Kajian Pengaruh Teknik Pembuatan Lubang terhadap Kekuatan Tarik Komposit Hibrid Serat Gelas dan Serat Karung Plastik

      In panels or components, there are holes for joinning with other part. There are two method for manufacturing a hole, i.e. by boring and molding processes. The objective of this research is to investigate the effect of hole manufacturing method on the tensile properties of hybride composite reinforced chopped strand mat of E-glass fiber and woven roving fiber of plastic bag.       The materials in this research are plastic bag fiber, chopped strand mat of E-glass fiber (300 gr/m2), unsaturated polyester 157 BQTN-EX, and MEKPO hardener. The composite was made using press mold method, prepared with 4 laminates of glass fiber and 3 laminates of plastic bag fiber. The weight fraction fiber (Wf) of the composite was around 38%. The tensile test specimens were produced according to ASTM D 5766. In the middle of each specimen, there is a hole with 4, 6, or 8 mm in diameter. There are two types hole, i.e. holes were manufactured using boring and molding process methods.       The result shows that the highest tensile strength of the composites occurs on the composite with 6 mm in diameter of hole manufactured by boring and molding process. It can be recommended that composite has the higher strength for 6 mm in diameter of hole for joining. The composites with 4 and 6 diameters of holes manufactured by molding process have higher tensile strength compared to that manufactured by boring process. In contrast, the tensile strength of the composite with 8 mm in diameter of hole produced by boring is higher than that of the composite with 8 mm in diameter of hole produced by molding process

Karakteristik lelah poros baja S45C bertakik V akibat beban amplitudo konstan dan beban tiba-tiba.

This study aims to investigate the effects of sudden loads on the fatigue characteristic 60° V-notched shaft of S45C steel under constant and sudden amplitude loads, and to identify the fracture surface. The fatigue tests were performed using rotary bending machine that was equipped by the sudden load equipment. The cyclic load was varied in three configurations, i.e constant amplitude load and two combination of sudden loads. The combination of sudden loads were designed with 84 and 52 cycles ON and OF periodically. The sudden load causes the stress increase to 76 MPa. The stress concentration factor on the V.. notched shaft was determined using finite element model. The S-N curve of three load configurations shows that stress amplitude of 154 MPa (35% a,. or 21% au), 108 MPa (25% o or 15% au) and 28 MPa (6% ay or 4% au) cause the materials fail above 1,6.106 cycles. In that cycle, the value of stress amplitude under combination loads decreases 70,13% and 18,18% compared to constant amplitude load. The fracture surfaces under sudden load have rougher and more brilliance of beach mark. Similarly, the failures under higher stress have rougher fracture surface

KEKUATAN BENDING KOMPOSIT HIBRID SANDWICH KOMBINASI SERAT KENAF DAN SERAT GELAS DENGAN CORE KAYU SENGON LAUT

The objective of this research is to investigate the ending strength characteristic of hybrid sandwich composites reinforced by woven roving kenaf and random glass fiber using sengon laut wood core. The used resin is unsaturated polyester 268 BQTN. The core is designed by cutting on cross section of the wood and treated by 5% borax solution. There are two kinds of sandwich composites, i.e. GFRP and hybrid sandwich composites, made by hand lay up method. The bending test method of the specimens is three point bending. The re t shows that the bending strength of hybrid sandwich composites (97.50 MPa) is .93% higher than GRFP sandwich composites (87.89 MPa). Similarly, the strength of the sandwich composites is higher than the strength of its components too. The racture surfaces indicate that the skin composite suffering tension stress failed at e first, and than the core was broken

THE USE OF ALBIZZIA SAWDUST AND SUGER PALM FIBER AS MATERIALS TO PRODUCE SANDWICH COMPOSITE PANE FOR OTOMOTIVE CAR BODY AND HOUSING

This study aims to investigate the optimum design of sandwich composite reinforced sugar palm fiber (SPF) with albizzia sawdust (AS) core and investigate effect of thermal cyclic and dynamic flexural loading on mechanical properties. The SPF was alkali treated (5% NaOH) to remove lignin. The matrix used for skin composite reinforced SPF was unsaturated polyester resin (UPRs), whereas urea formaldehyde (UF) resin was used as binder of the core. The result shows that the skin composite reinforced by 4 hour of alkali treated fiber has the highest strength. By using press mold method, the optimum fiber content of the skin composite is about 30-35% (v/v). The 60% of sawdust content (w/w) results the highest mechanical properties of core. By using the optimum properties of skin and core, the sandwich composite, whose 2 mm of skin and 10 mm of core thickness, has better mechanical performance compared to that with other dimension. The sandwich composite, treated by using thermal cyclic, has lower mechanical properties compared to untreated composite. The increasing of temperature and cyclic number decreases the bending strength and impact toughness of the sandwich composite. For dynamic flexural loading test, the increasing of load cyclic number increases deflection and decreases stiffness of the sandwich composite. This composite has a good opportunity to be applied for housing and furniture panels

