Showing papers on "Composite number published in 1980"

Thermal expansion and swelling of cured epoxy resin used in graphite/epoxy composite materials

Abstract: The paper presents results of experiments in which the thermal expansion and swelling behavior of an epoxy resin system and two graphite/epoxy composite systems exposed to water were measured. It was found that the cured epoxy resin swells by an amount slightly less than the volume of the absorbed water and that the swelling efficiency of the water varies with the moisture content of the polymer. Additionally, the thermal expansion of cured epoxy resin that is saturated with water is observed to be more than twice that of dry resin. Results also indicate that cured resin that is saturated with 7.1% water at 95 C will rapidly increase in moisture content to 8.5% when placed in 1 C water. The mechanism for this phenomenon, termed reverse thermal effect, is described in terms of a slightly modified free-volume theory in conjunction with the theory of polar molecule interaction. Nearly identical behavior was observed in two graphite/epoxy composite systems, thus establishing that this behavior may be common to all cured epoxy resins.

Wood fibre-reinforced cement composites

Abstract: The use of wood fibres as reinforcement for a structural composite material has been investigated. Although wood fibres have relatively poor mechanical properties compared with synthetic fibres, they have the advantages of low density, low cost and low energy demand during manufacture. A number of possible matrix materials were considered and Portland cement was chosen for further investigation. An examination was made of the effect of the pulping technique used to prepare the fibre on the strength of the composite and on the stability of the wood fibres in the cement matrix. A chemically pretreated high-temperature thermomechanical pulp and a pulp produced by the kraft process were selected for further study. The effect of the water-cement ratio of the matrix and the weight of fibre in the composite on the strength of the composite and the rate of increase in strength and fracture energy of composite are reported for composites containing these pulps. The results indicate that the kraft pulp is suitable for applications where slurry dewatering can be employed during the forming operation and that the thermomechanical pulp is more suited to applications where low water-cement ratio slurry is used.

Clutch with pyrolytic carbon friction material

Abstract: Disclosed is a locking differential (10) including an oil lubricated clutch assembly (18) having a plurality of interleaved friction discs (48, 50, 60, and 62) formed of steel and squeezed together to retard relative rotation of differential side gears (32 and 34). Adjacent friction discs have mutually facing friction surfaces. One of each mutually facing friction surface is defined by the metal forming the disc and the other surface is defined by a pyrolytic carbon composite friction material (78). In one form, the friction material includes a meshed cloth substrate formed of carbon fibers, which may be woven into a single layer of cloth, and a coating of carbon deposited on the fibers by chemical vapor deposition to a level forming a friction material having a relatively open mesh which is readily penetrated by an adhesive to improve bonding of the friction material to the discs.

Effects of fiber length on the tensile strength of epoxy/glass fiber and polyester/glass fiber composites

Abstract: In discontinuous fiber-reinforced composites, the shear strength at the fiber–matrix interface plays an important role in determining the reinforcing effect In this paper, a method was devised to accurately determine this shear strength, taking the strength distribution of glass fiber into consideration Calculated strength values based on the shear strenght obtained by the method were in better agreement with the experimental observations than those calculated by employing the shear strength obtained on the assumption that the fiber strength was uniform The tensile strength of composites increases with increasing aspect ratio of the reinforcing fibers This trend is almost the same regardless of the kind of matrix, the nature of interfacial treatment, and the environmental temperature When composites are reinforced with random-planar orientation of short glass fibers of 15 times the mean critical fiber length, the tensile strength of composite reaches about 90% of the theoretical strength of composites reinforced with continuous glass fiber Reinforcing with glass fibers 5 times the critical length, the tensile strength reaches about 97% of theoretical However, from a practical point of view, it is adequate to reinforce with short fibers of 15–20 times the mean critical fiber lenght

Internal combustion engine and composite parts formed from silicon carbide fiber-reinforced ceramic or glass matrices

Abstract: A high strength, fracture tough, high temperature oxidatively stable, heat insulating internal combustion engine combustion chamber component is described made of a silicon carbide fiber reinforced ceramic matrix or a silicon carbide fiber reinforced glass matrix material. An internal combustion engine containing combustion chamber components as above described is also disclosed.

