9 results about "Small strain" patented technology

The invention discloses a numerical simulation analysis method for a near-river ultra-deep foundation pit under the action of seepage flow, and the method comprises the following steps: S1, constructing a three-dimensional numerical model based on finite element software PLAXIS 3D, and constructing a non-uniform stratum model in combination with a Borehole module; s2, fine modeling is conducted through the underground diaphragm wall, the reinforced concrete supports and the latticed columns; s3, simulating a small strain hardening characteristic and a rigidity attenuation effect of the soil body by adopting an HSS model; s4, simulating underground water flow by combining plastic steady-state seepage analysis, and simplifying the three-axis cement mixing pile into an underground diaphragm wall structure through an equivalent stiffness principle; and S5, step-by-step excavation and support sequential control construction procedures are adopted, and finally, the reliability of the model is verified by comparing a horizontal displacement simulation result of the diaphragm wall with field monitoring data. According to the method, the foundation pit deformation rule is predicted through HSS constitutive model and seepage coupling analysis, and the foundation pit deformation prediction precision is remarkably improved.

The application discloses a preparation method of titanium / titanium alloy wire with a double-gradient structure, which comprises the following steps: (1) performing large-strain drawing on the titanium / titanium alloy wire with a strain of not less than 0.5; (2) performing heat treatment on the drawn wire at a medium-low temperature; (3) performing large-strain torsion on the heat-treated wire with a torsion angle of 3600-20000 degrees to obtain a wire with a gradient increase of strain from a core to an edge along a radial direction; (4) performing heat treatment on the torsioned wire at a medium temperature to obtain a wire with a gradient decrease of ultra-fine grain size from the core to the edge along the radial direction; and (5) performing small-strain torsion on the heat-treated wire with a torsion angle of 720-3600 degrees to obtain the titanium / titanium alloy wire with the double-gradient structure. By obtaining the titanium / titanium alloy wire with a double-gradient heterogeneous structure of grain size and strain, the application greatly improves the strength-plasticity matching of the wire and overcomes the problem that the existing strengthening methods of titanium / titanium alloy result in the deterioration of plasticity of the wire.

This invention provides a method for testing the roller tilt angle distribution of a double-row tapered roller bearing. First, a calibration experiment is performed. At least three strain gauges are arranged equidistantly on the outer surface of the bearing outer ring corresponding to each roller in the load-bearing area. By loading a single roller, the strain response of all strain measurement points on the outer ring corresponding to each roller in the load-bearing area of ​​the test bearing is obtained. This allows for the determination of the load measurement point positions unaffected by roller tilt under different tilt directions, as well as the corresponding load transfer coefficient and roller tilt angle calibration coefficient. Then, the strain measurement points of the test bearing are rearranged. The newly arranged test bearing and test bearing housing are installed at the work site. Combined with the calibration results, the roller tilt angle distribution of the bearing in its in-situ state can be calculated. This invention uses smaller strain gauges, making installation in practical environments more convenient and allowing for easier tilt angle distribution testing. This invention can be directly installed at the work site after calibration on a simple test bench, thus having wider applicability. This invention can monitor the roller tilt state of the load-bearing area of ​​the rolling bearing online in real time.

When the hammer for small strain detection is used, the left end and the right end of the cross rod are held by two hands respectively, the hammer is lifted, the lower end of the vertical rod of the hammer abuts against the pile top of a pile foundation to be detected, one end of the pull rope is wound through the pull rope winding device, and therefore the balance weight and the knocking head are pulled to rise. The counterweight is blocked by the lower end of the first vertical hole until reaching the upper limit position and cannot continue to rise; then, one end of the pull rope is not wound through the pull rope winding device any more, the balance weight and the knocking head freely fall, and knocking is completed through the knocking head. The hammer for small strain detection can conveniently and quickly knock a pile top in a small strain experiment, so that the working efficiency is improved, the same knocking force is ensured each time, and errors are reduced.

