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FSW is a welding process which done by movement of tool against the workpiece. Tool is an important part in FSW process because tool generates most of the heat in the FSW process, so the tool material and geometry are important because they receive high stress and temperature. This research was conducted to decide the best pin geometry for tool from the 4-pin geometry that has been decided, which is straight cylindrical, tapered cylindrical, hexagonal, and tapered square. The optimization process is done with Taguchi method using 4 factors where each factor has 4 levels, factors that used in this research are tool rotation speed, welding speed, tool shoulder angle, and tool tilt angle with the respond is temperature at welding joint. The optimization process will be done in all of the pin geometries that has been decided and the best pin geometry out of 4 geometries will be chosen. The best pin out of 4 geometries is the hexagonal pin with the optimized parameters are the rotational speed of 1208 rpm, welding speed of 65 mm/min, tilt angle of 2.5° and concave angle of 2° with max. temperature of 322.48°C. The significant factor obtained was the tool rotational speed and concave angle with significance level of 95%.

This study aims to determine the effect of the concave shoulder angle of the FSW tool on heat generation rate and temperature simulation results. The FSW tool used in this study is the FSW tool with straight cylindrical geometry, tapered cylinder, hexagonal, and tapered square. Calculation of heat generation rate is carried out for all FSW tools, then the optimal one is selected and then simulated. The process of calculating heat generation rate and simulation using the Taguchi method has 4 factors, each of which has 4 levels. The factors used in this study are tool rotation speed, welding speed, concave shoulder angle, and tool tilt angle with temperature response. on the weld joint. The results of this study indicate that the influence of the concave shoulder angle on the heat generation rate and temperature simulation is very influential. Based on the results of the heat generation rate calculation, the FSW tool with hexagonal pin geometry was chosen to be simulated. The simulation results show that the selected process parameters are tool rotation speed of 1208 rpm, welding speed of 90 mm/s, concave shoulder angle of 5°, and tool tilt angle of 3°. From the selected parameters, it was experimented with to produce a fairly good connection even though there were still surface defects.

The adhesive lap joints are extensively used in various engineering fields. Various methods were proposed to increase the strength of the lap joint. This paper presents the lap joint's characterization by applying three grades of adhesives in different material properties along the bond line. The stiffest adhesive is employed in the middle bond line, then gradually, those with a lower modulus of elasticity are placed at the ends of the lap joint. This technique reduces the stress concentration at the joining ends, so the stress distribution becomes smoother. Finite element analysis is used to model this problem in two dimensions. One of the adherent edges is applied to the fixed support, and the other end is subjected to tension. The analysis results show that the use of tri-adhesive changes the shear stress distribution along the bond line flatter and increases the strength of tri-adhesive lap joints compared to those single type adhesive applied individually.

In the design of critical components for railways, especially couplers, it is necessary to pay attention to the strength of the coupling between the couplers with each other. Coupling failure can have fatal consequences in the form of the train series being detached when operating. This study aims to improve the coupling strengthening of coupler prototype that meet international standard. The study begins with the calculation of longitudinal train force on light trains to obtain a coupler force followed by kinematics analysis on the initial coupler design to be improved using dimensional synthesis in the form of path generation and motion generation. Failsafe device design is done as an effort to strengthen the coupling. At the final stage, design verification is carried out in the form of structural strength analysis to compare the initial design with the new design. From the simulation results, it is found that the new design with a parallelogram configuration with 25° slope angle has a stronger coupling than the previous design. In addition, the addition of a failsafe device also plays a role in increasing the coupling strength of the coupler.

