11 results about "Shrinkage coefficient" patented technology

The invention provides a production size control method for a hard alloy roll collar blank and an intelligent production system, and belongs to the technical field of powder metallurgy. The method aims to solve the problems of low finished product qualification rate and high cost caused by uncontrollable sintering shrinkage of the hard alloy roll collar in the prior art. According to the technical scheme, the method comprises the steps that a set of linear shrinkage coefficients of a hard alloy roll collar pressed blank are designed in advance based on the target finished product size, and the target size of the pressed blank is calculated according to the set of linear shrinkage coefficients and the target finished product size; then, according to the calculated target size, wax-doped powder serving as a raw material is subjected to compression molding, and a compressed blank is obtained; and finally, the pressed blank is transferred into a low-pressure sintering furnace for dewaxing and sintering treatment. According to the method, the quantifiable linear shrinkage coefficient is introduced, empirical estimation is converted into accurate calculation, operation is simplified, the accuracy and consistency of the size of a finished product are remarkably improved, and the rejection rate and the production cost are reduced.

The invention discloses an image printing method suitable for multi-level high-fall natural slate, and relates to the technical field of printing, and the method comprises the following steps: S1, rock surface characteristic analysis: the section fall delta h and the edge inclination angle theta of the natural slate are obtained through three-dimensional scanning, delta h represents the vertical height difference of adjacent levels, and theta is the included angle between the edge tangent plane and the horizontal plane; s2, dynamic parameter modeling: on the basis of delta h and theta, a bottom layer shrinkage coefficient C1 and an upper layer expansion coefficient C2 are calculated through RIP control software, C1 is dynamically adjusted to be 0.8-1.2 pixels according to delta h, and C1 = 1.2, delta hlt when delta h is larger than or equal to 8 mm; when the thickness is 8 mm, C1 is equal to 0.8 + 0.05 delta h; c2 is dynamically adjusted to be 1.0-1.5 pixels according to theta, and C2 is equal to 1.0 + 0.03 theta; s3, ink dispersion compensation control: calculating the ink dispersion compensation value of each area according to Cadj = 0.15 delta h + 0.2 tan theta, and dynamically adjusting the ink jet pressure; s4, real-time trapping adjustment is conducted, specifically, when color printing and gold and silver hot stamping are overlapped, the nozzle distance d is monitored in real time, and when d-d0gt is detected; and when the thickness is 0.5 mm, the special image printing technology can adapt to the dynamic structure of slate, the natural texture is reserved, and the limit printing precision is achieved.

This invention relates to the field of PCB manufacturing technology, and more particularly to a method for manufacturing large-size PCBs, comprising: cutting a large-size substrate into several core boards conforming to the dimensions of a PCB; drilling several positioning holes with a first pre-expansion / shrinkage amount in the core boards; determining the position range of the circuit pattern on the core boards according to the positioning holes; determining the range of the rivet hole circuit pattern that coincides with the range of the positioning hole circuit pattern according to the range of the positioning hole circuit pattern; drilling several rivet holes with a second pre-expansion / shrinkage amount in the range of the rivet hole circuit pattern, wherein the first pre-expansion / shrinkage amount is the sum of the etching expansion / shrinkage amount and the pressing expansion / shrinkage amount during the process of cutting and laminating the core board; and the second pre-expansion / shrinkage amount is the etching expansion / shrinkage amount during the process of cutting and etching the core board. This invention can solve the problems of inconsistent expansion / shrinkage coefficients of core boards with different thicknesses or different copper thicknesses due to expansion / shrinkage during the manufacturing of large-size PCBs, and the problems of rivets not fitting or laminating layers being misaligned during lamination and riveting.

This application relates to the technical field of evaluating the discharge capacity of a practical weir and discloses a method and apparatus for measuring the lateral shrinkage coefficient of a special-shaped isolated pier of a practical weir. The method includes the steps of obtaining test data for a dam's overflow weir, conducting a model test based on the test data to determine fitting coefficients, obtaining parameters for the special-shaped isolated pier of the practical weir, determining a lateral shrinkage correction coefficient for the special-shaped isolated pier based on the parameters of the special-shaped isolated pier of the practical weir and the fitting coefficients, and calculating a comprehensive lateral shrinkage coefficient for the special-shaped isolated pier of the practical weir based on the parameters of the special-shaped isolated pier of the practical weir and the lateral shrinkage correction coefficient for the special-shaped isolated pier. The comprehensive lateral shrinkage coefficient of the special-shaped isolated pier of the practical weir is used to evaluate the discharge capacity of a practical weir with a special-shaped isolated pier. This application enables accurate measurement of the calculated flow coefficient of a practical weir with a special-shaped isolated pier, laying a foundation for evaluating the discharge capacity of a practical weir with a special-shaped isolated pier.

The invention relates to the technical field of civil engineering, in particular to a concrete structure random shrinkage creep calculation method which comprises the following steps: acquiring data of a concrete structure needing to be calculated; calculating a creep coefficient and shrinkage strain curve of the concrete structure; a concrete shrinkage and creep calculation model is constructed, and an updated stress-strain relation is obtained; combining a concrete shrinkage creep test database to construct a concrete shrinkage creep randomness coefficient, and finally obtaining a shrinkage creep deformation calculation result priori interval of the concrete structure; establishing a Gaussian process regression model; and performing Bayesian inference by adopting a Monte Carlo-Markov chain method and a Gaussian process regression model to obtain a posterior interval of a concrete structure shrinkage creep calculation result needing to be calculated. The problems that an existing concrete structure is high in shrinkage creep randomness and insufficient in prediction precision are solved. According to the method, Gaussian process regression is adopted, and the problem that a large amount of calculation cost of finite element calculation is needed in Bayesian inference is solved.

