65 results about "Tolerance analysis" patented technology

The objective of the invention is a bi-level method for modeling geometric tolerances compatible with the ANSI/ASME tolerance standard. At the local level, the model represents each tolerance-zone for a plane or an axis (line) as a tolerance map, and it includes the computational techniques that relate interdependencies between these regions and subregions within them. The model includes formulations for variations in size, form, orientation, position, and runout, and combinations of these, because all of these variations can be modeled using points, lines, and planes. Since variations in simple profiles that are formed from lines and circular arcs also can be described by such combinations, they too are includable in the formulation. The primary method is to overlay the geometry of tolerance-zones onto some traditional modes for representing planes, lines, and points. At the global level, the model inter-relates all frames of reference on a part or an assembly.

The invention discloses a digital twinning-based assembly precision simulation analysis method and system. According to the digital twinning-based assembly precision simulation analysis method and system, as for key processes in complex product assembly, the twin data of a physical assembly site are collected and processed, and twin data information is expressed and stored; an assembly process model is obtained in a 3D assembly process design system, and the assembly process model is reconstructed based on the twin data, so that an assembly process twin model is generated; the assembly processtwin model is introduced into commercial assembly tolerance analysis software, so that assembly precision simulation and sensitivity calculation can be performed; and the online compensation and precise control of the assembly process are performed according to assembly process precision simulation analysis results. With the digital twinning-based assembly precision simulation analysis method andsystem of the invention adopted, the deep fusion of the physical space and information space of the assembly site can be realized. The method and system are of great significance for realizing the intelligent closed-loop control of a complex product assembly process and improving assembly quality and efficiency.

The invention provides a salt-resistance Bacillusmethylotrophicus strain LJ and an application thereof. The salt-resistance Bacillusmethylotrophicus strain LJ is classified to be named as Bacillusmethylotrophicus, and the collection number of the salt-resistance Bacillusmethylotrophicus strain LJ is CGMCCNO.7570. By performing salt tolerance analysis on the salt-resistance Bacillusmethylotrophicus strain LJ, performing a pathogenicity test on crops, and performing a test on the inhibition effect of the strain on pathogenic bacteria, results show that the salt tolerance degree of the strain is 25-30%; the strain can not cause pathogenicity to the crops, has relatively ideal inhibition effects on bacterial diseases, viral diseases and fungous diseases of tobaccos, can be compounded with a great number of elements, is long in retention period and high in effective bacterium survival rate, can be applied to saline-alkali soils, and has the effects of improving the soil, resisting the diseases, increasing the yield and the like. The salt-resistance Bacillusmethylotrophicus strain LJ disclosed by the invention ensures that a microbial preparation has the positive effects of preventing the diseases and promoting the growth of plants in special environments; the microbial inoculum has the effects of salt-resistant growth-promoting bacteria and disease-prevention growth-promoting bacteria, and is suitable for improvement of salt marsh, alkali soil and acid soil.

The invention relates to a bolt design method. The method comprises the following steps that 1, stress analysis is conducted on the bolt structure position by means of CAE, and load needed by axial acting force, shearing acting force and the sealing function is determined; 2, the bolt specification is selected according to the experienced diameter-length ratio, a proper bolt head is selected through the type of the supporting surface of a bolt; 3, the friction coefficient range of the bolt is designed, and an assembly preload target value is calculated; 4, the bolt strength grade and the tightening strategy are determined according to the preload target value; 5, the proper bolt specification and the tightening strategy are determined finally. Accordingly, calculation is conducted according to the friction coefficient of the specific bolt, that is to say, the actual production condition, bolt type selection, security coefficient setting, tolerance analysis and bolt tightening specification establishing are achieved, and the method is applicable to a torque method, a corner method and a yield point method of the bolt.

The invention provides a high-precision multispectral integrated target for LED (Light Emitting Diode) illumination and a matched optical detecting method. The high-precision multispectral integrated target comprises a multispectral integrated target plate, a current controllable LED light source and a collimation system, wherein the multispectral integrated target plate is mounted on a focal plane of the collimation system; the current controllable LED light source is used for supplying infrared and white glimmer illumination to the multispectral integrated target plate; a Cassegrain collimation system subjected to aberration optimization, tolerance analysis and thermal design is taken as the collimation system; cross division lines and four different resolution ratio detection patterns are integrated on the multispectral integrated target plate. According to the high-precision multispectral integrated target for LED illumination, the multispectral integrated target plate is combined with the current controllable LED light source, so that the problems of frequently exchanging and repeatedly adjusting the target plate and the light source in one-target exclusive use are solved, and the Cassegrain collimation system subjected to aberration optimization and thermal design is adopted, so that the imaging quality is optimized, the volume mass of the system is reduced and the system is higher in tolerance and thermal adaptability.

