Analisis Penyerapan Energi Dan Pola Deformasi Crash Box Dengan Variasi Sudut Tirus Dinding Crash Box Pada Uji Simulasi Tabrakan Arah Frontal

Sistem transportasi merupakan salah satu kebutuhan yang penting untuk dipenuhi dalam mempermudah kehidupan pada zaman modern ini. Di sisi lain, meningkatnya kebutuhan akan hal tersebut juga akan ikut meningkatkan produksi kendaraan yang secara tidak langsung turut meningkatkan jumlah kecelakaan. Meninjau hal tersebut, standar keselamatan kendaraan yang lebih baik sangat dibutuhkan, salah satunya adalah crash box. Crash box merupakan sistem keamanan pasif yang digunakan untuk mengurangi tingkat keparahan kecelakaan yang dialami penumpang atau bagian kendaraan yang vital akibat tabrakan. Penelitian ini meninjau pengaruh variasi sudut tirus dinding crash box berpenampang lingkaran (circular) terhadap pola deformasi dan penyerapan energi pada uji simulasi tabrakan arah frontal. Penelitian dilakukan dengan software berbasis metode elemen hingga (MEH). Variasi yang digunakan dalam penelitian ini yaitu crash box dengan sudut tirus (α) 0,2°; 0,4°; 0,6°; 0,8; dan 1,0° dengan material crash box baja AISI 1340. Dari hasil penelitian diperoleh bahwa pola deformasi yang terbentuk adalah pola aksial dengan mode concertina dan campuran (concertina + diamond). Deformasi mode campuran terjadi pada crash box t a 1,6 α 0,0°; α 0,8°; α 1,0°. Penyerapan energi meningkat seiring bertambah besarnya sudut tirus dinding crash box, dengan kemampuan menyerap energi terbesar pada crash box dengan sudut tirus (α) 1,0° sebesar 10823 J. Semakin besarnya sudut tirus dinding crash box juga menunjukkan peningkatan penyerapan energi spesifik crash box

KARAKTERISASI LAPISAN Ni-Cr BAJA PADA ASME SA 210 C TERHADAP EROSI SUHU TINGGI

Combustion in a high-temperature circulating fluidized bed boiler produces pressurized circulation with silica sand and fly ash particles which can cause damage to pipes due to high-temperature erosional wear. Combustion oxy fuel thermal spray coating method is an alternative to overcome wear and tear. Variations of NiCr alloys were investigated to obtain compositions that could withstand temperatures of 600 °C with a fly ash impact speed of 200 m/s. The main compositions of the metal alloys that have been studied are NiCr, NiCrCo, and NiCrWc. The results of this study indicate that the coating is able to stick to the substrate and survive at 600 °C with a particle impact of 200 m/s in the high temperature erosion test. The highest hardness value obtained by the composition of the NiCr alloy was 177.79 HV and the lowest was found in the composition of the NiCrCo alloy 161.71 HV. The NiCrWc layer is the best layer compared to NiCr and NiCrCo with a weight loss ratio value of -0.00253 gram

Stress Corrosion Cracking Analysis of the ER70S Wire and SS400 Steel Plate Joints

The susceptibility of weld joints to the Stress Corrosion Cracking (SCC) load alarmed the researchers since pipeline blow-out which were initiated in the area closed to the weld joints. This article is evaluating the SCC resilience of the ER70S wire filler metal to the SS400 plate. The Capacitive Discharge Welding (CDW) with varied angle of the filler metal as an independent variable, whilst the other parameters were kept constant. The joint, then exposed to the SCC load, i.e., dipped in the 1M HCl solution with varied external tensile load to obtain the dependent variable: time to failure (time to brake). The results show that, generally, a sharper wire tip provides higher SCC resilience accept what was shown by the 30? specimen. With the sharper wire tip, the higher volume of weld nugget is provided which guarantee the enough number of weld metal. However, the impact phenomenon in the CDW process splashed this too much nugget beyond the formed joint which is proven by the many spatters in the weld joint. This thrown out nugget substance in turn decrease the intended nugget volume to form the joint. The results show the 60? wire tip angle provide the joint with the highest SCC resilience, indicated by the longest time to brake when loaded with an equal external loa

Implementation of composite paper-based coating for reducing room temperature under galvalume roofing

The increasing amount of paper waste can be enhanced in its utility by transforming it into composites to utilize it as a technology for coating metal roofs to absorb heat. Various paper types have been proven to reduce heat inside the room below when applied to Galvalume roofs. Therefore, multiple types of paper waste are highly suitable for metal roof coatings. This research investigates whether differences in the types of paper mixed with epoxy and applied to the surface of Galvalume roofs will affect the temperature reduction inside the room. These differences in paper types also affect the level of thermal conductivity when measured with the same instruments and dimensions. Data were obtained by mixing small-sized cut paper materials and layering them on Galvalume sheets with the help of epoxy as an adhesive. The temperature data collection process was conducted by preparing 6 boxes with 4 thermocouples supplemented with thermal imaging testing. To broaden the analysis, images of the roof were also taken and analyzed for color to assess the extent of sunlight absorption and reflection on the roof. Four thermocouples were placed 20cm above the roof, above the composite, below the Galvalume, and 40cm below the roof or inside the room. Thermal conductivity data were analyzed separately and integrated with roof color data, further corroborated with temperature data collected by the thermocouples. The four sensors can determine the temperature inside and around the room, focusing on the temperature around the installed composite roof. The analysis shows that adding paper and epoxy-based composites can reduce the thermal conductivity of Galvalume roofs and lower the temperature inside the room below it. Compared to a Galvalume roof without coating, the composite coating with cardboard paper is the most effective, with an estimated average room temperature reduction of 1.9 degrees Celsius. For reducing the air temperature above the roof, the newspaper coating is the best choice, with an estimated average temperature decrease of 2.6 degrees Celsiu

