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La polyarthrite rhumatoïde (PR) est une maladie prévalente et invalidante qui est à l'origine de coûts directs et indirects importants. La stratégie thérapeutique actuellement recommandée repose sur l'introduction rapide d'un traitement à base d'antirhumatismaux modificateurs de la maladie conventionnels, associée à un suivi régulier de la maladie par le rhumatologue. Le caractère onéreux d'un tel suivi intensif a motivé le développement de nouvelles stratégies moins exigeantes, telles que la télémédecine. Cette étude consistait à estimer le coût-utilité d'une interface de suivi connectée, BodySens, via un smartphone chez les patients atteints de polyarthrite rhumatoïde débutant un nouveau traitement sur six mois de suivi.

AbstractAimsPeople who make medically serious suicide attempts (MSSAs) share a number of features with those who die by suicide, and are at a high risk of suicide themselves. Studies to date have mostly focused on clinical samples of MSSAs. An epidemiological examination at a national level can help to identify risk profiles and pathways of care in this population.MethodsWe explored the French nationwide hospital discharge database (Programme de Médicalisation des Systèmes d'Information, PMSI) to identify any MSSA taking place between 2012 and 2019. Relevant demographic and medical information was collected about the first MSSA of each attempter. Data from 2010 and 2011 were used to verify the absence of prior attempts.ResultsFirst occurrences of MSSAs amounted to 81 959 cases over 8 years, with a mean age of 45.8 years, and 53.6% women. Incidence was higher in women (18.1 v. 17.3 per 1 00 000). The most common suicide method was deliberate self-poisoning (64.9% of cases). In comparison, violent methods associated higher mortality and comorbidity and were more frequent in men. The most common mental disorders were mood disorders (55.6%) and substance use disorders (46.2%). A minority of MSSA survivors were hospitalised in psychiatry (32.5%), mostly women.ConclusionsMSSAs are frequent and easy to identify. There is a need to reinforce the continuity of psychiatric care for this population given the high risk of subsequent suicide, and the low rates of psychiatric hospitalisation after an MSSA even if violent methods are used. Specific care targeting this population could reduce treatment gaps.

Il n’existe à ce jour aucun traitement consensuel des dysfonctions tubaires par obstruction. En cas d’échec de traitements médicamenteux et pressionnels bien conduits, certains auteurs proposent la dilatation tubaire par ballonnet comme alternative thérapeutique. Le but était d’évaluer l’efficacité et l’innocuité de la dilatation tubaire par ballonnet dans cette population.

L’omalizumab (OMA), anticorps monoclonal anti-IgE, peut être prescrit depuis 2015 en France dans les urticaires chroniques spontanées (UCS) résistantes aux antihistaminiques. Une rémission spontanée est possible et il n’existe pas de recommandation sur la durée optimale de traitement par OMA. Notre objectif était d’évaluer les modalités d’arrêt de l’OMA en vie réelle dans une cohorte multicentrique française.

Stresses for the top and bottom of an expansive cylinder in a half-space are investigated. The maximum hoop stress is used for controlled cracking of concrete in demolitions. A design formula is given for determination of spacing between holes necessary to fracture when many holes are lying in a straight line.

Les manifestations cutanées inflammatoires des patients atteints d’une maladie inflammatoire chronique de l’intestin (MICI) traités par anti-TNF affectent environ 1 patient sur 5. La survenue de lésions cutanées péri-orificielles, érosives, fissuraires et impétiginisées est mal comprise. L’objectif de ce travail était de décrire une série de cas de dermatoses inflammatoires péri-orificielles, survenant sous anti-TNF chez des patients MICI et d’évaluer à l’aide d’une population témoin, si la colonisation des gîtes par Staphylococcus aureus(S. aureus) ou la présence de carences vitaminiques étaient des facteurs de risque d’apparition de ces lésions.

