Al Emran Ismail

Effect of Velocity on the Impact Resistance of Woven Jute Fiber Reinforced Composites

is present project investigated the impact penetration response of woven jute fiber reinforced composites subjected to wide range of low impact velocities. Hand layout woven jute fibers are thermally compressed to ensure no internal defects formed in the composites. Six layers of woven jutes are stacked together using different fiber orientations [0/q/0]s. Low impact velocities are used ranging between 5 – 20 m/s. Force-time, force-displacement and energy-time curves are obtained automatically during the impact tests. The results are then discussed with considering the composite fragmentations and failure mechanisms. It is found that 00 composite orientations capable to absorb sufficiently impact energy for 5 m/s but not for velocity greater than 10 m/s. When fiber orientations used between 15 – 450, the composite impact resistance increased indicating two significant peak forces. These peak forces represent different type of failure mechanisms occurred during the striker progresses.

Modelling Analysis on Mechanical Damage of Kenaf Reinforced Composite Plates under Oblique Impact Loadings

This research focuses on the study of oblique impact on kenaf reinforced composite plate. This study summarizes modeling analysis of targets subjected to certain angle of collisions which ranging from 0o-45o. Due to the low density, natural fiber such as kenaf fiber provides relatively good mechanical properties than glass fiber. Thus, natural fibers have high potential for better reinforcement in light weight structures such as aircraft, automobile. In this research, the velocity impact analysis is conducted by using the commercial finite element analysis software, ANSYS. A few finite element models of the nonwoven composite panel and a rigid impactor is developed using ANSYS software. Experimental investigations in determining mechanical properties and validating purposes are conducted in earlier study by using Universal Testing Machine and High Speed Impact Puncher. Total force, total energy, deformation, and energy absorption of kenaf reinforced composite for oblique impact are analyzed and discussed. The rise of oblique angle will increase the energy absorption of the composite.

Tensile Strength of Natural Fiber Reinforced Polyester Composite

Nowadays, increasing awareness of replacing synthetic fiber such as glass fiber has emerged due to environmental problems and pollutions. Automotive manufacturers also seek new material especially biodegradable material to be non‐load bearing application parts. This present work discussed on the effect of silane treatment on coir fiber reinforced composites. From the results of tensile tests, fibers treated with silane have attained maximum material stiffness. However, to achieve maximum ultimate tensile strength and strain at failure performances, untreated fibers work very well through fiber bridging and internal friction between fiber and polymeric matrix. Scanning electron microscope (SEM) observations have coincided with these results.

Mode III Stress Intensity Factors of Surface Crack in Round Bars

This study presents a numerical investigation on the stress intensity factors (SIF), K of surface cracks in round bars that were obtained under pure torsion loadings or mode III. ANSYS finite element analysis (FEA) was used to determine the SIFs along the crack front of surface cracks embedded in the solid circular bars. 20-node isoparametric singular elements were used around the crack tip by shifting the mid-side node ¼-position close to a crack tip. Different crack aspect ratio, a/b were used ranging between 0.0 to 1.2 and relative crack depth, a/D were ranged between 0.1 to 0.6. Mode I SIF, KI obtained under bending moment was used to validate the proposed model and it was assumed this proposed model validated for analyzing mode III problems. It was found that, the mode II SIF, FII and mode III SIF, FIII were dependent on the crack geometries and the sites of crack growth were also dependent on a/b and a/D.

A Review on Effect of Orientation Fabric on Mechanical Energy Absorption Natural Fibres Reinforced Composites

This paper presents the combination technique in developing the woven kenaf fiber that is used as a new method to improve energy absorption performance. This method focuses on the effect energy absorption of angle orientation. Due to the low density, natural fiber such as kenaf fiber provides comparatively good mechanical properties. Thus, natural fibers have high potential for better reinforcement in light weight structures on automotive applications. Total force, total energy, and energy absorption of natural fibre reinforced composite for different type’s natural fibre and angle orientation are discussed and reviewed.

Low Velocity Impact on Woven Kenaf Fiber Reinforced Composites

This paper presents the experimental investigations on the low velocity impact response of woven kenaf fiber reinforced composites. Kenaf yarns are weaved with an orientation of 00 of warp and 900 of weft to form woven kenaf mat. Three woven kenaf mats are stacked together to achieve the specified sequences. The woven stacked kenaf mats are hardened with polymeric resin and compressed to squeeze off any excessive resin and to minimize voids content. The hardened composite plates are perforated using different impact velocities. Impact responses of the composite plates are examined according to stacking sequences, impact velocities and fragmentation patterns. According to the present results, the impact strength is strongly related with the impact velocity. If higher impact velocity is used, the performances of load bearing are reduced. It is obvious that no significant features of composite fragmentations occurred from the perforated holes. However, relatively larger area of mechanical damages is found distributed around the holes, indicating the capability of composites to absorb energy effectively.

A Platform for Digital Reproduction Sound of Traditional Musical Instrument Kompang

This work proposes a system for the digital reproduction sound of kompang. The kompang sounds are represented by bung and pak produced by palm beating to the membrane. The sounds are recorded in an acoustical sound recording system. In this proposed system, the recorded sounds are then analyzed in a frequency analyzer SpectraPLUS. This frequency contents data can be used as the reference to check the reproduced digital sound. The recorded wave data is converted to MIDI format before being manipulated in Ableton synthesizer system to create modern keyboard notes but representing kompang sound. For the validation purpose, a subjective approach as an additional to the objective comparison with frequency contents is also proposed.

Fatigue strength of woven kenaf fiber reinforced composites

Nowadays, green composites provide alternative to synthetic fibers for non-bearing and load-bearing applications. According to literature review, lack of information is available on the fatigue performances especially when the woven fiber is used instead of randomly oriented fibers. In order to overcome this problem, this paper investigates the fatigue strength of different fiber orientations and number of layers of woven kenaf fiber reinforced composites. Four types of fiber orientations are used namely 0°, 15°, 30° and 45°. Additionally, two numbers of layers are also considered. It is revealed that the fatigue life has no strong relationship with the fiber orientations. For identical fiber orientations, the fatigue life can be predicted considerably using the normalized stress. However as expected, the fatigue life enhancement occur when the number of layer is increased.

STRESS INTENSITY FACTORS OF THREE PARALLEL EDGE CRACKS UNDER BENDING MOMENTS

This paper reports the study of stress intensity factors (SIF) of three edge cracks in a finite plate under bending moments. The goal of this paper was to analyze the three edge crack interactions under such loading. Several studies can be found in literature discussing on mode I SIF. However, most of these studies obtained the SIFs using tensile force. Lack of SIF reported discussing on the SIFs obtained under bending moments. ANSYS finite element program was used to develop the finite element model where singular elements were used to model the cracks. Different crack geometries and parameters were utilized in order to characterize the SIFs. According to the present results, crack geometries played a significant role in determining the SIFs and consequently induced the crack interaction mechanisms.

A Study of Energy Absorption Performances of Pultruded Composites under Quasi-Static Compressive Loadings

This work presents a study of energy absorption performances of pultruded composite tubes under quasi-static compressive loadings. The as-received tubes were chamfered at 35, 45 and 550. The purpose of chamfered tube edge is to initiate the crushing process and to make sure the tubes were progressively collapsed under quasi-static compressive loadings. According to the present results, for 3 mm tube thickness, varying chamfering angles are not significantly affected the force-displacement curves. Except for the case of 550 showed higher peak force compared with other angles. However, if the thickness is increased to 5 mm, the effect on the curves of force versus displacement is tremendous where higher chamfering angles produced higher energy absorption performances.