Applied Engineering Letters

133-142

Authors: Tran Van Dua

For a machining processes, the material selection that is very important, greatly affect both on the economic and technical efficiency of these processes. The selection of each material often was considered many criteria, which have different values in different materials. Multi-criteria decision making that is a technique is used to slove with situations of this type. The collaborative unbiased rank list integration that is a recently proposed multi-criteria decision making method and has only used in a handful of published studies. In this study, this method was used to select the materials for the industrial fields. Material selection in three different areas was performed. In each case, the ranking results of the solutions by the collaborative unbiased rank list integration method were compared with those ones of other methods. The results showed that this method is completely reliable when using for material selection with the considering of multiple criteria. Moreover, the strength of this method is that it does not occur any ranking reversion phenomenon even when considered in different scenarios.

154-162

Authors: Ahmad K. Jassim, Raheem Al-Subar, Dhia Ch. Ali

Sustainable manufacturing technology is one of the requirements of the current industrial fields to reduce the weight and energy used. Friction stir welding (FSW) can be considered a quantum leap in the development of welding technology. A solid-state process utilizes a non-consumable tool and less electrical energy. Friction stir spot welding (FSSW) is a particular case of FSW that began to spread rapidly, especially for similar and dissimilar metals, which has extended to weld the polymers. The increase of FSSW use in different fields needs to simplify the equipment. This study used a portable drilling machine to construct an FSSW apparatus with a rotational speed between 1500 and 3000 rpm with a pin diameter of 2, 3 and 4 mm. The results indicated that the joints welded by the developed apparatus have good strength and hardness. Furthermore, many specimens succeeded in the bending test, especially when the rotational speed was set at 2250 rpm and the pin diameter was 3 mm. In addition, it was found that the mechanical properties increased with the rotational speed and pin diameter, then gradually decreased. Finally, the Response Surface Methodology (RSM), besides the analysis of variation (ANOVA), was utilized to maximize the lap-shear fracture load. The results indicated that the maximum lap-shear fracture load can be achieved at a tool speed N of {2300>N>1600} rpm with a pin diameter (d) of {2.75>N>3.75 mm}.

172-180

Authors: Kayode Saka, Bankole Adebanji , Paul Olulope, Taiwo Fasina, Adewale Abe, Wilfred Ajeba

In this work, a grid-connected small hydro-solar PV hybrid power system (HPS) was modeled to complement electricity supply in Ado-Ekiti metropolis in Nigeria, and hence, investigated the steady state stability of the distribution networks with and without HPS integration. Consumers’ load audit was carried out through measurement of apparent load at peak periods on each outgoing cable riser from the low voltage circuit of the distribution transformer using clamp-on ammeter which represents loads on respective 11 kV feeders. The solar PV system employed the use of JAP6- 72-30/4BB solar PV module and average solar radiation intensity of 4.95 w/m2 was considered when sizing the solar PV power system. The designed and modeled HPS was integrated into the grid through a hydro inverter and five numbers of parallel-connected 2000 kVA grid-tie solar PV inverters. Simulation analysis of the distribution networks with and without renewable energy integration was carried out using DigSILENT power factory. This work analyzed two scenarios for each of the distribution networks. Simulation results indicated that the networks were stable as evident in the analyses of the renewable grid integration and notable improvement on profile voltage (pu) of all the 11 kV distribution networks were observed.