Study On The Stress Wave Transfer Efficiency Of Impact Machine And Its Application In Lunar Soil Sampling Machinery

A great deal of power flow can be produced by impact machines. Compared with the static pressure machines of same power, they have compact construction and have been widely used in industrial production. They all have similar action principles: the impact machinery with certain speed and force come from accelerates under the effects of gravity, hydraulic or steam, knocking at the working object at a certain speed in order to make it shifted, deformational and broken.The mechanical parts are regarded as rigid bodies or mass points in the traditional mechanical dynamics, ignoring medium inertia of elements. The wave mechanics should be applied in analyzing energy transfer process considering that the motion parameters change significantly in milliseconds even nanoseconds.Because of the limited energy supplies of the lunar soil sampling machinery, the energy transfer efficiency is analyzed and compared under different waveforms and constant rock-soil’s dynamic stiffness based on the general impact machinery model. The hammer’s impedance is designed inversely, based on one-dimensional wave mechanics and Dirac delta function in order to achieve the optimal waveform and it is proved correctly by forwarding solution and FEM; the states of motion and stress between the hammer and rod are analyzed by separation first hypothesis which is proposed firstly based on linear superposition. The energy transfer efficiency and hammer’s impaction efficiency influenced by hammer’s geometry dimensionless parameters are analyzed and the optimal parameters are determined.Because there are reflected waves generating when the incident waves propagate along the non-uniform rod, the law of reflected and transmitted waves propagation along non-uniform rod is studied in this paper. Different samples’ energy transfer efficiencies are analyzed in frequency domain and FEM programs. The impedance expression of minimal mass subjected to anti-symmetry feature is solved by variational method in functional extreme value problem a t the request of certain high efficiency and light weight. The plateau junction superiorities which are conducive to engineering application are analyzed and compared with others.Relevant measures which can improve system working efficiency are applied in lunar soil sampling machinery featured by hollow geometry. The optimized designs of theoretic research are proved to improve system working efficiency by comparing the designs before and after the optimization with FEM programs.