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"ABSTRAKDewasa ini, material komposit banyak digunakan dalam berbagai aplikasi karena memiliki sifat mekanik yang lebih bagus dari pada logam, memiliki kekuatan pembentukan yang tinggi, memiliki ketahanan yang baik, memiliki kekuatan jenis dan kekakuan jenis (modulus Young) yang lebih tinggi daripada logam. Namun demikian, material komposit rentan terhadap degradasi termal pada temperatur tinggi. Oleh karena itu, penelitian dalam tesis ini bertujuan untuk meningkatkan ketahan termal dan sifat mampu bakar material komposit dengan mencampurkan zat tahan api berbasis halogen jenis brominated bisphenol A ke dalam material komposit serat karbon dengan dua variasi densitas serat, yaitu 200 dan 240 gr/m2. Penelitian yang dilakukan berbasis pada eksperimen skala laboratorium menggunakan kalorimeter kerucut. Fenomena pembakaran yang terjadi adalah piloted ignition dengan fluks kalor pembakaran dibatasi sampai dengan 25 kW/m2. Hasil penelitian menunjukkan bahwa sampel komposit serat karbon terbakar karena vaporisasi dari resinnya, sedangkan serat karbonnya sendiri hanya mengalami pengarangan (charring). Eksperimen pada fluks kalor 21,12 kW/m2, menunjukkan bahwa kebeadaan kandungan brominated bisphenol A di dalam sampel komposit serat karbon mampu menekan puncak laju produksi kalor dari sekitar 125 kW/m2 menjadi hanya sekitar 80 kW/m2. Hasil penelitian juga menunjukkan bahwa kandungan zat tahan api (fire retardant) mampu menunda waktu penyalaan api pembakaran dan memberikan ketahana termal yang lebih baik kepada material komposit

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ABSTRACTNowadays, carbon fiber reinforced epoxy-acrylate composite (CFRE) is used in various applications such as in aircraft and industrial applications including pressure vessels, civil engineering/construction-related uses, ship manufacturing, and automobile. That is because of its characteristics such as lightweight and high-strength. Nevertheless CFRE is very easy to be burned after preheating in a low heat flux, moreover with the presence of an external energy source. Hence, this study aimed to find out the effects of brominated bisphenol A as fire retardant agent on fire retardancy of CFRE using cone calorimeter with a spark igniter as a trigger to represent an amount of external energy source. Carbon fibers used in this study have density of 200 gr/m2 and 240 gr/m2. The parameter studied in this research includes density of carbon fiber, time to ignition, heat release rate and density of smoke production. In this initial work, the heat flux was limited up to 25 kW/m2 with piloted ignition. The measured temperatures of CFRE’s ignition range from 450oC to 575oC at atmospheric pressure. The initial result shows that the ignition of CFRE is strongly depend on the density of carbon fiber, the existing of an external energy source and the condition of gas mixture. For the density of of 200 gr/m2, CFRE starts to ignite under heat flux of 14.2 kW/m2 with peak heat release rate of 163.4 kW/m2. While for the density of of 240 gr/m2, CFRE starts to ignite under heat flux of 16.7 kW/m2 with peak heat release rate of 98 kW/m2. Combustion mechanism of CFRE started when a spark igniter is turned on after preheating at a certain sufficient heat flux, causing a flaming condition on the surface of CFRE. Next, vaporization of its resin causing a sustain flaming condition until reaching a decay period. When it burned, the resin vapor is forced out of the fiber pores, causing the material to swell and increased its volume. The effects of brominated bisphenol A as fire retardant agent in the CFRE give a significant impact to fire retardancy of the CFRE, especially in time to ignition and heat release rate aspect."

"Sistem pengereman adalah salah satu komponen vital pada sebuah kereta api yang berhubungan langsung dengan kemanan dan kenyamanan penumpang. Brack Shoe sebagai salah satu bagian penyusun sistem pengereman saat ini terbuat dari besi tuang kelabu yang memiliki densitas tinggi serta mudah mempercikan api saat pengereman. Dalam penelitian ini dipelajari sifat mekanik dari matriks ADC12 yang ditambahkan dengan variasi partikel penguat Silikon Nitrida (Si3N4) sebagai material komposit untuk menggantikan besi tuang kelabu dalam pembuatan brackshoe kereta api. Komposit dibuat dengan metode pengecoran aduk dengan penambahan fraksi volume partikel Si3N4 sebanyak 1,3,5,7, dan 10%vf untuk mengetahui titik optimal penambahan partikel penguat. Penambahan Magnesium sebesar 5 wt.% dilakukan untuk menghasilkan pembasahan yang baik antara matriks dan penguatnya. Penambahan Stronsium sebagai modifier sebanyak 0,04 wt.% dan Al-5Ti-1B sebanyak 0,15 wt.% sebagai grain refiner dilakukan untuk meningkatkan sifat mekanis komposit. Beberapa pengujian dilakukan untuk mengkarakterisasi material komposit tersebut, diantaranya OM, SEM, OES, XRD, dan Pengujian Merusak seperti pengujian tarik, kekerasan, impak dan keausan. Hasil pengujian mekanis menunjukkan penambahan partikel penguat Si3N4 sebanyak 3%Vf memiliki nilai sifat mekanis yang optimum. Terdapat penurunan nilai densitas komposit akibat porositas seiring dengan meningkatnya jumlah partikel Si3N4.

