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ABSTRAK
Latar belakang: transpalatal arch masih banyak digunakan pada perawatanortodonti dengan pencabutan premolar sebagai reinforced, untuk mencegahkehilangan penjangkaran. Dampak tekanan ortodonti pada jaringan periodontaldengan dan tanpa TPA dapat diketahui dengan mengetahui besar distribusi stresspada jaringan periodontal. Besar distribusi stress pada jaringan periodontal gigimolar satu dan dua secara in vivo tidak mungkin dilakukan. Maka dilakukanmelalui simulasi tiga dimensi 3D dengan Finite Element Analysis FEA .Tujuan: untuk melihat perbedaan distribusi stress minPS, maxPS dan vonMS pada gigi molar satu atas dengan TPA, TPA dan melibatkan gigi molar dua dantanpa TPA jika diberikan gaya distalisasi kaninus dengan daya sebesar 150g.Metode: Penelitian ini merupakan suatu penelitian eksperimental laboratorikdengan membuat model tengkorak secara tiga dimensi yang terdiri dari model gigimolar pertama atas dan tulang alveolar pendukungnya pada model maksila 3Ddengan TPA, dengan TPA dan melibatkan gigi molar dua dan tanpa TPA,kemudian dilakukan simulasi distalisasi kaninus dengan gaya 150g dengan FEA.Hasil: Ada perbedaan besar distribusi stress yang bermakna pada model 1 TPA ,model 2 TPA M2 dan model 3 tanpa TPA pada gigi molar satu atas dan tulangaveloar sekitar gigi molar satu atas p 0,000 ; p< 0,05 Kesimpulan: Nilai distribusi stress minPS, maxPS dan vonMS tertinggi padamodel tanpa TPA, kemudian nilainya menurun pada model TPA dan model TPAyang menyertakan gigi molar dua, baik pada gigi maupun tulang alveolar.

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ABSTRACT
The transpalatal arch is used as a reinforced anchorage onextraction case to prevent anchorage loss. It is impossible to measure humanperiodontal stress distribution, so an alternative approach with three dimensionsimulation using Finite Element Analysis FEA .Aim: This study aimed to compare stress distribution on upper first molar dan itsalveolar bone with TPA, with TPA and upper second molar and without TPAwhen 150g force was applied during canine movement.Methods: This experimental laboratory was done with the contruction of the 3Dmodel that consist of 3D model of maksila with TPA, with TPA and upper secondmolar and without TPA. Canine distalization simulation was done with 150 gramdistalization force.Result: The result showed that stress distribution on 1st model 1 TPA , 2ndmodel 2 TPA M2 and 3rd model 3 without TPA was significantly higher onthe upper first molar and its alveolar bone.Conclusion: The highest stress distribution minPS, maxPS dan vonMS is on themodel without TPA and the number decrease on a model with TPA and modelTPA with the upper second molar.

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ABSTRAK
Dengan semakin berkembangnya metode soil improvement, khususnya dengan menggunakan Prefabricated Vertical Drain (PVD), maka diperlukan perhatian khusus dalam menganalisa PVD. Pada umumnya kecepatan waktu konsolidasi dipengaruhi oleh jarak dan panjang PVD. Analisa yang digunakan biasanya menggunakan model konsolidasi 1 dimensi. Seiring perkembangan teknologi komputansi, perhitungan PVD dapat dilakukan dengan metode elemen hingga 3 dimensi. Model 3 dimensi memiliki keakuratan yang baik namun tingkat kompleksitas yang lebih tinggi. Perhitungan PVD pada umumnya menggunakan model 2 dimensi / plane strain model. Agar model 2 dimensi memiliki keakuratan yang baik diperlukan ekivalensi permeabilitas tanah asli dan jarak PVD. Penulis menitikberatkan kedua hal tersebut dengan harapan diperoleh model yang tepat dalam perhitungan PVD sesuai dengan kenyataan di lapangan

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ABSTRACT
With the development of the soil improvement method, especially using prefabricated vertical drain (PVD) it is necessary to analyize accurately. Generally the rate of consolidation time depends on two factor, spacing and the length of PVD. One dimension consolidation calculation is often used to analyze PVD. With development in computation technology, PVD calculation can be done by finite element method three dimension which has good accuration but more complex. In fact, two dimension model used to calculate PVD in order to have good accuration the permeability of soil and the spacing of PVD must be equivalent with three dimension model. Thw writer will focus in these factors in hopes to obtain the right PVD calculation model accordance with the fact in field;