The utility model relates to the technical field of power measurement, in particular to a riding power measuring device which comprises a main shaft, a chip and a spiral strain gauge. The main shaft is of a cylindrical structure, and one end of the main shaft is provided with a connecting structure used for being connected with external equipment. The spiral strain gauge is fixedly arranged at the end, close to the connecting structure, of the main shaft and used for detecting the strain condition of the main shaft in the riding process and sending measured strain data to the chip, and output power and power data are obtained through calculation of the chip and wirelessly transmitted to a user side. The spiral strain gauge is tightly attached to the main shaft, tiny strain changes in the riding process can be accurately captured, and accurate motion feedback is provided for a rider in combination with the computing power of a high-performance chip and real-time output power and power data.

This invention relates to a method for establishing a small-strain elastic model of clay considering inherent anisotropy and stress history. The method includes: establishing a mathematical model describing the stiffness degradation of clay with strain based on a modified Hardin-Drnevich curve; introducing a stress path rotation angle and constructing an interpolation function to quantify the influence of recent stress history on the small-strain stiffness of clay; introducing a fabric tensor to describe the inherent anisotropy of clay and establishing an expression for the elastic modulus to reflect the degree of anisotropy of clay in its initial state; and verifying the effectiveness of the model by comparing data from various natural clay experiments. The beneficial effects of this invention are: the proposed model can more accurately describe the anisotropic stiffness response of soil within a small strain range, especially after considering the influence of the stress path rotation angle and pavement orientation, which greatly improves the model's prediction accuracy.

This invention discloses a method for identifying fatigue cracks in wind turbine blades based on distributed optical fiber strain response, belonging to the field of wind power equipment condition monitoring technology. The method includes the following steps: collecting continuous optical strain response records formed during the wind turbine blade's operation; organizing these records according to a unified time scale to form a strain change trajectory; calculating the difference in amplitude between adjacent strains within the strain change trajectory and extracting continuous, slowly fluctuating segments to form a list of low-frequency oscillation segments. This invention identifies low-frequency oscillation segments in the strain change trajectory and constructs an oscillation unfolding trajectory, enabling the time unfolding of local strain changes in the low-frequency oscillation background, thereby revealing the minute strain change characteristics of the crack initiation stage; further, by extracting suspected crack fragments and reconstructing crack release trajectories, a crack strengthening trajectory is formed, allowing crack release changes to be continuously presented in a continuous time series, improving the early identification capability and the ability to identify the change process of fatigue cracks in wind turbine blades.

The invention discloses a shield cutter abrasion dynamic monitoring system and a monitoring method thereof. The monitoring system comprises a hob, hob shafts are arranged at the two ends of the hob, and the hob is provided with side pressed faces; the strain gauge is fixed on the side pressed surface of the hobbing cutter in a welding manner and is used for converting the mechanical strain of the hobbing cutter into a resistance change signal; the resistance strain gauge is connected with the strain gauge through a flexible wire, is arranged at a position far away from a welding point of the strain gauge, and is used for receiving and processing a resistance change signal of the strain gauge; and the conductive slip ring coaxially sleeves the peripheral side of the hob shaft through a fixing structure and is used for leading out an output signal of the resistance strain gauge in a rotating state. According to the invention, the strain gauges are mounted in a high-stress area near the cutting edge, so that the tiny strain change of the tool can be sensitively captured, and accurate early warning of early wear such as microcracks and tipping can be realized.

The invention discloses a three-dimensional crustal stress prediction method based on structure size deformation and numerical simulation. The method specifically comprises the following steps: S100, a first stage: constructing large deformation simulation; comprising the following steps: S110, establishing a three-dimensional frame model by using depth domain horizon data according to a seismic interpretation result; s120, setting a constitutive model and a strain softening mode; s130, stratum mechanical parameters are set; s140, setting a boundary condition; s150, setting speed boundary loading; s160, carrying out numerical calculation, comparing strain distribution in a simulation result with fault distribution obtained through geological exploration, and checking the correctness of a large-deformation simulation result of the structure; s200, in the second stage, small strain simulation is constructed, the simulation result in the first stage serves as an initial model, and speed boundary loading is modified into stress boundary loading; carrying out numerical calculation, and comparing stress distribution of a simulation result with an actual measurement result; according to the method, the model constraint degree is increased, and the reliability of a three-dimensional crustal stress prediction result can be improved.