Temperature management for battery packs installed in electric vehicles is crucial to ensure that the battery works properly. For lithium-ion battery cells, the optimal operating temperature is in the range of 25 to 40 °C with a maximum temperature difference among battery cells of 5 °C. This work aimed to optimize lithium-ion battery packing design for electric vehicles to meet the optimal operating temperature using an air-cooling system by modifying the number of cooling fans and the inlet air temperature. A numerical model of 74 V and 2.31 kWh battery packing was simulated using the lattice Boltzmann method. The results showed that the temperature difference between the battery cells decreased with the increasing number of cooling fans; likewise, the mean temperature inside the battery pack decreased with the decreasing inlet air temperature. The optimization showed that the configuration of three cooling fans with 25 °C inlet air temperature gave the best performance with low power required. Even though the maximum temperature difference was still 15 °C, the configuration kept all battery cells inside the optimum temperature range. This finding is helpful to develop a standardized battery packing module and for engineers in designing low-cost battery packing for electric vehicles.

This work aims to investigate piezoresistive behavior in plain-woven carbon fiber reinforced polymer (CFRP). Measurement method for electric resistant alteration in the woven CFRP under tensile loading by using a Wheatstone bridge circuit is introduced. Reversibility of the resistant alteration is also investigated whereas the gauge factor of the woven CFRP is evaluated. The result shows that the positive piezoresistive properties of the woven CFRP can be observed by the Wheatstone bridge circuit. The specific resistances of 43.8 μΩm and 10.1 μΩm are obtained for wrap and thickness directions, respectively. Reversibility with a hysteresis of the woven CFRP can also be confirmed with the gauge factor of 22.9 at loading conditions and 17.7 at unloading conditions. Positive piezoresistive behavior which has been revealed in this work can be utilized for structural health monitoring technology development.

The high number of freight vehicles that exercised overloading in Indonesia has led to a significant reduction in the quality of road pavement. The obsolete overload detection system using weigh bridges have been ineffective, since it requires vehicles to maneuver and enter the weighing station. In the above system, after manual checking, overloaded vehicles will be penalized. The Weigh-in-Motion (WIM) device that is developed in this research utilized a bending plate sensor with strain gage. As overloaded vehicle runs over the WIM, axle weight will be automatically recorded, and the data is processed further to assess the compliance to maximum freight weight as specified for the vehicle. In this research work, the WIM prototype is developed and tested using motorcycle under normal operation and overloaded conditions at different speeds. Arduino based signal processing and analysis system has been developed such that the overload detection may be performed automatically. When the system senses an overloaded vehicle, it will automatically trigger the alarm and a camera will capture the vehicle. The error of the prototype is within acceptable range and the system has shown the potential to detect whether the vehicle, i.e., the motorcycle, is overloaded or not. As a continuation, the development of a reliable microcontroller-based WIM and a robust automatic overloaded freight vehicle will be our future work.

Pengembangan Metode Rekonstruksi Jalan Berbasis Data Global Positioning System dan Giroskop

We designed a high-precision fertilizer applicator to distribute fertilizer with the required dose at every specified point. The dose necessary aims to meet the nutritional needs of plants, so that plant growth is more effective while reduce waste. The fertilizer applicator was designed to have an auger and drive system that can discharge the fertilizer precisely. A 3D CAD model of the applicator was created to conduct a discrete element simulation to predict the discharge fertilizer process. Experiment was carried out to validate the simulation model. The experiment utilized a small-scale applicator prototype manufactured by 3D printing. A small electric actuator controlled by Arduino microcontroller was installed to rotate the auger. The auger can push and release the fertilizer precisely depending on the rotation's number. Both simulation and experiment results were compared and showed a small error of 6.42%. The results show our designed fertilizer applicator have good accuracy and precision, which indicates the applicator was suitable to distribute fertilizer uniformly.

A track is a vehicle propulsion system that consists of a continuous band of chains connected with track shoes or may be entirely made of rubber. The track system is still commonly used on various vehicles, including bulldozers, excavators, tanks, and tractors, and has recently been used in lunar expedition vehicles. A tracked vehicle is mainly designed to provide better mobility in rough, uneven, or slippery terrain. The main component of the track system is track shoes or so-called grousers. This track shoe geometry will determine the tractive performance of the vehicle. If an incorrect shape is used, the excavator will most likely slip. The previous study approached this traction problem by using the semi-empirical method. However, until now, the track geometry and traction relation are still unclear. This research focuses on the effects of track shoe geometry on tractive performance and vehicle climbing ability. The analysis was mainly conducted with a DEM (Discrete Element Method) simulation. The result from the experimental test is also confirmed using a small-scale RC prototype on simulated terrain with different slope variations. It is proven that the grouser height directly affects the climbing performance of tracked vehicles. A higher grouser height proves to be better at a higher inclination slope. However, for a low inclination angle, the flattened track was better. The traction result from the EDEM simulation also yields a similar result. However, higher usable traction means more friction is generated; therefore, the track with higher traction also takes more energy to cover the same distance.