This research presents the durability assessment of cylinder block for a two-stroke free piston engine using narrow band approach. The life prediction results are worthy for improving the component design at the very early developing stage. This approach is adequate for periodic loading, however, requires very large time records to accurately describe random loading processes. Fatigue damage in conventionally determined from time signals of the loading, frequently in the form of stress and strain. However, there are scenarios when a spectral form of loading is more appropriate. In this case the loading is defined in terms of its magnitude at different frequencies in the form of a Power Spectral Density (PSD) plot. The vibration fatigue calculation can be utilized where the random loading and response are categorized using power spectral density functions and the dynamic structure is modeled as a linear transfer function. This research also investigates the effect of the mean stress on the fatigue life prediction using the random loading. The acquired results indicate that the Goodman mean stress correction method gives the most conservative results with the Gerber and no (zero) mean stress method. It is observed that the compressive mean stresses are beneficial while the tensile mean stresses are detrimental to the fatigue life. The proposed technique is capable of determining premature products failure phenomena. Therefore, this technique is able to reduce cost, time to market, improve the product reliability and finally the user confidence
Solar water heating using flat plate collector (FPC) is the widest application that had been used in residential and commercial area. The material for the absorber plate in FPC should have good thermal conductivity to ensure a high value for the heat removal yet able to store heat slightly high during minimum solar radiation period. An experimental of FPC water heating is conducted using copper and aluminium as absorber plate. The plates were exposed under intense sun radiation more than 800w/m2. The analysis is performed on the relationship between the material and the temperature difference of water. The results represented the heat gain and water heating efficiency between aluminium and copper. Aluminium had heat gain of 1100.69W. Copper had the heat gain of 1025.36W. The water heating efficiency calculated for aluminum is 0.97 while copper is 0.93. The paper finally justified that aluminium is better as the absorber plate in this flat plate solar collector compare to copper plate.
In this present work, the design and simulation of crankshaft for multi-cylinder Stirling engine is studied based on finite element analysis. The proposed crankshaft design is based on the typical crosshead slider-crank mechanism that is being used with the consideration of design needs for multi-cylinder Stirling engine. The study focused on the piston-crankshaft assembly that is subjected to compression load in Stirling cycle. Based on the simulation results, the maximum von Mises stress for crankshaft model varies from 0.82 MPa at 1 bar charge pressure to 1.65 MPa at 20 bar charge pressure. Minimum factor of safety is founded to be 33 with maximum deformation under maximum charge pressure. For piston-crankshaft assembly load, minimum factor safety of 2 was observed with maximum compression pressure for minimum charge pressure. The results indicate no yielding and structural failure under compression load case, can be satisfied.
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