50 results about "Computational mechanics" patented technology

This invention relates to an artificial memory system and a method of continuous learning for predicting and anticipating human operator's action as response to ego-intention as well as environmental influences during machine operation. More specifically the invention relates to an architecture with artificial memory for interacting with dynamic behaviors of a tool and an operator, wherein the architecture is a first neural network having structures and mechanisms for abstraction, generalization and learning, the network implementation comprising an artificial hierarchical memory system.

The invention discloses a computational fluid mechanics-based cerebrovascular reserve capacity simulation system and method. The system comprises an image data collection module used for obtaining a computed tomography image of a brain blood vessel of a human body, a blood vessel three-dimensional reconstruction module for performing three-dimensional reconstruction on the computed tomography image, a boundary condition extraction module for performing post-processing on the computed tomography image of the brain blood vessel to obtain boundary information required for simulation, a CFD preprocessing module for performing preprocessing required for numerical simulation on a three-dimensional geometric model of the brain blood vessel, a CFD computing module for performing solving on hemodynamics information of all parts of the three-dimensional geometric model of the brain blood vessel, and a CFD post-processing module for comparing a simulation result with a result measured by the boundary condition extraction module. Hemodynamic feature parameters are adopted as standards for evaluating cerebrovascular reserve capacity, so that the one-sidedness of judgment through a geometric structure of the brain blood vessel is avoided, and noninvasive, quantitative and personalized cerebrovascular reserve capacity evaluation can be realized.

A method of analyzing biological data containing expression values of a plurality of polypeptides in the blood of a subject. The method comprises: calculating a distance between a segment of a curved line and an axis defined by a direction, the distance being calculated at a point over the curved line defined by a coordinate along the direction. The method further comprises correlating the distance to the presence of, absence of, or likelihood that the subject has, a bacterial infection. The coordinate is defined by a combination of the expression values, wherein at least 90% of the segment is between a lower bound line and an upper bound line.

The invention discloses a method for inversion calibration of microscopic constitutive parameters of a metal material on the basis of nanoindentation and finite element simulation. The method comprises the following steps: S1, carrying out a nanoindentation test on the surface of the metal material through displacement control so as to obtain an experimental indentation response; S2, establishinga nanoindentation and finiteelement model under an ABAQUS or standard module, and carrying out finiteelement simulation to the process of the nanoindentation test on the metal material mentioned in the step S1 so as to obtain a simulated indentation response; and S3, constructing a multi-objective optimization platform, setting optimization objectives and constraint conditions, acquiring a non-inferior optimal solution set Pareto Front through a multi-objective optimization method based on FMOGA-II algorithm, and determining a unique optimal solution. The method provided by the invention has low cost, is rapid and accurate to calculate, is simple and practicable, is extensively applicable to inversion calibration of microscopic constitutive parameters of multi-metal materials, and has highpractical value in computational mechanics, experimental mechanics and engineering practical application.

The invention relates to a periodic unsteady flow field prediction method suitable for CFD (computational fluid mechanics) numerical simulation. According to the method, Fourier transform is adopted to transform a time-dependent periodic unsteady problem in a time domain into N coupled steady equations, and the whole period can be reconstructed through coupling and computing N steady moments, so that the computing efficiency can be greatly improved under the condition of not reducing the computing accuracy. The method can be used for efficiently and accurately obtaining the periodic unsteady flow field distribution of aircrafts, obtaining the periodic unsteady aerodynamic force of the aircrafts according to the obtained flow field distribution and guiding the dynamic stability design of the aircrafts according to the obtained periodic unsteady aerodynamic force.

The invention relates to the technical field of structure modal analysis, and discloses an active control method for inducting a thin-walled pipe fitting to absorb energy in order to improve the energy-absorbing capability of an energy-absorbing structure and ensure a stable deformation mode. The active control method comprises acquiring a structure parameter of a thin-walled square pipe to be analyzed; predicting the number of telescoping buckling wrinkles of the thin-walled square pipe under the action of an impact load according to the structure parameter, and calculating the mean force of the thin-walled square pipe when the thin-walled square pipe generates telescoping deformation, the half wave length of an effective plastic hinge and original energy absorption; establishing a finite element model of the thin-walled square pipe, carrying out finite element modal analysis on the thin-walled square pipe, and determining the number of additionally-installed separator plates according to a convergence formula of the number of the additionally-installed separator plates and expected energy absorption; then respectively arranging the additionally-installed separator plates on corresponding vibration mode nodes of a vibration mode graph of a selected higher-order sine buckling mode; establishing a square pipe impact dynamics simulation calculation mechanical model for the improved structure with the additionally-installed separator plates, carrying out simulation analysis, and comparing the previous energy-absorbing characteristic with the optimized energy-absorbing characteristic.

