An ideal engine mount should be able to completely isolate the engine vibration which is caused due to the engine Noise, Vibration and Harshness characteristics. Vibration in an automobile is due to different parts of the automobile, one of the main sources of vibration is the engine. In engine, the vibration is mainly due to drive trains. Hence, it is very important to optimize the engine mount to reduce vibration at the source itself, to increase the comfort of the passenger. In this paper,...

Topics: Passive Engine Rubber Mount, Finite Element Method, Elastic Characteristics, FEA Modeling,...

Across southern Alaska the northwest directed subduction of the Pacific plate is accompanied by accretion of the Yakutat terrane to continental Alaska. This has led to high tectonic strain rates and dramatic topographic relief of more than 5000 meters within 15 km of the Gulf of Alaska coast. The glaciers of this area are extensive and include large glaciers undergoing wastage (glacier retreat and thinning) and surges. The large glacier ice mass changes perturb the tectonic rate of deformation...

Topics: NASA Technical Reports Server (NTRS), GLACIERS, TECTONICS, ICE, SUBDUCTION (GEOLOGY), STRAIN RATE,...

A mechanism has been designed to apply the loads (the stirring and the resection forces and torques) in self-reacted friction stir welding. This mechanism differs somewhat from mechanisms used in conventional friction stir welding, as described below. The tooling needed to apply the large reaction loads in conventional friction stir welding can be complex. Self-reacted friction stir welding has become popular in the solid-state welding community as a means of reducing the complexity of tooling...

Topics: NASA Technical Reports Server (NTRS), FRICTION STIR WELDING, PINS, STIRRING, STRESS DISTRIBUTION,...

150
150

texts

######
eye 150

######
favorite 0

######
comment 0

This viewgraph presentation gives an overview of the control and observation in distributed environments. No existing system meets all our needs (e.g., they cannot be embedded in tools or applications and have limited fault management functionality). The goals of our infrastructure include the following: (1) to develop a general framework for observation and control; (2) the framework should be extensible for specific tasks; and (3) it must be compatible with emerging standards.

Topics: CRYSTALLOGRAPHY, COSTS, FATIGUE (MATERIALS), FINITE ELEMENT METHOD, HIGH TEMPERATURE, DUCTILITY,...

26
26

texts

######
eye 26

######
favorite 0

######
comment 0

Furnaces are most commonly used for melting of materials. Induction furnaces are more beneficial as no fuel is required. It is a problem to find life cycle of Induction Melting Furnace Wall under load variation. The induction melting furnace wall is made of alumina ramming mass which is one kind of refractory material. The failure occurs due to cyclic thermal stresses due to heating and cooling cycles. Temperature distribution and thermal stress distribution fields of the induction melting...

Topics: Advanced stress life analysis, Temperature distribution, Stress distribution, explicit finite...

The analytical approach used to develop a novel fatigue crack growth coupon for highly plastic stress field condition is presented in this paper. The flight hardware investigated is a large separation bolt that has a deep notch, which produces a large plastic zone at the notch root when highly loaded. Four test specimen configurations are analyzed in an attempt to match the elastic-plastic stress field and crack constraint conditions present in the separation bolt. Elastic-plastic finite...

Topics: NASA Technical Reports Server (NTRS), CRACK PROPAGATION, FATIGUE (MATERIALS), STRESS DISTRIBUTION,...

This paper presents the concept and a design methodology for robust damage-mitigating control (DMC) of aircraft. The goal of DMC is to simultaneously achieve high performance and structural durability. The controller design procedure involves consideration of damage at critical points of the structure, as well as the performance requirements of the aircraft. An aeroelastic model of the wings has been formulated and is incorporated into a nonlinear rigid-body model of aircraft flight-dynamics....

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT CONTROL, DAMAGE, DURABILITY, AEROELASTICITY, STRESS...

Bell System Technical Journal, 52: 9. November 1973 pp 1579-1588. Optical Fiber End Preparation for Low-Loss Splices. (Gloge, D.; Smith, P.W.; Bisbee, D.L.; Chinnock, E.L.)

Topics: fiber, fracture, fibers, splice, splices, silica, glass, optical, stress, hackle, optical fibers,...

