Anchor escapement anchor in his invention of the longcase or grandfather clock around 1680. When Clement's clock appeared Hooke claimed the invention of the escapement, saying that he had shown a clock with the same escapement to the Royal Society soon after the great fire of 1666. The earliest known anchor clock is Wadham College Clock, a tower clock built at Wadham College, Oxford, in 1670, probably by clockmaker Joseph Knibb. The anchor became the standard escapement used in almost all pendulum clocks. A variation without recoil called the deadbeat escapement was invented by Richard Towneley around 1675 and introduced by British
Strain energy release rate 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 to fracture mechanics because the energy that must be supplied to a crack tip for it to grow must be balanced by the amount of energy dissipated due to the formation of new surfaces and other dissipative processes such as plasticity. For the purposes of calculation, the energy release rate is defined as where formula_2 is the potential energy available for crack growth, formula_3 is the work associated