Maria Comninou | University of Michigan (original) (raw)

Papers by Maria Comninou

Research paper thumbnail of Can two solids slide without slipping?

International Journal of Solids and Structures, 1978

Research paper thumbnail of On the boundary conditions in contact problems with heat conduction

Research paper thumbnail of Thermoelastic contact involving a sharp corner

Wear, Mar 1, 1980

ABSTRACT Asymptotic analysis is used to study the thermoelastic contact near a sharp corner. It i... more ABSTRACT Asymptotic analysis is used to study the thermoelastic contact near a sharp corner. It is found that perfect contact involving no resistance to heat flow is always possible for relatively blunt corners for which the mechanically induced stress concentrations dominate. Otherwise perfect contact is possible only if heat flows into the material with the smaller distortivity. The corner separates if heat flows in the opposite direction.

Research paper thumbnail of Interface separation in the transonic range caused by a plane stress pulse

Journal of Sound and Vibration, Feb 1, 1979

Research paper thumbnail of Long‐Range Interaction between a Screw Dislocation and a Spherical Inclusion

Journal of Applied Physics, May 1, 1972

The long-range interaction between a screw dislocation and a spherical inclusion is investigated ... more The long-range interaction between a screw dislocation and a spherical inclusion is investigated by considering the Peach-Koehler force. The main features of the interaction are determined by the mismatch in the shear moduli. Thus the inclusion repels the dislocation if its shear modulus is higher than that of the matrix. However, the distribution of the force along the dislocation is strongly affected by Poisson's ratio of the matrix. For values of this ratio above 1/4, the distribution ceases to be bell shaped, and the maximum value of the Peach-Koehler force occurs at some distance from the point nearest the inclusion.

Research paper thumbnail of An Educational Elasticity Problem With Friction, Part 3: General Load Paths

Journal of Applied Mechanics, Mar 1, 1983

This concluding paper treats general load paths when the two components of the concentrated force... more This concluding paper treats general load paths when the two components of the concentrated force are allowed to change independently with time. It is shown that there are two kinds of dependence on the load path. For certain directions of the forward tangent, the dependence is strict in that the deformations depend on the full details of the path. For other directions, however, the dependence is loose, and the deformations do not depend on the exact nature of the path as long as the forward tangent falls within given bounds. The problem also shows that, given an initial state, the load space can be subdivided into different regions each corresponding to a certain mode of deformations.

Research paper thumbnail of A Closed Crack Tip Terminating at an Interface

Journal of Applied Mechanics, Mar 1, 1979

Considering a crack that lies in one solid, but has a tip that touches an interface with a second... more Considering a crack that lies in one solid, but has a tip that touches an interface with a second solid, Bogy found that the assumption of a traction-free crack tip leads to oscillating singularities for certain combinations of materials. Such oscillating singularities lead to overlapping of the crack faces, and the purpose of this article is to eliminate the oscillating singularities by allowing the crack tip to be closed. Using an asymptotic analysis and incorporating the effect of friction, the nature of the singularity at the closed crack tip is established and the various consequences explored.

Research paper thumbnail of Interface separation caused by a plane elastic wave of arbitrary form

Research paper thumbnail of Elastic Interface Waves and Sliding Between Two Solids

Journal of Applied Mechanics, Jun 1, 1978

The paper investigates possible interface waves between two solids in presence of separation and ... more The paper investigates possible interface waves between two solids in presence of separation and frictional slip and examines the effect of the waves on the sliding motion of the bodies. It is shown that interface waves are mathematically feasible between solids with identical mechanical properties, and that they can propagate with any phase velocity that falls between the Rayleigh and shear wave speeds. In the presence of such interface waves, global sliding may take place at much lower applied shearing tractions than would be required to slide the solids as rigid bodies. The waves also involve singular interface tractions that lead to energy emission and absorption at the singular points, and some aspects of them appear controversial.

