Recent content by MechEgr

Thanks for the reply!

Guys, I have a problem I'm trying to solve for work (we're trying to inspect a hole, and I'm trying to determine its angle using a gage pin and a ball bearing). An image of the problem is attached. The known dimensions which we can measure are shown in black, and I am trying to solve for...

Thanks for your replies, everyone. The loading will be performed with a mallet (hammer), so the most important feature is device toughness. Form the comments above, that leads me to believe that Charpy impact value is of some importance. However, the material must be harder than its...

Thanks for the suggestions. The failure mode is likely a combination of bending moment (from a compression impact load) and tensile stress (from a tensile impact load). I am surprised that H900 is the lowest hardened state though. I don't know a lot about heat treating, but from the table...

I am designing a surgical instrument which will be impacted many times over its life cycle. We are trying to determine the best heat treating option for the steel (17-4 precipitation hardened) so that we maximize its usable life. Typically, we heat treat 17-4 to H900. However, I'm not sure...

Jbriggs, I follow your logic all the way until your very last point. I don't quite understand where the pi term came from in your equation. I understand that the force exerted over half of the cross-sectional area should be 2T/(L*W). It seems that somehow when you convert that to pressure...

Imagine you are getting dressed in the morning and fastening a belt around your waste. You pull on the loose end of the belt, developing tension T throughout the length of the belt. Using this information, how can you determine the amount of compression the belt is applying to your waste? I...

Yes, what you're saying in both cases is true. The reason there are "shoulders" on the cylinder is that we need to be able to start with some positive pressure (as in the case with a pre-pressurized ball). Yes, I agree that there will be a material effect from the ball. the effect would...

I don't think I agree with you because I think for your example to be true, the starting pressure in the system must be zero. The pressure change inside a piston system (ΔP) is not necessarily ΔL/A if the starting pressure is positive (non-zero). I have attached a simple example which...

For the record I think I figured out the answer. If you start with a small pressure, the ball deforms significantly to compensate. If, on the other hand, you start with a large internal pressure, the deformation of the ball in response to the added load is much less noticeable...

Yes, the assumption is that this was done at constant temperature. I think what you're saying makes sense. Are saying essentially that at a smaller starting pressure, the internal pressure would have to increase more in order to support the same amount of load than if the starting pressure...

I am attempting to determine a method for calculating the final pressure in a deformable bladder given a starting pressure and an applied load. Scenario: This is actual data gathered in my lab: A) You have a ball made from a rubbery material with P1=3psi. You weigh 150lbs and step on...