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273 results about "Damage tolerance" patented technology

Damage tolerance is a property of a structure relating to its ability to sustain defects safely until repair can be effected. The approach to engineering design to account for damage tolerance is based on the assumption that flaws can exist in any structure and such flaws propagate with usage. This approach is commonly used in aerospace engineering, mechanical engineering, and civil engineering to manage the extension of cracks in structure through the application of the principles of fracture mechanics. In engineering, a structure is considered to be damage tolerant if a maintenance program has been implemented that will result in the detection and repair of accidental damage, corrosion and fatigue cracking before such damage reduces the residual strength of the structure below an acceptable limit.

Selected processing for non-equilibrium light alloys and products

A new class of light or reactive elements and monophase α′-matrix magnesium- and aluminum-based alloys with superior engineering properties, for the latter being based on a homogeneous solute distribution or a corrosion-resistant and metallic shiny surface withstanding aqueous and saline environments and resulting from the control during synthesis of atomic structure over microstructure to net shape of the final product, said α′-matrix being retained upon conversion into a cast or wrought form. The manufacture of the materials relies on the control of deposition temperature and in-vacuum consolidation during vapor deposition, on maximized heat transfer or casting pressure during all-liquid processing and on controlled friction and shock power during solid state alloying using a mechanical milling technique. The alloy synthesis is followed by extrusion, rolling, forging, drawing and superplastic forming for which the conditions of mechanical working, thermal exposure and time to transfer corresponding metastable α′-matrix phases and microstructure into product form depend on thermal stability and transformation behavior at higher temperatures of said light alloy as well as on the defects inherent to a specific alloy synthesis employed. Alloying additions to the resulting α′-monophase matrix include 0.1 to 40 wt. % metalloids or light rare earth or early transition or simple or heavy rare earth metals or a combination thereof. The eventually more complex light alloys are designed to retain the low density and to improve damage tolerance of corresponding base metals and may include an artificial aging upon thermomechanical processing with or without solid solution heat and quench and annealing treatment for a controlled volume fraction and size of solid state precipitates to reinforce alloy film, layer or bulk and resulting surface qualities. Novel processes are employed to spur production and productivity for the new materials.
Owner:HEHMANN FRANZ

Preparation method for carbon nanotube non-woven fabric interlayer modified fiber reinforced composite materials

The invention belongs to the advanced composite material preparing technology and relates to a preparation method for carbon nanotube non-woven fabric interlayer modified fiber reinforced composite materials. The method includes: enabling carbon nanotube non-woven fabric to enter resin rich areas of the layers of fiber reinforced thermosetting resin base composite materials in direct intercalation mode, using an autoclave molding process or a liquid forming process, and preparing interlayer the interlayer modified composite materials according to an original curing process of matrix resin. The carbon nanotube non-woven fabric can enter weak interlayer areas of the composite materials through direct intercalation mode, has no influence on flow of the resin in the curing process and a liquid forming process of the matrix resin, and simultaneously a network structure formed by carbon nanotubes in an interlayer can effectively prevent interlayer microcracks from being formed and extending, thereby improving strengthening-toughening performance of interlayer of the composite materials, obtaining high impact damage resistance and high damage tolerance, and covering a temperature range of typical aerospace composite structure application, in particular to a more than 300 DEG C high temperature range.
Owner:AVIC BEIJING INST OF AERONAUTICAL MATERIALS +1

Forming process of fiber reinforced thermoplastic composite material

The invention discloses a low-cost high-efficiency forming process of a fiber reinforced thermoplastic composite material, comprising the following steps of: arranging a workpiece to be formed, which is prepared by laying fiber reinforced materials, in a closed space containing a mold template; laying demolding cloth and a diversion grid in sequence on the workpiece; laying or coating a demolding material under the workpiece; arranging an impregnating pipe on one side of the width direction of the workpiece; arranging a vacuum pipeline on the other side along the length direction of the workpiece and parallel to the side surface; arranging a breathable material between the vacuum pipeline and the workpiece; then pumping vacuum in the closed space through the vacuum pipeline, simultaneously raising the temperature of the mold template to the impregnating temperature of 50-250 DEG C; and finally filling molten thermoplastic resin or the precursor of the thermoplastic resin of which the temperature is 50-250 DEG C and the viscosity is 0.15-1.0Pa.s into the workpiece from the impregnating pipe, and then insulating for polymerization or reducing the temperature for cooling and forming. The forming process needs not to prepare a pre-impregnated belt in advance and has low cost and high efficiency, and the workpiece can be formed easily and has superior toughness and damage tolerance.
Owner:NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI

