Verge escapement fifth of a second per day. Today the verge is seen only in antique or antique-replica timepieces. Many original bracket clocks have their Victorian-era anchor escapement conversions undone and the original style of verge escapement restored. Clockmakers call this a "verge reconversion". Verge escapement The verge (or crown wheel) escapement is the earliest known type of mechanical escapement, the mechanism in a mechanical clock that controls its rate by allowing the gear train to advance at regular intervals or 'ticks'. Its origin is unknown. Verge escapements were used from the 14th century until the mid 19th century in clocks and
Strain energy release rate a straight path, the mode I stress intensity factor (formula_10) is related to the energy release rate (formula_5) by where formula_13 is the Young's modulus and formula_14 for plane stress (as in a thin tensed elastic sheet) and formula_15 for plane strain (as in a thick elastic slab). Therefore, the energy release rate failure criterion may also be expressed as where formula_17 is the mode I fracture toughness. Strain energy release rate The strain energy release rate (or simply energy release rate) is the energy dissipated during fracture per unit of newly created fracture surface area. This quantity is central