Continuous length silicon carbide fiber reinforced ceramic composites

Abstract: A silicon carbide fiber reinforced ceramic matrix composite is disclosed having high strength, fracture toughness, and oxidative stability even at high temperature use. The composite is made up of a plurality of ceramic layers, each layer reinforced with a plurality of unidirectional continuous length silicon carbide fibers, each layer having an axial flexural strength greater than 70,000 psi and a high fracture toughness, exemplified by a critical stress intensity factor greater than 10×103 psi (inch)1/2. The composite is formed by starting with the ceramic matrix material in the glassy state and converting it from the glassy state to the ceramic state after densification of the composite.

Impact modified polycarbonates

Abstract: Polycarbonates having improved impact performance are provided, comprising a blend of polycarbonate resin and an acrylic rubber interpolymer composite.

Felt-like layered composite of PTFE and glass paper

Abstract: A felt-like layered composite of the following structure: a. a first layer of a predominantly horizontal coplanar superimposed layers of filamentary polytetrafluoroethylene components interrupted by occasional interlayered orientation; b. a thin high density nonwoven layer of fine glass staple fibers; c. a scrim fabric of polytetrafluoroethylene fibers and d. a second predominantly horizontal coplanar superimposed layers of filamentary polytetrafluoroethylene components interrupted by occasional interlayer orientation; wherein the layers are mechanically bonded together by filamentary polytetrafluoroethylene components extending vertically throughout the composite and a process for making this composite; the composite is useful as a filter fabric and is primarily used for bag filters to remove fly ash from the gaseous combustion products of coal fired furnaces and boilers.

Composite insulated wall

Abstract: A composite insulated wall includes a pair of outer poured concrete layers cured in a form and an organic or inorganic insulating panel or panels disposed between the concrete layers and retained in place by a number of lateral tie-rods extending through the insulating panel and into the concrete.

Heat-adhesive composite fibers

Abstract: The heat-adhesive fine composite fibers of the present invention have a denier within the range of 1-20, and consist of as a first component, a crystalline polypropylene and as a second component, an ethylene-vinyl acetate copolymer, a saponification product thereof or a mixture of any of these materials with polyethylene, the content in said second component, of vinyl alcohol and/or vinyl acetate units based upon the total of vinyl acetate, vinyl alcohol and ethylene units being 0.5-18 mol %, and said second component forming at least one part of the fiber surface of said fibers. These fine composite fibers are superior in low temperature heat-adhesiveness, in adhesiveness with foreign raw materials, and in low crimpability. Further the fine composite fibers in which the second component has a specific density of 0.93 or less show almost no crimpability and are useful for wet-type non-woven fabrics. When a polypropylene having a Q value of 3.5 or less is used as the first component, the composite fiber can be obtained by spinning process alone with sufficient fiber strength, and the composite fibers having almost no sensible and latent crimping are very suitable for wet type non-woven fabrics.

