Co-authors​ :

 Swapnil PATIL (INDIA), Syed KHADERI , M. RAMJI  

Rigid stiffeners, so-called rigid inclusions embedded in a soft matrix, are used in various applications, including short-fiber polymer composites, bio-logical composites, bio-inspired structures, and graphene-based composites. The rigid inclusions are extremely thin compared to the soft matrix, resulting in elastic mismatch and complex interfaces. Further, they are randomly oriented with geometric configurations ranging from straight (rigid line inclusion) to curved (rigid curved inclusion). In short fiber composites, rigid line inclusions are always combined with rigid curved inclusion, possibly due to the manufacturing process employed and the nature of curing. The rigid curved inclusions result in the shielding zone, also termed zero strain zones and stress amplification zones, signifying the traction jumps across the curved surface. Further, the nature of the stress field (unlike rigid line inclusion) for rigid curved inclusion is highly unsymmetric across the loading axis. Stimulated by the unsymmetric behavior of the stress field of curved inclusion, the current work aims to understand the interaction effect between the rigid line and curved inclusion. There will be stress amplification and shielding effects due to the curved inclusion. The interaction effect between the rigid line inclusion and the rigid curved inclusion has not received much attention compared to the interaction effect of circular inclusion and cracks. The detailed problem configurations under the study consists of (a) rigid line inclusion placed in shielding zone (b) rigid line inclusion placed in stress amplification zone. Preliminary investigations are performed using the photoelasticity technique to identify the stress shielding and amplification zones for the rigid curved inclusion. Photoelasticity is a non-contact, full-field experimental technique that provides information about isochromatics (contours of principal stress difference) and isoclinics (contours of principal stress direction). The ideal location for placing the rigid line inclusion within the shielding and stress amplification zones is obtained through numerical simulation performed using ABAQUS software. Later, the rigid line inclusion placed closer to the curved rigid inclusion within the stress amplification and shielding zones is studied using the photoelasticity technique. The fringe plotting algorithm is employed to convert the stress histories obtained from the numerical simulation into the isochromatic contours, which are further compared with the experimentally obtained isochromatics for completeness. Finally, the stress intensity factor is obtained experimentally for the problem under investigation.