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Studi numerikal dan parametrik dilakukan menggunakan ABAQUS pada sambungan spun pile - pile cap dengan beton pengisi bertulang serta perkuatan steel jacketing untuk menganalisis efektivitas confinement oleh steel jacketing. Studi eksperimen yang sebelumnya sudah dilakukan menunjukan steel jacketing masih belum mampu menghindari fenomena pinching dan tidak meningkatkan daktiltias secara signifikan. Efek confinement oleh steel jacketing akan ditinjau berdasarkan penurunan tegangan pada sengkang spun pile dan kenaikan kuat tekan beton inti spun pile. Studi parametrik dengan parameter koefisien friksi, tebal dan tinggi steel jacketing, serta beban aksial dilakukan untuk mendapatkan desain efektif dari perkuatan steel jacketing. Hasil pemodelan menunjukan bahwa penggunaan steel jacketing mampu memberikan efek confinement yang baik melalui penurunan stress development yang terjadi pada sengkang spun pile dan peningkatan beton inti spun pile. Desain efektif perkuatan steel jacketing yang disarankan adalah menggunakan zincalume tebal 1 mm dan tinggi 1,5D < H < 2D dimana D adalah diameter spun pile, untuk menghindari terjadinya local buckling pada zincalume. ......Numerical and parametric study was conducted using ABAQUS on a spun pile – pile cap connection filled with concrete reinforcement and steel jacket retrofitting to analyse the effectiveness of confinement by steel jacketing. Experimental study that has been conducted before shown that steel jacketing retrofitting wasn’t able to avoid pinching and didn’t significantly increase ductility. Confinement effect by steel jacket will be viewed based on the degradation of stress developed on spun pile’s stirrups and the enhancement of spun pile’s core concrete strength. Parametric study consisting of friction coefficient, thickness and height of steel jacketing, and axial load was conducted to achieve an effective design of steel jacket retrofitting. Modelling results shown that the use of steel jacket retrofitting was able to provide good confinement by reducing the stress development that occur on the spun pile’s stirrups as well as enhancement in spun pile’s core concrete strength. An effective design of steel jacketing retrofitting that was suggested is using a 1 mm in thickness zincalume and height of 1,5D < H < 2D, where D is the diameter of spun pile, to avoid local buckling on the zincalume.

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ABSTRAK
Prostetik merupakan salah satu inovasi di bidang kesehatan yang berfungsi untuk membantu maupun menggantikan salah satu fungsi organ. Prostetik yang ada di Indonesia saat ini masih didominasi oleh produk-produk luar negeri. Hal ini akan membuat harga prostetik menjadi tidak terjangkau oleh pasien. Seiring perkembangan zaman, metode produksi masal yang menggunakan CNC machining atau casting sudah mulai berubah ke batch yang lebih sedikit dengan menggunakan additive manufacturing seperti 3D printing. Penggunaan teknologi 3D Printing memiliki beberapa keunggulan dibandingkan dengan teknologi untuk produksi masal, di antaranya ramah proses kustomisasi, menghemat biaya bahan baku, waktu produksi lebih singkat untuk batch dengan jumlah kecil, dan lebih ramah lingkungan karena menghasilkan sedikit bahan sisa produksi. Penelitian ini dilakukan untuk dapat meningkatkan performa dari prostetik melalui sebuah desain prostetik lokal. Penentuan performa prostetik dilakukan dengan simulasi Finite Element Analysis dengan membandingkan tegangan von mises. Hasil simulasi menggambarkan bahwa desain modifikasi prostetik mampu meningkatkan performanya. Selain itu, dalam penelitian ini juga akan membahas permodelan biaya produksi prostetik antara tiga metode produksi, yaitu CNC Milling, 3D Printer FDM kelas penghobi, dan 3D Printer FDM kelas industri. Dari permodelan tersebut, terdapat dua parameter yang dibandingkan yaitu perbandingan waktu periode profit dalam nilai investasi yang sama dan perbandingan nilai investasi dengan harga jual prostetik yang sama. Hasil permodelan biaya menggambarkan bahwa teknologi 3D Printing mampu menginterupsi teknologi produksi masal CNC machining.

