43 results about "Stress equation" patented technology

Two finite difference algorithms on rectangular grids are provided for viscoelastic ink ejection simulations. The first algorithm is first-order accurate in time, while the second algorithm is second-order accurate in time. Each of these two algorithms seamlessly couples or incorporates several features: (1) a coupled level set-projection method for incompressible immiscible two-phase fluid flows; (2) a higher-order Godunov type algorithm for the convection terms in the momentum equations and level set convection equation; (3) the central difference for viscosity, surface tension, and upper-convected derivative terms; (4) an equivalent circuit for inflow pressure (or inflow rate). In the first algorithm, a simple first-order upwind algorithm is designed for the convection term in the viscoelastic stress equations. But in the second algorithm, a second-order Godunov type upwind scheme is employed for the convection term in the viscoelastic stress equations.

The invention provides an elastic migration seismic wave field construction method and an elastic migration seismic wave field construction device. The method includes computing a finite difference coefficient of extended compact staggered grids according to an elastic wave velocity stress equation; computing a finite difference operator matrix of the extended compact staggered grids; constructing forward direction extrapolation operator of a seismic source wave field, and a reverse-time extrapolation operator of a detection wave field; achieving forward direction extrapolation of a seismic wave field to obtain the seismic source wave field according to the forward direction extrapolation operator of the seismic source wave field, a preset medium model and a preset seismic source function; and achieving reverse-time extrapolation of the seismic wave field to obtain the detection wave field according to the reverse-time extrapolation operator of the detection wave field, a preset medium model and preset multi-component seismic data. Compared with an existing method for constructing an elastic deflection seismic wave field by utilization of a conventional finite difference method and a compact difference method, the number of difference base frame grid points is reduced under the condition of same difference orders, the construction precision of a complex medium wave field can be effectively improved, and therefore the imaging precision of reverse-time migration is improved.

The method of modeling residual stresses during laser cutting utilizes thermal diffusion and stress equations and a discretization numerical method to model temperature variation and residual stresses in a substrate material due to laser cutting therethrough of small-diameter holes.

The invention provides a liquid static pressure guide rail oil film thickness control system and method based on oil temperature compensation. According to the method, a flow rate equation between guide rails is built; the flow rate equation is subjected to linearization; a guide rail stress equation is built; then, the linearized flow rate equation and the guide rail stress equation are subjected to Laplace transformation, so that an oil film thickness response load mechanism is obtained. For the oil film thickness control, the set oil film thickness is compared with the actual oil film thickness detected by a sensor, a difference value signal is subjected to control algorithm calculation, then, through signal conversion and power amplification, a simulation signal is obtained; the simulation signal is used for controlling an alternating servo motor and a proportional overflow valve, and the alternating current servo motor drives a variable pump, so that the oil flow rate of oil liquid outputted by the variable pump adapts to the flow rate required between movable and fixed guide rails, meanwhile, when the oil temperature changes, the pressure of the proportional overflow valve is controlled by a computer, and the change of the static pressure guide rail oil liquid pressure due to temperature change is compensated.