26 results about "Matrix cracking" patented technology

The invention relates to the field of carbon fiber composite material mechanics, in particular to a fine evaluation method for the strength of a small-size large or full-opening CFRP (carbon fiber reinforced plastic) shell, which comprises the following steps: establishing a microscopic damage model containing material anisotropy, defining damage variables and evolution equations, uniformly quantifying multi-scale damage behaviors such as fiber fracture, matrix cracking and layered expansion, and evaluating the strength of the small-size large or full-opening CFRP shell. The problem that a traditional single-scale model cannot represent the multiphase coupling effect is solved; through cross-scale transmission of damage variables, whole-process prediction from microscopic damage initiation to macroscopic failure is realized, and the precision of strength evaluation of the complex opening structure is significantly improved. The method realizes refinement, reliability and engineering practicability of strength evaluation of the small-size large-opening or full-opening CFRP shell, is particularly suitable for the fields of aerospace and the like with extremely high requirements on structural weight and safety, and has remarkable technical leading and application value.

The invention relates to the field of a characterization method of a damage mechanism of a carbon fiber composite material, in particular to a characterization method of a microscomic damage mechanism of a small-size large or full-opening CFRP (Carbon Fiber Reinforced Plastics) shell, which comprises the following steps of: systematically researching initiation positions, expansion paths and interaction mechanisms of fiber fracture, matrix cracking and interface debonding in an opening area; determining the influence of multi-axial stress, dynamic load and temperature gradient on damage distribution and expansion rate; secondly, establishing cross-scale quantitative correlation; through multi-modal experimental data, a quantitative relation between microscopic damage parameters and macroscopic mechanical properties is constructed, and accurate mapping from material microscopic behaviors to structure macroscopic responses is achieved; and finally, constructing a damage high-precision characterization method. A damage model taking layer design, machining precision and environmental load into consideration is developed, the problems that a multi-damage coupling mechanism is not clear and cross-scale modeling depends on experience are solved, and theoretical support is provided for shell anti-damage design.

The present invention relates to an ABS composite material and a preparation method thereof, belonging to the technical field of polymer materials. The present invention is obtained by modifying ABS and simultaneously blending it with sisal fiber, carbon fiber, long glass fiber, and copolymerized polypropylene; in the present invention, sisal fiber, carbon fiber, long glass fiber, and copolymerized polypropylene are blended with modified ABS powder, increasing the stiffness and strength of the ABS composite material; through fiber fracture, fiber pull-out, and the expansion of matrix cracks, the impact toughness of the ABS material is enhanced, achieving the effect of dissipating impact energy, and also improving the durability and lifespan of ABS products; ABS is modified to form modified ABS powder, improving the bonding force between modifier particles and fibers, enabling the ABS composite material to have good toughness, with significant improvement in mechanical properties. At the same time, the toughness, stiffness, and hardness of the products made of ABS are also improved.

The invention belongs to the technical field of wind power blade damage early warning, and discloses a wind power blade structure fault damage early warning system which comprises a data sensing module, a damage simulation module, a damage modeling module, a crack tracking module and a risk decision module. The data sensing module is used for constructing a multi-dimensional sensing network covering the overall situation and the local situation of the blade and is responsible for capturing all-dimensional information data of the blade from overall situation response to local slight change; the data sensing module comprises an actual load acquisition unit, a local damage sensing unit and an environment acquisition unit; and the damage simulation module can construct a virtual mirror image completely corresponding to the wind power blade based on the omnibearing information data. The method is not limited to single blade vibration signal spectrum analysis through the global and local multi-dimensional sensing network of the blade, the subsequent early warning accuracy is replaced, and meanwhile, the progressive damage process of the wind power blade in matrix cracking, fiber fracture and interlayer stripping can be accurately simulated.

