Stress singularity at a sharp edge in contact problems with friction

The paper discusses the nature of the singularity that arises at a sharp edge in contact problems with friction. The theoretical treatment is based on the Mellin transform of the elastic fields. The results regarding the power singularities confirm the previous work of Gdoutos and Theocaris, but it is shown that logarithmic singularities are always present. Some experimental observations in photoelasticity are also presented. Die Art der Spannungssingularität, die an einer scharfen Ecke in Berührungsproblemen erscheint, ist für den Fall mit Reibung untersucht. Die theoretische Behandlung stützt sich auf die Mellin-Transformation der elastischen Felder. Die Ergebnisse bezüglich der Potenzsingularitäten bestätigen die früheren Resultate von Gdoutos und Theocaris. Es wird jedoch gezeigt, daß logarithmische Singularitäten stets anwesend sind. Auch einige Beobachtungen von photoelastischen Versuchen sind dargestellt.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43357/1/33_2005_Article_BF01594906.pd

An experimental study of stress singularities at a sharp corner in a contact problem

The photoelastic method was used to investigate the nature of the local stress field at a sharp corner of a wedge that was compressed against a larger body. Planar wedge specimens made of photoelastic material were compressed against a half plane (larger body) of identical material at various load levels. Several wedge angles were studied. The nature of the singular stress field postulated by linear elastic analysis was verified and the strength of the singularity was obtained by plotting the variation of fringe order as a function of radial distance from the sharp corner on a logarithmic scale. The experimental results were found to be in good agreement with the theoretical predictions. The effect of interface friction and the effect of rounding off the sharp edge are brietly discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43931/1/11340_2006_Article_BF02322823.pd

Reduction of contact stress by use of relief notches

The photoelastic method is used to investigate the possibility of relieving the large local stresses that develop in the corners of a right angled indenter compressing a semi-infinite body by inducing geometric changes to the indenter/semi-infinite body configuration. It is shown that a circular notch cut along the free edges of the indenter can totally eliminate the large corner stresses. The notch, if placed along the interface edge of the half plane, can reduce the stress concentration, but never eliminate it. The results obtained have wide practical application.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43932/1/11340_2006_Article_BF02326071.pd