Verge escapement orientation of the crown wheel and the need for a bulky fusee made the verge movement unfashionably thick. French watchmakers adopted the thinner cylinder escapement, invented in 1695. In England, high end watches went to the duplex escapement, developed in 1782, but inexpensive verge fusee watches continued to be produced until the mid 19th century, when the lever escapement took over. These later verge watches were colloquially called 'turnips' because of their bulky build. The verge was only used briefly in pendulum clocks before it was replaced by the anchor escapement, invented around 1660 and widely used beginning in 1680.
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