The invention discloses a method for evaluating the residual strength of a multi-scale fiber-reinforced flexible pipe under a stretch-bending load, and relates to the technical field of structural strength evaluation of ocean engineering composite materials, and the method comprises the following steps: extracting fiber distribution characteristics by adopting digital image processing based on a scanning electron microscope image; a Monte Carlo method is combined to construct a two-dimensional RVE geometric model of the fiber reinforced structure containing the damp-heat degradation, and macroscopic elastic parameters are predicted; a VUMAT user material subprogram containing dynamic damage is written based on Fortran, damage starting and evolution failure criteria of a fiber reinforced structure are embedded, and the nonlinear coupling evolution process of multiple damage modes such as fiber fracture, matrix cracking and interface debonding is simulated. According to the method, a material-damage-response multi-scale analysis framework is constructed by coupling microscopic material components, a microscopic damage model and macroscopic pipeline structure analysis, the problem that a traditional method lacks multi-scale damage coupling analysis under a complex load is solved, and the residual strength evaluation precision of the pipeline under the action of a stretching-bending combined load is improved.

This invention relates to a silicon carbide ceramic matrix composite material reinforced with unidirectional silicon carbide fibers and its preparation method, comprising: 1) winding silicon carbide fibers in the same direction to obtain a unidirectional tape; 2) depositing an interface phase on the surface of a single fiber using chemical vapor deposition; 3) preparing a prepreg slurry by mixing carbon powder, dispersant, etc.; 4) impregnating the unidirectional tape with the slurry to obtain a prepreg tape; 5) layering the prepreg tape and the unimpregnated unidirectional tape at a layer ratio of 1:1 to 16:1 and a silicon carbide fiber angle of 0° to 90°; 6) obtaining the composite material through curing, pyrolysis, and melt infiltration densification. This invention breaks away from the traditional single-layer layup mode, constructing a continuous gas flow path through mixed layering, guiding process gas generation, solving the drawbacks of high porosity and matrix cracking, optimizing the material's stress state, and obtaining a composite material with both low density and high compactness, excellent mechanical properties at room temperature and high temperature, and excellent oxidation stability, shortening the preparation cycle, and meeting extreme service requirements.

The invention discloses a method for predicting the crack width of a ceramic matrix composite matrix. The method comprises the following steps: fitting a relational expression between the crack width and stress through a quadratic polynomial; calculating crack widths under different temperature environments according to a thermal expansion theory, and constructing a relational expression between the crack widths and the environment temperature; analyzing the change of the interfacial shear stress of the ceramic-based composite material through microscopic and tensile curves, and constructing a relational expression between the interfacial shear stress of the ceramic-based composite material and the ambient temperature, the initial shear stress, the oxidation rate and the oxidation action time; constructing a relation model of the matrix width, the stress, the temperature and the oxidation time of the ceramic matrix composite material; and solving the crack width of the ceramic-based composite material by utilizing a Newton iteration method based on a relation model of the matrix width of the ceramic-based composite material and the stress, the temperature and the oxidation time according to the initial value condition. The method can accurately predict the crack width of the ceramic matrix composite matrix under different stress, temperature and oxidation effects.

The invention discloses a method for calculating the crack density of a ceramic matrix composite matrix. The method comprises the following steps: calculating the saturated crack density of the ceramic matrix composite matrix in different temperature environments; based on the saturated crack density of the ceramic matrix composite matrix in different temperature environments, fitting to obtain a relational expression of the saturated crack density and the temperature; analyzing the interface debonding conditions of the ceramic matrix composite material under different stress conditions, and fitting the interface debonding conditions to a relational expression of an interface debonding coefficient and stress; and correcting the Weibull distribution model based on the relational expression of the saturated crack density and the temperature and the relational expression of the interface debonding coefficient and the stress according to the change condition of the interface debonding, constructing a relation model of the change of the crack density of the ceramic-based composite material along with the stress and the temperature, and calculating the crack density of the ceramic-based composite material matrix. The method can accurately calculate the matrix crack density of the ceramic matrix composite material in different high-temperature load environments.

The invention discloses a ceramic matrix composite ultrasonic cutting machining device which comprises an ultrasonic cutting assembly, a workpiece clamping assembly is arranged under the ultrasonic cutting assembly, a workpiece is clamped on the workpiece clamping assembly and located under the ultrasonic cutting assembly, and a real-time force measuring device is arranged under the workpiece clamping assembly. A cutting chip and cooling liquid collecting assembly is arranged below the real-time force measuring device, a machine tool guide rail is fixedly connected below the cutting chip and cooling liquid collecting assembly, and the lubricating and cooling assembly sprays lubricating liquid to the cutting contact position of a workpiece and the ultrasonic cutting assembly. The problems that in the prior art, matrix cracks, fiber breakage and interface debonding are prone to being generated in traditional cutting machining of the ceramic matrix composite are solved. The invention further discloses an ultrasonic cutting machining method for the ceramic-based composite material.

