A cylinder is a Surface in the space defined by a right (d), called generating , passing by a variable point describing a Courbe planes closed (c), called direct curve and keeping a fixed direction. One also speaks about cylindrical surface . The prism S (whose Cubic S and Parallélépipède S rectangles) is particular cases of cylinder.

One can consider a cylinder as a cone whose top “is rejected ad infinitum”.

By extension, if a cylinder is cut by two parallel plans strictly , the solid obtained is still called a cylinder. If these plans are perpendicular S to the generating right-hand side, it is said that the cylinder is right . The distance separating the two parallel plans is called the height cylinder and the surface delimited by the direct curve is called the bases cylinder. If one notes H the height of the cylinder and With the surface of his base, then its Volume V is given by the equality: V = has × H.

Cylinder of cross-section

A cylinder of cross-section is a cylinder whose direct curve is a Cercle and whose generating right-hand side is perpendicular to the plan containing the directing circle.

In the space brought back to the orthonormal Reference mark \ (O, \ vec I, \ vec J, \ vec K) , the cylinder of axis \ (z' Z) has as an equation: \ x^2+y^2=r^2 where \ r is the radius directing circle.

Note: the majority of people think that the term cylinder applies exclusively to the cylinder of cross-section.

Mechanics

  • the cylinders are the parts which guide the movement of the Piston S in various devices:
    • Cylinder of an Engine spark-ignition
    • transmitting and receiving Cylinder of hydraulic Brake
    • Cylinder of Steam engine
  • Cylinder of safety of Lock

  • the term Cylindrée which is derived from the word cylinder is not solely used for the systems rolls/piston.

Roll in volume

There exists a more formal mathematical definition cylinder, which includes all the internal points. This definition is generalizable with N dimensions of a Euclidean Espace. In \ mathbb {R} ^n, the cylinder of cross-section and ray R , of axis \ mathrm {Vect} \ left (e_3, e_4, \ ldots, e_n \ right) , is defined by:
C = \ {X \ in \ mathbb {R} ^n; x_1^2 + x_2^2 \ Leq R^2 \}

See too

External bond

  • A. Javary, Treated descriptive geometry , 1881, (on Gallica): Cones and cylinders, sphere and surfaces of the second degree

  • the shortest way on the cylinder

Simple: Cylinder

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