Damage-tolerance testing method for whole wing spar of airplane

The invention pertains to airplane fatigue and damage-tolerance testing technologies, and relates to a damage-tolerance testing method for the whole wing spar of an airplane. The method comprises the steps of: (I) choosing a part with large load from the whole wing spar for serving as a testing part examining segment, (II) producing two same testing parts according to the examining segment, (III) reserving an interval of 20 to 30mm between the two back-to-back testing parts which are respectively provided with a coating in the upper part and the lower part (the coating is connected with an upper spar edge strip and a lower spar edge strip to form a case segment), (IV) fixing the root of the testing case segment completing assembly on a load-bearing wall, (V) exerting concentrated load at one end of the testing parts to simulate the bending moment of the spar at the testing segment and the shearing force of a web, without considering the influence of the shearing flow of the coating and (VI) using a finite element method to conduct damage tolerance analysis on the testing parts and comparing testing results. The method solves the difficulty that the crack expansion and remaining strength of the present airplane whole wing spar structure lack theoretical evidence; and the design of the testing parts adopts a method of simultaneously conducting tests to the two back-to-back testing parts, thereby eliminating the distortion of a single spar.
Owner:XIAN AIRCRAFT DESIGN INST OF AVIATION IND OF CHINA

High-efficiency multifunctional foliage fertilizer and production method thereof

The invention discloses a high-efficiency multifunctional foliage fertilizer and a production method thereof. The foliage fertilizer is prepared by chelating shrimp processing leftovers, which serve as the main raw material, with medium and minor elements. The foliage fertilizer is prepared from 10-30% of amino acids, 2-8% of medium and minor elements, 10-30% of organic nitrogen, 3-20% of phosphorus, 3-20% of potassium, and 10-30% of shrimp peptide protein, chitosan, chitosan oligosaccharide, chitin, glucosamine hydrochloride, astacin and shrimp cephalin. The foliage fertilizer disclosed by the invention enhances the low-temperature tolerance, drought tolerance, salt damage tolerance, chemical damage tolerance and other stress tolerances of crops on the premise of comprehensively and efficiently supplementing necessary nutrients for crops, and has the functions of restoring the wound in the root system, enhancing the disease resistance of the crops, inhibiting disease and pest and the like. The production technique can reduce the acidolysis consumption, avoids introducing abundant inorganic salts and chloride ions to destroy soil ecological equilibrium and influence plant growth, lowers the energy consumption and requirements for equipment strength, and can implement the clean production of complete utilization and zero pollution discharge.
Owner:ZHANJIANG BOTAI BIOCHEM IND

Method for knitting 2.5-dimension integral knit multiple-pass fabric

The invention relates to a weave method of 2.5-dimensional overall braided multi-through pipe fabric. The weave method is characterized in that (1) the structure of the fabric adopts a 2.5-dimensional shallow-cross bended-connection structure; (2) the overall weaving of the fabric adopts core imitation-shaped weaving to ensure the internal molded surface dimension of the fabric; (3) the fabric is divided into two parts, namely a connecting body part and a through pipe part, wherein the connecting body is a part connected with the through pipes, while the through pipes are connected through the same connecting body; (4) the lower section of each through pipe is provided with warp yarns of the part in advance; (5) weft yarns between through pipes in the same plane are lined between the warp yarns layer by layer through adopting a weft insertion process; (6) when the horizontal section of the connecting body increases, warp yarns are increased through adopting a shift yarn adding method, and the method can effectively improve the hole phenomenon in yarn-adding points; and (7) when the horizontal section of the connecting body decreases, warp yarns are reduced through adopting a shift yarn reduction method. The 2.5-dimensional multi-through pipe fabric woven by the weave method has the advantages of better overall property, controllable shaping, high damage tolerance, excellent performances of impact resistance, delamination resistance, fatigue resistance, and the like.
Owner:NANJING FIBERGLASS RES & DESIGN INST CO LTD

Method for preparing rigid three-dimensional crystal whisker interlayer modified continuous fiber composite material

ActiveCN101423618AImprove the strength-toughness performanceAvoid difficultiesMicron scaleTransfer molding
The invention belongs to a technology for preparing composite materials and relates to a method for preparing rigid three-dimensional crystal whisker interlaminar modified continuous fiber composite materials. The interlaminar modified thermosetting resin composite materials are prepared by the following method by adoption of a micron-scale heteropical rigid micro 3-3 structure and adoption of a four-pin zinc oxide crystal whisker as an interlaminar reinforcement: firstly, the four-pin zinc oxide crystal whisker which is subjected to vacuum drying for 2 hours at a temperature of 100 DEG C is deposited on the surface of fabrics by means of a mechanical vibrating screen or electrostatic adherence or deposition through a fluidized bed or powdering through a drum-type silk screen, and modified fabrics are obtained; and secondly, after the modified fabrics are laid as required, the resin transfer molding technology or the resin membrane permeation technology is utilized for preparing the composite materials by the prior matrix resin solidifying technology. The method can improve the strong interlaminar toughening performance of the composite materials, obtain high surge impedance and high damaged tolerance, and cover the temperature range of structural application of typical aerospace composite materials and particularly cover the high temperature range of more than 300 DEG C.
Owner:BEIJING AVIATION MATERIAL INST NO 1 GRP CORP CHINA AVIATION IND
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