The invention discloses a calculation method for an oxidation constitutive model of a fiber bundle ceramic-based composite material, which comprises the following steps: constructing an oxidation kinetic model of the ceramic-based composite material, and calculating oxygen concentration distribution in a crack depth direction; determining a carbon-oxygen reaction rate, and deducing a change relationship among the tensile strength of the C fiber bundle, the oxidation temperature and the oxygen concentration; according to the tensile strength of the C fiber bundle at different temperatures, performing equivalent offset on the strength distribution of the normal-temperature C fiber in-situ monofilament; calculating fiber stress distribution of an interface slip area, a forward slip area and a reverse slip area between the fiber and the matrix based on the shear hysteresis model; calculating matrix crack propagation and crack spacing distribution to obtain mechanical response of the matrix; and calculating a stress-strain response curve of the fiber bundle ceramic matrix composite material in a high-temperature oxidation environment according to a mechanical damage model of the fiber and the matrix. According to the method, the damage evolution of the fiber, the interface and the matrix in the oxidation process can be accurately described, and the calculation amount is greatly reduced.

This invention discloses a method for solving the solid-thermal coupling problem of CMC materials using a probabilistic model, belonging to the field of engineering thermophysics. This method addresses the mechanical damage that occurs in high-temperature CMC components after long-term service. It establishes a representative unit cell RVE model of the CMC material at the microscale, considering the stochastic characteristics of mechanical damage, and incorporates the characteristic patterns of mechanical damage occurring in the CMC material after long-term service into a complete RVE model. Based on this model, by applying axial and radial thermal boundary conditions respectively, the axial and radial thermal conductivity of the CMC material at the microscale are obtained. The corresponding elastic modulus is calculated using the CMC material matrix crack density formula and stress-strain relationship, establishing a mapping relationship between the thermophysical parameters and mechanical performance parameters of the CMC material when mechanical damage occurs, thus realizing the solid-thermal coupling analysis and solution of the CMC material after stochastic mechanical damage. Therefore, this method can improve the accuracy of temperature field prediction for high-temperature CMC components under long-term service conditions.

The invention discloses a tensile composite cable for a robot and a preparation method thereof, and belongs to the technical field of robot cables. The cable sequentially comprises a conductive core layer, an insulating layer, a tensile reinforcing layer, an electromagnetic shielding layer and an outer sheath layer from inside to outside, wherein the outer sheath layer is prepared from the following raw materials in parts by weight: 75-87 parts of ethylene propylene diene monomer, 11-17 parts of hydrophobic aluminum oxide, 3-9 parts of a functional aid, 2-5 parts of a processing aid and 0.05-0.15 part of an initiator. Wherein the hydrophobic aluminum oxide can reduce the cracking risk of the matrix and enhance the tensile property of the cable; wherein the molecular structure of the functional additive contains flame-retardant groups such as nitrogen and phosphorus and a rigid benzene ring structure, so that the flame retardance of the cable can be improved, and the tensile property and the heat resistance of the cable can also be improved; in conclusion, the cable prepared by the invention has excellent tensile property, flame retardance and heat resistance, can adapt to work in a high-temperature environment, and has important application value in the technical field of robot cables.

The application discloses a continuous fiber 3D printing high-bearing self-monitoring deformation ceramic matrix composite truss and a preparation method and application thereof, and relates to the technical field of additive manufacturing. The truss comprises top chords, bottom chords and built-in units arranged between the top chords and the bottom chords; the built-in units comprise one or more shapes of units selected from a triangle, a trapezoid, a circle and a rhombus; the structure of the truss comprises single-layer or multi-layer trusses; and the constituent material of the truss comprises continuous conductive fibers, pyrolytic carbon interfaces and precursor ceramic matrices. The application deposits a conductive layer on the fiber surface and the matrix crack of the composite material, so that an electrically poor ceramic matrix composite forms an electrically conductive network in the interior, the electrical conductivity of the ceramic matrix composite is improved, the ceramic matrix composite is endowed with piezoresistive performance, and bearing monitoring integration is realized.