The invention relates to a method for determining parameters of an 8mm substrate integrated waveguide circulator, which relates to the microwave and millimeter wave technology. The method comprises the following steps of step 1, determining a substrate integrated waveguide (SIW) circulator; step 2, changing partial parameters with a single variable, and conducting the simulation; step 3, obtaining the variation situation of each target function; step 4, calculating a standard deviation sigma(x) of each size parameter within a variation range and a standard deviation sigma (f) of each correspondent target function; step 5, analyzing the sensitivity; and step 6, utilizing a worst-case tolerance analysis method to obtain acceptable deviation of the size according to the normalization sensitivity of the target function. Due to the adoption of the method, the machining cost of the circulator can be reduced.

A method for designing linearity of a mounting surface for a rolling linear guide of a precision machine tool includes the steps of first, expressing a form error of a fitting characteristic surface by means of a modal base function based method, and generating a random error sample within a given linearity tolerance; second, establishing a finite element based form error propagation model according to the generated random error sample by means of finite element software ANSYS, acquiring a fitting error of the rolling linear guide by means of finite element analysis, using the Monte-Carlo method to input all random errors generated within a given tolerance zone, into the finite element based form error propagation model and to calculate the random errors so that a post-fitting linearity tolerance is obtained, and establishing a guide fitting tolerance analysis model; and third, on the basis of the guide fitting tolerance analysis model, designing the linearity of the mounting surface for the rolling linear guide according to the concept of cyclic search. The method has the advantages that dependence on experiences is reduced, reliable theoretical guidance is provided for the design of the linearity of the guide mounting surface, product development time can be shortened, cost can be reduced, and economic benefit can be increased.

The invention discloses a tolerance modeling method based on a peripheral Bezier parameter space. An ideal workpiece is embedded into a peripheral Bezier parameter space, the workpiece is expressed through control points of the peripheral parameter space, the positions of the control points are changed, the peripheral parameter space is changed, and therefore the size, the shape and the position of the embedded workpiece are indirectly changed. By establishing a mathematical model between the offset of the peripheral space control point and the workpiece tolerance range, the offset of the peripheral control point can be solved within a given tolerance range, and finally a tolerance representation and statistical tolerance model under the worst condition is obtained. According to the method, the assembly property under the actual working condition can be judged according to the calculation result, the tolerance design result is verified and checked, and then product performance changesunder different assembly design tolerances can be predicted and judged; The modeling mode is not only suitable for dimensional tolerance modeling, but also suitable for form and location tolerance modeling; And meanwhile, the method is suitable for tolerance analysis and integration under the worst condition, and is also suitable for tolerance analysis and design under statistical significance.

The invention relates to a circuit board card temperature tolerance analysis method. The method is used for testing the maximum heat-resistance temperature of a circuit board card at room temperature. The method comprises the following steps: a temperature difference measurement process, measuring the environment temperature of the card and the core temperature of a main control chip after the circuit board card is stable in temperature at a condition that preset air volume and air pressure of cooling air flow are kept in a working condition, and calculating the difference of the core temperature of the main control chip and the environment temperature of the card; a core temperature increment process; a maximum core temperature measurement process, measuring the core temperature of the main control chip as the maximum core temperature of the main control chip when the circuit board card is nearly ineffective or reduced in performance; and a maximum heat-resistance temperature calculation process, calculating the maximum heat-resistance temperature of the circuit board card based on the measured maximum core temperature of the main control chip and the temperature difference.

The invention discloses a method used for the united optimization of an iron shielding type superconducting magnet, taking the intensity of a magnetic field, the uniformity of the magnetic field, the range of an escape field, the use quantity of a superconducting wire material and the weight of a magnet as performance measure indexes, adopting a united optimization method of combining a finite element and a simulated annealing algorithm for design and analyzing a design result by a tolerance analysis method. The design method in the invention considers a plurality of performance indexes integrally, utilizes a global optimization algorithm, avoids running into the problem of local optimization, enables the structure of the superconducting magnet to be more reasonable, has better shielding effect and lower production cost, analyzes the design result by the tolerance analysis method and can provide a theoretical guide for engineering execution.