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ABSTRACT
Prosthetics is one of the innovations in health that serves to help or replace one of the organs' functions. Prosthetics in Indonesia is currently still dominated by foreign products. That will make prosthetic prices unaffordable for patients. Over the times, mass production methods that use CNC machining or casting have begun to change to fewer batches using additive manufacturing, such as 3D printing. 3D printing technology has several advantages compared to mass production technology, including friendly customization processes, saving raw material costs, shorter production time for batches in small quantities, and more environmentally friendly because it produces less material remaining production. This research conducted to improve the performance of prosthetics through a local prosthetic design. The determination of prosthetic performance is done by Finite Element Analysis simulation by comparing von mises stress. Simulation results illustrate that prosthetic modification design can improve performance. Besides, this research will also discuss the modeling of prosthetic production costs between three production methods, namely CNC Milling, hobbyist class FDM 3D Printer, and industrial class 3D Printer. From the modeling, two parameters are being compared namely the comparison of the period of profit in the same investment value and the comparison of investment values with the same prosthetic selling price. The cost modeling results illustrate that 3D Printing technology can interrupt CNC machining mass production technology.

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ABSTRAK
Resistance spot welding (RSW) merupakan proses pengelasan yang sering digunakan untuk menyambung pelat logam umumnya pada industri otomotif dan penerbangan. Proses pengelasan RSW (Resistance Spot Welding) melibatkan fenomena kelistrikan, termal-mekanik, metalurgi, dan permukaan yang kompleks. Tidak seperti proses pengelasan lainnya, peristiwa terbentuknya sambungan las pada proses RSW terjadi sangat cepat (dalam mili-detik) dan mengambil tempat diantara benda kerja yang tumpang tindih satu sama lain. Simulasi pengelasan memungkinkan pemeriksaan visual terhadap sambungan las tanpa harus melakukan eksperimen yang mahal. Ukuran nugget las merupakan parameter yang paling penting dalam menentukan perilaku mekanik dari sambungan las RSW karena kualitas dan kekuatan sambungan las RSW secara dominan ditentukan oleh bentuk dan ukuran dari nugget las. Simulasi pemodelan proses pengelasan RSW dilakukan menggunakan modul ANSYS Parametric Design Language (APDL) berbasis metode elemen hingga (finite element method) yang tersedia, dalam ANSYS. Interaksi elektrikal dan termal dikembangkan untuk mempelajari pertumbuhan nugget pada pengelasan pelat aluminium A1100 dengan ketebalan masing-masing 0.4 mm. Dengan menggunakan pendekatan model simulasi ini, ukuran diameter nugget dapat diprediksi dengan baik melalui distribusi temperatur yang terbentuk selama proses pengelasan berlangsung. Pengelasan dilakukan dengan membuat variasi pada pemberian kuat arus (1kA dan 2kA) dan waktu pengelasan untuk masing-masing kuat arus yaitu 0.5, 1.0, dan 1.5 CT (cycle time). Diamater nugget untuk masing-masing parameter pengelasan yang didapat melalui simulasi pemodelan adalah, 4.276 mm, 4.372 mm, 4.668 mm, 5.616 mm, dan 5.896 mm. Pada spesimen dengan kuat arus 2 kA dan waktu pengelasan 1.5 CT, weld expulsion terjadi dan ditandai dengan menurunnya kekuatan tarik-geser dari spesimen tersebut dalam eksperimen.

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ABSTRAK
Resistance spot welding (RSW), generally which is one of the most often used to joint metal plate in the automotive and aviation industries. RSW welding process involves electrical, thermal-mechanical, metallurgy, and complex surface phenomenon. Unlike the other welding processes, weld joint formation in RSW process occurs very quick (in milli-seconds) and took place between the workpieces overlap each other. Welding simulation allows visual examination of the weld joint without having to perform an expensive experiment. Weld nugget size is the most important parameter in determining the mechanical behavior of welded joints in RSW process. The quality and strength of the weld joint in RSW process is predominantly determined by the shape and size of the weld nugget. Simulation modeling of RSW process performed using ANSYS Parametric Design Language (APDL) module based on the finite element method (FEM), embedded in ANSYS Workbench. Electrical and transient-thermal interaction was developed to study the weld nugget growth on resistance spot welding of aluminum A1100 metal plate with a thickness of 0.4 mm respectively. Weld nugget diameter can be well predicted by using this simulation model from the temperature distribution during the welding process. Welding is performed by varying the weld current (1 kA and 2 kA) and the welding time for each electric current which are start from 0.5, 1.0, and 1.5 cycle time. Nugget diameter for each of the welding parameters from the simulation modelling were 4,276 mm, 4,372 mm, 4,668 mm, 5,616 mm and 5,896 mm. Weld expulsion occurred for the specimen with welding current 2 kA and welding time 1.5 cycle time, characterized by the decreasing of the tensile-shear strength of the specimen.