The application discloses a kind of oxidized coal pitch nanocarbon material modified water-related polymer friction pair materials and preparation method, belong to polymer material technical field.The water-related polymer friction pair material of the present application is made of soluble oxidized pitch nanomaterial of formic acid / hydrogen peroxide oxidation system oxidation coal pitch and ultra-high molecular weight polyethylene matrix.The present application utilizes the gap of polymer molecular chain of soluble oxidized pitch nanomaterial of ultra-small structure, and plastic rheology and adhesive wear of material are reduced in friction process by steric hindrance and interface anchoring effect;Combination of the "nanometer reinforcing network" formed by uniform dispersion can effectively transfer friction stress, avoid the matrix cracking caused by local stress concentration;While the nanometer size of soluble oxidized pitch nanomaterial and carbon-based characteristics give it unique dynamic lubrication function, its surface abundant functional groups can form high density, strong adhesion transfer film, significantly improve the wear resistance and service life of composite material.

The invention provides a composite material single-lap bonding joint damage clustering reliability evaluation method based on acoustic emission. The method comprises the following steps: 1, carrying out a tensile experiment to obtain an acoustic emission signal; 2, providing a noise separation method combining variational mode decomposition (VMD) and fast independent component analysis FastICA to remove environmental noise and ineffective components; 3, proposing a credibility evaluation method based on statistics based on the characteristic parameters of the time-frequency domain of the acoustic emission signal, namely, quantifying the neighborhood change before and after the dimension reduction of the signal by adopting a Pearson's correlation coefficient, and evaluating the credibility of an event according to a credibility threshold value; and 4, based on a clustering algorithm, identifying three kinds of damages including matrix cracking, adhesive layer debonding and fiber fracture, and analyzing the development mechanism. According to the method, the VMD and the FastICA are innovatively combined for noise separation, the clustering credibility evaluation index is provided, the accuracy and reliability of acoustic emission data analysis are effectively improved, and technical support is provided for damage evaluation and health monitoring of composite material single-lap bonding joints and other complex structures.

The present invention provides a damage clustering reliability assessment method for single-lap adhesive joints of composite materials based on acoustic emission, comprising the following steps: 1. performing a tensile test to obtain acoustic emission signals; 2. proposing a noise separation method combining variational mode decomposition (VMD) and fast independent component analysis (FastICA) to remove environmental noise and invalid components; 3. proposing a statistically based credibility assessment method based on the characteristic parameters of the acoustic emission signal in the time and frequency domains, i.e., using the Pearson correlation coefficient to quantify neighborhood changes before and after signal dimensionality reduction, and evaluating the credibility of the event based on a credibility threshold; 4. identifying three types of damage, namely matrix cracking, adhesive debonding, and fiber breakage, based on a clustering algorithm, and analyzing their development mechanisms. The present invention innovatively combines VMD and FastICA for noise separation and proposes a cluster credibility assessment index, effectively improving the accuracy and reliability of acoustic emission data analysis, and providing technical support for damage assessment and health monitoring of single-lap adhesive joints of composite materials and other complex structures.

The application discloses a kind of tensile composite cable for robot and preparation method thereof, belong to the technical field of robot cable.The inside to outside includes successively: conductive core layer, insulating layer, tensile reinforcing layer, electromagnetic shielding layer and outer sheath layer, wherein the material of outer sheath layer includes the following weight parts of raw materials: 75-87 parts of ethylene-propylene-diene rubber, 11-17 parts of hydrophobic aluminum oxide, 3-9 parts of functional additives, 2-5 parts of processing aids and 0.05-0.15 parts of initiator.Hydrophobic aluminum oxide can reduce the risk of matrix cracking, and enhance the tensile properties of cable;The functional additives contain nitrogen, phosphorus and other flame-retardant groups and rigid benzene ring structure in the molecular structure, which can not only improve the flame retardance of the cable, but also improve the tensile properties and heat resistance of the cable;In summary, the cable prepared by the application has excellent tensile resistance, flame retardance and heat resistance, and can work in high temperature environment, and has important application value in the field of robot cable technology.

