Paul wrote:

I have three motor mounts that take 400 pounds of thrust in the radial
direction. The radial spring rate is  400 pounds per inch for
the two front mounts and 200 pounds per inch for the rear mount.
What radial load  does each mount see? Ignore static weight and torque loads.

No takers so far. Is this too hard for you hotshots? :-)

Let a Math major take a crack.

Assuming the motor mount frame is utterly rigid, the deflection of each motor mount
will be the same.  Further, the deflection of all three motor mounts must yield a
combined 400 lb. force.  Assuming D is the deflection distance:

    F(rear) + F(port) + F(starboard) = 400 lbs.
    200 lbs/inch * D + 400 lbs/inch * D + 400 lbs/inch * D = 400 lbs
    D = 400 lbs / 1000 lbs/inch = 0.4 inch

F(rear) = 200 lbs/inch * 0.4 inch = 80 lbs
F(port) = 400 lbs/inch * 0.4 inch = 160 lbs
F(starboard) = 400 lbs/inch * 0.4 inch = 160 lbs

Russell Kent

 
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