Pada era revolusi industri 4.0, teknologi cetak tiga dimensi (3D printing) sedang berkembang pesat. Di Taiwan dan Korea Selatan, siswa sekolah menengah telah memiliki kemampuan menjalankan 3D printing. Sebaliknya di Indonesia, lulusan sekolah menengah be-lum memiliki kompetensi sejenis. Oleh sebab itu, tim Pengabdian Masyarakat dari departemen Teknik Mesin ITS memberikan pengenalan dasar teknologi cetak 3D untuk meningkatkan kompetensi siswa sekolah mene-ngah. Pelatihan ini diberikan secara singkat kepada 29 siswa SMAN 1 Boyolangu, Tulungagung dengan persen-tase 25% berupa pemberian teori dasar dan 75% berupa praktik mengerjakan proses 3D modelling-scanning-printing. Berdasarkan analisis kuantitatif, pemahaman peserta meningkat sebesar 35.05% untuk materi 3D modelling dan 22.55% untuk materi 3D scanning dan printing. Adapun berdasarkan analisis kualitatif, hasil pencetakan produk 3D dengan metode 3D printing yang dikerjakan oleh peserta sudah cukup bagus. Hal ini menunjukkan bahwa kegiatan pelatihan singkat selama dua hari mampu meningkatkan kompetensi siswa SMA dalam memahami dasar teknologi manufaktur 3D printing.

The regenerative braking effectiveness of electric vehicles (EVs), with 8-25% range, requires designers to produce better braking systems. The antilock braking system (ABS) was chosen because it offers various advantages, such as enhanced safety considerations, vehicle maneuverability, and so on. The measurement findings revealed that ABS took longer to stop the wheels with the same wheel rotation speed. Because of the lesser differentiation of magnetic flux to time, it created lower induced emf in the generator. ABS 50 Hz performance was 19.5% at 4500 pm, whereas hydraulic brake performance was 21% at the same speed. ABS used model-based algorithms (MBAs) to boost the friction frequency with the wheels from 10 to 50 Hz. As the frequency increased, the ABS graph approached the hydraulic graph, and the ABS performance improved. Although ABS loses to hydraulics in stopping wheel rotation, it gains in saved energy and battery temperature. Longer wheel stop-times allow the rotational kinetic energy of the wheel more time to be converted into electricity.

This research investigated the effect of the thickness of adhesive to the stiffness (Young’s modulus) of adhesive butt joint at high strain rate loading. A split Hopkinson pressure bar (SHPB) test is used to obtain the stress-strain response of join specimen at strain rate of 530±10 s-1. The joint is composed of aluminum adherend bonded by epoxy adhesive with 0.5, 1, 2, and 3 millimeter of thickness variation. The results show that the joint deformed elastically and the stiffness increases with the increase of adhesive thickness. However, the rate at which the stiffness increases with thickness decreases at thick adhesive layer. The facts of this research are important for the improvement of the crashworthiness of structure such as automobile structures.

Photoelasticity method was used to measure strain and stress fields to address the precision problem of determining fringe order of loading and cracking and notch areas. In this study, microscope was used as an additional tool in a photoelastic device for magnification of isochromatic fringe size. An experimental method was used by utilizing optical system and reflective polariscope. A simple compression tool was designed to provide a compression load on the solid disk-shaped specimens. Isochromatic fringe field was observed in the loading zone for different loading and captured image based on the following conditions: 9x, 15x and 20x without magnification and with magnification using SLR type Nikon camera Serie D3000. The image was processed using OpenCV software while C + + was used to produce clearer isochromatic fringe pattern formed on the surface of the specimen in the determination of the maximum fringe order observed. The average of additional fringe could be obtained as the optical magnification result. Data was analyzed using Finite Element Analysis Software. The result showed an increasing trend in fringe order with increasing levels of optical magnification. Its maximum value was obtained on20x optical zoom, which was 2-order fringe.