Fibrous composites in structural design

Abstract: Comments on the Status of Composite Structures Technology.- Session I Aircraft Structures.- Composite Aircraft Structures.- Composite Wing Substructure Technology on the AV-8B Advanced Aircraft.- Preliminary Design Development AV-8E Forward Fuselage Composite Structure.- Wing Fuselage Critical Component Development Program.- Development of a Preloaded Hybrid Advanced Composite Wing Pivot Fairing.- Design Concepts for Composite Fuselage Structure.- Advanced Composites Integral Structures Meet the Challenge of Future Aircraft Systems.- Session II Missile and Space Applications.- Organic Matrix Composite Application to Missile Structure.- Advanced Composite Satellite Equipment Support Module Study.- Inertial Upper Stage (IUS) Advanced Composite Structure.- Development and Fabrication of Graphite Polyimide Launch Vehicle Structures.- Continuous Filament Advanced Composite Isogrid: A Promising Structural Concept.- Session III Crashworthiness, Impact Damage, Post Buckling and Dynamics Response.- A Crashworthiness Test for Composite Fuselage Structure.- Recent Developments in the Design, Testing and Impact-Damage Tolerance of Stiffened Composite Panels.- Impact Resistance of Graphite and Hybrid Configurations.- Design of Stiffened Composite Panels in the Post-Buckling Range.- Dynamic Stability of Fibrous Composite Cylinders.- Session IV Special Design Considerations.- Effects of Lightning and Nuclear Electromagnetic Pulse on an Advanced Composites Aircraft.- Problems and Options in Advanced Composite Repair.- A Cad Approach to Cost Estimating Composite Aircraft.- Session V Laminate Plate Theories, Edge Effects, Flaw Growth.- Evaluation of a Hybrid-Stress Formulation for Thick Multilayer Laminates 399.- The Effect of Interlaminar Stresses on Composite Flywheel Design.- Interlaminar Stress Gradients and Impact Damage.- An Analytical and Experimental Investigation of Edge Delamination in Composite Laminates.- Serviceability of Composites Surface Damages.- Prediction of Cyclic Growth of Cracks and Debonds in Aluminum Sheets Reinforced with Boron/Epoxy.- Session VI Helicopter Applications.- Application of Advanced Composite Materials to Helicopter Airframe Structures.- Design and Production of Fiberglass Helicopter Rotor Blades.- Preliminary Design of an Advanced Composite Rotor Hub for the UH-60A Black Hawk.- Evaluation of Graphite/Epoxy Shims in a High Capacity Laminate Helicopter Bearing.- Session VII Composite Joints.- Mechanically-Fastened Joints for Advanced Composites - Phenomenological Considerations and Simple Analysis.- On the Structural Behavior of Mechanically Fastened Joints in Composite Structures.- Design of the Spar Wingskin Joint.- Sensitivity of Bonded and Bolted Joints in Composites to Load/Environmental Spectrum Variations.- Composite Fasteners - A Compatible Joining Technique for Fibrous Composites in Structural Design.- Session VIII Other Applications.- Development of an Advanced Composite Hydrofoil Control Flap.- Cost-Effective Application of Advanced Composites to Hydrofoil Structures.- Graphite Composite Box Beams for U.S. Army Mobile Bridging.- Advancements in Composite Material Flywheels.- Can Advanced Composite Materials Really Compete in the Automotive Market?.- Retrofit Hardening of Electronic Shelters with Composite Panels.- Session IX Reliability/Durability Analysis.- Statistical Analysis Methods for Characterizing Composite Materials.- Durability Evaluation of Highly Stressed Wing Box Structure.- Codstran: Composite Durability Structural Analysis.- Session X Environmental Effects.- Environmental Effects on the Mechanical Behavior of AS/3501-6 Material.- The Kinetics of Moisture Diffusion in Three Advanced Composite Epoxy Resin Matrix Material Systems.- Effects of Varying Hygrothermal Environments on Moisture Absorption in Exposy Composites.- Moisture Expansion and Thermal Expansion Coefficients of a Polymer-Matrix Composite Material.- Growth of Four Flaw Types in Graphite/Epoxy Composites Due to Fully Reversed Fatigue.- Effects of Defects on Tension Coupons Undergoing an Accelerated Environmental Spectrum.

Method of making a partial interlaminar separation composite system

Abstract: This invention relates to an interlaminar separation system for composites wherein a thin layer of a perforated foil film is interposed between adjacent laminae of a composite formed from prepreg tapes to thereby permit laminae adherence through the perforations and produce a composite structure having improved physical property characteristics

Composite sintered compact containing high density boron nitride and a method of producing the same

Abstract: A composite sintered compact containing high density boron nitride, which consists of zincblende-type boron nitride, wurtzite-type boron nitride, ceramic material and metal in a specifically limited mixing ratio and has a high abrasion resistance, can be obtained under a relatively mild sintering condition and can be easily worked into a cutting tool

Method of co-extruding a reinforced composite foamed resin channel-shaped sealing strip having an abraded surface portion

Abstract: The sealing strip includes a channel-shaped attachment profile of rubber, in which a metallic reinforcing strip is embedded; this profile has an external coating layer of sponge rubber with an outer surface rendered velvety by abrasion.

An Abrasion Test for Composite Resins

Abstract: An abrasive wear test for composite resins was proposed. A slurry of glass pearls and abrasive particles were used. The abrasive effect was examined for different particle sizes. Particle sizes were found which gave the same order of wear as found clinically for an amalgam, a composite resin, and unfilled resin.

