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avcg21

Student needs help

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I do not understand the question. So I am going to guess what you tried to ask. Can you design an assembly to convert rotation (such as a crankshaft) to constant velocity reciprocating motion? I already know about elliptical gears. But i do not want to cut custom gears. I just need a few pieces to alternately move back and forth with constant rate, no speeding up, as in a sine wave. Maybe the 4 bar linkage works best?

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Timothy, your answer is internally contradictory. If a sliding block moves at a constant rate to the right (or left), it cannot reciprocate. It must stop and reverse the direction of motion. Nor can it stop instantaneously. There must be an interval of negative acceleration to bring it to a stop followed by an interval of positive acceleration to bring it back up to speed. Sorry but that's life (and kinematics!)

DrD

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I will throw out a topic here for others to consider... Scheduling power assets is becoming more important, especially in Africa, where development is rapid. You can investigate this with an Excel spreadsheet. You can get and simulate demand over time (throughout the day and also with seasons). You can select a few assets and see how they might meet this demand. Consider a base-load plant, perhaps coal-fired, that ramps up slowly and is not quickly responsive. Add a 2x1, 3x1, or 4x1 combined cycle with duct firing. You can run one or more engines with or without the steam tail. You can experiment when to activate duct firing. You might even add solar panels or a hydro-electric dam. Each of these options provides different levels of power and also expense. The ramp rate (how long it takes to get from one power level to the other) varies with each type. You can get this information off the Web. If you can't find something, I have lots of real data. After you get this working, you can think about how to schedule maintenance on each asset.

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