No abstract

Propeller is part of a key component in fishing boat propulsion. Propeller can provide momentum to the fluid which can be a thrust on the ship. However, The failure of the propeller found prematurely. The failure of the propeller maybe because of overload on the propeller model so the fatigue life of the propeller becomes low. On the other hand, the rapid development of technology can simulate a design model to look for failures that occur. Finite Element Analysis is one of the designer solutions to determine the age of failure of a model and failure-prone areas in a model. This study uses propeller model data from fishing boat with engine 24HP in Dumai City TPI that always fail prematurely. The material used is copper alloy. While the drawing model uses Autodesk Inventor and Finite Element Analysis simulation using ANSYS R17.2 software with the number of model nodes is 51108 and the number of elements of the model is 26268. The results obtained from this study are Von Mises stress on the simulation model that is equal to 613.33 MPa to 0.01164 MPa. While the deformation value due to the effect of loading on the model is 5,3657 mm to 0 mm. These results affect the age of fatigue (fatigue life) on the model with the highest value 109 and the lowest 0. The results of the fatigue life value on the model affect the results of the level of damage and the safety number of the model with successive values of 1032 to 1 and 15 to 0.32446. The conclusion of the result is the propeller will fail prematurely.

Rice is one of the basic foodstuffs consumed by the people of Indonesia as well as Bangka Belitung Islands Province more precisely Bangka Regency Riau Silip Village Banyu Asin. Freshly harvested rice is usually still not separated from straw / malai. The process of harvesting rice still uses traditional tools or also called gebotan. The threshing machine available in Banyu Asin has not been able to maximize the results of the platform, which resulted in the length of the threshing process. Based on these needs, it was designed to build a rice threshing machine to facilitate the threshing process. Rice threshing machine design refers to the VDI 2222 method of development which has 4 (four) stages, namely: planning, conceptualizing, designing, and finishing, then assessed based on technical, and economic aspects. The conclusion obtained during the design process of the rice threshing machine is the design of the machine weighing 60 kg lighter than the existing machine is easy to move and the design of the machine whose components are easy to remove installs. The design of a rice threshing machine that is able to knock rice as much as 86.4kg / hour, compared to existing machines is only able to knock rice as much as 30kg / hour.

Punch force is the main factor in the success of making holes using the punching process. However, the punching process cannot make a hole when the punch force in the machine is smaller than the punch force in the material. Preheating can be used to reduce the punch force in the material. This research aims to develop the preheating method with low current electricity for reducing the punch force in the material. The preheating method is used two tubular type heating elements with an electric current of about 0.9 A. This method can be heating the material below recrystallization temperature (100 and 150 °C). Preheating at 100 and 150 °C can reduce the punch force by 4 and 11% compared to without preheating. These results can be concluded the material heating below recrystallization temperature is effectively enough to reduce the punch force. Thus, the punching process is able to make a hole even though the punch force in the machine is smaller than the punch force in the material.