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The braking system is one of the vital components of a train that is directyly related to the safety and comfort of the passengers. Brake Shoe as one of the constituents parts of the braking system is currently made by gray cast iron which has a high density and easily splashes fire during braking. In this study, studied the mechanical properties of ADC12 matrix added with variations of Silicon Nitride (Si3N4) reinforcing particles as a composite materials to replace gray cast iron in the manufacture of railway brackshoe. Composite was made by stirring casting method with the addition of volume fraction of Si3N4 particles as much as 1,3,5,7, and 10%Vf to determine the optimal point of addition of reinforcing particles. The addition of Magnesium at 5wt.% is done to produce good wetting between matrix and the reinforcement. Addition of Strontium as a modifier at 0,04 wt.% and Al-5Ti-1B at 0,15 wt.% as a grain refiner was carried out to improve mechanical properties of the composites. Several tests were carried out to characterize the composite material, including OM, SEM, OES, XRD, and Destructive Testing such as Tensile Testing, Hardness, Impact, and Wear. The mechanical test results showed that the addition of 3%Vf Si3N4 Reinforcing Particles has Optimum Mechanical Properties. There is a decrease in the value of composite density due to porosity along with increasing number of Si3N4 particles.

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"Penggunaan cangkang kelapa sawit (OPS) sebagai pengganti agregat kasar alami dalam campuran beton akan membantu mengurangi jumlah limbah yang dihasilkan dari sisa produksi industri minyak kelapa sawit. Objek studi pada penelitian ini adalah beton dengan substitusi 100% cangkang kelapa sawit (OPS) sebagai pengganti agregat kasar dengan penggunaan semen OPC. Penggunaan semen OPC dipilih untuk melihat perbedaan karakteristik beton OPS jika digunakan semen portland murni dengan mengacu pada proporsi campuran beton yang sudah pernah dilakukan pada penelitian sebelumnya. Pengujian karakteristik beton yang dilakukan pada penelitian ini meliputi pengujian kuat tekan, kuat tarik lentur, kuat tarik belah, susut beton, dan permeabilitas. Pada penelitian ini juga akan dilakukan pengujian untuk mengetahui respon struktur balok beton bertulang dengan menggunakan sampel balok berukuran 15x25x300 cm³. Pengujian sampel balok OPS dilakukan dengan metode four-point loading dengan alat pencetak respons 3D berupa Digital Image Correlation (DIC) untuk menganalisa respon struktur, distribusi pola retak, dan bukaan yang terjadi pada balok beton OPS. Metode pembebanan pada penelitian ini dilakukan secara bertahap (semi-siklik) dalam 4 siklus, yaitu siklus 2 ton, 4 ton, 6 ton, dan 8 ton. Hasil pengujian menunjukan kuat tekan maksimum beton OPS dengan semen OPC mencapai 19.84 MPa. Selain itu, berdasarkan hasil pengujian permeabilitas, beton OPS dengan semen OPC tidak tahan terhadap penetrasi air. Kuat tarik beton OPS dengan semen OPC berkisar 5- 8% dari kuat tekannya. Balok beton OPS dengan campuran semen OPC dapat menahan beban hingga 7300 kg dan menghasilkan lendutan sebesar 26.7 mm. Pola retak pada balok terdistribusi merata di sepanjang bentang dan dapat diamati dengan metode Digital Image Correlation (DIC). Hasil dari penelitian ini, beton campuran cangkang kelapa sawit dengan semen OPC dapat dijadikan sebagai beton struktural sederhana karena mampu menahan beban yang cukup besar dan menghasilkan kuat tekan yang tinggi serta lendutan yang tidak terlalu besar.