Kajian Sifat Tarik Komposit Serat Buah Sawit Acak Bermatrik Polyester

ABSTRAK The objective of this research is to assess tensile properties of palm oil fibers reinforced polyester composites. The fibers were obtained from a solid waste of palm oil plant located in Sumatra. The fibers were firstly separated from other waste materials and secondly washed using fresh water and subsequently dried naturally in an open space but not directly exposured by sun until the water content reached about 8%. The fibers were distributed randomly with their length approximately 4 to 6 cm. The surface offibers were observed using SEM to investigate their surface morphology. The composites with variation offibers from 19% to 42% (w/w) were manufactured using an open mould. All samples were post cured at 62°C during 4 hours. The samples were then cut using a hand grinding machine to produce tensile specimens according to ASTM D 638 Standard. Tensile tests were carried out using a servohydraulic universal testing machine and the elongation was recorded using an extensometer. The graphs of load versus elongation resulted from the tests were analyzed to determine ultimate strength, elasticity and strain. The fracture surface was observed using SEM to analyse the fracture mechanism. Experimental result shows that the increase of fiber content up to 42% can significantly increase the ultimate strength, i.e. 11 MPa, 14,21 MPa, 15,15 MPa, and 18,51 MPa for fiber content of 19%, 27%, 30%, 36% and 42%, respectively. The increase of fiber content up to 30% does not significantly increase the elasticity and strain. However, the elasticity and strain will increase when the fiber content is above 36%. Fracture surface of the composites was dominated by pullout mechanism. Keywords: palm oil fiber, fiber content, tensile properties, fracture mechanis

Pengaruh Grain Size Arang Aktif dari Bahan Limbah Industri Sagu Aren terhadap Penyerapan Polutan Limbah Batik

Sago palm industries leave large amount of wood waste that is about 30% of the volume of tree trunks, 20% in large size which can be used for the handcraft and about 10% in small-size which only wasted. On the other hand, batik industries produce hazardous and toxic waste (B3), that should be neutralized since this liquid waste are bad smell and  hard color, and even toxity  (contain various kinds of chemical elements and heavy metals such as Mercury (Hg), Lead (Pb), Chromium (Cr), Cadmium (Cd), and Copper (Cu)) and if the elements are absorbed by human body exceeds the threshold point, it would be dangerous. Therefore, experiment on activated carbon engineering and its use in adsorbing the B3 batik liquid waste is urgently required.  The main objective of the experiment is to know the adsorbsion effectivity of activated carbon in adsorbing the batik liquid waste. The main material used in producing activated carbon is waste palm tree trunks. The main material is heated to be charcoal in retort for about 5 hours, temperature around 500 º C. Furthermore, charcoal is crushed finely and screened in sizes of mesh 25, 35 and 50. Carbon powder then chemically activated using H2SO4 solution by heating in 500 ˚C for about 30 menutes. Finally this activated carbon used for adsorbing the hard colour and heavy metal (Pb, Cr, Cd) in the batik waste water. This research concluded that the sago aren industrial waste may be an alternative material for activated carbon which is effective in adsorbing the hard colour and hazardous heavy metal. Higher mesh size (grain size) of activated carbon give higher adsorbsion in colour and heavy metal. Activated carbon in mesh 25 adsorbed  68.59% Cd, 16.65% Cr, and 100% Pb, mesh 35 adsorb  76.25% Cd, 37.55% Cr and Pb at 100%, while mesh 50 adsorb 81.61% Cd, 58,33% Cr, and 100%  Pb

Pengaruh Fraksi Volume Serat dan Lama Perendaman Alkali terhadap Kekuatan Impak Komposit Serat Aren-Polyester

Palm fiber waste in the industrial processing of starch sugar palm has potential as reinforcing material composite material. This research to determine the effect of fiber volume fraction and long immersion in alkaline solution (NaOH) 5% for the impact strength composites waste palm fiber-polyester. The material used is a waste of palm fiber, unsaturated polyester 157 BQTN, MEKPO catalyst and 5% alkaline solution. Preparation of composites made by the method of press mould. The Composites made with variations of the volume fraction of 10%, 20%, 30%, 40%, 50% and long immersion alkali solution is 0, 2, 4, 6, and 8 hours. The impact test conducted by Izod impact testing machine refers to the standard ASTM D 5941. The results showed that increasing the volume fraction will increase the impact strength, but the subsequent decline. The longer the alkali treatment will reduce the impact strength because the fiber has undergone treatment. The impact strength maximum of the composites with fiber volume fraction of 40% and without alkaline immersion of 0.3211 J/mm2. Characteristics of a broken section of palm fiber composite material are a polyester matrix of a single fracture