Research paper thumbnail of An old elasticity problem in a unilateral setting

Journal of Elasticity, Apr 1, 1982

Research paper thumbnail of Total reflection of SH waves in the presence of slip and friction

Journal of the Acoustical Society of America, Sep 1, 1979

The paper examines the total reflection of SH waves by a contact interface that can locally slip ... more The paper examines the total reflection of SH waves by a contact interface that can locally slip when the incident wave is strong enough to break friction between the two solids. The solution is constructed by correcting the fields for the welded interface and takes advantage of known results for moving dislocations. The formulation leads to singular integral equations of the Cauchy type which must be treated numerically. Because of the number of independent variables, the problem cannot be exhausted through a parametric study, and only a specific combination of materials is worked out in detail. The results allow one to form some judgment, however, about the location of slip zones, their extent, the form of the slip velocity, and the interface shearing tractions.

Research paper thumbnail of Interface slip caused by an SH-pulse

International Journal of Solids and Structures, 1980

Research paper thumbnail of On Lack of Uniqueness in Heat Conduction through a Solid to Solid Contact

Journal of heat transfer, May 1, 1980

If two solids are pressed together and made to exchange heat by conduction, one possible steady s... more If two solids are pressed together and made to exchange heat by conduction, one possible steady state corresponds to the solids remaining in contact along the entire interface. It is shown that this state is not unique, and that it is possible to construct solutions involving localized separation if heat flows in one of the two possible directions.

Research paper thumbnail of Spring Trials

Between the Species, Oct 1, 1992

Research paper thumbnail of The Interface Crack in a Shear Field

Journal of Applied Mechanics, Jun 1, 1978

The interface crack in a tension field was reconsidered in a recent paper, and the unrealistic os... more The interface crack in a tension field was reconsidered in a recent paper, and the unrealistic oscillatory singularities were eliminated by assuming small frictionless contact zones near the crack tips. In the present paper, the interface crack in a shear field is studied. Some unexpected results emerge: one of the contact zones is large, affecting thus the global nature of the solution; the gap closes extremely abruptly at one of its ends, but the normal stresses remain zero at this point; and the shear stress-intensity factors have opposite signs at the crack tips.

Research paper thumbnail of The Interface Crack in a Combined Tension-Compression and Shear Field

Journal of Applied Mechanics, Jun 1, 1979

The interface crack was analyzed in two recent papers which considered applied tension and shear ... more The interface crack was analyzed in two recent papers which considered applied tension and shear fields separately. The unrealistic oscillatory singularities and the ensuing material interpenetration were eliminated in these solutions by assuming small frictionless contact zones near the crack tips. The present paper presents a solution for the interface crack under combined normal and shear tractions. Both tensile and compressive normal tractions are considered and numerical results of the extents of the contact zones, shear stress-intensity factors, and interface crack opening profiles are presented.

Research paper thumbnail of Closure to “Discussion of ‘Elastic Interface Waves Involving Separation’” (1978, ASME J. Appl. Mech., 45, pp. 226–227)

Journal of Applied Mechanics, Mar 1, 1978

Research paper thumbnail of On the Possibility of History Dependence and Instabilities in Thermoelastic Contact

Journal of Thermal Stresses, Jul 1, 1980

ABSTRACT A recent study of steady-state thermoelastic contact between two solids has shown that t... more ABSTRACT A recent study of steady-state thermoelastic contact between two solids has shown that the conventional boundary conditions lead to a lack of uniqueness for heat flowing in one of the two possible directions. Owing to the complexity of the fields satisfying the full equations of thermoelasticity, the resulting solutions are not well suited for investigating the stability of the different states. A model using a much simplified response of a material to stresses and temperature changes is proposed in this article for an eventual study of history dependence and stability in thermoelastic contact.

Research paper thumbnail of Green's functions for planar thermoelastic contact problems — Interior contact

Mechanics Research Communications, 1979

Research paper thumbnail of Partial closure of cracks at the interface between a layer and a half space

Engineering Fracture Mechanics, 1983

The paper treats the crack at the interface between a layer and a substrate. Using a formulation ... more The paper treats the crack at the interface between a layer and a substrate. Using a formulation based on dislocations, the problem is reduced to a pair of singular integral equations which can be solved numerically. It is found that a large contact zone exists whenever the interface transmits shear. The dependence of the contact zone size on the load parameters is determined for several combinations of materials. Also the shapes of the open part of the crack are shown for illustration.