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Latar Belakang: Implan gigi sebagai alternatif perawatan kehilangan gigi dapat mengalami kegagalan akibat distribusi stress yang berlebihan. Desain implan berupa implant thread depth menjadi bagian penting dari struktur implan yang dapat mempengaruhi distribusi stress. Adapun arah pembebanan dan tulang dengan densitas rendah merupakan faktor lain yang dapat mempengaruhi distribusi stress. Tujuan: Untuk mengetahui gambaran distribusi stress pada single implant dengan variasi ukuran thread depth dan arah pembebanan di tulang densitas rendah. Metode: Penelitian ini adalah penelitian observasional deskriptif. Model 3D regio posterior tulang maksila  dan tiga implan dengan komponen implan berupa panjang 10 mm, diameter 4,1 mm, thread pitch 0,8 mm, thread shape berupa V-thread dan kedalaman thread depth yang terbagi menjadi 0,25 mm; 0,35mm; dan 0,45mm dibuat dengan modeling software dan disusun menjadi solid model. Dilakukan simulasi pemberian beban preload 200 N arah axial pada screw dan dilanjutkan dengan pemberian beban mastikasi sebesar 100 N arah axial dan oblique pada molar pertama. Dilakukan analisis dengan metode finite element untuk mengetahui distribusi stress berupa von Mises stress pada komponen implan dan tulang. Hasil : Nilai von Mises stress maksimum tertinggi pada pembebanan axial (abutment = 222,63 MPa, implant body = 179,68 MPa, dan screw = 154,97 MPa), pada pembebanan oblique (abutment = 1086,9 MPa, implant body = 852,46 MPa, dan screw = 628,56 MPa). Pada tulang alveolar, nilai von Mises stress maksimum dengan pembebanan axial pada masing-masing thread depth (0,25 mm = 29,421 MPa; 0,35 mm = 30,201 MPa; 0,45 mm = 31,091 MPa), dan dengan pembebanan oblique pada masing-masing thread depth (0,25 mm = 74,103 MPa; 0,35 mm = 75,102 MPa; 0,45 mm = 76,557 MPa). Kesimpulan : Hasil metode finite element menunjukkan bahwa pada pembebanan axial, abutment mengalami peningkatan stress seiring peningkatan thread depth. Pada pembebanan oblique seluruh komponen implan mengalami peningkatan stress seiring peningkatan thread depth. Nilai von Mises stress terbesar pada tulang ditemukan pada thread depth 0,45 mm dengan pembebanan oblique.

 

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Background: Dental implants as an alternative treatment for tooth loss can fail due to excessive stress distribution. Implant design in the form of implant thread depth is an important part of the implant structure that can affect stress distribution. The direction of loading and low-density bone are other factors that can affect stress distribution. Objective: To determine the overview of stress distribution of a single implant with varying thread depth in low-density bone. Methods: This study was a descriptive observational study. A 3D model of the posterior region of the maxillary bone and three implants with implant components of 10 mm length, 4 mm diameter, 0.8 mm thread pitch, V-thread thread shape, and thread depth divided into 0.25 mm; 0.35mm; and 0.45mm were created with modeling software and compiled into a solid model.  Simulation of 200 N axial preload was applied to the screw and followed by 100 N axial and oblique mastication load on the first molar. Finite element method analysis was performed to determine the stress distribution in the form of von Mises stress on the implant and bone components. Results: The highest maximum von Mises stress values under axial loading (abutment = 222.63 MPa, implant body = 179.68 MPa, and screw = 154.97 MPa), under oblique loading (abutment = 1086.9 MPa, implant body = 852.46 MPa, and screw = 628.56 MPa). In alveolar bone, the maximum von Mises stress value with axial loading at each thread depth (0.25 mm = 29.421 MPa; 0.35 mm = 30.201 MPa; 0.45 mm = 31.091 MPa), and with oblique loading at each thread depth (0.25 mm = 74.103 MPa; 0.35 mm = 75.102 MPa; 0.45 mm = 76.557 MPa). Conclusion: The results of the finite element analysis showed that in axial loading, the abutment experienced increased stress as thread depth increased. In oblique loading, all implant components experienced increased stress as thread depth increased. The largest von Mises stress value in the bone was found at a thread depth of 0.45 mm with oblique loading.

