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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).
Calculations for the deflection of a freely supported beam with two different sections, loaded in the middle.

Identifier  ExFiles\Box 112\1\  scan0113
Date  10th January 1939 guessed
  
DEFLECTION OF A BEAM OF TWO DIFFERENT SECTIONS, FREELY SUPPORTED AT ITS ENDS & LOADED IN THE MIDDLE.

OMITTING THE ZERO TERMS :-

2 ((l₁ MBL / I₁) + (l₂ MBR / I₁)) + (a₂ W₂ / l₂ I₂) (l₂² - a₂²) = (6E/l₁) (δB - δA) + (6E/l₂) (δB - δC)

LET MBL = MBR = M : AND (δB - δA) = - (δB - δC) = δ

(2 l₁ M / I₁) + (2 l₂ M / I₂) = (2 a W / l₂ I₂) (l₂² - a²) = δ (1/l₁ - 1/l₂) 6 E.{Mr Elliott - Chief Engineer}

NOW IF l₁ = 4'-0", l₂ = 6'-0", a = 5'-0", & M = +4 W.

(32 W / I₁) + (48 W / I₂) + (110W / 6 I₁) = δ (¼ - ⅙) 6E = ½ δ E

OR δ = (64 W / E I₁) + (132.6 W / E I₂)

THEN IF I₁ = I₂, δ = (W / E I₂) x 196.6

BUT IF I₁ IS DOUBLED δ = (W / E I₂) x 164.6
  
  


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