Deteksi penggunaan masker pada pengemudi kendaraan termasuk tugas klasifikasi yang dapat diselesaikan secara otomatis oleh kecerdasaan artifisial. Untuk implementasi pada perangkat mobile, arsitektur neural network MobileNetV2 dipilih dengan pertimbangan akurasi yang baik. Penambahan teknik data augmentation dan pemilihan optimizer ADAM semakin meningkatkan akurasi klasifikasi dari MobileNetV2. Proses deteksi dilakukan pada 13 foto pengemudi dengan masker dan 13 pengemudi tanpa masker. Untuk pengemudi tanpa masker, sistem pendeteksi berhasil 100%, meskipun ada salah satu kondisi saat pengemudi memakai masker di dagu, tingkat akurasi hanya sebesar 65,59%. Sedangkan untuk pengemudi tanpa masker, ada 1 foto yang salah, disebabkan oleh warna gelap yang digunakan sebagai masker, sehingga sistem pendeteksi mengklasifikasikan sebagai pengemudi tanpa masker dengan tingkat akurasi hingga 97,76%. Hasil analisis lebih dalam menunjukkan bahwa aksesoris seperti jilbab dan kacamata mempengaruhi tingkat akurasi yang dihasilkan oleh sistem pendeteksi. Sementara itu, tingkat akurasi juga lebih dipengaruhi oleh warna dari masker yang dipakai ketimbang pemilihan masker medis ataupun masker kain.

Regenerative Braking System (RBS) converts kinetic energy into electrical energy by using a motor and functions as a generator when decelerations occur. Regenerative braking is an effective alternative to increase the driving range of a vehicle and can save around 8% - 25% of the total energy used by a vehicle. The purpose of this research is to produce a design of the FRCS Braking System (Flywheel Energy Regenerative Capture System) and its system topology. The design of this system is to optimize the download of vehicle kinetic energy based on the duration of energy transfer that occurs. This study focuses on the flywheel energy download system and is done by numerical simulation using Simulink. The method to be designed is to apply FRCS topologies.

Airless tires are designed and produced to overcome problems in the radial tires and solid tires. This tire provides a safe and comfortable driving experience in a vehicle during operation. Moreover, this tire still work when it hit by sharp objects (i.e., spike, nail, gun projectile, etc.). This research will be focused on designing airless tires using three parameters input, namely spoke thickness, rhombic angle, and rubber material. Each parameter uses three different levels, so the total design number is 27 designs. The thickness parameter of spoke levels was varied from 2 mm, 3 mm, and 4 mm, where the rhombic angles parameter was varied from 100°, 120°, and 135°. The last parameter (i.e., type of rubber material) was used in designing are Polyurathane L42, Polyurathane L100, and Polyurathane L135. The value of deflection and total stress every model are then calculated using finite element software. Furthermore, artificial intelligence using backpropagation of neural network (BPNN) was developed and utilized as a forecasting tool to predict the relationship between input (spoke thickness, rhombic angle, and rubber material) and output (deflection and total stress) of the airless tire models. Next, an optimization method using genetic algorithm (GA) is then employed to find the best design of the airless tire. Moreover, the best airless design will be selected to be produced as an airless-tire prototype.

Reliability on lance tube Soot-blower thickness and grade material, then overhung mechanical strength are very important for cleanliness of tube bank boiler 600 MW. Proper Operation and maintenance very effected for soot- blower system reliability. Objective of this research are knowing heat transfer characteristics of lance tube, thermal stress due to high temperature flue gas, and lance tube overhung mechanical stress. During soot-blowing there are area possibility of permanent deflection happened that showing plastic deformation and should avoided. This research is started with 3D geometry modeling, meshing and determine boundary condition with computational Fluid Dynamic software; Specify boundary and continuum types (steam flow, steam inlet temperature, steam density, maximum Heat flux into lance tube soot-blower). then steady temperature distribution is obtained. After that conduct finite element analysis (FEA) geometry modeling, meshing, define structural boundary types where load model are thermal stress, overhung mechanical stress, and stress due to steam jet, then solve. Material selecting is critical to lance tube reliability on radiation zone or super-heater platen area. CFD Simulation results are temperature distributions along lance tube body. For reliable condition, temperature distributions is kept in between 560°C until 650°C (According to ASME BPV Chapter II Section D). the maximum temperature of lance tube temperature is 751K near the nozzle of lance tube soot-blower. Creep-fatigue damage mechanism are two major problem on lance tube soot-blower system. Then FEA shows 3 joints is produce less stress-strain than 2 joints lance tube soot-blower.Reliability on lance tube Soot-blower thickness and grade material, then overhung mechanical strength are very important for cleanliness of tube bank boiler 600 MW. Proper Operation and maintenance very effected for soot- blower system reliability. Objective of this research are knowing heat transfer characteristics of lance tube, thermal stress due to high temperature flue gas, and lance tube overhung mechanical stress. During soot-blowing there are area possibility of permanent deflection happened that showing plastic deformation and should avoided. This research is started with 3D geometry modeling, meshing and determine boundary condition with computational Fluid Dynamic software; Specify boundary and continuum types (steam flow, steam inlet temperature, steam density, maximum Heat flux into lance tube soot-blower). then steady temperature distribution is obtained. After that conduct finite element analysis (FEA) geometry modeling, meshing, define structural boundary types where load model are thermal...