This invention relates to the field of spring testing technology, specifically disclosing a spring force testing device and method for spring production, comprising: an environmental parameter acquisition array to acquire temperature, humidity, and vibration distribution; a shrinkage parameter extraction module to extract vibration shrinkage coefficient and vibration shrinkage vector based on vibration distribution; an error coupling analysis module to calculate the non-uniformity of temperature field, humidity field, and vibration field and input it into a multi-field coupling error model to obtain a comprehensive error coupling coefficient; a parameter progressive correction module to progressively correct the original force value and deformation based on the vibration shrinkage coefficient and vibration shrinkage vector to obtain the final corrected force value and deformation; a stiffness progressive calculation module to calculate the initial stiffness coefficient and hysteresis coefficient; a vector composite navigation module to synthesize a composite navigation vector based on stiffness deviation and hysteresis deviation; and a navigation execution module to decompose the composite navigation vector into axial and radial components and perform adjustments. This invention achieves environmental adaptation and multi-parameter collaborative navigation for spring force testing.

The invention discloses a compaction pile hole shrinkage space-time change rule prediction method and system, and relates to the technical field of foundation treatment and geotechnical engineering.The method comprises the steps that data such as the depth of a to-be-measured pile hole is obtained; establishing a function relationship of the peak cohesion, the peak internal friction angle, the residual cohesion and the residual internal friction angle with respect to the water content based on the test data; establishing a softening constitutive relation of the strength evolved from a peak value to a residual value according to the accumulated plastic shear strain; determining far-field lateral stress by combining the depth, the soil weight and the static soil pressure coefficient, and constructing a three-zone stress field of a residual zone, a softening zone and an elastic zone around the pile hole according to the far-field lateral stress; further constructing a system shrinkage coefficient according to the relationship between the stress state at the hole wall and the viscoplastic strain rate, and establishing an evolution equation of the hole radius about time, depth and water content; and calculating a change result of the radius of the pile hole along with time and depth in the target time period according to the evolution equation. According to the method, unified calculation of the shrinkage process under the combined action of multiple factors is realized.

The utility model discloses an asphalt mixture core sample shrinkage coefficient testing device which comprises a base plate, a core sample placing groove is concavely formed in the top surface of the base plate, and a plurality of steel balls are arranged in the core sample placing groove; a displacement sensor is arranged on the base plate and located on the side of the core sample containing groove, and the displacement sensor is used for making contact with the outer side of the core sample in the core sample containing groove. Displacement sensors in multiple directions are arranged to measure the shrinkage of a core sample in different directions in real time, so that the effect of monitoring data in the cooling process of the round core sample in real time is realized, the multidirectional shrinkage coefficient of a test piece can be measured in real time, the influence of anisotropy of an asphalt mixture is considered, and the measurement accuracy is improved. And the problems of poor dial indicator precision and large manual reading error in the existing shrinkage coefficient test are solved.

The application relates to the technical field of PCB production and processing, in particular to a method for designing a PCB milling path, which comprises the following steps: calculating a single-board area and a boundary area by using polygon Boolean operation and inclusion operation according to the drilling position and the plate frame position of a PCB; generating a PCB milling path; adjusting path coordinates according to the milling path and a shrinkage coefficient; reading a milling file, checking milling data, and manually fine-tuning the data; outputting the milling file and converting the file into a format that can be read by numerical control equipment. Compared with the prior art, the method for designing a PCB milling path solves the problems that, in the current PCB milling process, there is a manual cognitive bias when designing a milling path, which leads to low efficiency and quality and excessive human resources, and the method has the advantages of strong universality, the ability to quickly design a reasonable milling path and a tool changing path, the reasonable use of processing time, and the improvement of design efficiency, processing efficiency and quality.

This application discloses a method and system for predicting the spatiotemporal variation law of borehole shrinkage in compaction piles, relating to the fields of foundation treatment and geotechnical engineering. The method includes: acquiring data such as the depth of the pile borehole to be tested; establishing functional relationships between peak cohesion, peak internal friction angle, residual cohesion, and residual internal friction angle with respect to water content based on experimental data; establishing a softening constitutive relationship based on the evolution of strength from peak to residual based on cumulative plastic shear strain; determining the far-field lateral stress by combining depth, soil weight, and at-rest earth pressure coefficient, and constructing a three-zone stress field around the pile borehole comprising a residual zone, a softened zone, and an elastic zone; further constructing a system shrinkage coefficient based on the relationship between the stress state at the borehole wall and the viscoplastic strain rate, and establishing an evolution equation for the borehole radius with respect to time, depth, and water content; and calculating the variation of the pile borehole radius with time and depth within a target time period based on the evolution equation. This method achieves unified calculation of the shrinkage process under the combined action of multiple factors.

The invention relates to the technical field of mechanical engineering, and discloses a keyless cooperation equipment disassembly and assembly method based on cooperation of cold contraction and heat expansion of liquid nitrogen, and the method comprises the steps of S1, early-stage general preparation, S2, specific disassembly, S3, specific assembly and S4, key quality control. Multi-point measurement is carried out on the outer diameter of the shaft and the inner hole of the mating part through a micrometer and a dial indicator tool (the measurement section of the outer diameter of the shaft is larger than or equal to 3, and the measurement mode of the inner hole is coaxial with the outer diameter of the shaft), the thermal expansion and cold shrinkage target size is calculated by combining the thermal expansion coefficient and the cold shrinkage coefficient of a part material, and it is ensured that the actual interference magnitude is stabilized within the design range of 0.08 mm-0. 1 mm; disassembly and assembly clamping stagnation or part damage caused by parameter deviation is effectively avoided, and the disassembly and assembly failure rate is reduced to the minimum.