# Why we have to tap the frame during Deflection of Beam Experiment?

by socrates_1
Tags: beam, deflection, experiment, frame
 P: 27 hi, last week we did an experiment to find the deflection of simply supported beams. During the experiment, after every measurement we had to tap the frame slightly. Does anyone know why we had to do this? If you could explain it to me I would be grateful.
 P: 5,462 Welcome to Physice Forums Firstly some protocol. You have posted duplicate threads. This is frowned upon, to put it mildly. As to your question, did you not ask the lecturer at the time?. If I were she I would have suggested you consider what force or forces might be acting that are not included in the general beam formulae you were testing.
 P: 27 Thank you for your response. I cant find out what forces u mean. Could you explain it further?
 Engineering Sci Advisor HW Helper Thanks P: 7,119 Why we have to tap the frame during Deflection of Beam Experiment? Since you were measuring deflections, something probably moved between each measurement. What sort of force tends to prevent things from moving, in any real-world situation?
P: 27
 Quote by AlephZero Since you were measuring deflections, something probably moved between each measurement. What sort of force tends to prevent things from moving, in any real-world situation?
Friction?
 P: 208 To set up the experiment you would of got some sort of beam and Clamped one end or both. The key word in there starts with a C.
 P: 27 Could someone else explain??I cant find out
 P: 208 I just gave you the answer without actually telling you. Straight just telling you the answer is frowned upon here.
 P: 27 anyone who could actually tell me???
P: 5,462
 socrates_1 Friction?
Many engineers call it "stiction". It is the same reason that we tap any mechanical indicating device that relies on mechanical movement to indicate a value, such as a meter movement a dial gauge, a barometer etc.

http://en.wikipedia.org/wiki/Stiction
P: 27
 Quote by Studiot Many engineers call it "stiction". It is the same reason that we tap any mechanical indicating device that relies on mechanical movement to indicate a value, such as a meter movement a dial gauge, a barometer etc. http://en.wikipedia.org/wiki/Stiction
really thank you

 Related Discussions Engineering, Comp Sci, & Technology Homework 7 Introductory Physics Homework 0 Mechanical Engineering 3 Special & General Relativity 5