Dielectric insulators are used in a variety of laboratory settings when performing experiments in rock mechanics, petrology, and electromagnetic studies of rocks in the fields of geophysics,material science, and civil engineering. These components may be used to electrically isolate geological samples from the experimental equipment, to perform a mechanical compliance function between brittle samples and the loading equipment, to match ultrasonic transducers, or perform other functions. In...

Topics: NASA Technical Reports Server (NTRS), DIELECTRICS, INSULATORS, ROCK MECHANICS, ELECTRIC POTENTIAL,...

FATIG computes fatigue damage/fatigue life using the stress rms (root mean square) value, the total number of cycles, and S-N curve parameters. The damage is computed by the following methods: (a) traditional method using Miner s rule with stress cycles determined from a Rayleigh distribution up to 3*sigma; and (b) classical fatigue damage formula involving the Gamma function, which is derived from the integral version of Miner's rule. The integration is carried out over all stress amplitudes....

Topics: NASA Technical Reports Server (NTRS), DAMAGE, FATIGUE (MATERIALS), PROBABILITY THEORY, COMPUTER...

The problem of a cracked plate reinforced by a line stiffener is reconsidered. The original solution of this problem was given in the literature. Also, a variation of the problem with debonding between the plate and the stiffener near the cracked region was reported in the literature. However, the special case of the problem in which the crack tip terminates at the stiffener does not appear to have been studied. In practice, the solution may be necessary in order to assess the crack arrest...

Topics: NASA Technical Reports Server (NTRS), CRACKING (FRACTURING), PLATES (STRUCTURAL MEMBERS),...

Fatigue life consists of crack nucleation and crack propagation periods. Fatigue crack nucleation period is shorter relative to the propagation period at higher stresses. Crack nucleation period of low cycle fatigue might even be shortened by material and fabrication defects and by environmental attack. In these cases, fatigue life is largely crack propagation period. The characteristic crack tip field was studied by the finite element method, and the crack tip field is related to the far field...

Topics: NASA Technical Reports Server (NTRS), CRACK INITIATION, CRACK PROPAGATION, CRACK TIPS, FATIGUE...

Cryogenic vessels, such as the Space Shuttle External Tank, are often insulated with closed-cell foam because of its low thermal conductivity. The coefficient of thermal expansion mismatch between the foam and metallic substrate places the foam under a biaxial tension gradient through the foam thickness. The total foam thickness affects the slope of the stress gradient and is considered a significant contributor to the initiation of subsurface cracks. Rigid polymeric foams are brittle in nature...

Topics: NASA Technical Reports Server (NTRS), FOAMS, CRACK INITIATION, CRACK PROPAGATION, EXTERNAL TANKS,...

The main objective of this project is to study the characteristics of different alloys such as Steel, Aluminum and Cast Iron and to the design and analyze the stress distribution of the piston with a suitable material above the actual engine condition for a heavy duty diesel engine. In this paper, thermal analysis and mechanical analysis is done. The parameters used for the analysis are operating gas pressure, temperature and material properties of the piston. In I.C. Engine, a piston is most...

Topics: Design and Analyze, Analysis of Piston & Stress Distribution

Purpose of research on rough-to-smooth transition of an equilibrium neutral constant stress layer is to develop a model for low-level atmospheric flow over terrains of abruptly changing roughness, such as those occurring near the windward end of a landing strip, and to use the model to derive functions which define the extent of the region affected by the roughness change and allow adequate prediction of wind and shear stress profiles at all points within the region. A model consisting of two...

Topics: NASA Technical Reports Server (NTRS), ROUGHNESS, STRESS ANALYSIS, ATMOSPHERIC CIRCULATION, BOUNDARY...

Experimental results of the mechanical behavior of two metal matrix composite systems at room temperature are presented. Ultimate stress, ultimate strain, Poisson's ratio, and initial Young's Modulus are documented for BORSIC/Aluminum in uniaxial tension and Boron/Aluminum in uniaxial tension and compression. Poisson's ratio is used for nonlinear stress-strain behavior. A comparison of compression results for B/Al as obtained from sandwich beam compression specimens and IITRI coupon compression...

Topics: NASA Technical Reports Server (NTRS), AXIAL COMPRESSION LOADS, COMPRESSION TESTS, METAL MATRIX...

A ceramic/metallic aircraft gas turbine outer gas path seal designed to enable improved engine performance is studied. Flexible numerical analysis schemes suitable for the determination of transient temperature profiles and thermal stress distributions in the seal are outlined. An estimation of the stresses to which a test seal is subjected during simulated engine deceleration from sea level takeoff to idle conditions is made. Experimental evidence has indicated that the surface layer of the...

