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Calculation of the deflection of a Bentley III yoke due to bending.


Identifier  ExFiles\Box 100\1\  scan0156
Date  27th May 1938
  
-3-
STIFFNESS OF BENTLEY III YOKE.

(1) Deflexion of A below O due to bending.

Diagram showing a simply supported beam with forces and moments:
- Point O: Moment M, Downward force 1400 lbs
- Point A: Upward force 1,000 lbs at distance 'a' from O
- Point B: Upward force 400 lbs at distance 10" from O
- Moment indicated: 14500 lbs-ins

Equations:
Mx {John H Maddocks - Chief Proving Officer} = -14,500 + 1,000 (a - x) + 400 (10 - x)
EI d²y/dx² = 14,500 - 1,000 (a - x) - 400 (10 - x)
EI dy {F R Danby} /dx = 14,500x - 1,000 (ax - x²/2) - 400 (10x - x²/2) + α
EI y = 14,500x²/2 - 1,000 (ax²/2 - x³/6) - 400 (10x²/2 - x³/6) + αx + β

α = 0 because dy {F R Danby} /dx = 0 at O
β = 0 " y = 0 at O

EI yA = 7,250 a² - 333a³ - 2,000a² + 67a³
= 5,250 a² - 267a³
yA = 1/EI (5,250 a² - 267a³)
  
  
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).


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