A method for predicting characteristics of a compound includes collecting a first experimental information database for characteristics of reference compounds according to a quantum phenomenon, collecting a simulation database for characteristics of the reference compounds according to the quantum phenomenon by applying density functional theory methods, comparing the simulation database to the first experimental information database for each reference compound to calculate accuracy of the simulation database, clustering the reference compounds into clusters based on the accuracy of the simulation database and designating a proper density functional theory method for each cluster, comparing a similarity between a test compound to predict a characteristic according to the quantum phenomenon and the reference compounds included in each cluster, determining a proper density functional theory method for the test compound according to the similarity, and conducting a simulation with the test compound according to the determined density functional theory method.

The invention provides an impact response simulation analog method based on a novel hybrid stress tetrahedron unit, and belongs to the field of computational mechanics. When the method solves an impact dynamics problem, the good fitting of a tetrahedron grid for a complex structure is kept, meanwhile, the accuracy of a stress field is improved, and the method is an explicit dynamics numerical value calculation method with good stability. Meanwhile, on the basis of a traditional tetrahedron unit, knot stress is subjected to smoothing, the complex model can be subjected to favorable fitting, inaddition, unit stress accuracy is greatly improved, and meanwhile, a calculated amount is small.

Systems and methods for computational analysis of chemical data to predict binding targets of a chemical are provided. A plurality of chemical pairs is established, each including a first chemical for which binding targets are to be predicted and a respective one of the second chemicals. For each chemical pair, values of at least two datatypes of the first chemical can be compared to values of the at least two datatypes of the respective one of the plurality of second chemicals in the chemical pair to generate a similarity score. The similarity scores can be converted to a likelihood value. For each chemical pair, a total likelihood value can be determined based on respective likelihood values for each of the at least two datatypes of the chemical pair. A candidate binding target is predicted to bind to the first chemical, based on the total likelihood value of each chemical pair.

The invention belongs to the field of computational mechanics, and provides a phase field material point method for large deformation fracture analysis of a rock-soil structure, which considers the complex fracture phenomenon of brittleness-to-plasticity transformation of a high-porosity rock-soil material under the action of complex external factors, and widens the application range of the material point method in the field of solid material fracture. According to the method, a phase field fracture model is adopted as a damage function, so that a complex crack propagation path can be accurately and efficiently captured, and a smooth double-yield-surface Drucker-Prager cap plastic constitutive model is adopted to accurately and comprehensively describe complex mechanical behaviors of the pressure-sensitive geotechnical material; and the coupling effect of the phase field fracture model and the plastic constitutive model is realized by introducing the phase field effective stress. In addition, a CPDI interpolation method is adopted to improve the numerical stability and the boundary application accuracy, and an interlaced iteration solution strategy is implemented to improve the calculation efficiency and reduce the numerical implementation complexity.

The invention belongs to the field of computational mechanics, and provides a time-discontinuous state-based near-field dynamics method for structural impact elastic-plastic fracture analysis, which introduces a time-discontinuous idea into a state-based near-field dynamics theory, and effectively improves the precision of near-field dynamics explicit dynamic analysis and the capability of accurately predicting structural fracture damage. According to the method, false numerical oscillation caused by a traditional time-history integral method can be effectively controlled by adopting a time-discontinuous explicit time-history integral format, and complex mechanical behaviors of the material under the impact load are simply, conveniently and comprehensively described by adopting an unconventional state-based near-field dynamic model; and the impact fracture failure mode of the structure is effectively represented through a plurality of damage fracture criteria. In addition, a material point neighborhood is constructed and a contact neighborhood is updated by adopting a fast neighborhood search algorithm, so that the calculation efficiency is improved. As a new numerical solution format, the method provided by the invention can be realized by simply modifying an original calculation program, and the numerical implementation complexity is reduced.