 

 

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ABSTRAK
Finite Element Method is one of the most power ful methods in numerical analysis techniques. The time consuming tasks and high costs can be reduced by using this method in the early stages of machine component design. The truck chassis is a base component of vehicles and integrates many of the truck component systems such as the axles, suspension, power train, cab and trailer. The truck chassis has been loaded by static, dynamic and also cyclic loading. Static loading comes from the weight of cabin, its contents and passengers. The movement of truck affects a dynamic loading to the chassis. The vibration of engines and the roughness of roads give a cyclic loading. The chassis used in trucks has almost the same appearance since models were developed 20 or 30 years ago, denoting that they are a result of slow and stable evolution of these frames throughout the years. The manufacturers of these chassis, in the past, and some still today, solve their structural problems by trial and error. Conducting experimental tests in the early stage of design are time consuming and expensive. In order to reduce these costs, it is important to conduct simulations using numerical software methods to find the optimum design. Determination of static, dynamic and fatigue characteristics of a truck chassis before manufacturing is important for design improvement. This paper presents the finite element analysis (FEA) of road roughness effects on stress distribution of heavy duty truck chassis.

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Concrete is a favoured building material due to its ease of production and use. Even though the concrete mix is designed to have a uniform strength throughout the entire member, casting, as well as the basic characteristics of the concrete materials, could yield a non-homogeneous constitution, resulting in a concrete strength gradation as a function of the depth of the member. A functionally continuous and smooth strength gradation of the concrete member along its axis or section is defined as graded concrete. The objective of this research is to analyse the influence of two different concrete compressive strengths that composed the graded concrete member. The study is split into two parts: the experimental work describing and identifying the mechanical properties of functionally graded concrete and the finite element analysis implementing these property variations in a model. The results showed that the concrete gradation influenced the ultimate strength of a member negatively and altered the stress distribution and displacement response of the specimen.

Abstrak :
Concrete is a favoured building material due to its ease of production and use. Even though the concrete mix is designed to have a uniform strength throughout the entire member, casting, as well as the basic characteristics of the concrete materials, could yield a non-homogeneous constitution, resulting in a concrete strength gradation as a function of the depth of the member. A functionally continuous and smooth strength gradation of the concrete member along its axis or section is defined as graded concrete. The objective of this research is to analyse the influence of two different concrete compressive strengths that composed the graded concrete member. The study is split into two parts: the experimental work describing and identifying the mechanical properties of functionally graded concrete and the finite element analysis implementing these property variations in a model. The results showed that the concrete gradation influenced the ultimate strength of a member negatively and altered the stress distribution and displacement response of the specimen.

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This paper introduced a nonlinear finite element model using Msc.MARC to study behavior of concrete columns partially confined with metal sheet strips under uniaxial compression. The concrete and the metal sheet parts were modeled using the linear Mohr-Coulomb yield criterion and the Von-Mises yield criterion, respectively. Behaviors of the interface (bonding) material, both in the normal direction and the parallel direction to the interface, were modeled as a bilinear function based on the cohesive energy and the crack widths. The columns in this study had circular cross sections with the diameter of 15 cm and the height of 75 cm, wrapped around by 5 cm metal sheet strips. The results from 3D finite element modeling were analyzed for internally induced stresses and strains. The predicted column behavior was compatible with observed experimental data. The detailed mechanisms that were difficult to visualize during the laboratory experiments could be obtained from the analysis. It was revealed that the area of confinement and the number of applied metal sheet layers were important factors to the strength increase. The discrete confinement system was shown to be a promising alternative to the one-piece full-wrap system.