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The use of palm kernel shell (OPS) as a substitute for natural coarse aggregates in concrete mixtures will help reduce the amount of waste generated from palm oil industry. The object of study in this research is concrete with 100% substitution of palm kernel shell (OPS) as a replacement for coarse aggregate using Ordinary Portland Cement (OPC). The used of Ordinary Portland Cement (OPC) was chosen to observe the differences in OPS concrete characteristics when pure Portland Cement is used, referring to the concrete mix proportions previously research. The concrete characteristics tested in this research include compressive strength, flexural tensile strength, split tensile strength, shrinkage, and permeability. This research also conducted tests to determine the structural response used a sample of reinforced concrete beams 15x25x300 cm³. The testing of OPS beam samples is perfomed using four-point loading method with 3D response printing tool called Digital Image Correlation (DIC) to analyze the structural response, crack pattern distribution, and crack opening in the OPS concrete beams. The loading method in this research is semi-cyclic in 4 cycles, namely 2 tons, 4 tons, 6 tons, and 8 tons. The test results show that the maximum compressive strength of OPS concrete with OPC reaches 19.84 MPa. Furthemore, based on the permeability test result, OPS concrete with OPC not resistant to water penetration. The tensile strength of OPS concrete with OPC reaches 5-8% of its compressive strength. OPS concrete beams with the OPC can withstand loads of up to 7300 kg and produce a deflection of 26.7 mm. The crack pattern is evely distributed along the span of beams and can be observed using the Digital Image Correlation (DIC) method. The results of this research indicate that the mixture of palm kernel shells and Ordinary Portland Cement (OPC) can be used as a simple structural concrete because it can withstand significant loads and has high compressive strength, as well as moderate deflection."

"This work revealed electrical and mechanical properties of phenolic resin composites made from Gigantochloa apus carbon fiber, or bamboo carbon fiber reinforced polymer (BCFRP) composites. Bamboo fibers were carbonized at a temperature of 800°C, with a temperature rate of 4.2°C/minutes, held for 120 minutes. Carbon fibers were arranged in one direction. Phenolic resin weights were determined to be 5% to 10%. Higher carbon fiber contents indicated higher electrical conductivity of the composite. Increased carbon fiber content tends to increase the tensile strength of the composite, although this result was unstable. Mechanical instability was caused by cracks and cavities formed between the fiber and the phenolic resin. Cracks primarily occurred at the interface between bamboo carbon fibers and phenolic resin. This was most likely caused by the intrusion of air at the time the phenolic resin was cast. This air became trapped in between the fiber surfaces. Bamboo carbon fiber is fragile and easily broken in both longitudinal and transverse directions. When an air bubble bursts between carbon fibers, the carbon fiber braid breaks up, causing electrical resistance in composites. Not all carbon fibers in phenolic resin disconnect this way; most still form the strands that can conduct electricity. These breaks are the cause of the instability of the electrical conductivity properties of the composite."

"Performance-based design (PBD) untuk struktur bawah belum diperbolehkan di Indonesia karena terdapat syarat yang harus dipenuhi, yaitu limited ductility dan repairable. Definisi dari repairable sendiri belum dijelaskan secara detail sehingga diperlukan penelitian lebih lanjut mengenai maknanya. Penelitian perbaikan dilakukan terhadap benda uji sambungan spun pile terhadap pile cap yang sudah rusak parah dan diperbaiki menggunakan fiber reinforced polymer (FRP) berupa FRP rod dan FRP wrap. Pengujian dilakukan untuk spun pile dengan beton pengisi yang diperbaiki dengan sepuluh buah FRP rod dan dua lapis FRP wrap. Parameter yang dilihat dalam menentukan perilaku dan efektivitas perbaikan adalah kekuatan, daktilitas, energi disipasi, momen rotasi, degradasi kekakuan, dan degradasi kekuatan. Hasil penelitian menunjukan bahwa benda uji mampu kembali ke kondisi awal dengan adanya penurunan kekuatan. Damage index dan performance levels juga dianalisa untuk eksperimen dan setiap model yang dibuat. Berdasarkan hal tersebut, dapat diketahui bahwa jumlah FRP rod yang digunakan dan kondisi awal benda uji sebelum perbaikan akan mempengaruhi efektivitas perbaikan yang dilakukan. Model dengan kondisi awal sebelum perbaikan berupa serviceable dan repairable berdasarkan damage index, memberikan perbaikan yang paling efektif untuk kembali ke kondisi awal sambungan spun pile terhadap pile cap sebelum mengalami kerusakan.

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Performance-based design (PBD) is not allowed for lower structures in Indonesia because there are conditions that must be met, namely limited ductility and repairability. The definition of repairable itself has not been explained in detail so further research is needed on its meaning. Repair research was carried out on test specimens for spun pile connections to pile caps that were severely damaged and repaired using fiber reinforced polymer (FRP) in the form of FRP rods and FRP wrap. Tests were carried out for spun piles with infill concrete repaired with ten FRP rods and two layers of FRP wrap. Parameters considered in determining the behavior and effectiveness of repairs are strength, ductility, energy dissipation, rotational moment, stiffness degradation, and strength degradation. The results showed that the test object was able to return to its initial condition with a decrease in strength. Damage index and performance levels were also analyzed for the experiment and each model was created. Based on this, it can be seen that the number of FRP rods used and the initial condition of the test object before a repair will affect the effectiveness of the repairs carried out. The model with the initial conditions before repair in the form of serviceable and repairable based on the damage index provides the most effective repair to return to the initial condition of the spun pile-pile cap connection before it was damaged"