Nb‐Al multifilamentary superconducting composites produced by powder processing

Abstract: Multifilamentary superconducting Nb‐Al composites were produced using powder processing with high overall critical currents Jc at high magnetic fields. A Nb–3 wt. % Al composite, reacted at 800 °C for 16 h, had Jc ≳104 A/cm2 at 14 T at 4.2 K. Jc was almost independent of strain for strains up to 1.3%.

Composite coatings for open-end machinery parts

Abstract: Disclosed are processes and articles for composite electroless coatings comprising at least two distinct layers, the first layer comprising a metal and/or a metal alloy plus particulate matter and the second layer comprising a metal and/or a metal alloy and being substantially free of particulate matter.

Composite structural system and method and applications to pallets and platforms.

Abstract: A new and improved structural system comprising an interpenetrating plastic and substrate network material composite including two phases, a first phase comprising a substrate of intersecting partitions of paper material (31, 32) or other fibrous or absorbent material defining a cellular lattice, and a second phase comprising a polymerized plastic material penetrating and intimately contacting the structure of the paper or other fibrous or absorbent material filling the voids and interstices between the fibers of the paper material and hardened to a desired condition of rigidity. The composite is formed by saturation and in situ polymerization from a solvolysis system. The cellular lattice of composite material is further incorporated in a monolithic laminar structure by application of layers of the solvolysis adjusted for sufficient agglomerating and aggregative characteristics to form plastic weldments or fillets (30) at the intersections of the substrate partitions. The structural system is characterized by monolithic interpolymerization between the layers. The invention is applied to pallets, platforms, and other load bearing applications.

Composite Parallel Counters

Abstract: A graphical representation is presented for parallel counters, i.e., multiple input combinatorial modules that count the number of inputs being in a given state (normally logic ONE).

Stress measurement in graphite/epoxy uniaxial composites by X-rays

Abstract: X-rays can be used to measure residual as well as applied stresses in polymers and reinforced polymeric composites by diffracting from filler particles that are embedded before curing. We have investigated various fillers that exhibit suitable stress-induced shifts of diffraction angle when embedded in uniaxial graphite fiber/epoxy composites. Stresses in the particles determined by X-rays are proportional to the corresponding composite stresses, in agreement with the model of H. T. Hahn. Results indicate that the stress sensitivity (change in X-ray strain per MPa applied to the composite) increases in the order W, CdO, Ni, Ag, Nb, Al. The elastic range terminates at a yield point beyond which the stress sensitivity is markedly reduced for metallic fillers, but no such yield point has appeared with CdO particles. Oppositely directed particle strains are seen after unloading from stress levels that have exceeded the yield point. Theoretical predictions for these findings are discussed. Residual stresses in the particles were determined after curing and storage under ambient conditions. In the fiber direction the residual stresses were always found to be positive and larger than the principal stresses orthogonal to these.

Metal-composite bonding

Abstract: A method of bonding a graphite fiber reinforced glass matrix composite to a metal structure comprising depositing a layer of eutectic alloy metal component to the bond surfaces of the metal and composite followed by placing the thus treated bond surfaces of the metal and composite together with a layer of eutectic alloy containing such metal therebetween. The metal-bond-composite is then heated to melt the alloy and bond the composite to the metal. Articles formed by such a process are also described. The method has particular utility in bonding cooling channel containing metal bases to graphite-glass composite laser mirrors.

Filament composite railroad car

Abstract: A filament wound railroad car including an elongated, load bearing body having walls formed of a specified fiber reinforced plastic resin composite of glass reinforcing filaments and a structural organopolymeric resin having particular characteristics.

Method of forming composite wound structure

Abstract: An elongate hollow structure with a plurality of reinforcements arranged in a pattern and acting as spacers between a pair of skins. The skins are of resin impregnated wound filaments with reinforcing strips of facing preimpregnated wound filaments that crisscross at the spacing reinforcements, abutting panels extend between adjacent reinforcing spacers to fill the space between the skins, and the structure is bonded with resin into a composite structure.