Topics: NASA Technical Reports Server (NTRS), GAS TURBINE ENGINES, SEALS (STOPPERS), STRESS ANALYSIS,...

A two-dimensional hybrid stress finite element analysis is described which was used to study the local stress field around delamination cracks in composite materials. The analysis employs a crack tip singularity element which is embedded in a matrix interlayer between plies of the laminate. Results are given for a unidirectional graphite/epoxy laminate containing a delamination emanating from a surface crack through the outside ply. The results illustrate several aspects of delamination cracks:...

Topics: NASA Technical Reports Server (NTRS), COMPOSITE MATERIALS, LAMINATES, REINFORCING FIBERS, SURFACE...

The performance of the NASTRAN level 16.0, twenty node, isoparametric bricks (CIHEX2) at thermal loading was studied. A free ceramic plate was modelled using twenty node bricks of varying thicknesses. The thermal loading for this problem was uniform over the surface with an extremely large gradient through the thickness. No mechanical loading was considered. Temperature-dependent mechanical properties were considered in this analysis. The NASTRAN results were compared to one dimensional stress...

Topics: NASA Technical Reports Server (NTRS), CERAMICS, NASTRAN, STRESS ANALYSIS, THERMAL STRESSES,...

The elastostatic problem for a nonhomogeneous plane which consists of two sets of periodically arranged dissimilar orthotropic strips is considered. It is assumed that the plane contains a series of collinear cracks perpendicular to the interfaces and is loaded in tension away from and perpendicular to the cracks. Cracks fully imbedded into the homogenous strips were analyzed as well as the singular behavior of the stresses for two special crack geometries. The analysis of cracks crossing...

Topics: NASA Technical Reports Server (NTRS), CRACKS, LAMINATES, ORTHOTROPISM, REINFORCING FIBERS, RIBBONS,...

A computerized analysis of the nonlinear behavior of fibrous composite laminates including axial loading, thermal loading, temperature dependent properties, and edge effects is presented. Ramberg-Osgood approximations are used to represent lamina stress-strain behavior and percent retention curves are employed to model the variation of properties with temperature. Balanced, symmetric laminates comprised of either boron/epoxy, graphite/epoxy, or borsic-aluminum are analyzed using a...

Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, LAMINATES, NONLINEARITY, REINFORCING...

The fracture problem of laminated plates which consist of orthotropic layers is considered. Symmetrical cracks are located normal to the bimaterial interfaces. The external loads are applied away from the crack region. Three cases are considered: (a) the case of internal cracks; (b) the case of broken laminates; and (c) case of a crack crossing the interface. A general formulation of the problem is given for plane strain and generalized plane stress cases. The singular behavior of stresses at...

Topics: NASA Technical Reports Server (NTRS), COMPOSITE STRUCTURES, FRACTURE MECHANICS, FRACTURES...

Elastic bodies or systems may not require external energy for certain finite and continuous deformations. Conditions providing these kinds of effortless, or neutral, deformations are discussed.

Topics: NASA Technical Reports Server (NTRS), DYNAMIC STRUCTURAL ANALYSIS, ELASTIC DEFORMATION, STRAIN...

The stress-intensity factor solutions proposed for a surface crack in a finite plate subjected to uniform tension are reviewed. Fourteen different solutions for the stress-intensity factors are compared. These solutions were obtained over the past 16 years using approximate analytical methods, experimental methods, and engineering estimates. The accuracy is assessed of the various solutions by correlating fracture data on surface-cracked tension specimens made of a brittle epoxy material....

Topics: NASA Technical Reports Server (NTRS), CRACK INITIATION, STRESS DISTRIBUTION, EPOXY RESINS, FAILURE...

An extension is presented of Rice's classic solution for the exceedances of a constant level by a single random process to its counterpart for an n-dimensional vector process. An interaction boundary, analogous to the constant level considered by Rice for the one-dimensional case, is assumed in the form of a hypersurface. The theory for the numbers of boundary exceedances is developed by using a joint statistical approach which fully accounts for all cross-correlation effects. An exact...

Topics: NASA Technical Reports Server (NTRS), DYNAMIC STRUCTURAL ANALYSIS, RANDOM LOADS, STRESS...

