Table of Contents
How much deflection in a shaft is acceptable?
Torsional and lateral deflection both contribute to lower critical speed. In addition, shaft angular deflection at rolling element bearings should not exceed 0.04 degree, with the exception being self-aligning rolling element bearings.
How is shaft deflection calculated?
It is often sufficient to calculate the deflections based on the shaft being one diameter. This clearly results in a conservative value if the diameter used is the minimum diameter. The simple basis of this method is that the change in slope between two points Δθ = Δx. (M/EI) ….
What is deflection in shaft?
Shaft deflection is the bending or displacement of a shaft under certain circumstances, such as an axial load.
How can I reduce my shaft deflection?
Shaft deflection can be minimized by: Using suitably spaced radial bearings, • Positioning the radial loads near a radial bearing, and • Making the shaft as stiff (large) as possible through & between the radial bearings.
What causes shaft deflection?
Shaft deflection is the bending of a pump shaft that occurs when the velocity of liquid being pushed by an impeller is not equal at all points around the impeller. When a pump operates at the best efficiency point (BEP), velocity and pressure are relatively equal all the way around the impeller.
How do you calculate deflection at a point?
Generally, deflection can be calculated by taking the double integral of the Bending Moment Equation, M(x) divided by EI (Young’s Modulus x Moment of Inertia).
What is I in beam deflection formula?
Calculating beam deflection requires knowing the stiffness of the beam and the amount of force or load that would influence the bending of the beam. We can define the stiffness of the beam by multiplying the beam’s modulus of elasticity, E, by its moment of inertia, I.
What is permissible deflection?
Allowable deflection is generally expressed as a fraction of the span, in inches. For example, the allowable deflection of a 12ft span floor joist with plaster (L/360) is 0.4″ (12ft divided by 360). If that same joist had gypsum ceiling (L/240), the allowable deflection is 0.6″.
What causes a pump shaft to bend?
A bent pump shaft can occur as the result of damage during operation, rigging, improper configuration, or even shipping. There are straightening methods that can be properly applied to salvage damaged pump shafting, although they are not possible in all scenarios.
What is the formula for deflection of beam?
Generally, we calculate deflection by taking the double integral of the Bending Moment Equation means M(x) divided by the product of E and I (i.e. Young’s Modulus and Moment of Inertia). The unit of deflection, or displacement, will be a length unit and normally we measure it in a millimetre.