Regenerative Braking System (RBS) converts kinetic energy into electrical energy by using a motor and functions as a generator when decelerations occur. Regenerative braking is an effective alternative to increase the driving range of a vehicle and can save around 8% - 25% of the total energy used by a vehicle. The purpose of this research is to produce a design of the Ratchet Flywheel Regenerative System and its system topology. The design of this system is to optimize the download of vehicle kinetic energy based on the duration of energy transfer that occurs. This study focuses on the flywheel energy download system and is done by numerical simulation using MATLAB software. The method to be designed is to apply of ratchet flywheel topologies.

One of the key components in an electric vehicle is brushless direct current (BLDC) motor controller. At present, it is difficult to match a self-made motor controller with several different BLDC motors available in the global market. One of the reasons is that the Hall sensors’ configuration is not well informed. Another reason is the motor parameter’s values used in the controller are not well suited with the real physical conditions of the motor. This study aims to design an intelligent reconfigurable BLDC motor controller. In this paper, a method for automatic commutation configuration and automatic parameter values detection is presented. The Hall sensors and motor phases configurations are identified. The BLDC motor parameter values are detected automatically using mathematical models. Those parameters include internal resistance, inductance, coefficient of back electromotive force (BEMF), torque coefficient, friction coefficient, and moment of inertia. Experimental results of the automatic commutation configuration and parameter values detection are presented. Those results were used to develop a current controller. Further experimental results indicated that the method could be implemented in a BLDC motor current controller.

Asymmetric spur gear is used in one-way rotation transmission. This spur gear has a higher bending strength than symmetric spur gear. In this research, the effect of asymmetrical spur gear level on bending stresses is studied dynamically. The asymmetric spur gear level is expressed as asymmetric factor (K). Asymmetric factors K = 1, K = 1.05, K = 1.06, K = 1.07 and K = 1.08 are used. Dynamic analysis is performed by explicit dynamics numerical modeling. Material used for five asymmetric factor is AISI 1045. Two variables applied on this spur gears are torque loads and rotational speeds to investigate that effect on bending stress. Torque loads varied from 100 Nm to 250 Nm with 50 Nm increment and rotational speeds varied from 1000 rpm to 2500 rpm with 500 rpm increment. The results of this study show that the asymmetric factor can reduce more significantly bending stress cause of torque loads than cause of rotational speeds.

The quality of product of manufacturing industries depends on dimension accurately and surface roughness quality. There are many types of surface defects and levels of surface roughness quality. Ironing process is one type of metal forming process, which aims to reduce the wall thickness of the cup-shaped or pipes products, thus increasing the height of the wall. Manually surface inspection procedures are very inadequate to ensure the surface in guaranteed quality. To ensure strict requirements of customers, the surface defect inspection based on image processing techniques has been found to be very effective and popular over the last two decades. The paper has been reviewed some papers based on image processing for defect detection. It has been tried to find some alternatives of useful methods for product surface defect detection of ironing process.