Research paper thumbnail of Can two solids slide without slipping?

International Journal of Solids and Structures, 1978

Research paper thumbnail of On the boundary conditions in contact problems with heat conduction

Research paper thumbnail of Thermoelastic contact involving a sharp corner

Wear, Mar 1, 1980

ABSTRACT Asymptotic analysis is used to study the thermoelastic contact near a sharp corner. It i... more ABSTRACT Asymptotic analysis is used to study the thermoelastic contact near a sharp corner. It is found that perfect contact involving no resistance to heat flow is always possible for relatively blunt corners for which the mechanically induced stress concentrations dominate. Otherwise perfect contact is possible only if heat flows into the material with the smaller distortivity. The corner separates if heat flows in the opposite direction.

Research paper thumbnail of Interface separation in the transonic range caused by a plane stress pulse

Journal of Sound and Vibration, Feb 1, 1979

Research paper thumbnail of Long‐Range Interaction between a Screw Dislocation and a Spherical Inclusion

Journal of Applied Physics, May 1, 1972

The long-range interaction between a screw dislocation and a spherical inclusion is investigated ... more The long-range interaction between a screw dislocation and a spherical inclusion is investigated by considering the Peach-Koehler force. The main features of the interaction are determined by the mismatch in the shear moduli. Thus the inclusion repels the dislocation if its shear modulus is higher than that of the matrix. However, the distribution of the force along the dislocation is strongly affected by Poisson's ratio of the matrix. For values of this ratio above 1/4, the distribution ceases to be bell shaped, and the maximum value of the Peach-Koehler force occurs at some distance from the point nearest the inclusion.

Research paper thumbnail of An Educational Elasticity Problem With Friction, Part 3: General Load Paths

Journal of Applied Mechanics, Mar 1, 1983

This concluding paper treats general load paths when the two components of the concentrated force... more This concluding paper treats general load paths when the two components of the concentrated force are allowed to change independently with time. It is shown that there are two kinds of dependence on the load path. For certain directions of the forward tangent, the dependence is strict in that the deformations depend on the full details of the path. For other directions, however, the dependence is loose, and the deformations do not depend on the exact nature of the path as long as the forward tangent falls within given bounds. The problem also shows that, given an initial state, the load space can be subdivided into different regions each corresponding to a certain mode of deformations.

Research paper thumbnail of A Closed Crack Tip Terminating at an Interface

Journal of Applied Mechanics, Mar 1, 1979

Considering a crack that lies in one solid, but has a tip that touches an interface with a second... more Considering a crack that lies in one solid, but has a tip that touches an interface with a second solid, Bogy found that the assumption of a traction-free crack tip leads to oscillating singularities for certain combinations of materials. Such oscillating singularities lead to overlapping of the crack faces, and the purpose of this article is to eliminate the oscillating singularities by allowing the crack tip to be closed. Using an asymptotic analysis and incorporating the effect of friction, the nature of the singularity at the closed crack tip is established and the various consequences explored.

Research paper thumbnail of Interface separation caused by a plane elastic wave of arbitrary form

Research paper thumbnail of Elastic Interface Waves and Sliding Between Two Solids

Journal of Applied Mechanics, Jun 1, 1978

The paper investigates possible interface waves between two solids in presence of separation and ... more The paper investigates possible interface waves between two solids in presence of separation and frictional slip and examines the effect of the waves on the sliding motion of the bodies. It is shown that interface waves are mathematically feasible between solids with identical mechanical properties, and that they can propagate with any phase velocity that falls between the Rayleigh and shear wave speeds. In the presence of such interface waves, global sliding may take place at much lower applied shearing tractions than would be required to slide the solids as rigid bodies. The waves also involve singular interface tractions that lead to energy emission and absorption at the singular points, and some aspects of them appear controversial.

