affect the uncertainty of the Islamic Calendar. Then it is necessary to unite the Islamic calendar universally. One of the initiators in uniting the Islamic calendar is Jamaluddin Abdur Raziq which is contained in at-Taqwim al-Qamariy al-Islam al-Muwaahid or famous for the term Universal Islamic Calendar. This idea arises because of the differences that often occur in beginning and ending the beginning of the lunar month. In this concept Jamaluddin Abdur Raziq hopes that all Muslims throughout the world have a permanent Islamic calendar. The method applied in this paper is descriptive analysis. The author will describe the concept of Jamaludin Abdur Raziq's idea of the unification of the Islamic Calendar. After describing it, then it will analyze the implementation of the idea of Jamaludin Abdur Raziq in Indonesia
Studi perbandingan konsep pendidikan islam menurut Mahmud Yunus dan Imam Zarkasyi
No full textKondisi pendidikan Islam Indonesia pada masa penjajahan kolonial Belanda, dunia pendidikan khususnya pendidikan Islam berada pada masa titik terendah dan belum bisa memberikan kontribusi terhadap kemajuan bangsa. Hal ini terjadi akibat pola pikir umat Islam yang sempit dalam menginterpretasikan ayat-ayat Al-Qur�an. Ditambah dengan adanya diskriminasi kaum penjajah terhadap pendidikan Islam. Pendidikan yang dikelolah umat Islam baru berupa pondok pesantren di anggap belum memenuhi tuntutan zaman. Dan juga pemerintah kolonial Belanda mendirikan sekolah yang bersifat sekuler, dalam arti pelajaran agama tidak diberikan. Muhammad Abduh murid setia Jamaluddin al-Afghani memperbaharui sistem pendidikan Islam di Mesir di antaranya merubah kurikulumnya. Pembaharuan ini melahirkan perguruan tinggi Dar al- Ulum dimana Mahmud Yunus menamatkan jenjang pendidikan Tingginya. Suasana pembaharuan yang dilakukan Muhammad Abduh, Mahmud Yunus kobarkan semangat pembaharuannya itu ketika kembali di Indonesia dengan mendirikan Normal Islam, al-Jami�ah al-Islamiyah, dan Islamic college, dan Mahmud Yunus sebagai pemimpinnya. Dan Imam Zarkasyi pendiri gontor dan penggagas berdirinya Kulliyat aln-Mu�allimin al-Islamiyah di gontor telah belajar di Normal Islam.dan Imam Zarkasyi juga merupakan murid kesayangan Mahmud Yunus. Penelitian ini ingin mengetahui bagaimana perbandingan konsep pendidikan Islam menurut Mahmud Yunus dan Imam Zarkasyi. Metode penelitian ini yang dipergunakan adalah metode penelitian kualitatif dengan pendekatan deskriptif analisis dengan pendekatan sejarah,tekstual dan komparatif. Dari temuan penulis menemukan adanya persamaan pemikiran Mahmud Yunus dan Imam Zarkasyi tentang tujuan pendidikan, yang mana Mahmud Yunus dan Imam Zarkasyi sama-sama mementingkan pendidikan akhlak pada tujuan pendidikan Islam. Dan adapun perbedaannya yaitu terletak pada social budaya yang mengitari kedua tokoh tersebut dan juga dari segi metode pendidikan menurut Mahmud Yunus metode lebih penting dari pada materi tetapi Imam Zarkasyi lebih mengembangkan bahwa kepribadian guru lebih penting dari pada materi dan metode tersebut karena guru adalah panutan dan contoh bagi siswanya. Dengan demikian penulis dapat menyimpulkan mengenai konsep pendidikan Islam dari kedua tokoh tersebut mengenai kelembagaan,metode dan sistem serta tujuan dan kurikulum itu sangat memberikan pengaruh besar terhadap pendidikan Islam di Indonesia
Failure analysis of composite laminate based on experiment-simulation integration
No full textThe finite element method is gaining acceptance in predicting mechanical response of various loading configurations and material orientations for failure analysis of composite laminates. Both fabrication of laminate samples and experimental procedures are often expensive and time consuming, and hence impractical, especially during the initial design stage. Finite element analyses require minimal amounts of input data, and the resulting stress and strain distributions can be determined throughout each individual ply. Using ANSYSTM, a commercially available finite element package, failure loads were predicted by simulating a uniaxial tensile loading on HTS40/977-2 Carbon/Epoxy composite with [+/-4512s lamination scheme. Two built-in failure theories in ANSYSTM features, viz., Maximum Stress and Tsai-Wu were applied in the simulation. The stress-strain and load-extension curves for both actual testing and FEA were then compared and the results are in good agreement. This paper is intended for researchers who have used or are considering using ANSYSTM for the prediction of failure in composite materials
Employing a failure criterion with interaction terms to simulate the progressive failure of carbon-epoxy laminates
No full textA failure criterion with the existence of coupling terms is employed to investigate the progressive failure in anisotropic laminated carbon-epoxy plates. The criterion is employed because it is developed recently. Moreover, the criterion allows interaction between fiber and matrix properties. This paper is aimed to investigate the contribution of the coupling terms and thus, to simulate the progressive failure of the carbon-epoxy plates. A mathematical model and computational model are presented for the analysis. The deformation of the plates is predicted based on higher order shear deformation theory. Variation of material properties through thickness is used and accommodated by a discrete layer approach. A program based on finite element method is developed to determine the lamina stresses. Stresses calculated are used in the present failure model to determine the first ply failure and last ply failure, by progressively reducing the stiffness of the laminas. Finally, the first ply failure and last ply failure results are used to determine the lower and upper bounds within which the true load carrying capacity lies. The numerical results obtained show some improvement compared to other failure criteria
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