Background:Inherited factor (F)VII deficiency is the commonest of the rare bleeding disorders, with a wide set of hemorrhagic features. Other than for the severe clinical forms (for which treatment guidelines are well defined), consistent recommendations regarding perioperative replacement management do not exist for mild and asymptomatic FVII‐deficient patients. Objectives:The present study aimed to evaluate the influence of bleeding history, FVII procoagulant activity levels (FVII:C) and the type of surgical procedure on the management of inherited FVII‐deficient patients before surgery. Patients:One hundred and fifty‐seven surgical procedures, performed without replacement therapy, in 83 unrelated FVII‐deficient patients (median FVII:C = 5%, range 0.6%–35%) were analyzed. Results:The overall bleeding rate was 15.3%. We found a significant relationship between previous deep traumatic hematomas and bleeding at surgery, although relationships with previous common epistaxis, easy bruising and menorrhagia were not significant. The receiver‐operating characteristic (ROC) curve analysis performed on the first 83 procedures allowed us to define a cut‐off value of 7% with a sensitivity of 87% (negative predictive value: 94%). To enhance the sensitivity, and to take into account the potential variation resulting from non‐standardized FVII:C measurements, we would suggest applying a threshold of 10%. Conclusion:We have proposed recommendations for the perioperative management of FVII‐deficient patients based on FVII:C levels, a thorough bleeding history and the type of surgery involved. By applying these recommendations, minor procedures that risk only external or controlled hemorrhage can be performed in asymptomatic or mildly affected adults, even those with FVII:C levels below 10%.

Abstract: The dislocation dipole accumulation model for fatigue crack initiation previously proposed by the authors is extended to an analysis of the fatigue strength reduction due to inclusions in high strength alloys. The initiation of a fatigue crack is determined by an energy criterion under the assumption that the crack initiation takes place when the self strain energy of dislocation dipoles accumulated at the damaged part in the material reaches a critical value. Explicit formulae for the crack initiation criterion in several cases are derived as functions of the applied stress, the inclusion size, the slip band shape, and the shear moduli of the inclusion and matrix. The following three types of fatigue crack initiation at inclusions are considered: the slip-band crack emanating from a debonded inclusion, the inclusion cracking due to impinging of slip bands, and the slip-band crack emanating from an uncracked inclusion. The first mechanism was reported to be operative in high strength steels, while the last two mechanisms were reported in high strength aluminum alloys. The present theoretical results are in good agreement with the experimental data published for each case of fatigue crack initiation at inclusions.

Description of a disc-shaped geothermal reservoir, pressurized and subject to thermal stresses, is given in terms of notions employed in mechanics of ductile fracture. The reservoir is assumed to extend in an infinite isotropic and impermeable medium. Range of the analysis, however, is extended to include a possibility of quasi-static stable cracking occurring along the reservoir circumference prior to spontaneous fracture. Extensive microcracking occuring in the region adjacent to the crack front prior to the onset of crack growth (and in the presence of high tectonic pressure encountered in a geothermal system) provides a stabilizing effect, similar in its nature to ductility exhibited in metal fracture.

The concept of Griffith fracture theory was extended to fatigue crack propagation problems by defining the Gibbs free energy of solids under cyclic loading.

This paper discusses the stress fields when a spheroidal inclusion, free to slip along its interface, is subjected to a constant nonshear eigenstrain, and when an elastic body containing the inhomogeneity is under all-around tension or uniaxial tension at infinity. In each case the stress field in the inclusion or the inhomogeneity is not constant, contrary to Eshelby's solution. When sliding takes place, the stress increases locally compared with the perfect bonding case, but the elastic energy decreases due to the relaxation. The relative displacement (slip) along the interface is also evaluated.

A new approach to estimate the overall behavior of an inhomogeneous body is applied to investigate the average elastic-plastic state of composite materials in small deformation. The method is based on the concept of the average field of an infinite body with inhomogeneities, which is replaced by an equivalent body with homogeneous inclusions having appropriate eigenstrains that are composed of the actual plastic misfit strains and the properly determined eigenstrains by the equivalent replacement of the inhomogeneities. A simple example is given for a pure shear state of the elastic-perfectly plastic composite materials with spherical inhomogeneities. The overall hardening rate, quantitative estimate of ductility improvement, and unloading behavior are discussed.

We propose the extended Hamilton's principle to investigate the dynamic plastic behavior of a beam or a plate under an impact loading. Material is assumed to be rigid perfectly plastic. The impact loading is given in the form of initial velocity. Good agreement between our numerical solutions and experimental results done by Parkes and Jones indicates that the proposed variational method is a powerful approximation method for the dynamic plasticity analysis. The effect of strain-rate sensitivity on the permanent deflection of a plate is investigated in some detail. Instead of nonlinear differential equations, nonlinear algebraic equations are solved in the proposed method.

The equivalency equations and the nature of the solution are investigated when an inhomogeneity under applied stresses is simulated by an inclusion with eigenstrains. The equivalency equations by which the equivalent eigenstrain is obtained becomes singular when the inhomogeneity is void and the applied stress has a form of polynomials of coordinates of degree one. The solutions of the system of the equivalency equations are not uniquely determined. Explicit expressions are given for the impotent eigenstrains which do not generate any stress field throughout a material.