Cyclic creep response was investigated and design methods applicable to thermal protection system structures were developed. The steady-state (constant temperature and load) and cyclic creep response characteristics of four alloys were studied. Steady-state creep data were gathered through a literature survey to establish reference data bases. These data bases were used to develop empirical equations describing creep as a function of time, temperature, and stress and as a basis of comparison...

Topics: NASA Technical Reports Server (NTRS), CREEP ANALYSIS, HEAT RESISTANT ALLOYS, HEAT SHIELDING, SPACE...

The line method of analysis is applied to the Navier-Cauchy equations of elastic equilibrium to calculate the displacement field in a finite geometry bar containing a variable depth rectangular surface crack under extensionally applied uniform loading. The application of this method to these equations leads to coupled sets of simultaneous ordinary differential equations whose solutions are obtained along sets of lines in a discretized region. Using the obtained displacement field, normal...

Topics: NASA Technical Reports Server (NTRS), SOLIDS, STRESS ANALYSIS, SURFACE CRACKS, CRACK OPENING...

Eolian erosion and deposition on earth was studied in order to interpret the eolian land forms of Mars. Emphasis of the wind tunnel studies was on the flow field around models of eolian forms. Areas of the wind tunnel studies include: simulation of the atmospheric boundary layer; velocity profile measurements around different models in the desert boundary layer, and estimating shear stress distributions on the model surfaces; flow visualization techniques; streamline mapping using tuft...

Topics: NASA Technical Reports Server (NTRS), MARS SURFACE, WIND EFFECTS, ATMOSPHERIC BOUNDARY LAYER, FLOW...

Cyclic debonding rates were measured during constant-amplitude loading of specimens made of graphite/epoxy bonded to aluminum and S-glass/epoxy bonded to aluminum. Both room-temperature and elevated-temperature curing adhesives were used. Debonding was monitored with a photoelastic coating technique. The debonding rates were compared with three expressions for strain-energy release rate calculated in terms of the maximum stress, stress range, or a combination of the two. The debonding rates...

Topics: NASA Technical Reports Server (NTRS), ADHESIVE BONDING, ALUMINUM, EPOXY RESINS, FATIGUE TESTS,...

Mode 1 stress intensity coefficients were obtained for an edge-cracked disk (round compact specimen). Results for this plane elastostatic problem, obtained by a boundary collocation analysis are presented for ratios 0.35 less than A/D less than 1, where A is the crack length and D is the disk diameter. The results presented are for two complementary types of loading. By superposition of these results the stress intensity factor K sub I for any practical load line location of a pin-loaded round...

Topics: NASA Technical Reports Server (NTRS), DISKS (SHAPES), LOADS (FORCES), MODE (STATISTICS), STRESS...

Two-dimensional duct flow computations for radial distributions of velocity, temperature, and electrical conductivity are reported. Calculations were carried out for the flow conditions representative of a hydrogen-oxygen combustion driven MHD duct. Results are presented for: profiles of developing flow in a smooth duct, and for profiles of fully developed pipe flow with a specified streamwise shear stress distribution. The predicted temperature and electrical conductivity profiles for the...

Topics: NASA Technical Reports Server (NTRS), DUCTED FLOW, FLOW EQUATIONS, MAGNETOHYDRODYNAMIC FLOW, TWO...

A new calculation of the effects of thermal stresses during growth on silicon ribbon quality is reported. Thermal stress distributions are computed for ribbon growth under a variety of temperature profiles. A growth rate of 55 cu cm/min with a single ribbon was achieved. The growth of RTR ribbon with a fairly uniform parallel dendritic structure was demonstrated. Results with two approaches were obtained for reducing the Mo impurity level in polycrystalline feedstock. Coating the Mo substrate...

Topics: NASA Technical Reports Server (NTRS), CRYSTAL GROWTH, SILICON, THERMAL STRESSES, MOLYBDENUM,...

The influence of hole quality on the structural behavior of composite materials was investigated. From an industry survey it was determined that the most frequent imperfections encountered during hole fabrication are chipout, delamination, and oversize conditions. These hole flaw types were generated in critical areas of static, compression, and fatigue specimens fabricated from T300/5208 graphite/epoxy system. The specimens were tested in static and cyclic pin bearing modes in addition to...

Topics: NASA Technical Reports Server (NTRS), GRAPHITE-EPOXY COMPOSITES, HOLES, HOLES (MECHANICS), JOINTS...