The application discloses a kind of fibre bundle ceramic matrix composite oxidation constitutive model calculation method, comprising: constructing ceramic matrix composite oxidation kinetics model, the oxygen concentration distribution in crack depth direction is calculated;Determine carbon-oxygen reaction rate, deduce the change relation of tensile strength of C fibre bundle and oxidation temperature, oxygen concentration;According to the tensile strength of C fibre bundle at different temperatures, the strength distribution of C fibre in-situ monofilament at room temperature is equivalently offset;Based on shear lag model, the fibre stress distribution of interface slip zone, positive slip zone and reverse slip zone between fibre and matrix is calculated;The distribution of matrix crack propagation and crack spacing is calculated, and the mechanical response of matrix is obtained;According to the mechanical damage model of fibre and matrix, the stress-strain response curve of fibre bundle ceramic matrix composite in high-temperature oxidation environment is calculated.The application can accurately describe the damage evolution of fibre, interface and matrix in the oxidation process, and greatly reduce the amount of calculation.

The invention relates to a high-density SiC / SiC composite material with uniformly distributed self-healing components and application of a preparation method of the high-density SiC / SiC composite material. UV-curable SiCw-SiBOC precursor slurry is pre-cured on the surface of two-dimensional SiC fiber cloth, stacked and compacted in a mold and then subjected to thermocuring to be qualitative as a SiC cellulose blank; the densification of the self-healing SiC / SiC composite material is realized through inert atmosphere cracking and reaction melt permeation under a vacuum condition. And uniform distribution of self-healing components such as B4C and SiBC in the two-dimensional SiC fiber cloth layers and between the two-dimensional SiC fiber cloth layers is realized. After the self-healing component is oxidized, diboron trioxide glass and borosilicate glass are generated to seal and fill matrix cracks so as to realize matrix self-healing, so that the whole water-oxygen service environment self-healing performance of the composite material is effectively improved. A high-toughness SiCw phase is introduced as an initial site of a carbon-silicon reaction, so that a part of pores among fiber bundles and pores among fiber cloth layers can be filled, and the problem of low fracture toughness caused by continuous distribution of a self-healing phase can be solved.

An embedded thin-walled reinforced structure made of hybrid materials and its preparation method are disclosed. The structure includes a lower composite material layer and a metal layer, the metal layer being disposed on the upper surface of the lower composite material layer and having a hollow structure. It also includes an upper composite material layer covering the upper surfaces of the metal layer and the lower composite material layer, and completely encapsulating the metal layer. A resin matrix is ​​further included, filling the voids between the lower composite material layer, the metal layer, and the upper composite material layer. This structure meets the performance requirements of composite material shell structures in terms of bending resistance, lightweight, impact resistance, and energy absorption characteristics. It also provides a connection scheme between the thin-walled hybrid material member and the composite material shell, ensuring connection strength and reliability without causing damage to either structure due to processing techniques. Such damage includes, but is not limited to, fiber breakage and matrix cracking of the composite material, as well as the initiation of cracks in the metal.

The invention belongs to the technical field of blade thermal barrier coating system nondestructive testing, and relates to an electromagnetic thermal decision level fusion thermal barrier coating system defect decoupling nondestructive evaluation method which comprises the following steps: 1, building an experimental device; 2, performing electromagnetic excitation on the detected blade by using an experimental device, and generating an electromagnetic field and a temperature field in a detected area of the detected blade; 3, acquiring a temperature field signal on the surface of the detected blade to realize rapid detection of defects; 4, scanning a defect target range quantified from a temperature field signal and acquiring an electromagnetic field signal, and realizing defect classification and decoupling quantification of a matrix crack through the electromagnetic field signal; 5, quantitative evaluation of interface debonding is achieved in combination with matrix crack information and temperature field signals; according to the method, the temperature field signals and the electromagnetic field signals are subjected to decision-level fusion to realize nondestructive decoupling quantitative evaluation of various typical defects of the blade thermal barrier coating system, and the method has the advantages that the detection speed is high, the system is integrated, and various defects can be detected at the same time.

