Grasshopper escapement As a result, on the 18th of April 2015, the Guinness World Records organisation presented a World Record certificate to Martin Burgess for having made the most accurate purely mechanical clock working in free air. The clock remains at the ROG; in 2017 it was moved to the gallery containing the Harrison marine timekeepers where its performance continues to be monitored. Grasshopper escapement The grasshopper escapement is a low-friction escapement for pendulum clocks invented by British clockmaker John Harrison around 1722. An escapement, part of every mechanical clock, is the mechanism that gives the clock's pendulum periodic pushes to keep
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