86 results about "Matrix cracking" patented technology

A fiber-reinforced ceramic matrix composite material exhibiting increased matrix cracking strength and fracture toughness is produced by sequentially depositing a plurality of 5-500 nanometer-thick layers of a primary ceramic matrix material phase periodically separated by 1-100 nanometer-thick intermediate layers of a secondary matrix material phase onto the reinforcing fibers upon their consolidation. The resultant nanolayered matrix enhances the resistance to the onset of matrix cracking, thus increasing the useful design strength of the ceramic matrix composite material. The nanolayered microstructure of the matrix constituent also provides a unique resistance to matrix crack propagation. Through extensive inter-layer matrix fracture, debonding and slip, internal matrix microcracks are effectively diverted and/or blunted prior to their approach towards the reinforcing fiber, thus increasing the apparent toughness of the matrix constituent. This unique toughening mechanism serves to dampen energetic co-planar macrocrack propagation typically observed in conventionally manufactured ceramic matrix composites wherein matrix cracks are usually deflected at the fiber/matrix interphase region.

The invention relates to a composite material structure failure analysis method based on a continuum damage mechanics degradation model. According to the method, a three-dimensional continuum damage mechanics degradation model of a unidirectional fiber enhanced composite material is constructed, two types of damage forms such as fiber cracks and matrix cracks and the orientation of damages are considered, and meanwhile, the crack closure effect caused by coupling of the fiber damage and the matrix damage and reverse loading of load in a fiber stretching and compressing damage process is considered; three damage variables are respectively used for representing the fiber crack damage and two mutually-perpendicular matrix crack damages respectively, so that the continuum damage mechanics degradation model for failure analysis of a composite material structure is obtained. Compared with the conventional anti-climax degradation model, the continuum damage mechanics degradation model has the advantages that the behavior characteristics of the damaged composite material under different load states are considered, and the performance of the damaged material can be accurately represented; the composite material structure failure analysis method is suitable for simulation of a composite material structure damage process and forecasting of the intensity under a condition that the load state and a constraint situation are more complicated.

The invention provides a self-healing microcapsule preparation method. The method comprises the following steps: A) mixing an emulsifier, urea, formaldehyde, a reaction promoter, ethyl phenylacetate and water, performing emulsification to obtain an emulsion; and B) heating the emulsion and reacting the emulsion to obtain the self-healing microcapsule. The self-healing microcapsule is characterized in that the capsule wall of the self-healing microcapsule is urea-formaldehyde resin, and a core material comprises ethyl phenylacetate. The invention also provides a paint containing the above self-healing microcapsule and an epoxy resin composite material. The self-healing microcapsule has the advantages of simple process, structured microcapsule morphology and good stability. The core material ethyl phenylacetate has swelling effect to epoxy resin, by using a principle, the solvent-type self-healing microcapsule is capable of healing the matrix crack of epoxy resin.

The invention discloses a prestressing tendon reinforced composite material and a manufacturing method of the prestressing tendon reinforced composite material. comprising the following steps of: arranging prestressing tendons according to stress condition of a composite material; weaving the prestressing tendons and fibers to form a prefabricated body or using the prestressing tendons individually to form the prefabricated body; preparing the composite material by chemical vapor infiltration method (CVI); heating up to Tm temperature of a core body to soften the core body; and releasing prestress when an outer pipe retracts elastically to compress a combined base body. According to the invention, due to the arrangement flexibility and convenience of the prestressing tendons, the tendons are arranged according to the principal tensile stress trace, so that the stress performance of the structure ceramics or carbon base is improved better, the toughness and strength of the ceramic or carbon-based composite material are strengthened, and the problem that the continuous fiber reinforced ceramic or carbon-based composite material matrix cracks too early is solved.

The invention relates to the technical field of building materials, and discloses a method for preparing a high-performance phosphogypsum-based self-leveling mortar. The method comprises the followingsteps: S1, obtaining raw materials comprising 40-60 parts of phosphorus building gypsum, 15-22 parts of cement, 10-24 parts of fly ash, 3-10 parts of stone powder, 1.5-4 parts of a redispersible latex powder, 0.05-0.15 part of cellulose ether, 0.02-0.06 part of a nano-carbon fiber, 0.3-0.8 part of a water retaining agent, 0.1-1.3 parts of a water reducer, 0.1-0.4 part of an anti-settling agent, 0.01-0.08 part of a defoaming agent and 30-42 parts of fine sand aggregates; and S2, mixing the materials obtained in step S1, stirring the obtained mixture until uniformity, and adding water accounting for 13-15% of the total weight of the mixture and performing stirring until uniformity when the mortar is used. The reinforcement of a phosphogypsum-based self-leveling material and the high fracture toughness of the carbon fiber effectively reduce and inhibit the expansion of matrix cracks, and greatly improve the interfacial pore structure of the self-leveling material. The method of the invention improves the bonding degree of the interface of the phosphogypsum matrix, increases the toughness of the phosphogypsum matrix and increases the overall strength.