The application discloses a composite material fracture energy calculation method considering reinforcement-matrix interface dispersion, and comprises the following steps: S1, a matrix crack fracture energy model is established; S2, a reinforcement-matrix interface fracture energy model is established; S3, a composite material fracture control equation model is established; S4, a composite material critical energy release rate is modified; S5, the interface phase field, the displacement field and the crack phase field in the composite material fracture control equation are discretized by using the finite element method, and an incremental iteration is carried out, so that the crack propagation in the composite material considering the interface dispersion is calculated. Through the adoption of the phase field model, the advantages of realizing the micro-to-macro multi-scale simulation are utilized, the properties of the interface in the composite material are associated with the properties of the matrix, that is, the interface crack propagation and other fracture properties of the composite material under the action of the load are dispersed to the surrounding matrix in the form of a continuous exponential function, and a mechanical model for more accurately predicting the mechanical behavior and fracture evolution of the composite material is established.

This invention relates to the field of building materials, specifically to a steel slag-based low-carbon ultra-high-performance concrete composite material and its preparation method. The composite material comprises, by weight, 30-50 parts mineralized steel slag powder, 20-30 parts cement, 10-15 parts silica fume, 5-10 parts fly ash, 1-3 parts water-reducing agent, 15-25 parts steel fiber, and 10-15 parts water. The mineralized steel slag powder is obtained by biochemical mineralization of steel slag powder through a mixture of alkaline bacterial solution containing Bacillus pasteurella and a calcium source substrate. A calcium carbonate crystal layer is deposited in situ on its surface, and residual bacterial protein adheres to the pores, forming a multi-scale stacked cementitious skeleton with silica fume and fly ash. The preparation includes mineralization, dry mixing, slurry preparation, fiber addition, and curing steps. This invention eliminates the free calcium oxide expansion source, preventing matrix cracking, fills the pores on the steel slag surface, and strengthens the interfacial bonding strength.

The invention discloses a crack prediction method for a unidirectional fiber reinforced epoxy resin-based composite material, and provides a crack propagation prediction model based on multi-physics field coupling aiming at the problem that a physical detection means is difficult to accurately detect a structural damage position and a failure position. Microscopic information of the unidirectional fiber reinforced epoxy resin matrix composite material is accurately represented, and a damage constitutive model of the unidirectional fiber reinforced epoxy resin matrix composite material is constructed, so that damage variables are introduced for effective analysis of damage modes such as fiber fracture, matrix cracking, fiber and matrix debonding and the like. A cohesive zone and a damage evolution mode of the unidirectional fiber reinforced epoxy resin matrix composite are established, the influence of the crack effect and the inelastic strain of the material on the damage of the component is considered, and effective analysis of the cumulative evolution process of the in-plane damage of the unidirectional fiber reinforced epoxy resin matrix composite is realized.

The invention discloses a probabilistic model-containing CMC material solid-thermal coupling solving method, and belongs to the field of engineering thermophysics. According to the method, for mechanical damage of a CMC high-temperature component after long-time service, CMC material micro-scale representative unit cell RVE modeling considering mechanical damage random characteristics is established, and a mechanical damage characteristic mode of the CMC material after long-time service is introduced into an intact RVE model. On the basis of the model, axial and radial thermal boundary conditions are applied respectively, so that the axial heat conductivity coefficient and the radial heat conductivity coefficient of the microscale of the CMC material are obtained, and the corresponding elastic modulus is calculated through a CMC material matrix crack density formula and a stress-strain relation; and establishing a mapping relation between the thermophysical property parameters and the mechanical property parameters of the CMC material when the mechanical damage occurs, and realizing solid-thermal coupling analysis solution of the CMC material after the random mechanical damage occurs. Therefore, the method can improve the temperature field estimation precision of the CMC high-temperature component in a long-time service environment.

A coated fiber structure for use in a ceramic matrix composite comprises a fiber extending along a fiber axis and an interface coating arrangement applied to and circumscribing the fiber. The interface coating arrangement comprises: a first boron nitride layer extending coaxially about and in direct contact with the fiber, a first silicon-doped boron nitride layer extending coaxially about and in direct contact with the first boron nitride layer, a carbon layer extending coaxially about and in direct contact with the first silicon-doped boron nitride layer, a second boron nitride layer extending coaxially about and in direct contact with the carbon layer, and a second silicon-doped boron nitride layer extending coaxially about and in direct contact with the second boron nitride layer. A silicon content of the first silicon-doped boron nitride layer is higher than the silicon content of the second silicon-doped boron nitride layer.