. The Encyclopaedia Britannica; ... A dictionary of arts, sciences and general literature. f load can bring tobear upon it; and the beam will be properly c/eai^detf ifits form is such as to enable it to bear the load with theleast possible quantity of material. A complete analysisof the internal forces in a loaded beam would in anycase be exceedingly difficult and with most designs impos-sible, but it is found by experiment that a beam will beara given load if we provide strength enough to resist thehorizontal components of those internal forces v/hich tendto extend or compress the beam in the
. The Encyclopaedia Britannica; ... A dictionary of arts, sciences and general literature. f load can bring tobear upon it; and the beam will be properly c/eai^detf ifits form is such as to enable it to bear the load with theleast possible quantity of material. A complete analysisof the internal forces in a loaded beam would in anycase be exceedingly difficult and with most designs impos-sible, but it is found by experiment that a beam will beara given load if we provide strength enough to resist thehorizontal components of those internal forces v/hich tendto extend or compress the beam in the direction of itslength, and if we also provide against the vertical com-ponents which tend to shear the beam across in planesperpendicular to the longitudinal axis of the beam. Thenature of the horizontal and vertical forces due to theelastic reaction of the material will be understood by refer-ence to figs. 9, 10, 11, Let a model be made of four stiff light frames of woodA, Aj, Aj, Aj, each say 18 inches deep, 18 inches long, and6 inches wide (fig. 9). Let these be connected with one. Fig. 9. another by smallcylinders of india-rubber, abed, a-^ Jj Cj rfj,and Oj h^ c^ d^. These cylinders must be so attached to theframes as to be capable of resisting both extension and com-pression. The whole structure will now have somewhat theappearance of a beam, but if it is placed between two sup-ports Q, N, it will be found unsuited to carry even its owaweight, because the middle frames will tend to slip downbetween the two others. This tendency wiU be still better, seen when a load isplaced on the imperfect beam. Fig. 10 shows the tendency
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectencyclo, bookyear1902