This study described how the ironing process to manufacture 20 mm caliber bullet case. For this purpose, the first step is analyzing the process parameters, and then calculates the forces needed to make the formation of bullet case. Through the analysis of the process it is known, that the ironing process parameters most influential to the magnitude of forming force are the die angle α and the reduction of the wall thickness. In this study a simulation is conducted to determine a minimum required of forming force until the process successful. That means the required bullet case accordance with the determined specifications and geometry. The material used for bullet case caliber 20 mm is brass Cu30% Zn 70% early-shaped cup with 33.5 mm outer diameter, 3 mm thick and 37 mm high. Based on material strength calculation, the ironing force is determined with value of 50.01 kN. By using this value the maximum allowable wall reduction thickness in the ironing process is 26.7%. The simulation is carried out using finite element method on a variety of die angle such as α = 5°, 10°, 15°, 20° and 25° respectively. The simulation results show that the shell cannot through the die on each angle die. Similarly, in variation of reduction by 5%, 10%, 15%, 20% and 25%, the ironing process is also unsuccessful. However, by load of 138 kN, in the 26.7% reduction and at die angle α=5°, the ironing process to produce cylinder is successfully. Similarly by the same of wall thickness reduction, with force of 148 kN and the die angle of 10°, the ironing process is also successfully to fulfill the bullet case with a specified geometry.

The variable stiffness and damping (VSVD) suspension system offers an interesting option to improve driver comfort in an energy efficient way. The aim of this study is to analyze the influence of the spring ratio on the VSVD. The realization of the VSVD is obtained by the application of variable damping with magnetorheological (MR) damper. In this study, the nonlinear damping force characteristic of the MR damper is modeled with the Bouc-Wen model and the road disturbance is modeled by a stationary random process with road displacement power spectral density. It is shown from simulation that VSVD has a potential benefit in improving performance of vehicle suspension.

Magnetic gear is an alternative to mechanical gear, where the magnetic gear has the advantages of no noise, minimum vibration, no maintenance required, increased reliability, overload protection capability, no physical contact between gears, and the resulting torque density is still below the mechanical gear torque density. In this research, the variation of the number of poles and air gap in the amount of torque density produced was carried out. The permanent magnet material used is Neodymium type with a gear ratio of 1:2. In the variation of the number of poles used by pairs of 4 and 8 poles, 8 and 16 poles, 10 and 20 poles, and 12 and 24 poles, in the variation of the air gap used, namely 1 mm, 1.2 mm, 1.3 mm, 1.4 mm and 1.5 mm. Magnetic gear performance can be seen through analysis simulation with the 3D finite element method using Finite Elements Software. The type of simulation used is the magnetostatic analysis method at the processing stage and the transient analysis method at the post-processing stage. From the simulation results, it is concluded that the greater the number of poles, the greater the torque density produced, and the closer the air gap distance will result in a greater torque density. The effect of the number of poles on the torque density is more significant than the effect of the air gap.

Pada umumnya, sepeda yang beredar menggunakan Chain and Sprocket sebagai sistem pemindah daya utama. Sistem chain and sprocket sendiri mempunyai beberapa kelemahan. Dari kelemahan sistem chain and sprocket tersebut, maka pada penelitian ini dirancang sepeda chainless dengan menggunakan poros. Untuk penelitian ini, sepeda Chain and Sprocket dimodifikasi menjadi sepeda Chainless Zerol Bevel Gear. Lalu, pengujian efisiensi sepeda dilakukan untuk mengetahui besar efisiensi sepeda Chainless Zerol Bevel Gear dan dibandingkan dengan sepeda Chain and Sprocket. Sepeda dimodifikasi dengan menggunakan Zerol Bevel Gear 90 o pada bagian sistem pemindah daya dari pedal ke roda. Pengujian dilakukan dengan memberikan putaran pada poros pedal dengan motor listrik sehingga roda belakang ikut berputar. Putaran roda belakang diukur daya outputnya untuk mengetahui besar efisiensinya. Hasil dari penelitian ini didapat geometri Zerol Bevel Gear diproduksi dengan spesifikasi rasio total 1:1,33 , diameter poros 0,67 in, panjang poros 395 mm dan alat pengujian untuk menguji nilai efisiensi total sepeda. Dari hasil pengujian didapatkan nilai efisiensi tertinggi pada sepeda chain and sprocket dengan putaran pedal 55 rpm pada gear-2 internal hub dengan nilai efisiensi 89,92%. Sementara nilai efisiensi tertinggi pada sepeda chainless dengan putaran pedal 55 rpm pada gear-1 internal hub dengan nilai efisiensi 79,26%.

