Of the Strength of a Beam to resist a Strain in the Direction of the Length
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This section is from the book "Elementary Principles Carpentry", by Thomas Tredgold. Also available from Amazon: Elementary Principles Of Carpentry.
Of the Strength of a Beam to resist a Strain in the Direction of the Length
81. The weight that will produce fracture is in proportion to the area of the section, multiplied by the weight that would fracture a unit of that area.
The following Tables contain the results of the chief experiments which have been made on the direct strength, and show the weight that will destroy the cohesive force of one square inch.
* Morin,' Resistance des Materiaux.'
82. Table III. - Cohesive Force of Different Woods from Various Sources.*
Description of Wood. | Cohesion of a square inch in lbs. | Authority. | |
Acacia ........................ | 20,582 | Muichenbrock. | |
Alder........ | 14,186 | " | |
Ash, English | from .. | 17,850 | Barlow. |
to .. | 15,784 | ||
" ....................... | 12,000 | Musehenbroek. | |
Beech........................ | 17,709 | " | |
" ........................ | 11,500 | Barlow. | |
Box, Berbice............ | 20,000 | " | |
Cedar....................... | 4,973 | Musehenbroek. | |
Chestnut, Spanish....... | 13,300 | Rondelet. | |
Cypress...................... | 6,000 | Musehenbroek. | |
Deal, Christiana.......... | 11,000 | Barlow. | |
" Memel................. | 11,000 | " | |
Elder........ | 10,000 | Musehenbroek. | |
Elm............................. | 13,489 | " | |
Fir.............................. | 8,506 | " | |
" New England......... | 12,000 | Barlow. | |
" Riga....................... | 12,600 | " | |
" Mar Forest ............ | 12,000 | " | |
Hickory........................ | 20,700 | ||
Larch............................. | 10,220 | Rofulelet. | |
Lemon.......................... | 9,250 | Musehenbroek. | |
Mulberry....................... | 12,500 | " | |
Description of Wood. | Cohesion of a square inch in lbs. | Authority. | ||
Mahogany................... | 8,000 | Barlow. | ||
Maple...................... | 15,400 | Hatfield. | ||
Norway Spars | 12,000 | Barlow. | ||
Oak ........ | 17,300 | Muschenbroek. | ||
" ........... | 13,950 | Rondelet. | ||
,, English | from .. | 9,000 | Barlow. | |
to ... | 15,000 | ,, | ||
,, African | 14,400 | ,, | ||
,, Adriatic | 14,000 | ,, | ||
,, Canadian .. | 12,000 | ,, | ||
,, Dantzic | 14,500 | ,, | ||
Pear-tree............... | 9,800 | ,, | ||
Pine, Pitch...... | 7,818 | Muschenbroek | ||
" " ...... | 10,500 | Barlow. | ||
,, Norway | 7,287 | Rondelet. | ||
,, Bed ...... | 10,000 | Barlow. | ||
Plum-tree............... | 11,800 | Muschenbroek. | ||
from | 6,641 | ,, | ||
to...... | 4,596 | |||
Teak, Indian | 15,000 | Barlow. | ||
Walnut ...... | 8,130 | Muschenbroek. | ||
Willow ...... | 12,500 | ,, | ||
* In this Table all the experiments were made by pulling specimens of the woods asunder in the direction of their length. Muschenbroek's are from his ' Intro, ad Phil. Nat., torn. i.; Barlow's, from his ' Essay on the Strength of Timber,' and ' Encyclopaedia Metropolitana;' Rondelet's from vol. iv. of his ' L'Art de Batir;' and Hatfield from his American House Carpenter.'
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