Development of a validated numerical model of an unreinforced T-section pipe for large dams

Abstract: This paper reports on the development of a validated numerical model (using 3-D finite element method (FEM)) of an unreinforced T-section pipe. Pipe profiling severely compromises the localized performance of the T-section pipe. The main objective was to develop a less conservative tool to investigate the key factors that influence failure in T-section pipes. Strain gauges were mounted on the T-section to capture the induced strains as the pressure was gradually increased until the pipe burst. The executed FEM analysis provided comparable results to the experimental measurements which provided a cost effective tool to validate the numerical model. This result allows for better placement of branch piece reinforcements based on experimentally obtained results. The developed tool c be used to optimize the design and sizing of reinforcing crotch plates

Energy efficiency enhancement of off-grid photovoltaic (PV) power plant

Abstract: The sizing of the off-grid PV systems is currently based on a manual approach, i.e. daily load is estimated by identifying commonly used load appliances for modelling system performance. If the system is not properly sized, it may not function according to expectation. The purpose of this paper is to present a conceptual design of an off-grid (autonomous) photovoltaic (PV) power plant, fitted with an efficient power regulating (EPR) management system of solar batteries and an instinctive solar tracking of PV panels. An optimization model for an Efficient Power Regulating (EPR) system of solar batteries was coupled to a solar tracking device so that the PV panels were constantly in full view of the sun. The objective function of the model was to maximize the efficiency of PV cells through PV battery charge regulation and load control in off-grid PV installations. This study revealed that the effectiveness of the EPR of solar battery (SB) when totally discharged can be realized when the accumulating battery (AB) charge reaches 50%.The study findings were indicative of the effectiveness of the EPR of SB. Hence, the EPR technique and the automatic tracking of PV solar panels proved to be the most effective technique of optimizing the energy efficiency of autonomous PV power plants

Mechanical properties and microstructure of Friction Stir and Laser Beam Welded 3mm Ti6Al4V Alloy

Abstract: In this paper the authors report the study done on welded Ti-6Al-4V alloy sheets by friction stir and laser beam welding. Fusion and solid-state techniques were compared to determine the most performance favourable welding process. Welds were accomplished by varying the process traverse speed. High traverse speeds indicated increased hardness in the weld nugget and wider nugget area for laser beam as compared to FSW. Tensile strength for both processes showed similar performance to that of the parent plate. Welds from laser beam welding exhibited superior fatigue strength under tension-tension loading than friction stir welds at intermediate speeds. Microstructure was discussed to explain the effect of the process parameters on joint integrity in relation to the parent plate. Additionally, residual stresses measured in the weld nugget are explained

Residual stress distribution and the concept of total fatigue stress in laser and mechanically formed commercially pure grade 2 titanium alloy plates

Abstract: This paper discusses the investigation of residual stresses developed as a result of mechanical and laser forming processes in commercially pure grade 2 Titanium alloy plates as well as the concept of total fatigue stress. The intention of the study was to bend the plates using the respective processes to a final radius of 120mm using both processes. The hole drilling method was used to measure residual strains in all the plates. High stress gradients were witnessed in the current research and possible cases analyzed and investigated. The effects of processing speeds and powers used also played a significant role in the residual stress distribution in all the formed plates. A change in laser power resulted in changes to residual stress distribution in the plates evaluated. This study also dwells into how the loads that are not normally incorporated in fatigue testing influence fatigue life of commercially pure grade 2 Titanium alloy plates..

Performance assessment of carbon dots based nano cutting fluids in improving the machining characteristics of additively manufactured 316L stainless steelFuture Recommendations

The advantages of additive manufacturing (AM) over conventional manufacturing techniques, such as the ability to build parts with complicated geometry, have led to a rise in its applications in recent years. However, the mechanical and tribological qualities of an additively manufactured (AMed) parts are distinct from those of a conventionally made components because of the layer-by-layer nature of AM process. However, there is a need to machine these complex geometries of AMed components to achieve the desired final dimension and surface finish. Therefore, this study investigates the impact of four environmental regimes (dry, flood, MQL, and N-MQL) on the metal cutting of AMed 316L stainless steel specimen, with a focus on the efficacy of N-MQL lubrication containing rice bran oil + carbon dots (CDs) particles. Responses measured include cutting temperature, surface roughness (Ra), tool wear, microstructure, and micro-hardness. Outcomes show that N-MQL outperforms other cutting regimes, offering enhanced machining performance and surface quality, making it a crucial choice for AMed specimens