Roda gigi atau gear merupakan salah satu elemen mesin yang berfungsi untuk mentransmisikan daya. Sumber transimisi sebuah gear berasal dari kontak dan gesekan yang terjadi pada pasangan gear yang diteruskan oleh porosnya. Kontak dan gesekan yang terjadi merupakan sumber utama kegagalan pada roda gigi apabila dipadukan dengan kesalahan-kesalahan ( error ) dalam perancangan, assembly, dan machining roda gigi. Usaha yang dapat dilakukan untuk mengurangi masalah tersebut adalah dengan memodifikasi profil gigi dengan bentuk tip relief pada involute spur gear. Tip relief adalah pemotongan bagian flank pada roda gigi dengan bentuk parabolik dan linier. Material yang digunakan untuk penelitian ini adalah S45C. Simulasi regangan dinamis dilakukan dengan analisa Transient Structure , sedangkan analisa getaran dilakukan dengan analisa Harmonic Response pada software FEA. Hasil yang didapatkan dari penelitian ini adalah terjadi reduksi nilai regangan dan getaran pada profil modifikasi parabolik dan linier. Nilai reduksi yang terjadinya selanjutnya dibandingkan dengan hasil eksperimen dan didapatkan error dari simulasi yang dilakukan. Hasil dari penelitian ini diharapkan dapat menjadi solusi pada perindustrian terhadap kesalahan proses assembly dan machining yang terjadi pada pasangan roda gigi.

The increase of collision cases experienced by two-wheeled vehicle occurs due to its unstable characteristic. In this study, double-gyroscope stabilization as a vehicle balancer system is going to be discussed. Double-gyroscope with a double flywheel direction of rotation on different directions will add greater precession torque compared with the single-gyroscope. The gyroscopic phenomenon with a double-gyroscope will show the effect of the rotation of the flywheel used. The goal of this system is to restore the tilting vehicle due to a collision to its original position of the vertical axis. The first step of this reasearch is formulation of dynamic equation of motion of two-wheeled motorcycle with two gyroscopes. The next step is to create a block diagram of the equation of motion that has been previously formulated in Simulink Matlab Software. The last step is 3D modeling of a two-wheeled motocycle using Autodesk Inventor Software. The vehicle tilt angle is used as input parameter (θ) at 0°, 1°, 2°, 3°, 4°, 5°. The result obtained from Simlink Matlab is 5600 rpm until 7544 rpmof flywheel rotation to stabilize tilt angle 0°-5° and from Autodesk Inventor result is 5700 rpm until 7700 rpm of flywheel rotation with the same tilt angle. The difference occurred due to the theoretical test, only described the state of mass component center in 2D only, while in the simulation, the system is described in 3D and has an additional component that can illustrate the angle of vehicle oscillation.

The quarter-car model has been proven for its simplicity and effectiveness for analyses of vehicle suspension dynamics. The quarter-car model also often used to design the semi-active and active suspension controller. However, the conflicting dynamics performance of the vehicle suspension studied without considering the effects of suspension kinematics. This article presents the study on the linkage geometry influences on the actively controller double-wishbone suspension ride comfort performance. First, the equivalent stiffness and damping are derived and used to design the controller. Then, the dynamic responses of actively controlled double-wishbone suspension model was evaluated under harmonic and bump excitation for several linkage geometry cases. The result shows that geometry variation has significant effects of the passive suspension case and less significant for the active suspension case.

