The HARDNESS POLYURETHANE AND NATURAL RUBBER EFFECT ON ADHESIVENESS OF AIRLESS TIRES

Airless tires are the best innovation for military tactical vehicles in carrying out the Army's main tasks for military tactical even peace support operations and war military operations. However, in its development there are still imperfections in the results, its fabrications in the adhesion between polyurethane and natural rubber. Therefore, the researchers aimed to develop the adhesion between polyurethane and natural rubber. In this research, a quantitative experimental method was used, namely by varying the hardness of natural rubber and polyurethane to determine the right hardness for airless tires for maximum adhesion. The problem that occurs is that the adhesive glue with the tire tread is problematic, resulting in a tire tread condition without air being released. In carrying out the research, a function test was carried out with a planned weight of 4,500 Kg. Based on the results of the tests that carried out, the correct result was obtained, namely the elongation at break of the most appropriate type of polyurethane L100, which was 9.287 MPa. In order to achieve the goal, namely the appropriate level of elasticity between polyurethane and natural rubber so as to be able to glue the spokes and tire treads, in the end the wheel rotation will rotate according to the desired elasticity.

Sistem Pemantauan Kelayakan Pelumas Oli pada Kendaraan Sepeda Motor dengan Memanfaatkan Teknologi Internet of Things

AbstrakSepeda motor memerlukan perawatan yang oprtimal terutama are mesin yaitu dengan melakukan pergantian oli yang berfungsi sebagai pelumas mesin. Oli mesin membantu menghindari gesekan langsung antara logam di mesin, sehingga mengurangi tingkat kerusakan mesin. Penelitian ini akan dirancang suatu sistem pemantauan pergantian oli sepeda motor berdasarkan jarak tempuh dan waktu pemakaian oli yang berbasis IoT. Dimana penggunaan sepeda motor digunakan untuk menyimulasikan perputaran roda, sensor proximity sebagai pendeteksi putaran roda, serta mikrokontroller ESP32 sebagai pengendali utama, buzzer untuk memperingati pengguna, relay digunakan untuk mematikan mesin sepeda motor, dan GSM sebagai pengirim data. Pada penelitian ini diperoleh hasil yang diharapkan, ketika jarak tempuh mencapai jarak 2000km maka sistem akan memperingati pengguna sepeda motor dan ketika pengguna mengabaikan peringatan tersebut dan jarak mencapai 2100km maka sistem mematikan kelistrikan sepeda motor. Namun jika jarak tidak tercapai tetapi pemakaian oli telah mencapai 60 hari maka sistem memperingati pengguna sepeda motor.Kata kunci: Gsm, Mikrokontroler, Otomasi, Sensor, Sepeda MotorAbstractMotorcycles require optimal maintenance, especially the engine, namely by changing the oil, which functions as an engine lubricant. Engine oil helps avoid direct friction between the metals in the engine, thereby reducing engine damage. This research will design a motorcycle oil change monitoring system based on mileage and time of oil usage based on IoT. Where the use of a motorcycle is used to simulate wheel rotation, a proximity sensor is used to detect wheel rotation, as well as the ESP32 microcontroller as the main controller, a buzzer to warn the user, a relay is used to turn off the motorcycle engine, and GSM as a data sender. In this study, the expected results are obtained, where when the distance reaches a distance of 2000km, the system will warn the motorcycle user and when the user ignores the warning and the distance reaches 2100km, the system will turn off the motorcycle electricity. However, if the distance is not reached but the oil consumption has reached 60 days, the system will warn motorcycle users.Keywords: Gsm, Microcontroller, Automation, Sensors, Motorcyle.

A simulator for both manual and powered wheelchairs in immersive virtual reality CAVE

A large number of people in the world need to use a wheelchair because of different disabilities. Driving a wheelchair requires complex physical and cognitive abilities which need to be trained. Virtual training helps users acquire driving skills in a safe environment. The aim of this paper is to describe and technically validate simulation models for both manual (MW) and powered wheelchairs (PW) based on immersive virtual reality CAVE (VR). As VR system, the Gait Real-time Analysis Interactive Lab (GRAIL) was used, a CAVE equipped with a motion platform with two degrees of freedom and an optoelectronic motion capture system. A real wheelchair was positioned onto the motion platform with rear wheels free to turn in MW modality, and a commercial joystick was installed on an armrest to simulate the PW modality. Passive markers were used to track the wheel rotation, the joystick and the user hand motion. Custom D-flow applications were developed to manage virtual scene response to user actions. Overground tests, based on single wheel rotation, were performed to verify the simulation model reliability. Quantitative results demonstrated that the MW simulator kinematics was consistent with a real wheelchair overground in the absence of wheel slip and inertia (median error for MW 0.40 °, no systematic bias p = 0.943, high correlation rho > 0.999, p < 0.01). The proposed solution is flexible and adaptable to different wheelchairs, joysticks and optoelectronic systems. The main limitation is the absence of force feedback. Nevertheless, it is a reliable prototype that can be used to validate new virtual scenarios as well as for wheelchair training. The next steps include the system validation with real end users and assessment of the simulator effectiveness as a training tool.