Algorithms are developed for computing stresses in a semi-infinite body when loaded by a uniform pressure acting over a circular area. The algorithm allows easy determination of any stress component in a semi-infinite body having a known Poisson's ratio. Example curves are plotted for Portland cement grout and metal representative values.

Topics: NASA Technical Reports Server (NTRS), CIRCULAR CYLINDERS, STATIC LOADS, STRESS DISTRIBUTION,...

The calculated stresses and displacements induced anisotropic plates by short duration impact forces are presented. The theoretical model attempts to model the response of fiber composite turbine fan blades to impact by foreign objects such as stones and hailstones. In this model the determination of the impact force uses the Hertz impact theory. The plate response treats the laminated blade as an equivalent anisotropic material using a form of Mindlin's theory for crystal plates. The analysis...

Topics: NASA Technical Reports Server (NTRS), COMPOSITE MATERIALS, IMPACT TESTS, STRESS ANALYSIS,...

A predictive method for the titled flows based on the Prandtl energy method was developed and assessed by comparing predicted results with experimental results. For constant-density flows, both gross properties such as spreading rate and maximum turbulent kinetic energy and detailed properties such as mean shear stress distributions are shown to be well predicted. For variable-density flows, considerable attention is devoted to the inclusion in the analysis of the added effect of pressure...

Topics: NASA Technical Reports Server (NTRS), TURBULENT MIXING, TWO DIMENSIONAL FLOW, DENSITY...

A quasi three dimensional finite element analysis was used to analyze the edge stress problem in four-ply, composite laminates. Convergence studies were made to explore the existence of stress singularities near the free edge. The existence of stress singularities at the intersection of the interface and the free edge is confirmed.

Topics: NASA Technical Reports Server (NTRS), DELAMINATING, EDGES, FINITE ELEMENT METHOD, INTERFACES,...

Issues which impact on the interpretation and quantification of proof test benefits are reviewed. The importance of each issue in contributing to the extra quality assurance conferred by proof testing components is discussed, particularly with respect to the application of advanced fracture mechanics concepts to enhance the flaw screening capability of a proof test analysis. Items covered include the role in proof testing of elastic-plastic fracture mechanics, ductile instability analysis,...

Topics: NASA Technical Reports Server (NTRS), FAULT DETECTION, FRACTURE MECHANICS, NONDESTRUCTIVE TESTS,...

It is common practice to use split sleeve coldworking of fastener holes as a means of extending the fatigue life of metal structures. In search of lower manufacturing costs, the aerospace industry is examining the split mandrel (sleeveless) coldworking process as an alternative method of coldworking fastener holes in metal structures. The split mandrel process (SpM) significantly extends the fatigue life of metal structures through the introduction of a residual compressive stress in a manner...

Topics: NASA Technical Reports Server (NTRS), AEROSPACE INDUSTRY, COMPRESSION LOADS, COST REDUCTION,...

Cold working holes for improved fatigue life of fastener holes are widely used on aircraft. This paper presents methods used by the authors to determine the percent of cold working to be applied and to analyze fatigue crack growth of cold worked fastener holes. An elastic, perfectly-plastic analysis of a thick-walled tube is used to determine the stress field during the cold working process and the residual stress field after the process is completed. The results of the elastic/plastic analysis...

Topics: NASA Technical Reports Server (NTRS), COLD WORKING, CRACK PROPAGATION, FASTENERS, FATIGUE LIFE,...

Large-eddy simulations of a turbulent boundary layer with Reynolds number based on displacement thickness equal to 3500 were performed with two grid resolutions. The computations were continued for sufficient time to obtain frequency spectra with resolved frequencies that correspond to the most important structural frequencies on an aircraft fuselage. The turbulent stresses were adequately resolved with both resolutions. Detailed quantitative analysis of a variety of statistical quantities...

Topics: NASA Technical Reports Server (NTRS), TURBULENT BOUNDARY LAYER, WALL PRESSURE, PRESSURE...

In an effort to support the design of zirconium diboride composite leading edges for hypersonic vehicles, a finite element model (FEM) of a prototype leading edge was created and finite element analysis (FEA) was employed to assess its thermal and structural response to aerothermal boundary conditions. Unidirectional material properties for the structural components of the leading edge, a continuous fiber reinforced diboride composite, were computed with COSTAR. These properties agree well with...