Wall-ironing is a metal forming process to reduce the wall thickness and increase the cup length. Ironing is a bulk forming process where the deformation force (tensile force) must be absorbed by the cup wall which is deformed. In the ironing process, the thickness reduction ratio or TRR is an important factor. If TRR is low to achieve the desired thickness, the process should be carried out several times. The greater the TRR, the more increased tensile force resulting in a larger stress. If the stress in the formed cup wall exceeds the tensile strength of the cup material, the base is torn off. This stress must be between the yield and the ultimate stress of the material. The die angle also affects the ironing force. This research is using CATIA software in order to get the die angle, TRR, and ironing force relationship.In this study, the products used are deep-drawn aluminum cup 37 mm of outer-diameter, 32 mm inner-diameter, 20 mm height, and 2.5 mm wall thickness. Outer wall thickness is reduced with varying TRR of 30%, 20% and 10%. Reducing process is done through ironing force on punch (punch force) inside the cup, whereas outer wall of cup is reduced through die ring with various die angle 5°, 10°, 15°, 20°, 25°, and 30°. By using CATIA modeling and stress analysis simulation, we can obtain stress (Von Misses stress) that occur on cup wall.The results of varying ironing force modeling simulation with 30%, 20%, 10% of TRR and 5°, 10°, 15°, 20°, 25°, 30° of die angle, can be obtained the occuring Von Misses stress. Based on this stress, the most optimal condition can be selected i.e. 30° of die angle for 30% of TRR, 15° of die angle for 20% of TRR, and 10° of die angle for 10% of TRR. Furthermore, this method can be used to analyze the research related to the press tool design on metal forming, especially the ironing with different methods.

This Research is aimed to predict the maximum varying blank holder force (VBHF) over the punch stroke in order to eliminate cracks on cup deep drawing product. The constant blank holder force during the process, it's frequently not capable to prevent cracking, effectively. Using the slab method with assuming a constant volume of material, the simple analytical approach of maximum VBHF, has been conducted under the failure deformation and cracking criteria on every stage punch stroke. The cracking criteria are based on the maximum strength of materials. Steel sheet of SPCD grade, thickness 0.2 mm was used in this study. And the diameter of the cylindrical cup-shaped product was 40 mm. The analytic calculation of the maximum VBHF has been compared to FEM simulations, and its effects in the prevention of cracking. Analytical Results of maximum VBHF, not much different with FEM simulation. Compared to the application of the constant blank holder force, VBHF can be quite effective for preventing the occurrence of cracking and increasing the formability of deep drawing.

This paper aims to investigate the magnitude of minimum blank holder gap to prevent wrinkles and cracks defects of the rectangular cup with T4 material Tin Plate CA. Punch-die domensions are determined based on the standard tool designed. The methods of this research are an analytic, finite element (FE), and experimental approach, respectively. Each method in this study had been mutually compared to other methods. According to the research, minimum blank holder gap is recommended by 120% to 130% of the thickness of the initial material (about 0.24 A· 0.26 mm). By using the value of this gap, the height of wrinkles is very small, and the magnitude of the drawing force is still below the critical limit, so the product does not occur wrinkles and cracks.

Seiring perkembangan zaman, teknologi roda gigi dituntut untuk mampu mentransmisikan daya yang besar dengan efisiensi yang besar pula. Pada jenis intersecting shaft gear, tipe roda gigi payung spiral (spiral bevel gear) merupakan perkembangan dari roda gigi payung bergigi lurus (straight bevel gear). Kelebihan dari spiral bevel gear antara lain adalah kemampuan transmisi daya dan efisiensi yang lebih besar pada geometri yang sama serta tidak terlalu berisik. Akan tetapi spiral bevel gear juga mempunyai kelemahan jika dibandingkan dengan straight bevel gear. Selain proses manufaktur yang lebih rumit, profil lengkung gigi spiral ini membuat distribusi tegangan yang terjadi menjadi lebih rumit untuk dimodelkan dengan persamaan matematika. Salah satu pendekatan yang dapat dilakukan adalah dengan menggunakan metode elemen hingga. Penelitian diawali dengan membuat model dari straight bevel gear dan juga spiral bevel gear yang sudut spiralnya divariasikan 20, 35, dan 45 derajat. Model dibuat dengan dimensi yang sama baik diameter maupun jumlah gigi gear. Langkah selanjutnya yaitu perhitungan analitis pada straight bevel gear dimana hasilnya akan dibandingkan dengan hasil simulasi statis. Setelah eror yang terjadi dibawah 15% maka dilakukan simulasi dinamis pada semua model yang telah dibuat yaitu straight bevel dan juga spira bevel gear. Hasil yang didapatkan dari penelitian ini adalah secara keseluruhan spiral bevel gear lebih kuat daripada straight bevel gear pada dimensi dan beban yang sama jika dilihat dari lebih kecilnya tegangan bending dan tegangan kontak maksimum yang terjadi. Tegangan terbesar terjadi pada jenis straight bevel gear baik pada tegangan bending maupun tegangan kontak sedangkan spiral bevel gear dengan variasi sudut Seiring spiral 35 mempunyai nilai tegangan terkecil. Prosntase selisih tegangan bending maksimum yang terjadi antara straight bevel gear dan spiral bevel gear dengan variasi sudut spiral 35 derajat sebesar 44,3%. Sedangkan selisih tegangan kontak maksimumnya sebesar 20,5%. Sehingga secara keseluruhan spiral bevel gear lebih baik daripada straight bevel gear. Kata Kunci- spiral bevel gear, tegangan bending, tegangan kontak, FEM.

