page_title: Compression (physics)
section_title: Uses
hierarchical_section_title: Compression (physics) / Uses
caption_attribution_description: English: Instron universal testing machine equipped with a 300 kN dynamometer. Measuring the compressive strength of a composite cylinder (glass bead-reinforced epoxy). Français&#160;: Machine d'essai universelle Instron équipée d'un dynamomètre de 300 kN. Mesure de la résistance en compression d'un cylindre en matériau composite (polyépoxyde renforcé microbilles de verre).
context_page_description: In mechanics, compression is the application of balanced inward forces to different points on a material or structure, that is, forces with no net sum or torque directed so as to reduce its size in one or more directions. It is contrasted with tension or traction, the application of balanced outward forces; and with shearing forces, directed so as to displace layers of the material parallel to each other. The compressive strength of materials and structures is an important engineering consideration.
  In uniaxial compression, the forces are directed along one direction only, so that they act towards decreasing the object's length along that direction. The compressive forces may also be applied in multiple directions; for example inwards along the edges of a plate or all over the side surface of a cylinder, so as to reduce its area, or inwards over the entire surface of a body, so as to reduce its volume.
  Technically, a material is under a state of compression, at some specific point and along a specific direction, if the normal component of the stress vector across a surface with normal direction is directed opposite to.
context_section_description: Compression of solids has many implications in materials science, physics and structural engineering, for compression yields noticeable amounts of stress and tension.
  By inducing compression, mechanical properties such as compressive strength or modulus of elasticity, can be measured.
  Compression machines range from very small table top systems  to ones with over 53 MN capacity.
  Gases are often stored and shipped in highly compressed form, to save space.  Slightly compressed air or other gases are also used to fill balloons, rubber boats, and other inflatable structures.  Compressed liquids are used in hydraulic equipment and in fracking.
caption: Compression test on a universal testing machine
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