The stress and displacement fields due to an eigenstrain outside of an ellipsoid are analyzed both inside and outside the ellipsoid and are given in terms of nonsingular surface integrals. Constant and inverse power eigenstrains are discussed as examples.

The present paper extends the dislocation dipole accumulation model to describe crack initiation in contact fatigue. The fatigue life under contact loading is calculated from an elastic solution. The plastic deformation may be taken into account by considering multi-slip layers. The present calculations show a qualitative consistency with experimental observations, although some additional parameters, such as the reversibility of dislocation pileup, are needed to make the theoretical prediction more comparable to the experimental data.

An attempt is made to correlate some morphological characteristics of pitting cracks with a simple asperity interaction model. The stress field created by a semispherical pressure is combined with the macroscopic Hertzian stress field. For the initiation of fatigue cracks, emphasis is given to two stresses: the maximum range of the superimposed average shear stress over a semicircular area inclined at an angle α to the rolling surface; and the maximum of the superimposed average normal stress over the same semicircular area. Possible mechanisms for initiation of surface pitting are proposed.

Elastic fields of a single ellipsoidal inhomogeneity embedded in an infinite elastic matrix subjected to plane time-harmonic waves are studied by employing the concept of eigenstrain and the extended version of Eshelby’s method of equivalent inclusion. Using the dynamic version of the Betti-Rayleigh reciprocal theorem, an integral representation of the displacement field, due to the presence of inhomogeneity, is given in terms of the eigenstrains. Two types of eigenstrains arise in the elastodynamic case. Expanding the eigenstrains and applied strains in the polynomial form in the position vector r and satisfying the equivalence conditions at every point, the governing simultaneous algebraic equations for the unknown coefficients in the eigenstrain expansion are derived. Elastodynamic field outside an ellipsoidal inhomogeneity in a linear elastic isotropic medium is given as an example. The angular and frequency dependence of the induced displacement field, which is in fact the scattered displacement field, the differential and the total cross sections are formally given in series expansion form for the case of uniformly distributed eigenstrains.

The problem of a plane crack in an infinite solid under normal internal pressure is formulated to result in an integral equation for the unknown normal stresses on the plane of the crack. Once these stresses are determined the stress intensity factor, KI, around the crack edge and the normal displacements of points inside the crack region are obtained numerically. The crack contour shape and the normal loading of the crack can be arbitrary. In this paper the integral equation is solved numerically and the stress intensity factor, KI, is obtained for cracks subjected to uniform and linearly varying normal pressure and having various convex contour shapes.

Using dislocation pileup theory, a model is given for the prediction of crack initiation life under contact fatigue. Near surface crack initiation is investigated by introducing the sliding contact boundary condition. Crack initiation originated at the surface and substrate are treated as extreme cases. The new model physically explains how a surface crack can be initiated and shows that the surface crack initiation life should be shorter than the subsurface crack initiation life under the same stress amplitude conditions. A discussion is given about the influence of residual stress, hardness, temperature, irreversibility of the plastic deformation, as well as other parameters that affect the crack initiation life. Preliminary comparisons show that the new model agrees well with the experimental observations of surface and near surface crack initiation.

The three-dimensional stress distribution for a periodic array of penny-shaped cracks in an infinite isotropic elastic solid under arbitrary uniform loadings is considered by means of the Somigliana dislocation method. The displacement discontinuity of the Somigliana dislocations, by which the penny-shaped cracks are simulated mathematically, is assumed to be in the form p(x'1, x'2)(1 − x'12− x'22)½. The unknown polynomial p(x'1, x'2) is determined from the boundary conditions on the surfaces of the penny-shaped cracks. It is shown that the singular behavior of the three-dimensional stresses in the vicinity of the crack border is easily examined and the stress intensity factors can be expressed explicitly as functions of position along the crack border. Numerical results for the stress intensity factors are shown for the case of the periodic array of coplanar penny-shaped cracks.

Stresses for the top and bottom of an expansive cylinder in a half-space are investigated. The maximum hoop stress is used for controlled cracking of concrete in demolitions. A design formula is given for determination of spacing between holes necessary to fracture when many holes are lying in a straight line.