Bio-Komposit Hybrid yang Memiliki Unjuk Kerja Maksimal pada Beban Fatik dengan Stress Ratio R = -1

Komposit dengan bahan dasar alami atau dikenal dengan nama bio-komposit akhir-akhir ini mulai banyak dikembangkan selain disebabkan tinjauan ekologis yakni material bio-komposit lebih ramah lingkungan juga disebabkan harganya yang murah dan untuk beberapa bahan alami memiliki kekuatan yang tidak kalah dibandingkan dengan bahan sintetis. Pada penelitian ini komposit menggunakan bahan pengisi serat kenaf dan serbuk kayu dengan matrik poliester 157 BQTN-EX. Kenaf diharapkan yang berupa serat diharapkan memberikan unjuk kerja yang baik beban tarik dan kayu dalam bentuk serbuk diharapkan memberikan unjuk kerja yang baik ketika menerima beban tekan. Komposisi serat kenaf dan serbuk kayu divariasikan dan dicampur bersama matrik polyester dan zat pengaktif kemudian dituang kedalam cetakan dengan cara diinjeksikan. Hasil cetakan berupa spesimen tarik, spesimen impak dan spesimen tekan kemudian diuji untuk mengetahu unjuk kerja dari komposit. Hasil uji sifat mekanik komposit menunjukkan bahwa serat kenaf memiliki unjuk kerja yang lebih baik dibanding serbuk kayu. Berdasar hasil dari uji impak dapat disimpulkan bahwa perbandingan komposisi serat kenaf dengan serbuk kayu tidak menunjukkan perbedaan. Hal ini disebabkan pada uji impak terdapat campuran bagian yang mengalami tarikan dimana serat kenaf akan menunjukkan kelebihannya dan bagian yang mengalami tekanan dimana serbuk kayu menunjukkan kelebihannya

Comparison of Corner-Butt 45 (Cb-45) and Corner-Lap (Cl) joints in friction stir welding

The 10 mm thick Aluminum 6061 plates have been corner joined using varied design and those were 45ᴼ Corner Butt and Corner Lap Joints (CB-45 & CL). Friction tool was hardened EMS 45. True experimental method was used with independent parameters is feed rate which varied at 10 mm/min, 15 mm/min and 30 mm/min respectively. Other parameter such as rotating speed was kept constant. Experiment results show that, CB-45 yields better properties than CL. The tensile strength of CB-45 reaches 163.7 MPa for 10 mm/min feed rate. Whilst CL produces joint with tensile strength equal 120 MPa for equal parameters. Microstructure observation showed that CB-45 produces fine and homogenous appearance of MgO compared to CL. This phenomenon is caused by the pin of CB-45 joint which fully penetrates the nugget zone which is not found in CL design. This microstructure in turn promotes higher tensile strength of CB-45

The Effect of Fiber Orientation and Stress Ratio on the Crack Growth Behavior of Fiber Metal Laminates (FMLs)

The crack growth behavior of fiber metal laminates (FMLs) with fiber orientations of 90°/0° and 45°/45° to load direction was investigated with varying stress ratios of the cyclic constant load. The study shows that crack growth behavior depends on the conditions of the cyclic load and the orientation of the fiberglass orientation. A higher stress ratio of the cyclic constant load causes fatigue life to decrease, and is associated with stress concentration just in front of the crack tip. The stress concentration in the FMLs with 45o/45o fiberglass orientation is higher than that of 90o/0o, which means the fatigue life in the former is shorter. The bridging of the fiber-epoxy composite takes place when the stress ratio of the constant cyclic load is lower than 0.4, which also enhances fatigue life

PENGARUH KOMPOSISI LAPISAN NI-CR PADA BAJA ASME SA 210 C TERHADAP LAJU EROSI SUHU TINGGI

The purpose of this study was to determine the high temperature erosion rate of the NiCr coating on ASME SA 210 C steel using the combustion oxy fuel thermal spray method. In Circulating Fluidized Bed (CFB) boiler, there is circulation of fly ash, silica sand and air in a high temperature environment which causes erosion. High temperature erosion can be minimized by using Ni-Cr alloy coating sing the combustion oxy fuel thermal spray method. NiCr alloy is proved a able to provider a metal alloy layer composition that can withstand temperatures of 600°C with a fly ash impact speed of 200m/s. The metal alloy compositions that have been studied are NiCr, NiCrCo, NiCrWc, NiCrWcCo, and NiCrCoMo. The results of this study indicates that metal alloys are generally atteche to the substrate and withstand at a high temperatures (600°C). The highest hardness provide by NiCrWcCo alloy which is 177.46 HV. The lowest hardness is found in the composition of the NiCrCo alloy (161.71 HV). The lowest high temperature erosion rate was found in the NiCrWcCo alloy, which was -0.00481 gram/minute. This low erosion rate because the NiCrWcCo alloy produces a good weeting effect for metal alloys and has a high hardness value

Perilaku Tarik Komposit Laminat Serat Kulit Waru-Aluminium

Waru fiber-aluminium laminate composite is engineering materials which have high stiffness, strength properties and weight to strength ratio. The aim of this study is to find out the effect of the number of waru fiber to tensile strength on laminate composite waru fiber-Aluminium. The process of laminating composite waru fiber-aluminium is done by vacuum infusion resin method with layers variation 1, 2, 3, 4  and fiber direction 45/45 angle woven basket. The result shows that the tensile strength of the waru-Al fiber composite decreases and the elongation value of the composite increases due to the addition of layers of fiber waru lower bond strength on adhesive-aluminum and adhesive-waru. The lowest tensile strength of 153,642 MPa has occurred in composite with 4 layers of waru fibre