The invention discloses an elastic hypersonic aircraft modeling method based on computational mechanics. The method comprises the following steps: step 1, establishing a geometric model of a hypersonic aircraft and performing grid division; 2, based on computational fluid mechanics and computational structural mechanics, performing simulation calculation on elastic characteristics and aerodynamic parameters of the hypersonic aircraft under different working conditions to obtain fitting data; 3, establishing a rigid body dynamic model of the hypersonic aircraft according to the fitting data, and obtaining deformation angles of different positions according to a vibration equation; and 4, according to the rigid body dynamic model and the vibration equation, in combination with simulation calculation results in the above steps, obtaining a six-degree-of-freedom elastic dynamic model of the elastic hypersonic aircraft through curve fitting. On the basis that elastic characteristics under different working conditions are obtained, the aircraft rigid body dynamic model is expanded, the influence of the elastic characteristic is added, and a basis is provided for the integrated design of the shape of the aircraft and the design of a controller.

The invention provides a blocking net working state monitoring and early warning method in combination of computational mechanics and field monitoring, which belongs to the technical field of blockingnet working state monitoring. Through port engineering design standards, various loads in the blocking net working environment are classified, various load applied to the blocking net are converted to a main rope of the blocking net. Through the computational mechanics method, the main rope of the blocking net after load conversion is subjected to iterative solution, geometric constraint conditions of the main rope of the blocking net are introduced, the tensioning shape of the main rope of the blocking net under effects of various single environment loads or a combined environment load of the blocking net can be solved and the pulling force at a concerned place is solved. Historical monitoring data of each section of the blocking net are selected for comparison and analysis, the workingstrength limit of the blocking net system under effects of various loads is determined, the blocking net system working reliability safety grade is divided, the alarming value and the risk matrix of each section of the blocking net are determined, early warning on the blocking net working state is realized, and a basis is provided for reasonable maintenance on the blocking net.

The invention discloses a method for the simulation analysis of oil field blocks in the petroleum field. The method comprises the steps: (a) at first, simulating the basic overview of blocks; (b) then, selecting physical models; (c) computing mechanical parameters; and (d) finally, calculating a result and analyzing. The method can quickly complete the simulation analysis of the oil field blocks in the petroleum field, has an accurate analytical result, is simple in analytical step and the analytical correction cost is greatly reduced.

The invention discloses a rapid self-correction indentation testing method of a material testing machine. A total confidence interval is established by analyzing mechanical property parameters and selecting a load-depth curve; the total confidence interval is used as reference basis of a tested material; when the load-depth curve of the tested material is within the total confidence interval, the testing does not need to be repeated, and the mechanical property parameters can be calculated according to the load-depth curve. The testing repetition rate is reduced, and the pressure head utilization rate is reduced, so that the effect of prolonging the service life of a pressure head is well achieved, and non-noticeable positive effects in aspects such as equipment inspection and fault judgment are achieved.

The invention provides a method for determining random distribution carbon nano tube network rigidity thresholds. The method comprises the steps of (1) establishing a random distribution carbon nano tube network periodic geometric model, and establishing parameters describing geometric topological relation of carbon nano tubes in the network model, that is, the stability; (2) changing the number of the carbon nano tubes under given carbon nano tube geometric parameters to change the network density and calculating the network stability under different densities; (3) determining the network rigidity threshold according to the variation trend of the stability along with the network density. By the aid of the method, the network rigidity threshold is determined through the geometric topological relation among the carbon nano tubes, and the method has the advantages of being capable of guiding experimental studies and production applications of the carbon nano tube network, good for rapid prediction of rigidity thresholds of the carbon nano tube network, capable of reducing the calculation scale and cost through a computational mechanic method, adaptable to development of advanced nano materials and provided with important engineering application values.

The invention relates to a universal gridless numerical result post-processing method, and belongs to the technical field of computational mechanics. The method includes the following steps that particle physical information obtained in a gridless method is stored; a computing domain of a researched problem is divided into grids, and grid joint information is stored; by means of a particle searching method, gridless particles in an influence domain of each grid node are determined; kernel functions and derivatives in the influence domains of the grid nodes are calculated; an inverse matrix of a coefficient matrix is calculated; the physical quantity on the grid nodes is calculated; the physical quantity on the grid nodes is led into drawing software, and a result is displayed. According to the method, the physical information obtained through numerical simulation is added to the new grid nodes in a differential mode, and visuality of calculation results of the gridless method is improved.