Plane-deformation problems of thermal stresses around an elastic ribbonlike conductor in an infinite, homogeneous, isotropic medium under uniform heat flow are analyzed by the method of continuous distribution of singular points. The line heat sources and concentrated forces are distributed continuously along the ribbonlike conductor. The boundary conditions yield a system of singular integral equations for density functions with Cauchy kernels and logarithmic singular kernel. A solution is assumed in the form of the product of a series of Chebyshev polynomials of the first kind and their weight function and is determined by transforming the singular integral equations into linear algebraic equations. One of the advantages of this method is that the strength of the thermal-stress singularity at the tips of the ribbonlike conductor can be easily evaluated. Numerical results for the strength of the thermal-stress singularity are plotted in terms of nondimensional parameters, consisting of the dimensions of the ribbonlike conductor and the material constants of the conductor and matrix.

The open system elastic constants for a multicomponent alloy are derived and used to determine the equilibrium solute concentration profile surrounding an isolated coherent M2C carbide precipitate with a transformation strain with three unequal eigenstrains in an elastically anisotropic AF1410 steel. The open system bulk modulus was found to vary with stress in this alloy, indicating that the chemical thermodynamics of AF1410 in an open system can result in the material becoming nonlinearly elastic. However, the open system shear moduli are identical to their usual constant composition values as a result of the cubic symmetry of the solute expansion tensor. We find that the nonuniform stress field surrounding the misfitting precipitate will induce significant nonuniformities in the concentration of the chemical components in this alloy. At certain positions in the matrix, the change in the concentration of Cr and Mo due to the elastic stresses, relative to their average concentrations in the alloy, can be as large as 100 to 250 pct. Although the solute redistribution reduces the matrix effective bulk modulus by 12 pct, the coherent carbide elastic self-energy is reduced by only 0.45 pct, reflecting a large contribution of shear distortions to the elastic self-energy, which are relatively unaffected by the dilating solutes.

Transform methods are used to solve the problem of an elastic quarter space subjected to tractions on its surface. The present analysis uses the reflection principle to formulate problem as the solution of unknown residual surface tractions. A Fourier transform is taken in the direction of the edge of the quarter space. The problem is thereby reduced to decouplable integral equations, which are similar to those for the elastic quarter plane. Field quantities are obtained by performing the appropriate inverse transforms and the present results are compared with those of Hetenyi for the normally loaded case. Additional results are given for the cases of tangential surface loading.

Qualitative considerations are given in the present paper concerning the effects of localized plastic deformation on the fatigue crack initiation life and stress intensity factor of a microcrack. The localized plastic zone is modelled as an elliptical inhomogeneity with eigenstrains. With the consideration of this localized plastic deformation, the calculated crack initiation cycle number is greater and the stress intensity factor of a micro-crack lower than those obtained without considering the plastic deformation effect.

The interaction problem of adhesive contact between an axisymmetrically loaded thin circular plate and an isotropic or transversely isotropic elastic half-space is reduced to a problem of solving a pair of coupled integral equations for the unknown normal and shearing interfacial tractions. The system of integral equations is solved numerically and some results are presented.

The stress relaxation caused by diffusion round a second-phase particle has been measured by internal friction in Al-Si alloys. Reproducible clear internal-friction peaks were found at ∼420 K at a frequency of ∼ 1 Hz. These were unambiguously assigned to the presence of Si particles in Al. In accordance with a theory of the relaxation caused by diffusion along the matrix - particle interface, the relaxation time is proportional to the third power of the particle size. The activation energy and the pre-exponential factor of this diffusion are ∼ 0·92 eV and ∼ 3·9 × 10-5 m2/s, respectively. The magnitude of the relaxation strength agrees with the theory.

The elastic field produced by a straight dislocation dipole in an unbounded anisotropic elastic medium is investigated in the framework of the elastic continuum approximation. The problem is formulated on the basis of the solution of eigen-strain problem of anisotropic media. The result is expressed by line integrals along a contour on a unit sphere.

When plastic damage regions are accumulated in a material, there exist residual displacements on the surface of the material after all the loadings are removed. The residual displacements are defined as the difference between before and after loading, and can be measured experimentally without destruction of the material. This paper addresses the problem of evaluating the residual stress field caused by the accumulation of the plastic damage regions in a subdomain of the material. The problem is formulated as a system of integral equations relating the surface displacements to the unknown plastic strains. The damage domain, which appears as the domain of integration of the integral equations, is also unknown. Determination of the shape of the damage domain, together with the plastic strains, is a very complicated nonlinear problem. In addition to the residual surface displacement data, it requires more information about the loading history or other restrictive assumptions. However, the residual stress field in the vicinity of the damage domain is obtained after the equivalent damage domain and the equivalent plastic strains are introduced. The problem is an inverse problem, which is substantially different from the conventional forward analysis of structural mechanics. Special attention is given to the uniqueness and stability of the solution.

