Damage and Failure of Interfaces (Ed. H.P.Rossmanith), pp. 91-98, 1997


FREE EDGE EFFECTS AT INTERFACES IN SELECTIVELY
REINFORCED STRUCTURES

C.M. Chimani¹, H.J. Böhm¹, F.G. Rammerstorfer¹ and C. Hausmann²

¹Institute of Lightweight Structures and Aerospace Engineering,
TU Wien, Vienna, Austria
²Swiss Federal Laboratories for Material Testing and Research,
Thun, Switzerland


Abstract - At intersections between interface and free edges of multi material structures complex tri-axial stress states occur which often are critical with respect to damage. In the following an axisymmetric component selectively reinforced with a metal matrix composite is analyzed under thermal loading, special consideration being given to the free edge effect. When the stress fields are studied in terms of a bimaterial junction problem using homogenized material descriptions singular stress fields are typically predicted. An analytical method was utilized to improve the interface design with respect to the free edge effect. It employs the Airy stress function to set up the corresponding boundary value problem, which is solved via the Mellin transform.

Using a micromechanical approach it is then shown, that under certain conditions these theoretically derived stress singularities disappear when the inhomogeneous micro structure of a selectively reinforced component is accounted for explicitly.


(hjb,980205)