The invention discloses a basalt fiber/polypropylene composite material based on surface roughening interface enhancement and a preparation method of the basalt fiber/polypropylene composite material, and belongs to the technical field of new composite materials. The preparation method comprises basalt fiber surface roughening treatment and composite material preparation. The basalt fiber surface roughening treatment comprises the following steps: (1) acrylic acid dipping treatment; (2) electron beam irradiation treatment; and (3) in-situ growth of nano silicon dioxide on the surface of the basalt fiber. The surface of the short-cut basalt fiber is roughened, and part of alkyl is grafted on the surface of the short-cut basalt fiber, so that the contact area and interaction force between the basalt fiber and a polypropylene matrix are greatly increased, interface mechanical interlocking is enhanced, epiphytic crystallization of the polypropylene matrix on the fiber surface is promoted, stress conduction of the interface of the composite material is enhanced, the inhibition capability of the fibers on the development of matrix cracks in the deformation process is improved, and thus the mechanical property of the composite material is remarkably improved.

The invention discloses a method for predicting a tension-compression fatigue hysteresis loop of a metal matrix composite material. The method specifically comprises the following steps of determiningthe fiber, matrix and shear stress distribution of a one-way silicon carbide fiber reinforced titanium matrix composite material debonding section and a non-debonding section according to a BHE shearhysteresis model; determining the length of the debonding area, the initial debonding stress of the interface and the complete debonding stress of the interface; determining the length of a reverse sliding area and the critical stress of reverse sliding; determining the stress-strain relationship between the stretching loading and unloading stages of the composite material; determining a stress-strain relationship between the compression loading stage and the unloading stage of the composite material; determining a change rule of the crack spacing and the interface shear stress along with thecycle number; determining a fiber breakage fraction of a given cycle number; and giving a cycle number N, and combining the above steps to obtain the fatigue hysteresis loop of the composite materialchanging with the cycle number. According to the method, the stress-strain relationship of the composite material under different matrix crack intervals, different sliding interface shear stresses, different fiber breakage volume fractions and different cycle numbers can be accurately predicted.

The invention discloses a method for predicting an arbitrary loading and unloading stress-strain curve of a ceramic-based composite material in a high-temperature oxidation environment. The method caneffectively simulate the arbitrary loading and unloading stress-strain curve of a unidirectional SiC/SiC composite material in a high-temperature oxidation environment; according to the method, the influences of the matrix crack density and width, the interface oxidation consumption length and the fiber tensile strength on the length and distribution of an interface slip region during loading ona stress-strain curve of the composite material in a high-temperature oxidation environment are considered; according to the method, a theoretical basis can be provided for the calculation of the fatigue life of the unidirectional SiC/SiC composite material under spectral load loading in the high-temperature oxidation environment; the method overcomes the defects of high test cost and high manpower and material resource consumption in the oxidation test of the arbitrary loading and unloading of the unidirectional ceramic-based composite material, and can save a large amount of manpower and material resources.

The invention belongs to the technical field of ceramic matrix composite steady-state matrix cracking stress prediction, and particularly relates to a method for predicting the cracking stress of a steady-state matrix of a woven ceramic-based composite material by considering the environmental influence. The invention provides a steady-state matrix cracking stress distribution equation, which is constructed and obtained by utilizing the length of a fiber/matrix interface oxidation area, and the fiber/matrix interface oxidation zone friction shear stress under the temperature condition and thefiber/matrix interface debonding zone friction shear stress under the temperature condition are constructed, so that the temperature and oxidation factors are included into a steady-state matrix cracking stress equation, and a basis is provided for accurately predicting the cracking stress of the steady-state matrix of the woven ceramic matrix composite material. Results of the embodiment show that the prediction method provided by the invention can predict the cracking stress of the woven ceramic-based composite material at different use temperatures.

The invention relates to a drill bit and a diamond thin-wall drill, and belongs to the technical field of drilling tools. A sharpening structure is arranged on the drill bit, the sharpening structurecomprises shallow grooves which are formed in two side surfaces at an interval, and the shallow grooves extend from the working surface of the drill bit to the bottom surface; and according to the drill bit, a matrix structure is formed by diamond particles and metallic bond through cold pressing and sintering, and the metallic bond is prepared from the compositions in percentage by weight: 15-25wt% of electrolytic copper powder, 3-5wt% of atomized tin powder, 3-8wt% of nickel tetracarbonyl powder, 5-12wt% of FeCoCu superfine alloy powder, 10-20wt% of FeCuNiSn superfine alloy powder, 1-10wt% high-chromium iron powder and the balance of electrolytic iron powder. The drill bit is provided with a weakening structure, the sharpness can be maintained not to be decreased under a condition of drilling at circulation break, an anti-impact property and an anti-corrosion property of the drill bit are good, and a phenomenon of matrix cracking or tooth breaking under a high-speed drilling at circulation break condition can be significantly reduced.

The invention discloses a defect hot-deply method of carbon fiber-reinforced modified bismaleimide laminates. The method comprises the following steps: determining defects of a sample by non-destructive testing, preparing a label solution, soaking, pyrolyzing, deplying and protecting the sample. After being deplied, the sample keeps morphology features of a defect area, makes out the types, the sizes and the positions of the defects such as gap, delamination, poor (rich) lipid, matrix cracking and fiber bending (fracture), and provides the realest and most direct evidence for the further defect (breakage) forming mechanism analysis and the structural part failure analysis.