The elastic fields due to a spheroidal inclusion, which undergoes constant shear eigenstrains and a spheroidal inhomogeneity under uniform shear stress applied at infinity are investigated. The interface between the material and the spheroid allows free sliding (cannot sustain shear tractions). The Papkovich-Neuber displacement potentials in the form of infinite series are used in the analysis. The dependence of stresses and displacements on the shear moduli ratio, Poisson's ratio and the shape of the subdomain is analyzed. It is discovered that stresses in the sliding spheroidal subdomain are not uniform, unlike the perfectly bonded inclusion solution where Eshelby's result holds. The applications to the evaluation of average elastic properties of the composites with sliding interfaces are also investigated and it is observed that sliding causes relaxation of the elastic moduli.

The present paper reconsiders the inhomogeneity problem via an elastic modulus perturbation approach. By using the eigenstrain concept, the inhomogeneity problem is converted to a series of inclusion problems in the present modulus perturbation procedure. A homogeneous state is chosen as reference state or the 0th order solution. Some extensions of the modulus perturbation approach by example are also discussed in the paper.

The initiation and propagation of fatigue cracks in bonded sheets are investigated. Two sheets of 2024 T346 aluminum alloy are bonded together either with CC15 or Epoxy adhesive and a center notch is created in one of them. The bonded second sheet tends to reduce the stress intensity factor at the tip of the notch in the first sheet, thereby retarding both crack initiation and propagation. The experiment is compared with calculated reductions in stress intensity factor and the crack growth results show reasonable agreement.

The present review on inclusion problems emphasizes papers primarily published after 1982. Materials associated with inclusions are composite materials, precipitated or transformed alloys, porous media, and polycrystals. The inclusion problems deal with the following subjects of these materials: (1) stress fields caused by non-elastic strains (eigenstrains) and; (2) stress disturbances due to heterogeneity and inhomogeneities of materials under applied stresses; (3) average elastic moduli and average thermal properties; (4) nonelastic constitutive equations; (5) behavior of inclusions including nucleation, growth, and collapse of voids; (6) cracks and inclusions including the transformation toughening, crack growth through composites and stress intensity factors; (7) sliding and debonding inclusions; and (8) dynamic effects of inclusions. The present review is an update to the review paper, which appeared in Applied Mechanics Reviews, Volume 41 (1988), and includes opinions of some of the experts who made significant contributions to the field of inclusion problems. It is our hope that we cited all the important papers relevant to the subject of inclusion problems. The first author would welcome anyone’s comments and any references which were not included in this review.

The elastic field outside an ellipsoidal inclusion is investigated. No particular restrictions are imposed to eigenstrain distributions throughout the inclusion and to the anisotropy of elastic media for matrices. The solution is expressed in the form of integrals defined on a subspace of a unit sphere. Since the integrands of these integrals have no singularities, the numerical calculation on a computer can easily be performed.

By using the solution of eigenstrain problems in anisotropic media, flat ellipsoidal inclusions and crack problems are investigated. When a dilatational misfit strain is defined in a flat ellipsoidal inclusion (i.e., disk-shaped precipitate), the elastic strain energy associated with the misfit becomes minimum when the plane of the inclusion coincides with one of the crystalline planes, where the matrix and the inclusion are assumed as two different cubic crystals having the same crystalline directions. The minimum value, however surprisingly, depends only on the elastic moduli of the inclusion. When crystalline directions of the inclusion are parallel to the principal axes of the ellipsoid, the elastic strain energy is independent of the orientation of the inclusion with respect to the crystalline directions of the matrix and the constant value is equal to the minimum value in the first case. If an inclusion is simply defined by giving a uniform dilatational misfit strain in an ellipsoidal domain in a homogeneous material (i.e., matrix and inclusion are same material), the condition for the minimum elastic strain energy is the same as that of the first case, namely the minimum occurs when the plane of the inclusion is parallel to one of the crystalline directions. The method employed here can be applied equally to generally anisotropic materials. The method is also applicable to fracture problems by taking the elastic moduli of the inclusion as zero. As examples, an elliptical crack is considered for a simple tension and a pure shear. The interaction energy between the applied stress and a crack is calculated. By using this result, the Griffith criterion for fracture is derived for the penny-shaped crack. Some numerical results for cubic crystals are shown.

