We Knew that the overpressure devices that can keep the pressure from building to the point where the vessel ruptures. But what about keeping pressure vessels from rupturing under normal operating pressure? You know, pressures well below the point where an overpressure device would kick in. This can happen if there is some sort of…
Statics is the study of how forces are transmitted to and throughout stationary objects. Let’s learn a little bit about how statics is used by mechanical engineers to solve problems. Consider a perfectly rigid bridge beam sitting on two supports (see Figure 1). Now suppose you decide to stand on it. The weight of your body would push down on the beam,…
When we refer to the study of the kinematics of machines, we’re referring to the relationship between machine parts and how those parts behave as they move through their ranges of motion. What this means is that there is particular concern with the relative motion of machine parts, that is, how they relate to each other,…
Ever get out of bed on a cold winter morning and feel as stiff as a ladder? Summer’s heat doesn’t have the same effect on aging joints as winter’s chill, and many retirees have been motivated to move into warmer climates because of it. Heat can change the properties of metals like steel, too. By properties,…
Last time we saw how compound pulleys within a dynamic lifting scenario result in increased mechanical advantage to the lifter, mechanical advantage being an engineering phenomenon that makes lifting weights easier. here we’ll see how the mechanical advantage increases when more fixed and movable pulleys are added to the compound pulley arrangement we’ve been working with.More Pulleys Increase Mechanical Advantage The image shows a…
We’re all familiar with the phrase, “too much of a good thing.” As a professional engineer, I’ve often found this to be true. No matter the subject involved, there inevitably comes a point when undesirable trade offs occur. We’ll begin our look at this phenomenon in relation to compound pulleys here, and we’ll see how the pulley arrangement we’ve been…
We’ve been discussing the mechanical advantage that compound pulleys provide to humans during lifting operations and last time we hit upon the fact that there comes a point of diminished return, a reality that engineers must negotiate in their mechanical designs. Here we’ll discuss one of the undesirable trade offs that results in a diminished return within a compound pulley arrangement when we compute the length of rope the…
The presence of friction in mechanical designs is as guaranteed as conflict in a good movie, and engineers inevitably must deal with the conflicts friction produces within their mechanical designs. But unlike a good movie, where conflict presents a positive, engaging force, friction’s presence in pulleys results only in impediment, wasting energy and reducing mechanical advantage. We’ll investigate the math behind…
Last time we saw how the presence of friction reduces mechanical advantage in an engineering scenario utilizing a compound pulley. We also learned that the actual amount of effort, or force, required to lift an object is a combination of the portion of the force which is hampered by friction and an idealized scenario which is friction-free. here we’ll begin…
We left off Previously with an engineering analysis of energy factors within a compound pulley scenario, in our case a Grecian man lifting an urn. We devised an equation to quantify the amount of work effort he exerts in the process. That equation contains two terms, one of which is beneficial to our lifting scenario, the other of which is not. HERE we’ll explore…