Research paper thumbnail of An old elasticity problem in a unilateral setting

Journal of Elasticity, Apr 1, 1982

Research paper thumbnail of Total reflection of SH waves in the presence of slip and friction

Journal of the Acoustical Society of America, Sep 1, 1979

The paper examines the total reflection of SH waves by a contact interface that can locally slip ... more The paper examines the total reflection of SH waves by a contact interface that can locally slip when the incident wave is strong enough to break friction between the two solids. The solution is constructed by correcting the fields for the welded interface and takes advantage of known results for moving dislocations. The formulation leads to singular integral equations of the Cauchy type which must be treated numerically. Because of the number of independent variables, the problem cannot be exhausted through a parametric study, and only a specific combination of materials is worked out in detail. The results allow one to form some judgment, however, about the location of slip zones, their extent, the form of the slip velocity, and the interface shearing tractions.

Research paper thumbnail of Interface slip caused by an SH-pulse

International Journal of Solids and Structures, 1980

Research paper thumbnail of On Lack of Uniqueness in Heat Conduction through a Solid to Solid Contact

Journal of heat transfer, May 1, 1980

If two solids are pressed together and made to exchange heat by conduction, one possible steady s... more If two solids are pressed together and made to exchange heat by conduction, one possible steady state corresponds to the solids remaining in contact along the entire interface. It is shown that this state is not unique, and that it is possible to construct solutions involving localized separation if heat flows in one of the two possible directions.

Research paper thumbnail of Spring Trials

Between the Species, Oct 1, 1992

Research paper thumbnail of The Interface Crack in a Shear Field

Journal of Applied Mechanics, Jun 1, 1978

The interface crack in a tension field was reconsidered in a recent paper, and the unrealistic os... more The interface crack in a tension field was reconsidered in a recent paper, and the unrealistic oscillatory singularities were eliminated by assuming small frictionless contact zones near the crack tips. In the present paper, the interface crack in a shear field is studied. Some unexpected results emerge: one of the contact zones is large, affecting thus the global nature of the solution; the gap closes extremely abruptly at one of its ends, but the normal stresses remain zero at this point; and the shear stress-intensity factors have opposite signs at the crack tips.

Research paper thumbnail of The Interface Crack in a Combined Tension-Compression and Shear Field

Journal of Applied Mechanics, Jun 1, 1979

The interface crack was analyzed in two recent papers which considered applied tension and shear ... more The interface crack was analyzed in two recent papers which considered applied tension and shear fields separately. The unrealistic oscillatory singularities and the ensuing material interpenetration were eliminated in these solutions by assuming small frictionless contact zones near the crack tips. The present paper presents a solution for the interface crack under combined normal and shear tractions. Both tensile and compressive normal tractions are considered and numerical results of the extents of the contact zones, shear stress-intensity factors, and interface crack opening profiles are presented.

Research paper thumbnail of Closure to “Discussion of ‘Elastic Interface Waves Involving Separation’” (1978, ASME J. Appl. Mech., 45, pp. 226–227)

Journal of Applied Mechanics, Mar 1, 1978

Research paper thumbnail of On the Possibility of History Dependence and Instabilities in Thermoelastic Contact

Journal of Thermal Stresses, Jul 1, 1980

ABSTRACT A recent study of steady-state thermoelastic contact between two solids has shown that t... more ABSTRACT A recent study of steady-state thermoelastic contact between two solids has shown that the conventional boundary conditions lead to a lack of uniqueness for heat flowing in one of the two possible directions. Owing to the complexity of the fields satisfying the full equations of thermoelasticity, the resulting solutions are not well suited for investigating the stability of the different states. A model using a much simplified response of a material to stresses and temperature changes is proposed in this article for an eventual study of history dependence and stability in thermoelastic contact.

Research paper thumbnail of Green's functions for planar thermoelastic contact problems — Interior contact

Mechanics Research Communications, 1979

Research paper thumbnail of Partial closure of cracks at the interface between a layer and a half space

Engineering Fracture Mechanics, 1983

The paper treats the crack at the interface between a layer and a substrate. Using a formulation ... more The paper treats the crack at the interface between a layer and a substrate. Using a formulation based on dislocations, the problem is reduced to a pair of singular integral equations which can be solved numerically. It is found that a large contact zone exists whenever the interface transmits shear. The dependence of the contact zone size on the load parameters is determined for several combinations of materials. Also the shapes of the open part of the crack are shown for illustration.