Study on Material Removal Model by Reciprocating Magnetorheological Polishing

In this study, a new reciprocating magnetorheological polishing (RMRP) method for a flat workpiece was proposed. Based on the RMRP principle and Preston equation, the material removal rate (MRR) model of the RMRP as well as its normal polishing pressure model was established. On this basis, the effects of different technological parameters including workpiece rotation speed, eccentric wheel rotation speed and eccentricity on the MRR of the workpiece were investigated. The K9 optical flat glass was polished with the RMRP setup to verify the MRR model. The experimental results showed that the effect of workpiece rotation speed on the MRR was much greater than that of eccentric wheel rotation speed and eccentricity, and the MRR increased from 0.0115 ± 0.0012 to 0.0443 ± 0.0015 μm/min as workpiece rotation speed rose. The optimum surface roughness reduced to Ra 50.8 ± 1.2 from initial Ra 330.3 ± 1.6 nm when the technical parameters of the workpiece rotation speed of 300 rpm, the eccentric wheel rotation speed of 20 rpm and the eccentricity of 0.02 m were applied. The average relative errors between the theoretical and experimental values were 16.77%, 10.59% and 7.38%, respectively, according to the effects of workpiece rotation speed, eccentric wheel rotation speed and eccentricity on MRR.

Impact of wheel rotation on the aerodynamic drag of a time trial cyclist

Aerodynamic drag is the main resistive force in cycling at high speeds and on flat terrain. In wind tunnel tests or computational fluid dynamics simulations, the aerodynamic drag of cycling wheels is often investigated isolated from the rest of the bicycle, and sometimes in static rather than rotating conditions. It is not yet clear how these testing and simulating conditions influence the wheel aerodynamic performance and how the inclusion of wheel rotation influences the overall measured or computed cyclist drag. This study presents computational fluid dynamics simulations, validated with wind tunnel tests, that indicate that an isolated static spoked front wheel has a 2.2% larger drag area than the same wheel when rotating, and that a non-isolated static spoked front wheel has a 7.1% larger drag area than its rotating counterpart. However, rotating wheels are also subjected to the rotational moment, which increases the total power required to rotate and translate the wheel compared to static conditions where only translation is considered. The interaction with the bicycle frame and forks lowers the drag area of the front wheel by 8.8% for static and by 12.9% for the rotating condition, compared to the drag area of the isolated wheels. A different flow behavior is also found for static versus rotating wheels: large low-pressure regions develop from the hub for rotating wheels, together with a lower streamwise velocity region inside the circumference of the wheel compared to static wheels. The results are intended to help in the selection of testing/simulating methodologies for cycling spoked wheels.

Numerical Investigation of the Effect of Tread Pattern on Rotating Wheel Aerodynamics

The present work investigates the dynamic effect of wheel rotation on the aerodynamic characteristics of slick type (ST) wheel of Formula One racing cars using a computational approach. The ST wheel model was compared to experimental results as a validation case. The pressure coefficient over the ST wheel circumference at its middle plane (xy) has been considered as an experimental case from literature and the computed results showed a reasonable agreement. Furthermore, a quantitative evaluation of the numerically-determined wheel drag, local separation and stagnation angles has been also compared to those extracted experimentally from literature. The validation work served by assessing the suitability of using Moving Reference Frame (MRF) method to simulate the effect of wheel rotation, as well as defining the most reliable conditions of testing such as the optimal meshing criteria, the computational domain size, and the adopted turbulence model. According to wheel studies, all computational work was performed at a Reynolds number of 6.8×105 based on the wheel diameter. The wheels aerodynamic drag, lift, and moment coefficients were computed for each wheel model. Further parametric study on the tread design of the tread type (TT) wheel was performed by varying the tread depth, h. Besides, general schematic pictures of the flow behavior around the TT wheel are presented.