The invention discloses an elastic constitutive model suitable for rubber materials, and application thereof, and belongs to the technical field of solid mechanics, computational mechanics and experimental mechanics. The constitutive model which is put forward can adopt a single type of experiment data to obtain an accurate model of rubber incompressible hyperelastic materials. Compared with an existing model, the elastic constitutive model is high in accuracy and reliability and can obtain the accurate and comprehensive rubber material characteristic model only by a simple uniaxial elongationexperiment test, an equal biaxial drawing and plane drawing test which is difficult to be carried out in China at present does not need to be adopted, and the model has an extremely high engineeringapplication value and a computational mechanics use scene.

Implementations described herein generally relate to detecting excursions in intended geometric features in an integrated circuit substrate. In one implementation, a method includes determining a set of suspect contours in a design window of the integrated circuit substrate based on proximities of a plurality of points of interest in the design window to intended geometric features. The method further includes obtaining a set of imaged contours from one or more images of a defect-free integrated circuit substrate. The method further includes comparing the set of imaged contours to the set of suspect contours to obtain a set of potential excursions from the imaged contours. The method further includes determining a probability that a potential excursion from the set of potential excursions is a valid excursion. The method further includes taking a corrective action based on the determined probability.

The invention relates to a high-speed train body random response detection method of confidence interval, comprising the following steps: a step of expressing nondeterminacy of random vibration and structure parameters of a train and generating a random sample; a step of analyzing the random response sample based on a pseudo excitation method; and a step of carrying out statistic analysis on the random response sample and providing a confidence interval. According to the invention, nondeterminacy of train's structure parameters and randomness of track excitation are both taken into consideration, and statistic analysis of composite random vibration response is carried out. With the combination of an efficient method of computational mechanics and with the application of the pseudo excitation method to take a track spectrum containing statistical information as a motivator, the input problem of random excitation is solved. By the symplectic-mathematics theory, a track model is simplified and a hybrid coordinates equation is established, thus making it possible to calculate a large-capacity sample. Statistics provides a certain confidence level of random response estimation, thus providing a basis for a dynamic design for raising operation safety and comfort of a train.

The invention provides a system for simulating cerebral vessels by applying computational fluid mechanics, and brings forward a method for early warning of cerebrovascular diseases on the basis of thesystem. The method comprises the following steps: (1) reconstructing a geometric model of a cerebrovascular system based on medical tomography image data; (2) importing the geometric model of the cerebrovascular system, pressure, heart rate and other information into a computational fluid mechanics module for scientific calculation; (3) modifying the geometric model of the cerebrovascular system,and simulating operations such as carotid artery bypass grafting; (4) re-importing the modified geometric model into the computational fluid mechanics module for scientific calculation; and (5) processing and comparing results of the two scientific calculations, and predicting the surgical effect and the risk of possible cerebrovascular diseases. By the computational fluid mechanics model for analog computation of the cerebrovascular system before and after an operation, the occurrence risk of cerebrovascular diseases can be predicted in advance.

The invention relates to an improved FPM method, and belongs to the technical field of computational mechanics. The method comprises the following steps: firstly arranging particles in a computational domain of a question being researched, secondly initializing physical attributes of the particles according to the initial conditions and boundary conditions of the question being researched, next carrying out approximation on a governing equation of the question being researched by utilizing a discrete format of an improved KGF-SPH (kernel gradient free-smoothed particle hydrodynamics) method, and finally carrying out iteration on the governing equation of the question being researched, thus obtaining a numerical simulation result. The method provided by the invention keeps the characteristic of nuclear-free gradient of the KGF-SPH method, and is relatively high in numerical precision and stability, and the processing of the boundary conditions is facilitated.

The invention relates to computational mechanics and constitutive modeling of granular material, and particularly to a microfabric quantitative test and analysis method for orthogonal anisotropy of granular material. The method is characterized by comprising the following steps: (1) curing the initial internal structure of granular material; (2) slicing a cured granular material sample, and milling and polishing the surface of a slice; and (3) observing and analyzing the microstructure on the surface of the slice by a scanning electron microscope, and performing quantitative test and analysis on the microfabric of orthogonal anisotropy of the granular material. Trial of the method shows that, by the method, the initial internal structure of the granular material can be fixed well, after the initial internal structure is maintained and cured elaborately and the surface of the slice is milled and polished, the internal structure of the granular material can be observed clearly in the scanning electron microscope, and on the basis, accurate execution of following analysis work is facilitated, and mechanical behaviors under complex conditions, such as granular material anisotropy and stress anisotropy, can be simulated accurately.

