8 Fig. 9-8. The springs or elastic bands which secure this punching bag to floor and ceiling are being subjected to repeated, but not alternating, stress. Impact Strength; Fracture Toughness. Both of these terms refer to the ability of a material to withstand shock, or large forces suddenly applied. Neither property can be defined mathematically, for engineering use, in the same sense that tensile strengths can be defined. Impact strength is usually stated in terms of the energy absorbed by a metal when it is broken under carefully-defined and limited conditions. In the Charpy V-notch impact test, a specimen of fixed dimensions, which has been precisely notched, is broken by a blow from a pendulum hammer. Continued on next page... Fig. 9-9. The piston rod in this double air pump is being subjected to alternating stress. Each half of the rod is first pulled, then pushed. At some point in each cycle, stress in one half of the rod is zero.
Hard- Surfacing, Building Fusion Welding Carbon Welding Non-Ferrous Metals Heating & Heat Treating Braze Welding Welding Cast Iron Welding Ferrous Metals Brazing & Soldering Equipment Set-Up Operation Equipment For OXY-Acet Structure of Steel Mechanical Properties of Metals Oxygen & Acetylene OXY-Acet Flame Physical Properties of Metals How Steels Are Classified Expansion & Contraction Prep For Welding OXY-Acet Welding & Cutting Safety Practices Manual Cutting Oxygen Cutting By Machine Appendices Testing & Inspecting