This paper presents the mathematical approach of minimum blank holder force to prevent wrinkling in deep drawing process of the cylindrical cup. Based on the maximum of minor-major strain ratio, the slab method was applied to determine the modeling of minimum variable blank holder force (VBHF) and it compared to FE simulation. The Tin steel sheet of T4-CA grade, with the thickness of 0.2 mm was used in this study. The modeling of minimum VBHF can be used as a simple reference to prevent wrinkling in deep drawing.

Structural stiffness loaded with bending force is influenced by its dimension, especially by height and cross section. As the natural frequency of the structure depends on the structural stiffness, therefore the changes in the structure dimension will also change its natural frequency. In machining process of thin wall box-shaped workpiece using vertical milling machine the workpiece can be treated as a structure subject to bending force due to the cutting force. Therefore the structural stiffness of the workpiece is a crucial aspect to be considered. The natural frequency of the workpiece, especially its first natural frequency serves as a preliminary information of the workpiece modal parameter to avoid the self excited vibration called chatter. A new model based on parametric beam modeling was developed and implemented on computer programming to predict the first natural frequency of thin wall box-shaped workpieces. The first natural frequency of thin wall box-shaped workpiece can be calculated using this model for varying wall thickness, height, and length to width ratio of the workpiece cross section. The result of the parametric beam modeling is verified though an experimental modal analysis and also compared to a finite element numerical analysis.

In this paper, an electromagnetic shock absorber for passenger car has been designed, fabricated and tested. Multi objective H∞ Controller has been designed and implemented on quarter car test rig. Controllers have been designed to minimize sprung mass acceleration, power requirement and to maximize harvesting energy. Proportional-Integral (PI) Controller with currents input tracking reference has been also implemented for comparisons. Shock absorber has been designed and prototyped to harvest vibration energy and to be controlled by electric current. The shock absorber uses DC permanent magnet motor. Damping force and regenerated current of prototype have been tested on Auto Damping Test Machine (ADFT). The prototype is able to generate 2.59A maximum current with 183.3N damping force when 20 Ω external loads are applied. A DOF mass-spring-damper test rig has been constructed for controller implementation. Simulations have been conducted for verification. With optimal state feedback gain, Kopt = [-514.11 -127.59 -0.00017 -1.14 -0.42 0 0.26], H∞ Multi objective controller is attaining RMS of body acceleration arms= 1.2m/s2, maximum suspension stroke SWSmax= 0.016m, and average power consumption Pcons = 134 Watt. Root Mean Squared Error (RMSE) among experimental and simulations are: 0.31 m/s2, 0.0058m and 2.91 A respectively for body acceleration, suspension travelling and supplied current. With PI controller parameter: Kp = 0.4 and Ki =0.5, feedback gain Cg = 2 and Cs= 0.3, RMS of body acceleration arms= 1.16m/s2, maximum suspension stroke SWSmax = 0.03m, and average power consumption Pcons = 178 Watt. Root Mean Squared Error (RMSE) among experimental and simulations are: 0.85m/s2, 0.0066m and 2.73 A respectively for body acceleration, suspension travelling and supplied current.