An improved part optimization process in additive manufacturing is provided, which uses a finite element analysis only where boundary parameter differentiation is detected. For a given part being manufactured, such as in DMLS, thermal effects of adjacent volumes with no boundary parameter differentiation are ignored in the part optimization process. For example, if a given volume is over a volume of the same material, no computational analysis is conducted, but if a volume of metal is over air, then the computational analysis is conducted. This results in significantly less computational time being required. Further, the present invention uses computation equipment remote from the DMLS part production equipments, connected instead via the internet or other such “cloud computing” arrangements.

The invention discloses a big data flowmeter development method based on computational fluid mechanics and solves the problems that traditional flowmeter development methods are long in development cycle and high in cost consumption, the reliability and stability of flowmeters designed by the traditional flowmeter development methods are poor, the measurement accuracy is influenced, and the use effect is poor. The method relies on computational fluid mechanics, and by conducting numerical simulation analysis of computational fluid mechanical characteristics on flowmeters different in type, a performance law of the flowmeters is obtained; an optimal flowmeter is selected for shaping design and processing, and then with assistance of real flow calibration for correcting, an industrial flowmeter with stable performance is obtained. The method can not only greatly shorten the development cycle of the flowmeters but also save expenses for a real flow calibration process; the design range ofthe flowmeters can be enlarged, the reliability and stability of the flowmeters are ensured to a greater extent, and the development cost of the flowmeters is remarkably reduced.

The invention belongs to the technical field of geotechnical engineering computational mechanics, and relates to a vector limit equilibrium safety coefficient calculation method based on a projection direction extreme value. Comprising a sliding surface stress vector calculation sketch of a projection direction extreme value principle theoretical model, an unbalanced vector limit equilibrium control equation establishment implementation process and limit equilibrium safety coefficient K contribution of sliding surface stress vector imbalance in the projection extreme value direction. The stress state plasticity change safety reserve 1 / lambda contributes from non-collinear imbalance to collinear limit equilibrium condition closeness degree coefficient lambda formed in the vector force acting direction in the vertical direction, and the anti-sliding stability safety degree coefficient of the theoretical model is equal to the product of two potential energy ratio extreme value orthogonal direction contribution factors, namely the safety degree coefficient of the theoretical model; according to the method, restrictions of human experience simplified assumed conditions and human uncertain factors in anti-sliding stability calculation of rock and soil slopes or dam foundations are overcome, and calculation and evaluation of the anti-sliding stability safety degree of the complex slip crack surface become an objective, quantitative and reliable theoretical unified model solution.

A method and electronic device for image compression are disclosed. The method includes: step A, for the initial grid, storing the color value (shown in the description) of the pixel with coordinates(l, h) in the image to the ni-th grid node with coordinates (xi, yi) in the grid; B, generating an optimized adaptive anisotropic mesh through an adaptive anisotropic mesh technology; Step C, restoring the original image by spline linear interpolation, checking whether the image pixel information stored in the optimized adaptive anisotropic mesh meets the requirements, if not, using the optimizedadaptive anisotropic mesh as a new initial mesh, and returning to step A for next iteration. The invention utilizes the characteristics of the finite element mesh in the computational mechanics and based on the adaptive anisotropic mesh optimization technology, is applied in the image compression technology, and greatly saves the storage space of the image. This technique is not only limited to two-dimensional image compression, but also extends to three-dimensional image compression applications.

The invention discloses an optimization method and system of a double-flat arm embracing rod waist ring stay cable based on a firefly algorithm, wherein, the method comprises the following steps: setting the cross-sectional area of the waist ring stay cable as a size variable, the height of each layer of stay cable as a shape variable and the form of each layer of stay cable as a topological variable, and determining the preset value range of each variable; The preset maximum allowable stress of the double-arm embracing bar and cable, the preset maximum allowable displacement of the embrackingrod and the preset minimum allowable buckling factor are used to restrict. The synchronous optimization model is established, and the mass of the lumbar loop cable is taken as the objective function.The improved firefly algorithm is used to optimize the size, shape and topology synchronously. The mechanical properties are analyzed and calculated. The penalty function is used to deal with the constraint conditions and iteratively update the global optimal solution. The optimization method has the advantages of clear logic, concise flow, easy operation, few parameters to be adjusted, high computational efficiency and remarkable optimization effect.