The paper of Lindeman, Witemberg-Perzyk and Perzyk claiming that Goodier's solution for the stress concentration around a spherical inclusion under tension is in correct is criticized. It is concluded that Goodier's solution is still correct.

Matrix cracking in brittle-matrix fiber-reinforced composites is investigated when the fracture strain of the fiber is greater than that of the matrix. The axisymmetric problem of an infinitely long elastic fiber perfectly bonded to an elastic matrix which contains an annular crack surrounding the fiber is considered for the case of uniform longitudinal strain. The problem is formulated in terms of a singular integral equation with a Cauchy type kernel. When the inner crack tip terminates at the interface, it is shown that the characteristic equation is the same as that for the case of plane strain. Stress intensity factors at the crack tips are given when (a) the inner crack tip is away from the interface and (b) the inner crack tip is at the interface.

The high stress concentration near the interface of fiber-matrix in composite materials causes the accumulation of the interfacial damages and the degradation of mechanical properties of the materials. In this paper, by using the residual surface displacement data, we evaluate the microscopic damages in terms of Somigliano's dislocations in composites near the interface caused by a series of unknown loadings. The goal of this research is to monitor the processes of the damage evolution near the interface and to relate this microscopic damage to the degradation of the macroscopic mechanical properties of the materials.

A general method of numerical solution in the non-Hertzian elastic contact problem is developed using rectangular subdivisions. The major application of the method given is in the sliding contact of a short rough cylinder with an elastic half space; the contact region is the side of the cylinder, whose axis may not be exactly aligned to the surface of the half space. The stress singularity at the ends of the cylinder is taken as either square root (to determine stress intensification factor) or is approximated by compact elements to reduce computing time. An iterative scheme is used and the convergence to the unknown shape of the contact region is rapid.

The problem of the contact between a smooth, rigid indenter and an elastic quarter space is solved using integral transform techniques. The indenter can have an arbitrary plan form and can extend to the edge of the quarter space. Numerical results are given when a rigid, right-circular body is pressed into the top surface of the quarter space, while keeping its axis parallel to the surface and perpendicular to the edge.

Based upon the Mori-Tanaka method, the constitutive equations of power-law materials and the failure criteria of multiple cracks materials are investigated. The piecewise linear incremental approach is also employed to analyze the effective stress and strain of the power-law materials. Results are presented for the case of pure shear where the matrix is a power-law material with rigid or void inhomogeneities. For the multiple cracked materials, the Griffith fracture criterion is applied to determine the critical volume fraction which causes the catastrophic failure of a material. The failure criteria of penny shaped, flat ellipsoidal, and slit-like cracked materials are examined and it is found that the volume fraction of cracks and critical applied stress are in linear relation.

The problem of adhesive contact between a thin circular plate under temperature loading and an isotropic elastic half-space is reduced to a problem of solving a pair of coupled integral equations for the unknown interfacial tractions. A numerical procedure for its solution is outlined and some results are presented in graphical form.

The stress field produced by a dislocation segment in an unbounded anisotropic elastic medium is derived. The solution, which does not require solving one sextic equation, is expressed by a line integral of rational functions along a unit circle.

Based on morphological tests in rolling and sliding contact, the effect of surface film, the subsurface heavily dislocated layer, crack initiation, crack propagation, and micropitting have been investigated by using a two-disk rig. A micro-macro contact model is presented for surface pitting in rolling and sliding contacts. In this model the pressures related to asperity interaction and the subsurface stress map along whole contact area have been analyzed by superimposing the asperity contacting loads on the Hertzian load for a given specimen surface. Compared to the experimental results, this model is capable of predicting the onset of micropits for given mechanical and lubrication conditions. Cracking is assumed to occur when the accumulated strain energy of the dislocation reaches a critical value. A three-dimensional crack propagating model has also been used for pitting life prediction in rolling and sliding contact.

A series solution is presented for a hemispheroidal elastic inhomogeneity at the free surface of an elastic half space. The loading is either all around tension at infinity, perpendicular to the axis of symmetry of the inhomogeneity, or uniform, nonshear type eigenstrains sustained by the inhomogeneity. The displacement potentials of Boussinesq are used to represent the solution and several numerical calculations are performed to illustrate the results.