Novel strength enhancing insert assemblies
Engineers at IIT Mumbai’s department of aerospace engineering have been able to research and design unique insert assemblies of high specific strength to reduce stress concentration at the locations where multidirectional stresses act on sandwhich structures in conjugation with novel method of reliably mapping stress distribution and prediction of failure initiation in sandwhich structures with diverse geometrical configurations.
Light weight sandwich structures are used in structural applications such as vehicles, the aerospace industry, and framework. The sandwhich structures have superior strength and stiffness properties along with the through-the thickness direction under bending loads. The use of inserts is essential to strengthen the sandwich sandwhich structures withstand a localized load/s. Inserts are also needed when external members or sub-structures are attached to the sandwhich structures.
The specific strength of the insert assembly is gauged as a ratio at load failure initiation to weight of insert assembly which should be as high as possible to achieve effective utilization of sandwhich structure with inserts. In practice these inserts are made of aluminium alloys, other metals or their alloys. High density of metals and alloys increase the weight of the assembly resulting in undesirable reduction in specific strength. Another issue is the difference in material properties at the interface between the insert and potting material such as resin leads to high stress concentration at the interfaces between insert and potting material and between potting material and core.