The invention discloses an STL file-based precision machine tool computer-aided tolerance analysis method. The method comprises the following steps of: 1) extracting a vertex coordinate value in an STL file of a precision machine tool in any cascaded structure, judging coincident surfaces to obtain a relative position relationship and a connection relationship among basic major parts of the precision machine tool and a normal vector of a key feature surface, and setting an assembling sequence; 2) establishing a coordinate system on the key feature surface, and generating an error propagation chain so as to realize mathematic description of error propagation and accumulation in the assembling process; and 3) predicting geometric precision after the whole precision machine tool is assembledby combining the error propagation chain and considering part machining errors in the practical production process and measurement and adjustment links in the practical assembling process. Aiming at precision machine tool tolerance analysis problems, the method is capable of researching the error propagation and accumulation in the machine tool assembling process, and comprehensively considering the measurement and adjustment links in the practical assembling process for the whole precision after the assembling, so that the engineers can be effectively helped to carry out precision prediction.

The invention discloses a tolerance optimization method for all-welded assemblies, relates to welding deformation accumulated error prediction and tolerance optimization of multiple assemblies, and solves the problem of tolerance design optimization requirements of all-welded assemblies. The method comprises the steps that original design information of all-welded assemblies is collected, and various kinds of tolerance information are summarized; a three-dimensional tolerance analysis model is established, simulation analysis is conducted through virtual assembly, and the deviation of the total deflection amount of the all-welded assembly is predicted; and a weighted calculation value is established based on the contribution degree factor and the sensitivity factor of each deviation and the control difficulty factor of welding deformation, and iteration is continuously performed according to a simulation analysis result until a tolerance optimization scheme meeting an optimization target is obtained and output. According to the method, the welding deformation accumulative error can be effectively predicted, tolerance optimization is achieved, and the efficiency of tolerance secondary design is improved.

The invention discloses an angle vector analysis method for a 2D dimension chain. Included angles consisting of the ring surface characteristics and non-ring surface characteristics in 3D data are directly measured to obtain angles, and then the angles are substituted into T0/T1=cosa, so that the angle vector is obtained. The invention not only can effectively consider the influence of the included angles consisting of the ring tolerance zone and closed ring tolerance zone on the whole tolerance analysis result, but also can realize the measurement of the included angles conveniently, so that the accuracy and reasonability of dimension tolerance analysis are accordingly improved, and the tolerance distribution is finally ensured to meet the requirement of finished automobile assembly.

The invention belongs to the technical field of genetic engineering and biology, and discloses a screening method for an artemisia japonica plasma membrane Na+/H+ reverse transport protein AjSOS1 salt tolerance key amino acid site. Transformation of SOS1s gene recombinant vectors, transformed cells and yeast mutants and salt tolerance analysis of the transformed cells are provided. The screening method for the AjSOS1 salt tolerance key amino acid site comprises the steps of 1, cloning of an SOS1s gene; 2, construction of yeast expression vector pAG426GPD-SOS1s; 3, salt tolerance analysis of four SOS1s yeast transformed cells; 4, screening of the AjSOS1 salt tolerance key amino acid site. A series of AjSOS1muts are generated through site-specific mutagenesis, and anaplerosis is performed on yeast mutants ANT3, the salt tolerance key amino acid site in an AjSOS1 sequence is found, a novel and practical method is provided for research of chrysanthemum and affinis species plant salt tolerance molecular mechanism, and the breeding process of the chrysanthemum biological technology is effectively promoted.

The invention relates to the technical field of virtual design, in particular disclosing an analysis method and a device of geometric tolerance influencing the control precision of the track of a machine tool. The method comprises the following steps: setting geometric tolerance to be analyzed for key parts in a dynamic model of the machine tool; using the driving moment of the machine tool as an input signal to generate the dynamic model of the machine tool after being added with the geometric tolerance, and then, generating a corresponding mathematical model through the dynamic model; and calling a corresponding solver to solve the mathematical model to acquire the deviation of the motion track of the machine tool caused by the geometric tolerance. The embodiment of the invention can analyze the influence of the geometric tolerance of each part on the dynamic performance of the machine tool.