Topics: NASA Technical Reports Server (NTRS), LEADING EDGES, AEROTHERMODYNAMICS, FINITE ELEMENT METHOD,...

A solution is presented for the problem of a finite length crack branching off the interface between two bonded dissimilar isotropic materials. Results are presented in terms of the ratio of the energy release rate of a branched interface crack to the energy release rate of a straight interface crack with the same total length. It is found that this ratio reaches a maximum when the interface crack branches into the softer material. Longer branches tend to have smaller maximum energy release...

Topics: NASA Technical Reports Server (NTRS), CRACK INITIATION, CRACK PROPAGATION, FRACTURE MECHANICS,...

Generally, two types of theory are used to describe the field equations for suspensions. The so-called postulated equations are based on the kinetic theory of mixtures, which logically should give reasonable equations for solutions. The basis for the use of such theory for suspensions is tenuous, though it at least gives a logical path for mathematical arguments. It has the disadvantage that it leads to a system of equations which is underdetermined, in a sense that can be made precise. On the...

Topics: NASA Technical Reports Server (NTRS), MULTIPHASE FLOW, SOLUTIONS, STRESS DISTRIBUTION, CONSTITUTIVE...

Techniques were developed and described for performing three-dimensional finite element analysis of plain weave composites. Emphasized here are aspects of the analysis which are different from analysis of traditional laminated composites, such as the mesh generation and representative unit cells. The analysis was used to study several different variations of plain weaves which illustrate the effects of tow waviness on composite moduli, Poisson's ratios, and internal strain distributions....

Topics: NASA Technical Reports Server (NTRS), FIBERS, LAMINATES, PLY ORIENTATION, STRESS ANALYSIS, STRESS...

Delamination is a common failure mode of laminated composite materials. Edge delamination is important since it results in reduced stiffness and strength of the laminate. The tension/torsion load condition is of particular significance to the structural integrity of composite helicopter rotor systems. Material coupons can easily be tested under this type of loading in servo-hydraulic tension/torsion test stands using techniques very similar to those used for the Edge Delamination Tensile Test...

Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, DELAMINATING, FINITE ELEMENT METHOD,...

The mechanical behavior of continuous fiber reinforced SiC/RBSN (Reaction Bonded Silicon Nitride) composites with various fiber contents is evaluated. Both catastrophic and noncatastrophic failures are observed in tensile specimens. Damage and failure mechanisms are identified via in-situ monitoring using NDE (nondestructive evaluation) techniques through the loading history. Effects of fiber/matrix interface debonding (splitting) parallel to fibers are discussed. Statistical failure behavior...

Topics: NASA Technical Reports Server (NTRS), CERAMIC MATRIX COMPOSITES, FIBER COMPOSITES, MATRIX...

A user's guide for the computer program mccm.f is presented. The program is based on a recently developed solution methodology for the inelastic response of an arbitrarily layered, concentric cylinder assemblage under thermomechanical loading which is used to model the axisymmetric behavior of unidirectional metal matrix composites in the presence of various microstructural details. These details include the layered morphology of certain types of ceramic fibers, as well as multiple fiber/matrix...

Topics: NASA Technical Reports Server (NTRS), CERAMIC FIBERS, CONCENTRIC CYLINDERS, METAL MATRIX...

The accuracy and robustness of a two-dimensional smoothing methodology is examined for the problem of recovering accurate interlaminar shear stress distributions in laminated composite and sandwich plates. The smoothing methodology is based on a variational formulation which combines discrete least-squares and penalty-constraint functionals in a single variational form. The smoothing analysis utilizes optimal strains computed at discrete locations in a finite element analysis. These discrete...

Topics: NASA Technical Reports Server (NTRS), FINITE ELEMENT METHOD, INTERLAMINAR STRESS, LAMINATES,...

The axial residual stress distribution as a function of radius was determined from the fiber surface to the core including the average residual stress in the core. Such measurements on boron on tungsten (B/W) fibers show that the residual stresses for 102, 142, 203, and 366 micron diameter fibers were similar, being compressive at the surface and changing monotonically to a region of tensile within the boron. At approximately 25 percent of the original radius, the stress reaches a maximum...

Topics: NASA Technical Reports Server (NTRS), AXIAL STRESS, BORON REINFORCED MATERIALS, RESIDUAL STRESS,...